Improved UI. Added playlist manager

.gitignore

@@ -2,3 +2,4 @@
 /nul
 /.claude
 /media
+/federation

Cargo.toml

@@ -1,11 +1,14 @@
 [package]
 name = "furumusic"
-version = "0.5.0"
+version = "0.7.1"
 edition = "2024"
 description = "Reusable web-app boilerplate: auth, OIDC/SSO, admin panel, user management, i18n, PostgreSQL"
 
 [dependencies]
-cot = { version = "0.6.0", features = ["postgres", "json", "openapi", "swagger-ui"] }
+# default-features off: cot's defaults include the sqlite backend, whose old
+# libsqlite3-sys collides with music-dht's rusqlite (one native sqlite3 per
+# binary). This server only ever talks PostgreSQL.
+cot = { version = "0.6.0", default-features = false, features = ["postgres", "json", "openapi", "swagger-ui"] }
 schemars = { version = "0.9", features = ["derive"] }
 serde = { version = "1", features = ["derive"] }
 openidconnect = "4.0"
@@ -13,6 +16,7 @@ reqwest = { version = "0.12", default-features = false, features = ["rustls-tls"
 tokio = { version = "1", features = ["sync", "fs", "io-util"] }
 tower = "0.5"
 base64 = "0.22"
+blake3 = "1"
 serde_json = "1"
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
@@ -28,5 +32,9 @@ anyhow = "1.0"
 tokio-cron-scheduler = "0.15"
 croner = "3"
 async-trait = "0.1"
+postcard = { version = "1", features = ["alloc"] }
 uuid = "1"
 librqbit = { version = "8.1.1", features = ["disable-upload"] }
+# P2P federation: publishes the library into a shared DHT and serves audio /
+# catalogs to furumi peers (TUI clients) over the frid stack.
+music-dht = { git = "https://gt.hexor.cy/ab/frid.git" }

src/admin/mod.rs

@@ -415,6 +415,38 @@ impl App for AdminApp {
                 }),
                 "admin_v2_settings_probe",
             ),
+            Route::with_handler_and_name(
+                "/v2/api/federation",
+                get(move |session: Session, db: Database| async move {
+                    v2::federation_status(session, db).await
+                }),
+                "admin_v2_federation_status",
+            ),
+            Route::with_handler_and_name(
+                "/v2/api/federation/sync",
+                cot::router::method::post(move |session: Session, db: Database| async move {
+                    v2::federation_sync(session, db).await
+                }),
+                "admin_v2_federation_sync",
+            ),
+            Route::with_handler_and_name(
+                "/v2/api/federation/ticket",
+                get(move |session: Session, db: Database| async move {
+                    v2::federation_ticket(session, db).await
+                }),
+                "admin_v2_federation_ticket",
+            ),
+            Route::with_handler_and_name(
+                "/v2/api/federation/connect",
+                cot::router::method::post(
+                    move |session: Session,
+                          db: Database,
+                          json: Json<v2::FederationConnectRequest>| async move {
+                        v2::federation_connect(session, db, json).await
+                    },
+                ),
+                "admin_v2_federation_connect",
+            ),
             Route::with_handler_and_name(
                 "/v2/api/jobs/{name}/toggle",
                 cot::router::method::post({

src/admin/v2.rs

@@ -448,6 +448,10 @@ struct AdminSettingsValues {
     agent_confidence_threshold: String,
     agent_context_limit: String,
     agent_concurrency: String,
+    #[serde(default)]
+    federation_enabled: bool,
+    #[serde(default)]
+    federation_network_id: String,
 }
 
 #[derive(Debug, Clone, Serialize, JsonSchema)]
@@ -472,6 +476,8 @@ struct AdminSettingsSources {
     agent_confidence_threshold: &'static str,
     agent_context_limit: &'static str,
     agent_concurrency: &'static str,
+    federation_enabled: &'static str,
+    federation_network_id: &'static str,
 }
 
 #[derive(Debug, Deserialize)]
@@ -496,6 +502,10 @@ pub(super) struct UpdateSettingsRequest {
     agent_confidence_threshold: String,
     agent_context_limit: String,
     agent_concurrency: String,
+    #[serde(default)]
+    federation_enabled: bool,
+    #[serde(default)]
+    federation_network_id: String,
 }
 
 #[derive(Debug, Serialize, JsonSchema)]
@@ -978,6 +988,11 @@ pub async fn update_settings(
             "agent_concurrency",
             body.agent_concurrency.trim().to_string(),
         ),
+        ("federation_enabled", body.federation_enabled.to_string()),
+        (
+            "federation_network_id",
+            body.federation_network_id.trim().to_string(),
+        ),
     ];
     for (key, value) in fields {
         let mut entry = ConfigEntry::new(key.to_string(), value);
@@ -986,9 +1001,78 @@ pub async fn update_settings(
             .await
             .map_err(|e| cot::Error::internal(e.to_string()))?;
     }
+    // Federation applies on the fly: (re)start or stop the node to match
+    // the freshly saved settings — no server restart involved.
+    let (fresh, _) = AppConfig::load_with_db(&db).await;
+    tokio::spawn(async move {
+        crate::federation::handle().apply(&fresh).await;
+    });
     Json(serde_json::json!({ "ok": true })).into_response()
 }
 
+// ---------------------------------------------------------------------------
+// Federation (status + manual controls)
+// ---------------------------------------------------------------------------
+
+pub async fn federation_status(
+    session: Session,
+    db: Database,
+) -> cot::Result<cot::response::Response> {
+    if let Err(response) = require_admin_json(&session, &db).await {
+        return Ok(response);
+    }
+    Json(crate::federation::handle().status().await).into_response()
+}
+
+pub async fn federation_sync(
+    session: Session,
+    db: Database,
+) -> cot::Result<cot::response::Response> {
+    if let Err(response) = require_admin_json(&session, &db).await {
+        return Ok(response);
+    }
+    let fed = crate::federation::handle();
+    if let Err(err) = fed.sync_now().await {
+        return Ok(json_error(
+            StatusCode::BAD_REQUEST,
+            &format!("sync failed: {err:#}"),
+        ));
+    }
+    Json(fed.status().await).into_response()
+}
+
+pub async fn federation_ticket(
+    session: Session,
+    db: Database,
+) -> cot::Result<cot::response::Response> {
+    if let Err(response) = require_admin_json(&session, &db).await {
+        return Ok(response);
+    }
+    match crate::federation::handle().ticket().await {
+        Ok(ticket) => Json(serde_json::json!({ "ticket": ticket })).into_response(),
+        Err(err) => Ok(json_error(StatusCode::BAD_REQUEST, &format!("{err:#}"))),
+    }
+}
+
+#[derive(Debug, Deserialize, JsonSchema)]
+pub(super) struct FederationConnectRequest {
+    ticket: String,
+}
+
+pub async fn federation_connect(
+    session: Session,
+    db: Database,
+    Json(body): Json<FederationConnectRequest>,
+) -> cot::Result<cot::response::Response> {
+    if let Err(response) = require_admin_json(&session, &db).await {
+        return Ok(response);
+    }
+    match crate::federation::handle().connect(&body.ticket).await {
+        Ok(peer) => Json(serde_json::json!({ "connected": peer })).into_response(),
+        Err(err) => Ok(json_error(StatusCode::BAD_REQUEST, &format!("{err:#}"))),
+    }
+}
+
 pub async fn settings_probe(
     session: Session,
     db: Database,
@@ -1057,6 +1141,8 @@ fn settings_dto(config: AppConfig, sources: ConfigSources) -> AdminSettingsDto {
             agent_confidence_threshold: config.agent_confidence_threshold.to_string(),
             agent_context_limit: config.agent_context_limit.to_string(),
             agent_concurrency: config.agent_concurrency.to_string(),
+            federation_enabled: config.federation_enabled,
+            federation_network_id: config.federation_network_id,
         },
         sources: AdminSettingsSources {
             auth_password_enabled: sources.auth_password_enabled.code(),
@@ -1079,6 +1165,8 @@ fn settings_dto(config: AppConfig, sources: ConfigSources) -> AdminSettingsDto {
             agent_confidence_threshold: sources.agent_confidence_threshold.code(),
             agent_context_limit: sources.agent_context_limit.code(),
             agent_concurrency: sources.agent_concurrency.code(),
+            federation_enabled: sources.federation_enabled.code(),
+            federation_network_id: sources.federation_network_id.code(),
         },
     }
 }

src/config.rs

@@ -135,6 +135,8 @@ pub struct ConfigSources {
     pub agent_concurrency: ConfigSource,
     pub lastfm_api_key: ConfigSource,
     pub lastfm_shared_secret: ConfigSource,
+    pub federation_enabled: ConfigSource,
+    pub federation_network_id: ConfigSource,
 }
 
 impl Default for ConfigSources {
@@ -162,6 +164,8 @@ impl Default for ConfigSources {
             agent_concurrency: ConfigSource::Default,
             lastfm_api_key: ConfigSource::Default,
             lastfm_shared_secret: ConfigSource::Default,
+            federation_enabled: ConfigSource::Default,
+            federation_network_id: ConfigSource::Default,
         }
     }
 }
@@ -270,6 +274,12 @@ pub struct AppConfig {
     pub lastfm_api_key: String,
     /// Last.fm shared secret for authenticated scrobbling calls.
     pub lastfm_shared_secret: String,
+    /// Whether this server participates in the furumi federation (publishes
+    /// its library into the shared DHT and serves audio to peers).
+    pub federation_enabled: bool,
+    /// Federation network id — the shared secret every peer of the network
+    /// uses to find the others.
+    pub federation_network_id: String,
 }
 
 impl Default for AppConfig {
@@ -297,6 +307,8 @@ impl Default for AppConfig {
             agent_concurrency: 2,
             lastfm_api_key: String::new(),
             lastfm_shared_secret: String::new(),
+            federation_enabled: false,
+            federation_network_id: String::new(),
         }
     }
 }
@@ -325,6 +337,8 @@ impl_env_overrides!(
     agent_concurrency,
     lastfm_api_key,
     lastfm_shared_secret,
+    federation_enabled,
+    federation_network_id,
 );
 
 impl AppConfig {
@@ -452,6 +466,8 @@ impl AppConfig {
         apply_db_field!(agent_concurrency);
         apply_db_field!(lastfm_api_key);
         apply_db_field!(lastfm_shared_secret);
+        apply_db_field!(federation_enabled);
+        apply_db_field!(federation_network_id);
     }
 }
 

src/federation/mod.rs

@@ -0,0 +1,656 @@
+//! P2P federation for the furumusic server.
+//!
+//! When enabled in the admin settings, the server becomes a regular peer of
+//! the furumi federation: it publishes its whole visible library (artists,
+//! releases, tracks — names and small metadata, never files) into the
+//! shared DHT and serves audio, track metadata, cover art and per-artist
+//! catalogs to other peers (TUI clients) over the same wire protocols the
+//! clients speak among themselves. Serve-only: the server does not search
+//! or download from other peers.
+//!
+//! Settings are the regular admin config entries (`federation_enabled`,
+//! `federation_network_id`) and apply on the fly — saving the settings
+//! starts, stops or re-joins the node without a server restart.
+
+mod serve;
+mod storage;
+
+use std::collections::{HashMap, HashSet};
+use std::path::PathBuf;
+use std::sync::{Arc, OnceLock};
+use std::time::Duration;
+
+use anyhow::{Context, Result};
+use music_dht::{
+    ItemKind, ItemSpec, MusicDhtConfig, MusicDhtService, NetworkId, PeerTicket, PublishStats,
+    RendezvousConfig, SyncStats,
+};
+use serde_json::{Value, json};
+use sqlx::PgPool;
+use sqlx::Row as _;
+
+use crate::config::AppConfig;
+use storage::PostgresFederationStorage;
+
+pub use serve::{AUDIO_ALPN, CATALOG_ALPN};
+
+/// How often the published library is re-synchronized with the database.
+const SYNC_INTERVAL: Duration = Duration::from_secs(60);
+
+struct Running {
+    service: Arc<MusicDhtService>,
+    network_name: String,
+    tasks: Vec<tokio::task::JoinHandle<()>>,
+}
+
+struct ContentHashJob {
+    media_file_id: i64,
+    sha256_hash: String,
+    file_path: String,
+}
+
+pub struct Federation {
+    /// Transport data directory; server-side DHT state and identity live in PostgreSQL.
+    data_dir: PathBuf,
+    database_url: std::sync::Mutex<String>,
+    storage_dir: std::sync::Mutex<String>,
+    content_cache: std::sync::Mutex<HashMap<i64, (String, String)>>,
+    content_pending: std::sync::Mutex<HashSet<i64>>,
+    pool: tokio::sync::OnceCell<PgPool>,
+    running: tokio::sync::Mutex<Option<Running>>,
+    last_sync: std::sync::Mutex<Option<String>>,
+    last_error: std::sync::Mutex<Option<String>>,
+}
+
+fn now_iso() -> String {
+    chrono::Utc::now().format("%Y-%m-%dT%H:%M:%SZ").to_string()
+}
+
+fn lock<T>(mutex: &std::sync::Mutex<T>) -> std::sync::MutexGuard<'_, T> {
+    mutex
+        .lock()
+        .unwrap_or_else(std::sync::PoisonError::into_inner)
+}
+
+/// The process-wide federation handle.
+pub fn handle() -> Arc<Federation> {
+    static HANDLE: OnceLock<Arc<Federation>> = OnceLock::new();
+    Arc::clone(HANDLE.get_or_init(|| {
+        Arc::new(Federation {
+            data_dir: PathBuf::from(crate::media_paths::resolve_config_path("federation")),
+            database_url: std::sync::Mutex::new(String::new()),
+            storage_dir: std::sync::Mutex::new(String::new()),
+            content_cache: std::sync::Mutex::new(Default::default()),
+            content_pending: std::sync::Mutex::new(Default::default()),
+            pool: tokio::sync::OnceCell::new(),
+            running: tokio::sync::Mutex::new(None),
+            last_sync: std::sync::Mutex::new(None),
+            last_error: std::sync::Mutex::new(None),
+        })
+    }))
+}
+
+impl Federation {
+    fn set_error(&self, message: Option<String>) {
+        *lock(&self.last_error) = message;
+    }
+
+    async fn pool(&self) -> Result<PgPool> {
+        let url = lock(&self.database_url).clone();
+        anyhow::ensure!(!url.is_empty(), "database is not configured");
+        let pool = self
+            .pool
+            .get_or_try_init(|| async {
+                sqlx::postgres::PgPoolOptions::new()
+                    .max_connections(4)
+                    .connect(&url)
+                    .await
+            })
+            .await?;
+        Ok(pool.clone())
+    }
+
+    /// Starts the node at boot when federation was left enabled. The
+    /// settings live in the config KV table, so this waits for the database
+    /// and resolves the same default → DB → env precedence the config uses.
+    pub async fn boot(self: &Arc<Self>, config: &AppConfig) {
+        *lock(&self.database_url) = config.database_url.clone();
+        if config.database_url.is_empty() {
+            return;
+        }
+        let pool = match self.pool().await {
+            Ok(pool) => pool,
+            Err(err) => {
+                tracing::warn!("federation boot: database unavailable: {err:#}");
+                return;
+            }
+        };
+        // `config` carries defaults + env; overlay the DB rows for fields
+        // that have no env override (env > DB > default).
+        let mut effective = config.clone();
+        let rows = sqlx::query(
+            "SELECT key, value FROM furumusic__config_entry
+             WHERE key IN ('federation_enabled', 'federation_network_id', 'agent_storage_dir')",
+        )
+        .fetch_all(&pool)
+        .await
+        .unwrap_or_default();
+        for row in rows {
+            let key: String = row.get(0);
+            let value: String = row.get(1);
+            let env_key = format!("FURU_{}", key.to_ascii_uppercase());
+            if std::env::var(&env_key).is_ok() {
+                continue;
+            }
+            match key.as_str() {
+                "federation_enabled" => {
+                    if let Ok(parsed) = value.parse() {
+                        effective.federation_enabled = parsed;
+                    }
+                }
+                "federation_network_id" => effective.federation_network_id = value,
+                "agent_storage_dir" => {
+                    effective.agent_storage_dir = crate::media_paths::resolve_config_path(&value);
+                }
+                _ => {}
+            }
+        }
+        self.apply(&effective).await;
+    }
+
+    /// Applies the effective configuration: starts, stops or re-joins the
+    /// node. Called at boot and every time the admin settings are saved.
+    pub async fn apply(self: &Arc<Self>, config: &AppConfig) {
+        *lock(&self.database_url) = config.database_url.clone();
+        *lock(&self.storage_dir) = config.agent_storage_dir.clone();
+        let network = config.federation_network_id.trim().to_string();
+        if config.federation_enabled && !network.is_empty() {
+            if let Err(err) = self.start(network, config.agent_storage_dir.clone()).await {
+                tracing::error!("federation start failed: {err:#}");
+                self.set_error(Some(format!("start failed: {err}")));
+            }
+        } else {
+            self.stop().await;
+        }
+    }
+
+    /// Starts the DHT node. Idempotent per network name; a node on another
+    /// network is stopped and re-joined.
+    async fn start(self: &Arc<Self>, network_name: String, storage_dir: String) -> Result<()> {
+        let pool = self.pool().await?;
+        let mut guard = self.running.lock().await;
+        if let Some(running) = guard.as_ref() {
+            if running.network_name == network_name {
+                return Ok(());
+            }
+            stop_running(guard.take()).await;
+        }
+
+        let dht_storage = Arc::new(PostgresFederationStorage::new(pool.clone()).await?);
+        let secret_key = dht_storage.load_or_create_secret_key().await?;
+
+        let config = MusicDhtConfig::builder()
+            .data_dir(&self.data_dir)
+            .network_id(NetworkId::from_name(&network_name))
+            // Peers of the network find each other knowing only its name.
+            .rendezvous(RendezvousConfig::default())
+            .stream_protocol(AUDIO_ALPN)
+            .stream_protocol(CATALOG_ALPN)
+            .build()
+            .map_err(|err| anyhow::anyhow!("invalid federation config: {err}"))?;
+        let (service, mut events) =
+            MusicDhtService::start_with_storage_and_secret_key(config, dht_storage, secret_key)
+                .await
+                .map_err(|err| anyhow::anyhow!("failed to start the DHT node: {err}"))?;
+        let service = Arc::new(service);
+        tracing::info!(
+            endpoint_id = %service.endpoint_id(),
+            network = %network_name,
+            "federation started"
+        );
+
+        // Drain DHT events into the log; the channel is bounded.
+        let event_task = tokio::spawn(async move {
+            while let Some(event) = events.recv().await {
+                tracing::debug!("federation event: {event:?}");
+            }
+        });
+        // Keep the published library in sync with the database.
+        let sync_self = Arc::clone(self);
+        let sync_service = Arc::clone(&service);
+        let sync_task = tokio::spawn(async move {
+            let mut interval = tokio::time::interval(SYNC_INTERVAL);
+            loop {
+                interval.tick().await;
+                let _ = sync_self.sync_once(&sync_service).await;
+            }
+        });
+        // Serve audio and catalog requests from other peers.
+        let audio_acceptor = service
+            .stream_acceptor(AUDIO_ALPN)
+            .map_err(|err| anyhow::anyhow!("failed to take the audio acceptor: {err}"))?;
+        let audio_task = tokio::spawn(serve::serve_audio(
+            audio_acceptor,
+            pool.clone(),
+            storage_dir.clone(),
+            service.endpoint_id(),
+        ));
+        let catalog_acceptor = service
+            .stream_acceptor(CATALOG_ALPN)
+            .map_err(|err| anyhow::anyhow!("failed to take the catalog acceptor: {err}"))?;
+        let catalog_task = tokio::spawn(serve::serve_catalog(
+            catalog_acceptor,
+            pool,
+            storage_dir,
+            service.endpoint_id(),
+        ));
+
+        *guard = Some(Running {
+            service,
+            network_name,
+            tasks: vec![event_task, sync_task, audio_task, catalog_task],
+        });
+        self.set_error(None);
+        drop(guard);
+        // Publish right away instead of waiting for the first timer tick.
+        self.spawn_sync_soon().await;
+        Ok(())
+    }
+
+    async fn stop(&self) {
+        let mut guard = self.running.lock().await;
+        stop_running(guard.take()).await;
+    }
+
+    async fn service(&self) -> Result<Arc<MusicDhtService>> {
+        self.running
+            .lock()
+            .await
+            .as_ref()
+            .map(|running| Arc::clone(&running.service))
+            .context("federation is not running")
+    }
+
+    async fn spawn_sync_soon(self: &Arc<Self>) {
+        if let Ok(service) = self.service().await {
+            let fed = Arc::clone(self);
+            tokio::spawn(async move {
+                let _ = fed.sync_once(&service).await;
+            });
+        }
+    }
+
+    pub async fn sync_now(self: &Arc<Self>) -> Result<()> {
+        let service = self.service().await?;
+        let sync_stats = self.sync_once(&service).await?;
+        let publish_stats = match service.republish().await {
+            Ok(stats) => stats,
+            Err(err) => {
+                tracing::warn!("federation republish failed: {err}");
+                self.set_error(Some(format!("republish failed: {err}")));
+                anyhow::bail!("republish failed: {err}");
+            }
+        };
+        self.record_publish_success(sync_stats, publish_stats);
+        Ok(())
+    }
+
+    async fn sync_once(self: &Arc<Self>, service: &MusicDhtService) -> Result<SyncStats> {
+        let specs = match self.collect_specs().await {
+            Ok(specs) => specs,
+            Err(err) => {
+                tracing::warn!("federation sync: library read failed: {err:#}");
+                self.set_error(Some(format!("library read failed: {err}")));
+                anyhow::bail!("library read failed: {err}");
+            }
+        };
+        match service.sync_library(specs).await {
+            Ok(stats) => {
+                self.record_sync_success(stats);
+                if stats.failed > 0 {
+                    self.set_error(Some(format!(
+                        "{} item(s) failed to publish in the last sync",
+                        stats.failed
+                    )));
+                } else {
+                    self.set_error(None);
+                }
+                Ok(stats)
+            }
+            Err(err) => {
+                tracing::warn!("federation sync failed: {err}");
+                self.set_error(Some(format!("sync failed: {err}")));
+                Err(anyhow::anyhow!("sync failed: {err}"))
+            }
+        }
+    }
+
+    fn record_sync_success(&self, stats: SyncStats) {
+        *lock(&self.last_sync) = Some(format!(
+            "{} (+{} ~{} −{}, unchanged {}, failed {})",
+            now_iso(),
+            stats.added,
+            stats.updated,
+            stats.removed,
+            stats.unchanged,
+            stats.failed
+        ));
+    }
+
+    fn record_publish_success(&self, sync_stats: SyncStats, publish_stats: PublishStats) {
+        *lock(&self.last_sync) = Some(format!(
+            "{} (+{} ~{} −{}, unchanged {}, failed {}; republished {} records, {} keys, remote nodes {})",
+            now_iso(),
+            sync_stats.added,
+            sync_stats.updated,
+            sync_stats.removed,
+            sync_stats.unchanged,
+            sync_stats.failed,
+            publish_stats.records,
+            publish_stats.keys,
+            publish_stats.remote_nodes,
+        ));
+        self.set_error(None);
+    }
+
+    /// Everything the regular player shows, as DHT item specs: non-hidden
+    /// artists, releases and tracks (a track also hides with its release).
+    async fn collect_specs(self: &Arc<Self>) -> Result<Vec<ItemSpec>> {
+        let pool = self.pool().await?;
+        let mut specs = Vec::new();
+
+        let artists = sqlx::query("SELECT id, name FROM furumusic__artist WHERE is_hidden = false")
+            .fetch_all(&pool)
+            .await?;
+        for row in &artists {
+            let id: i64 = row.get(0);
+            specs.push(ItemSpec {
+                local_key: format!("artist:{id}"),
+                kind: ItemKind::Artist,
+                name: row.get(1),
+                artist_names: Vec::new(),
+                featured_artist_names: Vec::new(),
+                year: None,
+                release_type: None,
+                release_title: None,
+                track_number: None,
+                disc_number: None,
+                duration_seconds: None,
+                content_id: None,
+            });
+        }
+
+        let release_artists = sqlx::query(
+            "SELECT ra.release_id, a.name FROM furumusic__release_artist ra
+             JOIN furumusic__artist a ON a.id = ra.artist_id
+             ORDER BY ra.release_id, ra.position",
+        )
+        .fetch_all(&pool)
+        .await?;
+        let mut artists_of_release: std::collections::HashMap<i64, Vec<String>> =
+            Default::default();
+        for row in &release_artists {
+            artists_of_release
+                .entry(row.get(0))
+                .or_default()
+                .push(row.get(1));
+        }
+        let releases = sqlx::query(
+            "SELECT id, title, year, release_type FROM furumusic__release
+             WHERE is_hidden = false",
+        )
+        .fetch_all(&pool)
+        .await?;
+        for row in &releases {
+            let id: i64 = row.get(0);
+            specs.push(ItemSpec {
+                local_key: format!("release:{id}"),
+                kind: ItemKind::Release,
+                name: row.get(1),
+                artist_names: artists_of_release.remove(&id).unwrap_or_default(),
+                featured_artist_names: Vec::new(),
+                year: row.get(2),
+                release_type: row.get(3),
+                release_title: None,
+                track_number: None,
+                disc_number: None,
+                duration_seconds: None,
+                content_id: None,
+            });
+        }
+
+        let track_artists = sqlx::query(
+            "SELECT ta.track_id, a.name, ta.role FROM furumusic__track_artist ta
+             JOIN furumusic__artist a ON a.id = ta.artist_id
+             WHERE ta.role IN ('main', 'featuring')
+             ORDER BY ta.track_id,
+                      CASE ta.role WHEN 'main' THEN 0 ELSE 1 END,
+                      ta.position",
+        )
+        .fetch_all(&pool)
+        .await?;
+        let mut artists_of_track: std::collections::HashMap<i64, Vec<String>> = Default::default();
+        let mut featured_of_track: std::collections::HashMap<i64, Vec<String>> = Default::default();
+        for row in &track_artists {
+            let id: i64 = row.get(0);
+            let name: String = row.get(1);
+            if row.get::<String, _>(2) == "featuring" {
+                featured_of_track.entry(id).or_default().push(name);
+            } else {
+                artists_of_track.entry(id).or_default().push(name);
+            }
+        }
+        let tracks = sqlx::query(
+            "SELECT t.id, t.title, COALESCE(t.year, r.year), t.duration_seconds,
+                    r.title, r.release_type, t.track_number, t.disc_number,
+                    t.audio_file_id, m.file_path, m.sha256_hash, c.content_id
+             FROM furumusic__track t
+             JOIN furumusic__release r ON r.id = t.release_id
+             JOIN furumusic__media_file m ON m.id = t.audio_file_id
+             LEFT JOIN furumusic__federation_content_id_cache c
+                    ON c.media_file_id = m.id AND c.sha256_hash = m.sha256_hash
+             WHERE t.is_hidden = false AND r.is_hidden = false",
+        )
+        .fetch_all(&pool)
+        .await?;
+        let storage_dir = lock(&self.storage_dir).clone();
+        let mut content_hash_jobs = Vec::new();
+        for row in &tracks {
+            let id: i64 = row.get(0);
+            let duration: f64 = row.get(3);
+            let media_file_id: i64 = row.get(8);
+            let file_path: String = row.get(9);
+            let sha256_hash: String = row.get(10);
+            let cached_content_id: Option<String> = row.get(11);
+            let content_id = cached_content_id
+                .or_else(|| self.cached_content_id_for_media(media_file_id, &sha256_hash));
+            if content_id.is_none()
+                && !storage_dir.trim().is_empty()
+                && self.mark_content_hash_pending(media_file_id)
+            {
+                content_hash_jobs.push(ContentHashJob {
+                    media_file_id,
+                    sha256_hash,
+                    file_path,
+                });
+            }
+            specs.push(ItemSpec {
+                local_key: format!("track:{id}"),
+                kind: ItemKind::Track,
+                name: row.get(1),
+                artist_names: artists_of_track.remove(&id).unwrap_or_default(),
+                featured_artist_names: featured_of_track.remove(&id).unwrap_or_default(),
+                year: row.get(2),
+                release_type: row.get(5),
+                release_title: Some(row.get(4)),
+                track_number: row.get(6),
+                disc_number: row.get(7),
+                duration_seconds: (duration > 0.0).then_some(duration),
+                content_id,
+            });
+        }
+        self.spawn_content_warmer(pool.clone(), storage_dir, content_hash_jobs);
+
+        Ok(specs)
+    }
+
+    fn cached_content_id_for_media(&self, media_file_id: i64, sha256_hash: &str) -> Option<String> {
+        if let Some((cached_hash, content_id)) = lock(&self.content_cache).get(&media_file_id)
+            && cached_hash == sha256_hash
+        {
+            return Some(content_id.clone());
+        }
+        None
+    }
+
+    fn mark_content_hash_pending(&self, media_file_id: i64) -> bool {
+        lock(&self.content_pending).insert(media_file_id)
+    }
+
+    fn spawn_content_warmer(
+        self: &Arc<Self>,
+        pool: PgPool,
+        storage_dir: String,
+        jobs: Vec<ContentHashJob>,
+    ) {
+        if jobs.is_empty() {
+            return;
+        }
+        let fed = Arc::clone(self);
+        tokio::spawn(async move {
+            let total = jobs.len();
+            let mut stored = 0usize;
+            for job in jobs {
+                let job_storage_dir = storage_dir.clone();
+                let job_file_path = job.file_path.clone();
+                let content_id = tokio::task::spawn_blocking(move || {
+                    audio_content_id(&job_storage_dir, &job_file_path)
+                })
+                .await
+                .ok()
+                .flatten();
+                lock(&fed.content_pending).remove(&job.media_file_id);
+                if let Some(content_id) = content_id {
+                    lock(&fed.content_cache).insert(
+                        job.media_file_id,
+                        (job.sha256_hash.clone(), content_id.clone()),
+                    );
+                    if let Err(err) =
+                        persist_content_id(&pool, job.media_file_id, &job.sha256_hash, &content_id)
+                            .await
+                    {
+                        tracing::warn!(
+                            media_file_id = job.media_file_id,
+                            "federation content-id cache write failed: {err:#}"
+                        );
+                    } else {
+                        stored += 1;
+                    }
+                }
+            }
+            tracing::info!(total, stored, "federation content-id cache warm finished");
+        });
+    }
+
+    /// Live status for the admin page.
+    pub async fn status(&self) -> Value {
+        let guard = self.running.lock().await;
+        let node = match guard.as_ref() {
+            Some(running) => {
+                let service = &running.service;
+                let published = service
+                    .list_local_items()
+                    .await
+                    .map(|items| items.len())
+                    .unwrap_or(0);
+                let peers: Vec<String> = service
+                    .connected_peers()
+                    .iter()
+                    .map(|p| p.to_string())
+                    .collect();
+                json!({
+                    "running": true,
+                    "network": running.network_name,
+                    "endpoint_id": service.endpoint_id().to_string(),
+                    "connected_peers": peers,
+                    "known_contacts": service.known_peers().len(),
+                    "published_items": published,
+                })
+            }
+            None => json!({ "running": false }),
+        };
+        json!({
+            "node": node,
+            "last_sync": lock(&self.last_sync).clone(),
+            "last_error": lock(&self.last_error).clone(),
+        })
+    }
+
+    pub async fn ticket(&self) -> Result<String> {
+        let service = self.service().await?;
+        let ticket = service
+            .ticket()
+            .await
+            .map_err(|err| anyhow::anyhow!("cannot create a ticket: {err}"))?;
+        Ok(ticket.to_string())
+    }
+
+    pub async fn connect(&self, ticket: &str) -> Result<String> {
+        let service = self.service().await?;
+        let ticket: PeerTicket = ticket
+            .trim()
+            .parse()
+            .map_err(|err| anyhow::anyhow!("malformed ticket: {err}"))?;
+        let peer = service
+            .connect(ticket)
+            .await
+            .map_err(|err| anyhow::anyhow!("connect failed: {err}"))?;
+        Ok(peer.to_string())
+    }
+}
+
+async fn persist_content_id(
+    pool: &PgPool,
+    media_file_id: i64,
+    sha256_hash: &str,
+    content_id: &str,
+) -> Result<()> {
+    sqlx::query(
+        "INSERT INTO furumusic__federation_content_id_cache
+         (media_file_id, sha256_hash, content_id, updated_at)
+         VALUES ($1, $2, $3, $4)
+         ON CONFLICT (media_file_id) DO UPDATE SET
+            sha256_hash = EXCLUDED.sha256_hash,
+            content_id = EXCLUDED.content_id,
+            updated_at = EXCLUDED.updated_at",
+    )
+    .bind(media_file_id)
+    .bind(sha256_hash)
+    .bind(content_id)
+    .bind(now_iso())
+    .execute(pool)
+    .await?;
+    Ok(())
+}
+
+fn audio_content_id(storage_dir: &str, file_path: &str) -> Option<String> {
+    if storage_dir.trim().is_empty() {
+        return None;
+    }
+    let path = crate::media_paths::resolve_media_file_path(storage_dir, file_path);
+    let mut file = std::fs::File::open(path).ok()?;
+    let mut hasher = blake3::Hasher::new();
+    std::io::copy(&mut file, &mut hasher).ok()?;
+    Some(format!("b3:{}", hasher.finalize().to_hex()))
+}
+
+async fn stop_running(running: Option<Running>) {
+    let Some(running) = running else { return };
+    for task in &running.tasks {
+        task.abort();
+    }
+    if let Err(err) = running.service.shutdown().await {
+        tracing::warn!("federation node shutdown reported an error: {err}");
+    }
+    tracing::info!("federation stopped");
+}

src/federation/serve.rs

@@ -0,0 +1,691 @@
+//! Serve side of the federation wire protocols (audio + catalog), backed by
+//! the PostgreSQL library and the media storage directory. Wire compatible
+//! with the furumi TUI client and any other furumi peer.
+
+use std::path::{Path, PathBuf};
+
+use anyhow::Result;
+use music_dht::{ByteStream, EndpointId, ItemId, ItemKind, StreamAcceptor};
+use serde::{Deserialize, Serialize};
+use sqlx::PgPool;
+use sqlx::Row as _;
+use tokio::io::{AsyncRead, AsyncReadExt, AsyncSeekExt, AsyncWriteExt};
+
+/// ALPN of the peer-to-peer audio streaming protocol.
+pub const AUDIO_ALPN: &[u8] = b"furumi-fd/audio/1";
+/// ALPN of the per-artist catalog protocol.
+pub const CATALOG_ALPN: &[u8] = b"furumi-fd/catalog/1";
+
+/// Maximum size of a JSON protocol line (request or response header).
+const MAX_PROTOCOL_LINE: usize = 4096;
+/// Images above this size are skipped rather than transferred.
+const MAX_IMAGE_BYTES: u64 = 16 * 1024 * 1024;
+
+// ---------------------------------------------------------------------------
+// Wire shapes (shared with the furumi TUI client)
+// ---------------------------------------------------------------------------
+
+#[derive(Debug, Deserialize)]
+struct AudioRequest {
+    item_id: String,
+    #[serde(default)]
+    offset: u64,
+    #[serde(default)]
+    want_cover: bool,
+}
+
+#[derive(Debug, Default, Serialize)]
+struct AudioResponseHeader {
+    ok: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    error: Option<String>,
+    mime_type: String,
+    total_size: u64,
+    offset: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    metadata: Option<TrackMetadata>,
+    cover_size: u64,
+    cover_mime: String,
+    artist_image_size: u64,
+    artist_image_mime: String,
+}
+
+#[derive(Debug, Clone, Default, Serialize)]
+struct TrackMetadata {
+    title: String,
+    artists: Vec<String>,
+    featured_artists: Vec<String>,
+    album_artists: Vec<String>,
+    release_title: String,
+    release_type: Option<String>,
+    year: Option<i32>,
+    track_number: Option<i32>,
+    disc_number: Option<i32>,
+}
+
+#[derive(Debug, Deserialize)]
+struct CatalogRequest {
+    artist: String,
+    #[serde(default)]
+    want: Option<String>,
+    #[serde(default)]
+    release: Option<String>,
+}
+
+#[derive(Debug, Default, Serialize)]
+struct CatalogResponse {
+    ok: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    error: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    artist: Option<CatalogArtist>,
+}
+
+#[derive(Debug, Default, Serialize)]
+struct CatalogArtist {
+    name: String,
+    releases: Vec<CatalogRelease>,
+}
+
+#[derive(Debug, Default, Serialize)]
+struct CatalogRelease {
+    title: String,
+    release_type: String,
+    year: Option<i32>,
+    tracks: Vec<CatalogTrack>,
+}
+
+#[derive(Debug, Default, Serialize)]
+struct CatalogTrack {
+    title: String,
+    track_number: Option<i32>,
+    disc_number: Option<i32>,
+    duration_seconds: Option<f64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    content_id: Option<String>,
+    item_id: String,
+}
+
+#[derive(Debug, Default, Serialize)]
+struct ImageHeader {
+    ok: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    error: Option<String>,
+    mime_type: String,
+    size: u64,
+}
+
+// ---------------------------------------------------------------------------
+// Framing helpers
+// ---------------------------------------------------------------------------
+
+fn hex_encode(bytes: &[u8]) -> String {
+    bytes.iter().map(|b| format!("{b:02x}")).collect()
+}
+
+fn hex_decode_item_id(value: &str) -> Option<ItemId> {
+    if value.len() != 64 {
+        return None;
+    }
+    let mut bytes = [0u8; 32];
+    for (i, byte) in bytes.iter_mut().enumerate() {
+        *byte = u8::from_str_radix(&value[i * 2..i * 2 + 2], 16).ok()?;
+    }
+    Some(ItemId::from_bytes(bytes))
+}
+
+async fn read_line<R: AsyncRead + Unpin>(reader: &mut R) -> Result<Vec<u8>> {
+    let mut line = Vec::new();
+    let mut byte = [0u8; 1];
+    loop {
+        let n = reader.read(&mut byte).await?;
+        if n == 0 {
+            anyhow::bail!("stream ended before the protocol line was complete");
+        }
+        if byte[0] == b'\n' {
+            return Ok(line);
+        }
+        line.push(byte[0]);
+        if line.len() > MAX_PROTOCOL_LINE {
+            anyhow::bail!("protocol line exceeds {MAX_PROTOCOL_LINE} bytes");
+        }
+    }
+}
+
+async fn write_line<W: AsyncWriteExt + Unpin>(
+    writer: &mut W,
+    value: &impl Serialize,
+) -> Result<()> {
+    let mut line = serde_json::to_vec(value)?;
+    line.push(b'\n');
+    writer.write_all(&line).await?;
+    Ok(())
+}
+
+fn item_id_of(own: &EndpointId, track_id: i64) -> String {
+    hex_encode(ItemId::derive(own, ItemKind::Track, &format!("track:{track_id}")).as_bytes())
+}
+
+fn resolve_media_path(storage_dir: &str, file_path: &str) -> PathBuf {
+    crate::media_paths::resolve_media_file_path(storage_dir, file_path)
+}
+
+fn guess_mime(path: &Path) -> &'static str {
+    match path
+        .extension()
+        .and_then(|e| e.to_str())
+        .unwrap_or_default()
+        .to_ascii_lowercase()
+        .as_str()
+    {
+        "mp3" => "audio/mpeg",
+        "flac" => "audio/flac",
+        "ogg" | "oga" => "audio/ogg",
+        "opus" => "audio/opus",
+        "wav" => "audio/wav",
+        "m4a" | "mp4" | "alac" => "audio/mp4",
+        "aac" => "audio/aac",
+        "aiff" | "aif" => "audio/aiff",
+        _ => "application/octet-stream",
+    }
+}
+
+/// Reads an image media file from disk, bounded by [`MAX_IMAGE_BYTES`].
+async fn read_image(
+    storage_dir: &str,
+    media: Option<(String, String)>,
+) -> Option<(Vec<u8>, String)> {
+    let (file_path, mime) = media?;
+    let path = resolve_media_path(storage_dir, &file_path);
+    let size = tokio::fs::metadata(&path).await.ok()?.len();
+    if size == 0 || size > MAX_IMAGE_BYTES {
+        return None;
+    }
+    let bytes = tokio::fs::read(&path).await.ok()?;
+    let mime = if mime.trim().is_empty() {
+        "image/jpeg".to_string()
+    } else {
+        mime
+    };
+    Some((bytes, mime))
+}
+
+// ---------------------------------------------------------------------------
+// Library lookups (PostgreSQL)
+// ---------------------------------------------------------------------------
+
+/// Finds the visible track whose derived DHT item id matches `item_id`.
+async fn resolve_track_id(pool: &PgPool, own: &EndpointId, item_id: ItemId) -> Result<Option<i64>> {
+    let rows = sqlx::query(
+        "SELECT t.id FROM furumusic__track t
+         JOIN furumusic__release r ON r.id = t.release_id
+         WHERE t.is_hidden = false AND r.is_hidden = false",
+    )
+    .fetch_all(pool)
+    .await?;
+    for row in rows {
+        let track_id: i64 = row.get(0);
+        if ItemId::derive(own, ItemKind::Track, &format!("track:{track_id}")) == item_id {
+            return Ok(Some(track_id));
+        }
+    }
+    Ok(None)
+}
+
+/// (file_path, mime_type) of the track's audio media file.
+async fn track_audio_file(pool: &PgPool, track_id: i64) -> Result<Option<(String, String)>> {
+    let row = sqlx::query(
+        "SELECT m.file_path, m.mime_type FROM furumusic__track t
+         JOIN furumusic__media_file m ON m.id = t.audio_file_id
+         WHERE t.id = $1",
+    )
+    .bind(track_id)
+    .fetch_optional(pool)
+    .await?;
+    Ok(row.map(|row| (row.get(0), row.get(1))))
+}
+
+/// Track cover (falling back to the release cover) as (file_path, mime).
+async fn track_cover_file(pool: &PgPool, track_id: i64) -> Result<Option<(String, String)>> {
+    let row = sqlx::query(
+        "SELECT m.file_path, m.mime_type FROM furumusic__track t
+         JOIN furumusic__release r ON r.id = t.release_id
+         JOIN furumusic__media_file m ON m.id = COALESCE(t.cover_file_id, r.cover_file_id)
+         WHERE t.id = $1",
+    )
+    .bind(track_id)
+    .fetch_optional(pool)
+    .await?;
+    Ok(row.map(|row| (row.get(0), row.get(1))))
+}
+
+/// The main artist's image of a track as (file_path, mime).
+async fn track_artist_image_file(pool: &PgPool, track_id: i64) -> Result<Option<(String, String)>> {
+    let row = sqlx::query(
+        "SELECT m.file_path, m.mime_type FROM furumusic__track_artist ta
+         JOIN furumusic__artist a ON a.id = ta.artist_id
+         JOIN furumusic__media_file m ON m.id = a.image_file_id
+         WHERE ta.track_id = $1 AND ta.role = 'main'
+         ORDER BY ta.position LIMIT 1",
+    )
+    .bind(track_id)
+    .fetch_optional(pool)
+    .await?;
+    Ok(row.map(|row| (row.get(0), row.get(1))))
+}
+
+async fn track_metadata(pool: &PgPool, track_id: i64) -> Result<Option<TrackMetadata>> {
+    let Some(track) = sqlx::query(
+        "SELECT t.title, t.track_number, t.disc_number, COALESCE(t.year, r.year),
+                t.release_id, r.title, r.release_type
+         FROM furumusic__track t
+         JOIN furumusic__release r ON r.id = t.release_id
+         WHERE t.id = $1",
+    )
+    .bind(track_id)
+    .fetch_optional(pool)
+    .await?
+    else {
+        return Ok(None);
+    };
+    let release_id: i64 = track.get(4);
+
+    let mut artists = Vec::new();
+    let mut featured = Vec::new();
+    let artist_rows = sqlx::query(
+        "SELECT a.name, ta.role FROM furumusic__track_artist ta
+         JOIN furumusic__artist a ON a.id = ta.artist_id
+         WHERE ta.track_id = $1 ORDER BY ta.position",
+    )
+    .bind(track_id)
+    .fetch_all(pool)
+    .await?;
+    for row in artist_rows {
+        let name: String = row.get(0);
+        match row.get::<String, _>(1).as_str() {
+            "featuring" => featured.push(name),
+            "main" => artists.push(name),
+            _ => {}
+        }
+    }
+    let album_artists: Vec<String> = sqlx::query(
+        "SELECT a.name FROM furumusic__release_artist ra
+         JOIN furumusic__artist a ON a.id = ra.artist_id
+         WHERE ra.release_id = $1 ORDER BY ra.position",
+    )
+    .bind(release_id)
+    .fetch_all(pool)
+    .await?
+    .into_iter()
+    .map(|row| row.get(0))
+    .collect();
+
+    Ok(Some(TrackMetadata {
+        title: track.get(0),
+        artists,
+        featured_artists: featured,
+        album_artists,
+        release_title: track.get(5),
+        release_type: Some(track.get(6)),
+        year: track.get(3),
+        track_number: track.get(1),
+        disc_number: track.get(2),
+    }))
+}
+
+// ---------------------------------------------------------------------------
+// Audio protocol
+// ---------------------------------------------------------------------------
+
+/// Runs the audio accept loop until the acceptor closes. Every visible
+/// track of the library is streamable by every peer of the network.
+pub async fn serve_audio(
+    mut acceptor: StreamAcceptor,
+    pool: PgPool,
+    storage_dir: String,
+    own: EndpointId,
+) {
+    while let Some(stream) = acceptor.accept().await {
+        let pool = pool.clone();
+        let storage_dir = storage_dir.clone();
+        tokio::spawn(async move {
+            let peer = stream.peer_id;
+            if let Err(err) = serve_audio_one(stream, pool, storage_dir, own).await {
+                tracing::warn!(peer = %peer, "federation audio stream failed: {err:#}");
+            }
+        });
+    }
+}
+
+async fn serve_audio_one(
+    mut stream: ByteStream,
+    pool: PgPool,
+    storage_dir: String,
+    own: EndpointId,
+) -> Result<()> {
+    let request: AudioRequest = serde_json::from_slice(&read_line(&mut stream.recv).await?)?;
+    tracing::info!(
+        peer = %stream.peer_id,
+        item = %request.item_id,
+        offset = request.offset,
+        "federation peer requested audio"
+    );
+
+    let track_id = match hex_decode_item_id(&request.item_id) {
+        Some(item_id) => match resolve_track_id(&pool, &own, item_id).await {
+            Ok(Some(track_id)) => track_id,
+            Ok(None) => return refuse_audio(stream, "track not found in the library").await,
+            Err(err) => {
+                return refuse_audio(stream, &format!("library lookup failed: {err:#}")).await;
+            }
+        },
+        None => return refuse_audio(stream, "malformed item_id").await,
+    };
+
+    let Some((file_path, mime_type)) = track_audio_file(&pool, track_id).await? else {
+        return refuse_audio(stream, "audio file record is missing").await;
+    };
+    let path = resolve_media_path(&storage_dir, &file_path);
+    let mut file = match tokio::fs::File::open(&path).await {
+        Ok(file) => file,
+        Err(err) => {
+            return refuse_audio(stream, &format!("audio file is not readable: {err}")).await;
+        }
+    };
+    let total_size = file.metadata().await?.len();
+    let offset = request.offset.min(total_size);
+    if offset > 0 {
+        file.seek(std::io::SeekFrom::Start(offset)).await?;
+    }
+
+    let metadata = match track_metadata(&pool, track_id).await {
+        Ok(metadata) => metadata,
+        Err(err) => {
+            tracing::warn!(track_id, "federation metadata lookup failed: {err:#}");
+            None
+        }
+    };
+    let (cover, artist_image) = if request.want_cover {
+        (
+            read_image(
+                &storage_dir,
+                track_cover_file(&pool, track_id).await.ok().flatten(),
+            )
+            .await,
+            read_image(
+                &storage_dir,
+                track_artist_image_file(&pool, track_id)
+                    .await
+                    .ok()
+                    .flatten(),
+            )
+            .await,
+        )
+    } else {
+        (None, None)
+    };
+
+    let mime_type = if mime_type.trim().is_empty() {
+        guess_mime(&path).to_string()
+    } else {
+        mime_type
+    };
+    write_line(
+        &mut stream.send,
+        &AudioResponseHeader {
+            ok: true,
+            error: None,
+            mime_type,
+            total_size,
+            offset,
+            metadata,
+            cover_size: cover.as_ref().map_or(0, |(bytes, _)| bytes.len() as u64),
+            cover_mime: cover
+                .as_ref()
+                .map(|(_, mime)| mime.clone())
+                .unwrap_or_default(),
+            artist_image_size: artist_image
+                .as_ref()
+                .map_or(0, |(bytes, _)| bytes.len() as u64),
+            artist_image_mime: artist_image
+                .as_ref()
+                .map(|(_, mime)| mime.clone())
+                .unwrap_or_default(),
+        },
+    )
+    .await?;
+    if let Some((bytes, _)) = &cover {
+        stream.send.write_all(bytes).await?;
+    }
+    if let Some((bytes, _)) = &artist_image {
+        stream.send.write_all(bytes).await?;
+    }
+    tokio::io::copy(&mut file, &mut stream.send).await?;
+    stream.send.finish()?;
+    // Wait until the peer read everything before dropping the stream,
+    // otherwise the tail of the file is lost.
+    let _ = stream.send.stopped().await;
+    Ok(())
+}
+
+async fn refuse_audio(mut stream: ByteStream, message: &str) -> Result<()> {
+    write_line(
+        &mut stream.send,
+        &AudioResponseHeader {
+            ok: false,
+            error: Some(message.to_string()),
+            ..AudioResponseHeader::default()
+        },
+    )
+    .await?;
+    stream.send.finish()?;
+    let _ = stream.send.stopped().await;
+    anyhow::bail!("refused audio request: {message}");
+}
+
+// ---------------------------------------------------------------------------
+// Catalog protocol
+// ---------------------------------------------------------------------------
+
+/// Runs the catalog accept loop until the acceptor closes.
+pub async fn serve_catalog(
+    mut acceptor: StreamAcceptor,
+    pool: PgPool,
+    storage_dir: String,
+    own: EndpointId,
+) {
+    while let Some(stream) = acceptor.accept().await {
+        let pool = pool.clone();
+        let storage_dir = storage_dir.clone();
+        tokio::spawn(async move {
+            let peer = stream.peer_id;
+            if let Err(err) = serve_catalog_one(stream, pool, storage_dir, own).await {
+                tracing::warn!(peer = %peer, "federation catalog request failed: {err:#}");
+            }
+        });
+    }
+}
+
+async fn serve_catalog_one(
+    mut stream: ByteStream,
+    pool: PgPool,
+    storage_dir: String,
+    own: EndpointId,
+) -> Result<()> {
+    let request: CatalogRequest = serde_json::from_slice(&read_line(&mut stream.recv).await?)?;
+    tracing::info!(
+        peer = %stream.peer_id,
+        artist = %request.artist,
+        want = request.want.as_deref().unwrap_or("catalog"),
+        "federation peer requested a catalog"
+    );
+
+    match request.want.as_deref() {
+        None | Some("catalog") => {
+            let response = match build_catalog(&pool, &own, &request.artist).await {
+                Ok(response) => response,
+                Err(err) => CatalogResponse {
+                    ok: false,
+                    error: Some(format!("catalog lookup failed: {err:#}")),
+                    artist: None,
+                },
+            };
+            stream
+                .send
+                .write_all(&serde_json::to_vec(&response)?)
+                .await?;
+        }
+        Some(want @ ("artist_image" | "release_cover")) => {
+            let media = if want == "release_cover" {
+                release_cover_by_names(
+                    &pool,
+                    &request.artist,
+                    request.release.as_deref().unwrap_or_default(),
+                )
+                .await?
+            } else {
+                artist_image_by_name(&pool, &request.artist).await?
+            };
+            let image = read_image(&storage_dir, media).await;
+            let header = match &image {
+                Some((bytes, mime)) => ImageHeader {
+                    ok: true,
+                    error: None,
+                    mime_type: mime.clone(),
+                    size: bytes.len() as u64,
+                },
+                None => ImageHeader {
+                    ok: false,
+                    error: Some("no image".to_string()),
+                    ..ImageHeader::default()
+                },
+            };
+            write_line(&mut stream.send, &header).await?;
+            if let Some((bytes, _)) = &image {
+                stream.send.write_all(bytes).await?;
+            }
+        }
+        Some(other) => {
+            let response = CatalogResponse {
+                ok: false,
+                error: Some(format!("unknown request kind '{other}'")),
+                artist: None,
+            };
+            stream
+                .send
+                .write_all(&serde_json::to_vec(&response)?)
+                .await?;
+        }
+    }
+    stream.send.finish()?;
+    let _ = stream.send.stopped().await;
+    Ok(())
+}
+
+async fn build_catalog(pool: &PgPool, own: &EndpointId, artist: &str) -> Result<CatalogResponse> {
+    let Some(artist_row) = sqlx::query(
+        "SELECT id, name FROM furumusic__artist
+         WHERE LOWER(name) = LOWER($1) AND is_hidden = false
+         LIMIT 1",
+    )
+    .bind(artist)
+    .fetch_optional(pool)
+    .await?
+    else {
+        return Ok(CatalogResponse {
+            ok: false,
+            error: Some("artist not found in the library".to_string()),
+            artist: None,
+        });
+    };
+    let artist_id: i64 = artist_row.get(0);
+
+    let release_rows = sqlx::query(
+        "SELECT r.id, r.title, r.release_type, r.year
+         FROM furumusic__release r
+         JOIN furumusic__release_artist ra ON ra.release_id = r.id
+         WHERE ra.artist_id = $1 AND r.is_hidden = false
+         ORDER BY r.year NULLS LAST, r.title",
+    )
+    .bind(artist_id)
+    .fetch_all(pool)
+    .await?;
+    let mut releases = Vec::new();
+    for release_row in release_rows {
+        let release_id: i64 = release_row.get(0);
+        let track_rows = sqlx::query(
+            "SELECT t.id, t.title, t.track_number, t.disc_number, t.duration_seconds,
+                    c.content_id
+             FROM furumusic__track t
+             JOIN furumusic__media_file m ON m.id = t.audio_file_id
+             LEFT JOIN furumusic__federation_content_id_cache c
+                    ON c.media_file_id = m.id AND c.sha256_hash = m.sha256_hash
+             WHERE t.release_id = $1 AND t.is_hidden = false
+             ORDER BY t.disc_number NULLS FIRST, t.track_number NULLS LAST, t.title",
+        )
+        .bind(release_id)
+        .fetch_all(pool)
+        .await?;
+        let mut tracks = Vec::with_capacity(track_rows.len());
+        for row in track_rows {
+            let track_id: i64 = row.get(0);
+            let duration: f64 = row.get(4);
+            tracks.push(CatalogTrack {
+                title: row.get(1),
+                track_number: row.get(2),
+                disc_number: row.get(3),
+                duration_seconds: (duration > 0.0).then_some(duration),
+                content_id: row.get(5),
+                item_id: item_id_of(own, track_id),
+            });
+        }
+        releases.push(CatalogRelease {
+            title: release_row.get(1),
+            release_type: release_row.get(2),
+            year: release_row.get(3),
+            tracks,
+        });
+    }
+
+    Ok(CatalogResponse {
+        ok: true,
+        error: None,
+        artist: Some(CatalogArtist {
+            name: artist_row.get(1),
+            releases,
+        }),
+    })
+}
+
+async fn artist_image_by_name(pool: &PgPool, artist: &str) -> Result<Option<(String, String)>> {
+    let row = sqlx::query(
+        "SELECT m.file_path, m.mime_type FROM furumusic__artist a
+         JOIN furumusic__media_file m ON m.id = a.image_file_id
+         WHERE LOWER(a.name) = LOWER($1) AND a.is_hidden = false
+         LIMIT 1",
+    )
+    .bind(artist)
+    .fetch_optional(pool)
+    .await?;
+    Ok(row.map(|row| (row.get(0), row.get(1))))
+}
+
+async fn release_cover_by_names(
+    pool: &PgPool,
+    artist: &str,
+    release: &str,
+) -> Result<Option<(String, String)>> {
+    let row = sqlx::query(
+        "SELECT m.file_path, m.mime_type FROM furumusic__release r
+         JOIN furumusic__release_artist ra ON ra.release_id = r.id
+         JOIN furumusic__artist a ON a.id = ra.artist_id
+         JOIN furumusic__media_file m ON m.id = r.cover_file_id
+         WHERE LOWER(a.name) = LOWER($1) AND LOWER(r.title) = LOWER($2)
+         LIMIT 1",
+    )
+    .bind(artist)
+    .bind(release)
+    .fetch_optional(pool)
+    .await?;
+    Ok(row.map(|row| (row.get(0), row.get(1))))
+}

src/federation/storage.rs

@@ -0,0 +1,349 @@
+use std::str::FromStr;
+
+use async_trait::async_trait;
+use music_dht::{
+    DhtKey, EndpointId, LibraryItem, MAX_RECORDS_PER_RESPONSE, MusicDhtError, MusicDhtStorage,
+    NodeContact, NodeId, SecretKey, StoreDecision, StoredRecord, decide_store,
+};
+use sqlx::{PgPool, Row as _};
+
+const IDENTITY_NAME: &str = "default";
+
+const SCHEMA: &[&str] = &[
+    "CREATE TABLE IF NOT EXISTS furumusic__federation_identity (
+        name        TEXT PRIMARY KEY,
+        secret_key  BYTEA NOT NULL,
+        created_at  TEXT NOT NULL,
+        updated_at  TEXT NOT NULL
+    )",
+    "CREATE TABLE IF NOT EXISTS furumusic__federation_local_item (
+        id              BYTEA PRIMARY KEY,
+        normalized_name TEXT NOT NULL,
+        revision        BIGINT NOT NULL,
+        deleted         BOOLEAN NOT NULL DEFAULT false,
+        updated_at_ms   BIGINT NOT NULL,
+        payload         BYTEA NOT NULL
+    )",
+    "CREATE INDEX IF NOT EXISTS idx_furumusic_federation_local_item_normalized_name
+        ON furumusic__federation_local_item(normalized_name)",
+    "CREATE TABLE IF NOT EXISTS furumusic__federation_dht_record (
+        dht_key          BYTEA NOT NULL,
+        item_id          BYTEA NOT NULL,
+        owner_peer_id    TEXT NOT NULL,
+        payload          BYTEA NOT NULL,
+        revision         BIGINT NOT NULL,
+        deleted          BOOLEAN NOT NULL,
+        expires_at_ms    BIGINT NOT NULL,
+        PRIMARY KEY (dht_key, item_id, owner_peer_id)
+    )",
+    "CREATE INDEX IF NOT EXISTS idx_furumusic_federation_dht_record_expires_at
+        ON furumusic__federation_dht_record(expires_at_ms)",
+    "CREATE TABLE IF NOT EXISTS furumusic__federation_known_peer (
+        peer_id       TEXT PRIMARY KEY,
+        node_id       BYTEA NOT NULL,
+        ticket        TEXT NOT NULL,
+        last_seen_ms  BIGINT NOT NULL
+    )",
+    "CREATE TABLE IF NOT EXISTS furumusic__federation_content_id_cache (
+        media_file_id  BIGINT PRIMARY KEY,
+        sha256_hash    TEXT NOT NULL,
+        content_id     TEXT NOT NULL,
+        updated_at     TEXT NOT NULL
+    )",
+    "CREATE INDEX IF NOT EXISTS idx_furumusic_federation_content_id_cache_content_id
+        ON furumusic__federation_content_id_cache(content_id)",
+];
+
+#[derive(Debug, Clone)]
+pub struct PostgresFederationStorage {
+    pool: PgPool,
+}
+
+impl PostgresFederationStorage {
+    pub async fn new(pool: PgPool) -> music_dht::Result<Self> {
+        let storage = Self { pool };
+        storage.ensure_schema().await?;
+        Ok(storage)
+    }
+
+    pub async fn load_or_create_secret_key(&self) -> music_dht::Result<SecretKey> {
+        if let Some(bytes) = sqlx::query_scalar::<_, Vec<u8>>(
+            "SELECT secret_key FROM furumusic__federation_identity WHERE name = $1",
+        )
+        .bind(IDENTITY_NAME)
+        .fetch_optional(&self.pool)
+        .await
+        .map_err(db_error)?
+        {
+            return secret_from_bytes(bytes);
+        }
+
+        let key = SecretKey::generate();
+        let key_bytes = key.to_bytes();
+        let now = now_iso();
+        let inserted = sqlx::query(
+            "INSERT INTO furumusic__federation_identity
+             (name, secret_key, created_at, updated_at)
+             VALUES ($1, $2, $3, $4)
+             ON CONFLICT (name) DO NOTHING",
+        )
+        .bind(IDENTITY_NAME)
+        .bind(key_bytes.as_slice())
+        .bind(&now)
+        .bind(&now)
+        .execute(&self.pool)
+        .await
+        .map_err(db_error)?
+        .rows_affected();
+        if inserted == 1 {
+            return Ok(key);
+        }
+
+        let bytes = sqlx::query_scalar::<_, Vec<u8>>(
+            "SELECT secret_key FROM furumusic__federation_identity WHERE name = $1",
+        )
+        .bind(IDENTITY_NAME)
+        .fetch_one(&self.pool)
+        .await
+        .map_err(db_error)?;
+        secret_from_bytes(bytes)
+    }
+
+    async fn ensure_schema(&self) -> music_dht::Result<()> {
+        for sql in SCHEMA {
+            sqlx::query(sql)
+                .execute(&self.pool)
+                .await
+                .map_err(db_error)?;
+        }
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl MusicDhtStorage for PostgresFederationStorage {
+    async fn upsert_local_item(&self, item: &LibraryItem) -> music_dht::Result<()> {
+        let payload = postcard::to_stdvec(item).map_err(db_error)?;
+        sqlx::query(
+            "INSERT INTO furumusic__federation_local_item
+             (id, normalized_name, revision, deleted, updated_at_ms, payload)
+             VALUES ($1, $2, $3, $4, $5, $6)
+             ON CONFLICT (id) DO UPDATE SET
+                normalized_name = EXCLUDED.normalized_name,
+                revision = EXCLUDED.revision,
+                deleted = EXCLUDED.deleted,
+                updated_at_ms = EXCLUDED.updated_at_ms,
+                payload = EXCLUDED.payload",
+        )
+        .bind(item.id.as_bytes().as_slice())
+        .bind(&item.normalized_name)
+        .bind(item.revision as i64)
+        .bind(item.deleted)
+        .bind(item.updated_at_ms as i64)
+        .bind(payload)
+        .execute(&self.pool)
+        .await
+        .map_err(db_error)?;
+        Ok(())
+    }
+
+    async fn list_local_items(&self, include_deleted: bool) -> music_dht::Result<Vec<LibraryItem>> {
+        let rows = sqlx::query(
+            "SELECT payload
+             FROM furumusic__federation_local_item
+             WHERE $1 OR deleted = false
+             ORDER BY normalized_name",
+        )
+        .bind(include_deleted)
+        .fetch_all(&self.pool)
+        .await
+        .map_err(db_error)?;
+        Ok(rows
+            .into_iter()
+            .filter_map(|row| postcard::from_bytes::<LibraryItem>(&row.get::<Vec<u8>, _>(0)).ok())
+            .collect())
+    }
+
+    async fn store_dht_record(&self, key: DhtKey, record: StoredRecord) -> music_dht::Result<bool> {
+        let mut conn = self.pool.acquire().await.map_err(db_error)?;
+        store_record_in_conn(&mut conn, &key, &record).await
+    }
+
+    async fn store_dht_records(
+        &self,
+        entries: Vec<(DhtKey, StoredRecord)>,
+    ) -> music_dht::Result<Vec<bool>> {
+        let mut tx = self.pool.begin().await.map_err(db_error)?;
+        let mut stored = Vec::with_capacity(entries.len());
+        for (key, record) in &entries {
+            stored.push(store_record_in_conn(&mut tx, key, record).await?);
+        }
+        tx.commit().await.map_err(db_error)?;
+        Ok(stored)
+    }
+
+    async fn dht_records_by_key(
+        &self,
+        key: DhtKey,
+        now_ms: u64,
+    ) -> music_dht::Result<Vec<StoredRecord>> {
+        let rows = sqlx::query(
+            "SELECT payload
+             FROM furumusic__federation_dht_record
+             WHERE dht_key = $1 AND expires_at_ms > $2
+             ORDER BY expires_at_ms DESC, item_id
+             LIMIT $3",
+        )
+        .bind(key.as_bytes().as_slice())
+        .bind(now_ms as i64)
+        .bind(MAX_RECORDS_PER_RESPONSE as i64)
+        .fetch_all(&self.pool)
+        .await
+        .map_err(db_error)?;
+        Ok(rows
+            .into_iter()
+            .filter_map(|row| postcard::from_bytes::<StoredRecord>(&row.get::<Vec<u8>, _>(0)).ok())
+            .collect())
+    }
+
+    async fn delete_expired_records(&self, now_ms: u64) -> music_dht::Result<usize> {
+        let result =
+            sqlx::query("DELETE FROM furumusic__federation_dht_record WHERE expires_at_ms <= $1")
+                .bind(now_ms as i64)
+                .execute(&self.pool)
+                .await
+                .map_err(db_error)?;
+        Ok(result.rows_affected() as usize)
+    }
+
+    async fn upsert_known_peer(&self, contact: &NodeContact) -> music_dht::Result<()> {
+        sqlx::query(
+            "INSERT INTO furumusic__federation_known_peer
+             (peer_id, node_id, ticket, last_seen_ms)
+             VALUES ($1, $2, $3, $4)
+             ON CONFLICT (peer_id) DO UPDATE SET
+                node_id = EXCLUDED.node_id,
+                ticket = EXCLUDED.ticket,
+                last_seen_ms = EXCLUDED.last_seen_ms",
+        )
+        .bind(contact.peer_id.to_string())
+        .bind(contact.node_id.as_bytes().as_slice())
+        .bind(&contact.ticket)
+        .bind(contact.last_seen_ms as i64)
+        .execute(&self.pool)
+        .await
+        .map_err(db_error)?;
+        Ok(())
+    }
+
+    async fn delete_known_peer(&self, peer_id: EndpointId) -> music_dht::Result<()> {
+        sqlx::query("DELETE FROM furumusic__federation_known_peer WHERE peer_id = $1")
+            .bind(peer_id.to_string())
+            .execute(&self.pool)
+            .await
+            .map_err(db_error)?;
+        Ok(())
+    }
+
+    async fn load_known_peers(&self) -> music_dht::Result<Vec<NodeContact>> {
+        let rows = sqlx::query(
+            "SELECT peer_id, node_id, ticket, last_seen_ms
+             FROM furumusic__federation_known_peer",
+        )
+        .fetch_all(&self.pool)
+        .await
+        .map_err(db_error)?;
+        let mut contacts = Vec::new();
+        for row in rows {
+            let peer_id: String = row.get(0);
+            let node_id: Vec<u8> = row.get(1);
+            let ticket: String = row.get(2);
+            let last_seen_ms: i64 = row.get(3);
+            let Ok(peer_id) = EndpointId::from_str(&peer_id) else {
+                continue;
+            };
+            let Ok(node_id) = <[u8; 32]>::try_from(node_id.as_slice()) else {
+                continue;
+            };
+            contacts.push(NodeContact {
+                node_id: NodeId::from_bytes(node_id),
+                peer_id,
+                ticket,
+                last_seen_ms: last_seen_ms as u64,
+            });
+        }
+        Ok(contacts)
+    }
+}
+
+fn now_iso() -> String {
+    chrono::Utc::now().format("%Y-%m-%dT%H:%M:%SZ").to_string()
+}
+
+fn secret_from_bytes(bytes: Vec<u8>) -> music_dht::Result<SecretKey> {
+    let bytes: [u8; 32] = bytes
+        .as_slice()
+        .try_into()
+        .map_err(|_| MusicDhtError::Database("stored federation identity is corrupted".into()))?;
+    Ok(SecretKey::from_bytes(&bytes))
+}
+
+/// Applies one validated record following the revision/tombstone rules.
+/// Returns `true` if the record was written or refreshed. Runs against a
+/// pooled connection or an open transaction.
+async fn store_record_in_conn(
+    conn: &mut sqlx::PgConnection,
+    key: &DhtKey,
+    record: &StoredRecord,
+) -> music_dht::Result<bool> {
+    let existing = sqlx::query(
+        "SELECT revision, deleted, expires_at_ms
+         FROM furumusic__federation_dht_record
+         WHERE dht_key = $1 AND item_id = $2 AND owner_peer_id = $3",
+    )
+    .bind(key.as_bytes().as_slice())
+    .bind(record.item.id.as_bytes().as_slice())
+    .bind(record.item.owner.to_string())
+    .fetch_optional(&mut *conn)
+    .await
+    .map_err(db_error)?
+    .map(|row| {
+        (
+            row.get::<i64, _>(0) as u64,
+            row.get::<bool, _>(1),
+            row.get::<i64, _>(2) as u64,
+        )
+    });
+
+    match decide_store(existing, record) {
+        StoreDecision::Ignore => return Ok(false),
+        StoreDecision::Write | StoreDecision::RefreshExpiry(_) => {}
+    }
+
+    let payload = postcard::to_stdvec(record).map_err(db_error)?;
+    sqlx::query(
+        "INSERT INTO furumusic__federation_dht_record
+         (dht_key, item_id, owner_peer_id, payload, revision, deleted, expires_at_ms)
+         VALUES ($1, $2, $3, $4, $5, $6, $7)
+         ON CONFLICT (dht_key, item_id, owner_peer_id) DO UPDATE SET
+            payload = EXCLUDED.payload,
+            revision = EXCLUDED.revision,
+            deleted = EXCLUDED.deleted,
+            expires_at_ms = EXCLUDED.expires_at_ms",
+    )
+    .bind(key.as_bytes().as_slice())
+    .bind(record.item.id.as_bytes().as_slice())
+    .bind(record.item.owner.to_string())
+    .bind(payload)
+    .bind(record.item.revision as i64)
+    .bind(record.item.deleted)
+    .bind(record.expires_at_ms as i64)
+    .execute(&mut *conn)
+    .await
+    .map_err(db_error)?;
+    Ok(true)
+}
+
+fn db_error(err: impl std::fmt::Display) -> MusicDhtError {
+    MusicDhtError::Database(err.to_string())
+}

src/i18n/phrases.rs

@@ -309,6 +309,7 @@ translations! {
     player_cancel:           "Cancel"                          , "Отмена";
     player_create:           "Create"                          , "Создать";
     player_save:             "Save"                            , "Сохранить";
+    player_done:             "Done"                            , "Готово";
     player_delete:           "Delete"                          , "Удалить";
     player_delete_playlist_confirm: "Delete this playlist?"     , "Удалить этот плейлист?";
     player_rename:           "Rename"                          , "Переименовать";

src/main.rs

@@ -3,6 +3,7 @@ mod agent;
 mod api;
 mod auth;
 mod config;
+mod federation;
 mod i18n;
 mod jobs;
 mod lastfm;
@@ -559,6 +560,13 @@ impl Project for FuruProject {
                 .await;
         });
 
+        // Join the federation at boot when it was left enabled (the settings
+        // live in the config KV table; changes apply live from the admin).
+        let fed_config = Arc::clone(&self.app_config);
+        tokio::spawn(async move {
+            federation::handle().boot(&fed_config).await;
+        });
+
         apps.register(cot::session::db::SessionApp::new());
         apps.register_with_views(
             FuruApp {

src/player/dto.rs

@@ -74,6 +74,13 @@ pub(super) struct TrackItem {
     pub(super) lastfm_updated_at: Option<String>,
 }
 
+#[derive(Debug, Serialize, JsonSchema)]
+pub(super) struct PlaylistTrackItem {
+    pub(super) playlist_track_id: Option<i64>,
+    #[serde(flatten)]
+    pub(super) track: TrackItem,
+}
+
 #[derive(Debug, Serialize, JsonSchema)]
 pub(super) struct ArtistAppearanceTrack {
     pub(super) id: i64,
@@ -286,7 +293,7 @@ pub(super) struct PlaylistDetail {
     pub(super) is_public: bool,
     pub(super) is_saved: bool,
     pub(super) kind: String,
-    pub(super) tracks: Vec<TrackItem>,
+    pub(super) tracks: Vec<PlaylistTrackItem>,
 }
 
 #[derive(Debug, Serialize, JsonSchema)]

src/player/mod.rs

@@ -3414,6 +3414,7 @@ async fn artist_detail_handler(
     let top_tracks = sqlx::query_as::<_, PlaylistTrackRow>(
         r#"SELECT * FROM (
                SELECT DISTINCT ON (lower(t.title::text))
+                      NULL::bigint AS playlist_track_id,
                       t.id, t.title::text as title, t.track_number, t.disc_number,
                       t.duration_seconds, t.cover_file_id,
                       r.cover_file_id as release_cover_file_id,
@@ -3515,7 +3516,8 @@ async fn release_detail_handler(
     .map_err(|e| cot::Error::internal(e.to_string()))?;
 
     let tracks = sqlx::query_as::<_, PlaylistTrackRow>(
-        r#"SELECT t.id, t.title::text as title, t.track_number, t.disc_number,
+        r#"SELECT NULL::bigint AS playlist_track_id,
+                  t.id, t.title::text as title, t.track_number, t.disc_number,
                   t.duration_seconds, t.cover_file_id,
                   r.cover_file_id as release_cover_file_id,
                   r.id as release_id,
@@ -3687,7 +3689,8 @@ async fn playlist_detail_handler(
     };
 
     let tracks = sqlx::query_as::<_, PlaylistTrackRow>(
-        r#"SELECT t.id, t.title::text as title, t.track_number, t.disc_number,
+        r#"SELECT pt.id AS playlist_track_id,
+                  t.id, t.title::text as title, t.track_number, t.disc_number,
                   t.duration_seconds, t.cover_file_id,
                   r.cover_file_id as release_cover_file_id,
                   r.id as release_id,
@@ -3715,7 +3718,7 @@ async fn playlist_detail_handler(
     .await
     .map_err(|e| cot::Error::internal(e.to_string()))?;
 
-    let track_items = build_track_items(tracks, pool).await?;
+    let track_items = build_playlist_track_items(tracks, pool).await?;
 
     Json(PlaylistDetail {
         id: info.id,
@@ -3813,13 +3816,34 @@ async fn build_track_items(
         .collect())
 }
 
+async fn build_playlist_track_items(
+    tracks: Vec<PlaylistTrackRow>,
+    pool: &sqlx::PgPool,
+) -> cot::Result<Vec<PlaylistTrackItem>> {
+    let playlist_track_ids = tracks
+        .iter()
+        .map(|track| track.playlist_track_id)
+        .collect::<Vec<_>>();
+    let track_items = build_track_items(tracks, pool).await?;
+
+    Ok(track_items
+        .into_iter()
+        .zip(playlist_track_ids)
+        .map(|(track, playlist_track_id)| PlaylistTrackItem {
+            playlist_track_id,
+            track,
+        })
+        .collect())
+}
+
 async fn load_track_items_by_ids(pool: &sqlx::PgPool, ids: &[i64]) -> cot::Result<Vec<TrackItem>> {
     if ids.is_empty() {
         return Ok(Vec::new());
     }
 
     let tracks = sqlx::query_as::<_, PlaylistTrackRow>(
-        r#"SELECT t.id, t.title::text as title, t.track_number, t.disc_number,
+        r#"SELECT NULL::bigint AS playlist_track_id,
+                  t.id, t.title::text as title, t.track_number, t.disc_number,
                   t.duration_seconds, t.cover_file_id,
                   r.cover_file_id as release_cover_file_id,
                   r.id as release_id,
@@ -3976,7 +4000,8 @@ async fn likes_playlist_handler(
     pool: &sqlx::PgPool,
 ) -> cot::Result<cot::response::Response> {
     let tracks = sqlx::query_as::<_, PlaylistTrackRow>(
-        r#"SELECT t.id, t.title::text as title, t.track_number, t.disc_number,
+        r#"SELECT NULL::bigint AS playlist_track_id,
+                  t.id, t.title::text as title, t.track_number, t.disc_number,
                   t.duration_seconds, t.cover_file_id,
                   r.cover_file_id as release_cover_file_id,
                   r.id as release_id,
@@ -4004,7 +4029,14 @@ async fn likes_playlist_handler(
     .await
     .map_err(|e| cot::Error::internal(e.to_string()))?;
 
-    let track_items = build_track_items(tracks, pool).await?;
+    let track_items = build_track_items(tracks, pool)
+        .await?
+        .into_iter()
+        .map(|track| PlaylistTrackItem {
+            playlist_track_id: None,
+            track,
+        })
+        .collect();
 
     Json(PlaylistDetail {
         id: -1,
@@ -5609,6 +5641,110 @@ async fn add_tracks_to_playlist_handler(
     Json(serde_json::json!({"ok": true})).into_response()
 }
 
+// ---------------------------------------------------------------------------
+// PUT /api/player/playlists/{id}/tracks  — reorder playlist tracks
+// ---------------------------------------------------------------------------
+
+async fn reorder_playlist_tracks_handler(
+    auth_ctx: auth::AuthContext,
+    session: Session,
+    db: Database,
+    pool: &sqlx::PgPool,
+    path: Path<PathId>,
+    Json(body): Json<ReorderPlaylistRequest>,
+) -> cot::Result<cot::response::Response> {
+    let Some(user) = auth::get_request_user(&auth_ctx, &session, &db).await else {
+        return Ok(json_error(StatusCode::UNAUTHORIZED, "not authenticated"));
+    };
+    let playlist_id = path.0.id;
+    let owner: Option<(i64,)> =
+        sqlx::query_as("SELECT owner_id FROM furumusic__playlist WHERE id = $1")
+            .bind(playlist_id)
+            .fetch_optional(pool)
+            .await
+            .map_err(|e| cot::Error::internal(e.to_string()))?;
+    let Some(owner) = owner else {
+        return Ok(json_error(StatusCode::NOT_FOUND, "playlist not found"));
+    };
+    if owner.0 != user.id {
+        return Ok(json_error(StatusCode::FORBIDDEN, "not your playlist"));
+    }
+
+    let requested_ids = body
+        .playlist_track_ids
+        .into_iter()
+        .filter(|id| *id > 0)
+        .collect::<Vec<_>>();
+    let unique_requested = requested_ids.iter().copied().collect::<HashSet<_>>();
+    if unique_requested.len() != requested_ids.len() {
+        return Ok(json_error(
+            StatusCode::BAD_REQUEST,
+            "duplicate playlist track ids",
+        ));
+    }
+
+    let visible_ids = sqlx::query_scalar::<_, i64>(
+        r#"SELECT pt.id
+           FROM furumusic__playlist_track pt
+           JOIN furumusic__track t ON t.id = pt.track_id
+           WHERE pt.playlist_id = $1 AND t.is_hidden = false
+           ORDER BY pt.position"#,
+    )
+    .bind(playlist_id)
+    .fetch_all(pool)
+    .await
+    .map_err(|e| cot::Error::internal(e.to_string()))?;
+    let visible_set = visible_ids.iter().copied().collect::<HashSet<_>>();
+    if visible_set != unique_requested {
+        return Ok(json_error(
+            StatusCode::BAD_REQUEST,
+            "playlist track ids do not match this playlist",
+        ));
+    }
+
+    let hidden_ids = sqlx::query_scalar::<_, i64>(
+        r#"SELECT pt.id
+           FROM furumusic__playlist_track pt
+           JOIN furumusic__track t ON t.id = pt.track_id
+           WHERE pt.playlist_id = $1 AND t.is_hidden = true
+           ORDER BY pt.position"#,
+    )
+    .bind(playlist_id)
+    .fetch_all(pool)
+    .await
+    .map_err(|e| cot::Error::internal(e.to_string()))?;
+
+    let mut ordered_ids = requested_ids;
+    ordered_ids.extend(hidden_ids);
+    if !ordered_ids.is_empty() {
+        sqlx::query(
+            r#"WITH ordered AS (
+                 SELECT id, ord::integer - 1 AS position
+                   FROM unnest($1::bigint[]) WITH ORDINALITY AS u(id, ord)
+               )
+               UPDATE furumusic__playlist_track pt
+                  SET position = ordered.position
+                 FROM ordered
+                WHERE pt.id = ordered.id AND pt.playlist_id = $2"#,
+        )
+        .bind(&ordered_ids)
+        .bind(playlist_id)
+        .execute(pool)
+        .await
+        .map_err(|e| cot::Error::internal(e.to_string()))?;
+    }
+
+    let now = chrono::Utc::now().format("%Y-%m-%dT%H:%M:%SZ").to_string();
+    sqlx::query("UPDATE furumusic__playlist SET updated_at = $1 WHERE id = $2")
+        .bind(&now)
+        .bind(playlist_id)
+        .execute(pool)
+        .await
+        .map_err(|e| cot::Error::internal(e.to_string()))?;
+
+    Json(serde_json::json!({"ok": true})).into_response()
+}
+
 // ---------------------------------------------------------------------------
 // DELETE /api/player/playlists/{id}/tracks  — remove a track from playlist
 // ---------------------------------------------------------------------------
@@ -5638,12 +5774,29 @@ async fn remove_track_from_playlist_handler(
         return Ok(json_error(StatusCode::FORBIDDEN, "not your playlist"));
     }
 
-    sqlx::query("DELETE FROM furumusic__playlist_track WHERE playlist_id = $1 AND track_id = $2")
-        .bind(playlist_id)
-        .bind(body.track_id)
-        .execute(pool)
-        .await
-        .map_err(|e| cot::Error::internal(e.to_string()))?;
+    match (body.playlist_track_id, body.track_id) {
+        (Some(playlist_track_id), _) => {
+            sqlx::query("DELETE FROM furumusic__playlist_track WHERE playlist_id = $1 AND id = $2")
+                .bind(playlist_id)
+                .bind(playlist_track_id)
+                .execute(pool)
+                .await
+                .map_err(|e| cot::Error::internal(e.to_string()))?;
+        }
+        (None, Some(track_id)) => {
+            sqlx::query(
+                "DELETE FROM furumusic__playlist_track WHERE playlist_id = $1 AND track_id = $2",
+            )
+            .bind(playlist_id)
+            .bind(track_id)
+            .execute(pool)
+            .await
+            .map_err(|e| cot::Error::internal(e.to_string()))?;
+        }
+        (None, None) => {
+            return Ok(json_error(StatusCode::BAD_REQUEST, "missing track id"));
+        }
+    }
 
     // Re-number positions
     sqlx::query(
@@ -5660,6 +5813,14 @@ async fn remove_track_from_playlist_handler(
     .await
     .map_err(|e| cot::Error::internal(e.to_string()))?;
 
+    let now = chrono::Utc::now().format("%Y-%m-%dT%H:%M:%SZ").to_string();
+    sqlx::query("UPDATE furumusic__playlist SET updated_at = $1 WHERE id = $2")
+        .bind(&now)
+        .bind(playlist_id)
+        .execute(pool)
+        .await
+        .map_err(|e| cot::Error::internal(e.to_string()))?;
+
     Json(serde_json::json!({"ok": true})).into_response()
 }
 
@@ -7618,6 +7779,33 @@ impl App for PlayerApp {
                         }
                     }
                 })
+                .put({
+                    let pool = Arc::clone(&pool);
+                    let pool_config = Arc::clone(&pool_config);
+                    move |auth_ctx: auth::AuthContext,
+                          session: Session,
+                          db: Database,
+                          path: Path<PathId>,
+                          json: Json<ReorderPlaylistRequest>| {
+                        let pool = Arc::clone(&pool);
+                        let pool_config = Arc::clone(&pool_config);
+                        async move {
+                            let pg_pool = pool
+                                .get_or_init(|| async {
+                                    sqlx::postgres::PgPoolOptions::new()
+                                        .max_connections(5)
+                                        .connect(&pool_config.database_url)
+                                        .await
+                                        .expect("player pool")
+                                })
+                                .await;
+                            reorder_playlist_tracks_handler(
+                                auth_ctx, session, db, pg_pool, path, json,
+                            )
+                            .await
+                        }
+                    }
+                })
                 .delete({
                     let pool = Arc::clone(&pool);
                     let pool_config = Arc::clone(&pool_config);

src/player/queries.rs

@@ -42,7 +42,13 @@ pub(super) struct AddTracksRequest {
 
 #[derive(Debug, Deserialize)]
 pub(super) struct RemoveTrackRequest {
-    pub(super) track_id: i64,
+    pub(super) track_id: Option<i64>,
+    pub(super) playlist_track_id: Option<i64>,
+}
+
+#[derive(Debug, Deserialize)]
+pub(super) struct ReorderPlaylistRequest {
+    pub(super) playlist_track_ids: Vec<i64>,
 }
 
 #[derive(Debug, Deserialize)]

src/player/rows.rs

@@ -95,6 +95,7 @@ pub(super) struct PlaylistInfoRow {
 
 #[derive(sqlx::FromRow)]
 pub(super) struct PlaylistTrackRow {
+    pub(super) playlist_track_id: Option<i64>,
     pub(super) id: i64,
     pub(super) title: String,
     pub(super) track_number: Option<i32>,

templates/admin/v2.html

@@ -2265,6 +2265,73 @@ tbody tr:hover {
                             </div>
                         </section>
 
+                        <section class="panel">
+                            <div class="panel-head">
+                                <div class="panel-title">
+                                    <strong>Federation</strong>
+                                    <span>Publish this library into the furumi P2P network</span>
+                                </div>
+                                <span class="badge" :class="federationStatus.node && federationStatus.node.running ? 'ok' : 'disabled'" x-text="federationStatus.node && federationStatus.node.running ? 'running' : 'stopped'"></span>
+                            </div>
+                            <div class="settings-grid">
+                                <div class="setting-toggle">
+                                    <label>
+                                        <span>Federation enabled</span>
+                                        <span class="source-pill" :class="sourceClass('federation_enabled')" x-text="settingSource('federation_enabled')"></span>
+                                    </label>
+                                    <div class="setting-toggle-row">
+                                        <span x-text="settingsDraft.federation_enabled ? 'Enabled' : 'Disabled'"></span>
+                                        <input type="checkbox" x-model="settingsDraft.federation_enabled" />
+                                    </div>
+                                    <div class="setting-help">Applies immediately on save — no restart needed. Peers can browse and stream every visible track.</div>
+                                </div>
+                                <div class="setting-field settings-wide">
+                                    <label>
+                                        <span>Network ID (shared secret)</span>
+                                        <span class="source-pill" :class="sourceClass('federation_network_id')" x-text="settingSource('federation_network_id')"></span>
+                                    </label>
+                                    <input x-model="settingsDraft.federation_network_id" placeholder="my-crew-music-7f3a" autocomplete="off" />
+                                    <div class="setting-help">Every peer using the same id finds the others automatically.</div>
+                                </div>
+                            </div>
+                            <div class="probe-body" x-show="federationStatus.node">
+                                <div class="probe-table" x-show="federationStatus.node && federationStatus.node.running">
+                                    <div class="probe-row"><span>Endpoint</span><strong x-text="fedShort(federationStatus.node && federationStatus.node.endpoint_id)"></strong></div>
+                                    <div class="probe-row"><span>Network</span><strong x-text="(federationStatus.node && federationStatus.node.network) || '-'"></strong></div>
+                                    <div class="probe-row"><span>Connected peers</span><strong x-text="federationStatus.node && federationStatus.node.connected_peers ? federationStatus.node.connected_peers.length : 0"></strong></div>
+                                    <div class="probe-row"><span>Known contacts</span><strong x-text="(federationStatus.node && federationStatus.node.known_contacts) ?? '-'"></strong></div>
+                                    <div class="probe-row"><span>Published items</span><strong x-text="(federationStatus.node && federationStatus.node.published_items) ?? '-'"></strong></div>
+                                    <div class="probe-row"><span>Last sync</span><strong x-text="federationStatus.last_sync || 'not yet'"></strong></div>
+                                </div>
+                                <p class="probe-intro muted" x-show="federationStatus.last_error" x-text="federationStatus.last_error"></p>
+                                <div class="toolbar" style="margin-top:14px; flex-wrap:wrap; gap:8px">
+                                    <button class="btn" type="button" @click="loadFederation()" :disabled="federationLoading">
+                                        <i data-lucide="refresh-cw"></i>
+                                        Refresh
+                                    </button>
+                                    <button class="btn" type="button" @click="fedSyncNow()" :disabled="federationLoading || !(federationStatus.node && federationStatus.node.running)">
+                                        <i data-lucide="upload-cloud"></i>
+                                        Publish now
+                                    </button>
+                                    <button class="btn" type="button" @click="fedShowTicket()" :disabled="federationLoading || !(federationStatus.node && federationStatus.node.running)">
+                                        <i data-lucide="ticket"></i>
+                                        Show ticket
+                                    </button>
+                                </div>
+                                <div class="setting-field settings-wide" x-show="federationTicket" style="margin-top:10px">
+                                    <label>Connection ticket (share with a peer)</label>
+                                    <textarea readonly rows="3" style="width:100%; font-family:monospace; font-size:11px" x-text="federationTicket"></textarea>
+                                </div>
+                                <div class="setting-field settings-wide" x-show="federationStatus.node && federationStatus.node.running" style="margin-top:10px">
+                                    <label>Connect to a peer by ticket</label>
+                                    <div style="display:flex; gap:8px">
+                                        <input x-model="fedConnectTicket" placeholder="fnet..." style="flex:1" autocomplete="off" />
+                                        <button class="btn" type="button" @click="fedConnect()" :disabled="federationLoading || !fedConnectTicket.trim()">Connect</button>
+                                    </div>
+                                </div>
+                            </div>
+                        </section>
+
                         <section class="panel">
                             <div class="panel-head">
                                 <div class="panel-title">
@@ -2832,10 +2899,16 @@ function adminV2() {
             agent_llm_auth: '',
             agent_confidence_threshold: '',
             agent_context_limit: '',
-            agent_concurrency: ''
+            agent_concurrency: '',
+            federation_enabled: false,
+            federation_network_id: ''
         },
         settingsProbe: { status: 'idle', ok: false },
         settingsProbeLoading: false,
+        federationStatus: {},
+        federationLoading: false,
+        federationTicket: '',
+        fedConnectTicket: '',
         settingsSaving: false,
         routeReady: false,
         poller: null,
@@ -3115,6 +3188,7 @@ function adminV2() {
                     body: JSON.stringify(this.settingsDraft)
                 });
                 await this.loadSettings(false);
+                await this.loadFederation(false);
                 this.showToast('Settings saved');
             } catch (error) {
                 this.showToast(error.message);
@@ -3128,11 +3202,72 @@ function adminV2() {
             this.activeView = 'settings';
             this.setRoute('#settings');
             await this.loadSettings();
+            await this.loadFederation(false);
             if (!this.settingsProbe.status || this.settingsProbe.status === 'idle') {
                 await this.loadSettingsProbe(false);
             }
         },
 
+        async loadFederation(showErrors = true) {
+            this.federationLoading = true;
+            try {
+                this.federationStatus = await this.request(`${this.apiBase}/federation`);
+            } catch (error) {
+                if (showErrors) this.showToast(error.message);
+            } finally {
+                this.federationLoading = false;
+                this.icons();
+            }
+        },
+
+        async fedSyncNow() {
+            this.federationLoading = true;
+            try {
+                this.federationStatus = await this.request(`${this.apiBase}/federation/sync`, { method: 'POST', body: '{}' });
+                this.showToast('Library published to the federation');
+            } catch (error) {
+                this.showToast(error.message);
+            } finally {
+                this.federationLoading = false;
+                this.icons();
+            }
+        },
+
+        async fedShowTicket() {
+            this.federationLoading = true;
+            try {
+                const data = await this.request(`${this.apiBase}/federation/ticket`);
+                this.federationTicket = data.ticket || '';
+            } catch (error) {
+                this.showToast(error.message);
+            } finally {
+                this.federationLoading = false;
+                this.icons();
+            }
+        },
+
+        async fedConnect() {
+            this.federationLoading = true;
+            try {
+                const data = await this.request(`${this.apiBase}/federation/connect`, {
+                    method: 'POST',
+                    body: JSON.stringify({ ticket: this.fedConnectTicket.trim() })
+                });
+                this.fedConnectTicket = '';
+                this.showToast(`Connected to ${(data.connected || '').slice(0, 12)}…`);
+                await this.loadFederation(false);
+            } catch (error) {
+                this.showToast(error.message);
+            } finally {
+                this.federationLoading = false;
+                this.icons();
+            }
+        },
+
+        fedShort(id) {
+            return id ? `${id.slice(0, 12)}…` : '-';
+        },
+
         async loadSettingsProbe(showErrors = true) {
             this.settingsProbeLoading = true;
             try {

templates/player/scripts.html

@@ -2745,6 +2745,7 @@ document.addEventListener('alpine:init', () => {
 
         async openPlaylist(id, options = {}) {
             this._beginNavigation('#playlist/' + id, options);
+            Alpine.store('playlists')?.stopEdit?.();
             this.view = 'playlist_detail';
             this.currentPlaylist = null;
             try {
@@ -2756,6 +2757,7 @@ document.addEventListener('alpine:init', () => {
         },
 
         showSharedPlaylist(share, options = {}) {
+            Alpine.store('playlists')?.stopEdit?.();
             this._saveScrollPosition(this._activeHash);
             this.searchQuery = '';
             this.searchResults = null;
@@ -4301,6 +4303,11 @@ document.addEventListener('alpine:init', () => {
         list: [],
         modal: null,   // { mode: 'create'|'rename', title: '', id?: number }
         picker: null,  // { trackIds: [1,2,3] }
+        editingPlaylistId: null,
+        _dragIdx: null,
+        _dragOverIdx: null,
+        _pointerDragMove: null,
+        _pointerDragEnd: null,
 
         init() {
             this.reload();
@@ -4333,6 +4340,214 @@ document.addEventListener('alpine:init', () => {
             return pl?.kind === 'likes' ? T.likesPlaylist : (pl?.title || '');
         },
 
+        currentPlaylist() {
+            return Alpine.store('library')?.currentPlaylist || null;
+        },
+
+        canEditCurrent() {
+            const playlist = this.currentPlaylist();
+            return !!playlist && playlist.kind === 'user' && playlist.is_own && Number(playlist.id) > 0;
+        },
+
+        isEditingCurrent() {
+            const playlist = this.currentPlaylist();
+            return this.canEditCurrent() && Number(this.editingPlaylistId) === Number(playlist.id);
+        },
+
+        toggleEditCurrent() {
+            if (this.isEditingCurrent()) {
+                this.stopEdit();
+                return;
+            }
+            if (!this.canEditCurrent()) return;
+            this.editingPlaylistId = Number(this.currentPlaylist().id);
+        },
+
+        stopEdit() {
+            this._endPointerReorder(false);
+            this.endDrag();
+            this.editingPlaylistId = null;
+        },
+
+        _updateListTrackCount(playlistId, count) {
+            const id = Number(playlistId);
+            this.list = this.list.map(pl => (
+                Number(pl.id) === id ? { ...pl, track_count: count } : pl
+            ));
+        },
+
+        _playlistTrackIds(tracks) {
+            return (tracks || []).map(track => Number(track?.playlist_track_id || 0)).filter(Boolean);
+        },
+
+        async removeCurrentTrack(track, idx) {
+            if (!this.isEditingCurrent() || !track) return;
+            const playlist = this.currentPlaylist();
+            const playlistId = Number(playlist.id);
+            const playlistTrackId = Number(track.playlist_track_id || 0);
+            const previous = (playlist.tracks || []).slice();
+            if (!playlistTrackId) return;
+
+            playlist.tracks = previous.filter(item => Number(item.playlist_track_id || 0) !== playlistTrackId);
+            this._updateListTrackCount(playlistId, playlist.tracks.length);
+
+            try {
+                const res = await fetch(`/api/player/playlists/${playlistId}/tracks`, {
+                    method: 'DELETE',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: JSON.stringify({ playlist_track_id: playlistTrackId }),
+                });
+                if (!res.ok) throw new Error('remove failed');
+                await this.reload();
+            } catch (err) {
+                if (Number(this.currentPlaylist()?.id) === playlistId) {
+                    this.currentPlaylist().tracks = previous;
+                    this._updateListTrackCount(playlistId, previous.length);
+                }
+                console.warn(err);
+            }
+        },
+
+        startDrag(event, idx) {
+            const tracks = this.currentPlaylist()?.tracks || [];
+            if (!this.isEditingCurrent() || idx < 0 || idx >= tracks.length || !tracks[idx]?.playlist_track_id) {
+                return false;
+            }
+            this._dragIdx = idx;
+            this._dragOverIdx = idx;
+            if (event?.dataTransfer) {
+                event.dataTransfer.effectAllowed = 'move';
+                event.dataTransfer.setData('text/plain', String(tracks[idx].playlist_track_id));
+            }
+            return true;
+        },
+
+        dragOver(event, idx) {
+            if (!this.isEditingCurrent() || this._dragIdx === null) return;
+            const tracks = this.currentPlaylist()?.tracks || [];
+            if (idx < 0 || idx >= tracks.length) return;
+            this._dragOverIdx = idx;
+            if (event?.dataTransfer) event.dataTransfer.dropEffect = 'move';
+            document.querySelectorAll('.playlist-track-row.drag-over').forEach(el => el.classList.remove('drag-over'));
+            if (idx !== this._dragIdx) event.currentTarget.classList.add('drag-over');
+        },
+
+        dropOn(idx) {
+            const fromIdx = this._dragIdx;
+            this.endDrag();
+            if (!Number.isInteger(fromIdx) || fromIdx === idx) return;
+            this.moveCurrentTrack(fromIdx, idx);
+        },
+
+        endDrag() {
+            document.querySelectorAll('.playlist-track-row.drag-over').forEach(el => el.classList.remove('drag-over'));
+            this._dragIdx = null;
+            this._dragOverIdx = null;
+        },
+
+        async moveCurrentTrack(fromIdx, toIdx) {
+            if (!this.isEditingCurrent()) return;
+            const playlist = this.currentPlaylist();
+            const playlistId = Number(playlist.id);
+            const previous = (playlist.tracks || []).slice();
+            if (fromIdx < 0 || fromIdx >= previous.length || toIdx < 0 || toIdx >= previous.length) return;
+            const next = previous.slice();
+            const [track] = next.splice(fromIdx, 1);
+            next.splice(toIdx, 0, track);
+            playlist.tracks = next;
+
+            const playlistTrackIds = this._playlistTrackIds(next);
+            if (playlistTrackIds.length !== next.length) {
+                playlist.tracks = previous;
+                return;
+            }
+
+            try {
+                const res = await fetch(`/api/player/playlists/${playlistId}/tracks`, {
+                    method: 'PUT',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: JSON.stringify({ playlist_track_ids: playlistTrackIds }),
+                });
+                if (!res.ok) throw new Error('reorder failed');
+                await this.reload();
+            } catch (err) {
+                if (Number(this.currentPlaylist()?.id) === playlistId) {
+                    this.currentPlaylist().tracks = previous;
+                }
+                console.warn(err);
+            }
+        },
+
+        startPointerReorder(event, idx) {
+            if (event.pointerType === 'mouse') return;
+            if (event.button && event.button !== 0) return;
+            const tracks = this.currentPlaylist()?.tracks || [];
+            if (!this.isEditingCurrent() || idx < 0 || idx >= tracks.length || !tracks[idx]?.playlist_track_id) return;
+            event.preventDefault();
+            this._endPointerReorder(false);
+            this._dragIdx = idx;
+            this._dragOverIdx = idx;
+            const handle = event.currentTarget;
+            try {
+                handle?.setPointerCapture?.(event.pointerId);
+            } catch (_) {}
+
+            this._pointerDragMove = (moveEvent) => {
+                moveEvent.preventDefault();
+                this._autoScrollDuringReorder(moveEvent.clientY);
+                const target = document
+                    .elementFromPoint(moveEvent.clientX, moveEvent.clientY)
+                    ?.closest?.('.playlist-track-row[data-playlist-index]');
+                const targetIdx = Number(target?.dataset?.playlistIndex);
+                const currentTracks = this.currentPlaylist()?.tracks || [];
+                if (!Number.isInteger(targetIdx) || targetIdx < 0 || targetIdx >= currentTracks.length) return;
+                this._dragOverIdx = targetIdx;
+                document.querySelectorAll('.playlist-track-row.drag-over').forEach(el => el.classList.remove('drag-over'));
+                if (targetIdx !== this._dragIdx) target.classList.add('drag-over');
+            };
+
+            this._pointerDragEnd = (endEvent) => {
+                try {
+                    if (handle?.hasPointerCapture?.(endEvent.pointerId)) handle.releasePointerCapture(endEvent.pointerId);
+                } catch (_) {}
+                this._endPointerReorder(true);
+            };
+
+            window.addEventListener('pointermove', this._pointerDragMove, { passive: false });
+            window.addEventListener('pointerup', this._pointerDragEnd, { passive: false });
+            window.addEventListener('pointercancel', this._pointerDragEnd, { passive: false });
+        },
+
+        _autoScrollDuringReorder(clientY) {
+            const scroller = document.getElementById('center-scroll');
+            if (!scroller) return;
+            const rect = scroller.getBoundingClientRect();
+            const edge = 52;
+            if (clientY < rect.top + edge) {
+                scroller.scrollTop -= Math.ceil((rect.top + edge - clientY) / 4);
+            } else if (clientY > rect.bottom - edge) {
+                scroller.scrollTop += Math.ceil((clientY - (rect.bottom - edge)) / 4);
+            }
+        },
+
+        _endPointerReorder(commit) {
+            if (this._pointerDragMove) window.removeEventListener('pointermove', this._pointerDragMove);
+            if (this._pointerDragEnd) {
+                window.removeEventListener('pointerup', this._pointerDragEnd);
+                window.removeEventListener('pointercancel', this._pointerDragEnd);
+            }
+            document.querySelectorAll('.playlist-track-row.drag-over').forEach(el => el.classList.remove('drag-over'));
+            const fromIdx = this._dragIdx;
+            const toIdx = this._dragOverIdx;
+            this._pointerDragMove = null;
+            this._pointerDragEnd = null;
+            this._dragIdx = null;
+            this._dragOverIdx = null;
+            if (commit && Number.isInteger(fromIdx) && Number.isInteger(toIdx) && fromIdx !== toIdx) {
+                this.moveCurrentTrack(fromIdx, toIdx);
+            }
+        },
+
         showCreate() {
             this.modal = { mode: 'create', title: '' };
         },

templates/player/shell.html

@@ -951,7 +951,23 @@
                         <span>/</span>
                         <span x-text="$store.playlists.displayTitle($store.library.currentPlaylist)"></span>
                     </div>
-                    <h1 class="section-title" x-text="$store.playlists.displayTitle($store.library.currentPlaylist)"></h1>
+                    <div class="playlist-detail-heading">
+                        <h1 class="section-title" x-text="$store.playlists.displayTitle($store.library.currentPlaylist)"></h1>
+                        <button class="release-action-btn secondary playlist-edit-toggle"
+                                x-show="$store.playlists.canEditCurrent()"
+                                x-cloak
+                                @click="$store.playlists.toggleEditCurrent()"
+                                :title="$store.playlists.isEditingCurrent() ? '{{ t.player_done }}' : '{{ t.player_edit }}'">
+                            <svg x-show="!$store.playlists.isEditingCurrent()" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                                <path d="M11 4H4a2 2 0 00-2 2v14a2 2 0 002 2h14a2 2 0 002-2v-7"/>
+                                <path d="M18.5 2.5a2.12 2.12 0 013 3L12 15l-4 1 1-4 9.5-9.5z"/>
+                            </svg>
+                            <svg x-show="$store.playlists.isEditingCurrent()" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                                <path d="M20 6L9 17l-5-5"/>
+                            </svg>
+                            <span x-text="$store.playlists.isEditingCurrent() ? '{{ t.player_done }}' : '{{ t.player_edit }}'"></span>
+                        </button>
+                    </div>
                     <div class="playlist-detail-meta"
                          x-show="$store.library.currentPlaylist.owner_name || $store.library.currentPlaylist.is_public">
                         <span x-show="$store.library.currentPlaylist.owner_name"
@@ -963,27 +979,61 @@
                     <template x-if="$store.library.currentPlaylist.description">
                         <p style="color:var(--text-subdued);margin-bottom:16px" x-text="$store.library.currentPlaylist.description"></p>
                     </template>
-                    <div class="track-list-header">
+                    <div class="track-list-header playlist-track-list-header"
+                         :class="{ editing: $store.playlists.isEditingCurrent() }">
+                        <span class="playlist-edit-cell"
+                              x-show="$store.playlists.isEditingCurrent()"
+                              x-cloak></span>
                         <span>#</span>
                         <span>{{ t.player_title }}</span>
                         <span></span>
                         <span></span>
                         <span style="text-align:right">{{ t.player_duration }}</span>
                     </div>
-                    <template x-for="(track, idx) in $store.library.currentPlaylist.tracks" :key="track.id">
-                        <div class="track-row"
-                             :class="{ playing: $store.player.currentTrack && $store.player.currentTrack.id === track.id }"
-                             @dblclick="$store.queue.playRelease($store.library.currentPlaylist.tracks, idx)">
+                    <template x-for="(track, idx) in $store.library.currentPlaylist.tracks" :key="track.playlist_track_id || (track.id + '-' + idx)">
+                        <div class="track-row playlist-track-row"
+                             :data-playlist-index="idx"
+                             :class="{ playing: $store.player.currentTrack && $store.player.currentTrack.id === track.id, editing: $store.playlists.isEditingCurrent(), dragging: $store.playlists._dragIdx === idx }"
+                             :draggable="$store.playlists.isEditingCurrent() && !!track.playlist_track_id"
+                             @dblclick="if (!$store.playlists.isEditingCurrent()) $store.queue.playRelease($store.library.currentPlaylist.tracks, idx)"
+                             @dragstart="if (!$store.playlists.startDrag($event, idx)) $event.preventDefault()"
+                             @dragend="$store.playlists.endDrag()"
+                             @dragover.prevent="$store.playlists.dragOver($event, idx)"
+                             @dragleave="$event.currentTarget.classList.remove('drag-over')"
+                             @drop.prevent="$event.currentTarget.classList.remove('drag-over'); $store.playlists.dropOn(idx)">
+                            <button class="playlist-track-remove"
+                                    x-show="$store.playlists.isEditingCurrent()"
+                                    x-cloak
+                                    @click.stop="$store.playlists.removeCurrentTrack(track, idx)"
+                                    title="{{ t.player_remove }}"
+                                    aria-label="{{ t.player_remove }}">
+                                <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                                    <line x1="18" y1="6" x2="6" y2="18"/>
+                                    <line x1="6" y1="6" x2="18" y2="18"/>
+                                </svg>
+                            </button>
                             <span class="track-num" x-text="idx + 1"></span>
-                            <div class="track-info">
-                                <div class="track-title" x-text="track.title"></div>
-                                <div class="track-artists-inline">
-                                    <template x-for="(artist, artistIdx) in $store.library.trackArtistLinks(track)" :key="artist.label + '-' + artist.id + '-' + artistIdx">
-                                        <span>
-                                            <template x-if="artistIdx > 0"><span>, </span></template>
-                                            <a class="artist-link" @click.stop="$store.library.openArtist(artist.id)" x-text="artist.label"></a>
-                                        </span>
-                                    </template>
+                            <div class="track-info playlist-track-info">
+                                <button class="playlist-drag-handle"
+                                        x-show="$store.playlists.isEditingCurrent() && !!track.playlist_track_id"
+                                        x-cloak
+                                        @mousedown.stop
+                                        @click.stop
+                                        @pointerdown.stop="$store.playlists.startPointerReorder($event, idx)"
+                                        title="{{ t.player_edit }}"
+                                        aria-label="{{ t.player_edit }}">
+                                    <svg viewBox="0 0 24 24" fill="currentColor"><circle cx="9" cy="6" r="1.5"/><circle cx="15" cy="6" r="1.5"/><circle cx="9" cy="12" r="1.5"/><circle cx="15" cy="12" r="1.5"/><circle cx="9" cy="18" r="1.5"/><circle cx="15" cy="18" r="1.5"/></svg>
+                                </button>
+                                <div class="playlist-track-copy">
+                                    <div class="track-title" x-text="track.title"></div>
+                                    <div class="track-artists-inline">
+                                        <template x-for="(artist, artistIdx) in $store.library.trackArtistLinks(track)" :key="artist.label + '-' + artist.id + '-' + artistIdx">
+                                            <span>
+                                                <template x-if="artistIdx > 0"><span>, </span></template>
+                                                <a class="artist-link" @click.stop="$store.library.openArtist(artist.id)" x-text="artist.label"></a>
+                                            </span>
+                                        </template>
+                                    </div>
                                 </div>
                             </div>
                             <span></span>

templates/player/styles.html

@@ -489,6 +489,25 @@ button.user-stat:hover {
     font-size: 13px;
 }
 
+.playlist-detail-heading {
+    display: flex;
+    align-items: flex-start;
+    justify-content: space-between;
+    gap: 12px;
+    margin-bottom: 14px;
+}
+
+.playlist-detail-heading .section-title {
+    min-width: 0;
+    margin-bottom: 0;
+    overflow-wrap: anywhere;
+}
+
+.playlist-edit-toggle {
+    flex: 0 0 auto;
+    margin-top: 4px;
+}
+
 .breadcrumb {
     display: flex;
     align-items: center;
@@ -735,6 +754,93 @@ button.user-stat:hover {
 .track-row:hover { background: var(--bg-hover); }
 .track-row.playing { color: var(--accent); }
 .track-row.playing .track-num { color: var(--accent); }
+.playlist-track-list-header.editing,
+.playlist-track-row.editing {
+    grid-template-columns: 32px 40px minmax(0, 1fr) minmax(0, 1fr) 154px 60px;
+}
+
+.playlist-track-row.editing {
+    cursor: grab;
+}
+
+.playlist-track-row.editing:active {
+    cursor: grabbing;
+}
+
+.playlist-track-row.dragging {
+    opacity: 0.45;
+}
+
+.playlist-track-row.drag-over {
+    border-top: 2px solid var(--accent);
+    margin-top: -2px;
+}
+
+.playlist-track-remove {
+    width: 28px;
+    height: 28px;
+    border: 0;
+    border-radius: 4px;
+    background: transparent;
+    color: var(--text-subdued);
+    cursor: pointer;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    padding: 0;
+    transition: color 0.15s, background 0.15s;
+}
+
+.playlist-track-remove:hover {
+    color: var(--text-primary);
+    background: var(--bg-active);
+}
+
+.playlist-track-remove svg {
+    width: 16px;
+    height: 16px;
+}
+
+.playlist-track-info {
+    display: flex;
+    align-items: center;
+    gap: 10px;
+}
+
+.playlist-track-copy {
+    min-width: 0;
+    overflow: hidden;
+}
+
+.playlist-drag-handle {
+    width: 24px;
+    height: 28px;
+    border: 0;
+    background: transparent;
+    color: var(--text-subdued);
+    cursor: grab;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    flex: 0 0 24px;
+    padding: 0;
+    touch-action: none;
+    user-select: none;
+}
+
+.playlist-drag-handle:active {
+    cursor: grabbing;
+}
+
+.playlist-drag-handle:hover {
+    color: var(--text-primary);
+}
+
+.playlist-drag-handle svg {
+    width: 14px;
+    height: 14px;
+}
+
 .track-row.shared-target {
     background: rgba(29, 185, 84, 0.12);
     box-shadow: inset 3px 0 0 var(--accent);
@@ -4233,6 +4339,16 @@ button.user-stat:hover {
         justify-content: flex-end;
     }
 
+    .playlist-track-list-header.editing,
+    .playlist-track-row.editing {
+        grid-template-columns: 30px 32px minmax(0, 1fr) auto 54px;
+    }
+
+    .playlist-track-list-header.editing span:nth-child(4),
+    .playlist-track-row.editing > span:nth-child(4) {
+        display: none;
+    }
+
     .history-table-head,
     .history-row.track-row {
         grid-template-columns: 44px minmax(0, 1fr) auto;
@@ -5158,6 +5274,26 @@ button.user-stat:hover {
         padding: 10px 6px;
     }
 
+    .playlist-detail-heading {
+        align-items: center;
+        gap: 8px;
+        margin-bottom: 12px;
+    }
+
+    .playlist-edit-toggle {
+        padding: 8px 10px;
+        margin-top: 0;
+    }
+
+    .playlist-track-row.editing {
+        grid-template-columns: 30px minmax(0, 1fr) auto;
+    }
+
+    .playlist-track-row.editing .track-num,
+    .playlist-track-row.editing > span:nth-child(4) {
+        display: none;
+    }
+
     .track-row > span:nth-child(3),
     .track-duration {
         display: none;