Furumi init

src/agent/metadata.rs

@@ -0,0 +1,169 @@
+use std::path::Path;
+
+use symphonia::core::{
+    codecs::CODEC_TYPE_NULL,
+    formats::FormatOptions,
+    io::MediaSourceStream,
+    meta::{MetadataOptions, StandardTagKey},
+    probe::Hint,
+};
+
+use super::dto::RawMetadata;
+
+/// Extract metadata from an audio file.
+///
+/// For MP3, falls back to the `id3` crate when Symphonia cannot probe the file
+/// (e.g. ID3 tag with large embedded cover art exceeds Symphonia's probe limit).
+///
+/// Must be called from a blocking context (`spawn_blocking`).
+pub fn extract(path: &Path) -> anyhow::Result<RawMetadata> {
+    match extract_via_symphonia(path) {
+        Ok(meta) => Ok(meta),
+        Err(e) => {
+            let is_mp3 = path
+                .extension()
+                .and_then(|e| e.to_str())
+                .map(|e| e.eq_ignore_ascii_case("mp3"))
+                .unwrap_or(false);
+            if is_mp3 {
+                tracing::debug!(error = %e, "Symphonia failed on MP3, falling back to id3 crate");
+                extract_mp3_via_id3(path)
+            } else {
+                Err(e)
+            }
+        }
+    }
+}
+
+fn extract_via_symphonia(path: &Path) -> anyhow::Result<RawMetadata> {
+    let file = std::fs::File::open(path)?;
+    let mss = MediaSourceStream::new(Box::new(file), Default::default());
+
+    let mut hint = Hint::new();
+    if let Some(ext) = path.extension().and_then(|e| e.to_str()) {
+        hint.with_extension(ext);
+    }
+
+    let mut probed = symphonia::default::get_probe().format(
+        &hint,
+        mss,
+        &FormatOptions {
+            enable_gapless: false,
+            ..Default::default()
+        },
+        &MetadataOptions::default(),
+    )?;
+
+    let mut meta = RawMetadata::default();
+
+    // Check metadata side-data (e.g. ID3 tags probed before format)
+    if let Some(rev) = probed.metadata.get().as_ref().and_then(|m| m.current()) {
+        extract_tags(rev.tags(), &mut meta);
+    }
+
+    // Also check format-embedded metadata
+    if let Some(rev) = probed.format.metadata().current() {
+        if meta.title.is_none() {
+            extract_tags(rev.tags(), &mut meta);
+        }
+    }
+
+    // Duration
+    meta.duration_secs = probed
+        .format
+        .tracks()
+        .iter()
+        .find(|t| t.codec_params.codec != CODEC_TYPE_NULL)
+        .and_then(|t| {
+            let n_frames = t.codec_params.n_frames?;
+            let tb = t.codec_params.time_base?;
+            Some(n_frames as f64 * tb.numer as f64 / tb.denom as f64)
+        });
+
+    Ok(meta)
+}
+
+/// Read MP3 tags via the `id3` crate. Duration is not available this way.
+fn extract_mp3_via_id3(path: &Path) -> anyhow::Result<RawMetadata> {
+    use id3::TagLike;
+
+    let tag =
+        id3::Tag::read_from_path(path).map_err(|e| anyhow::anyhow!("id3 read failed: {}", e))?;
+
+    let mut meta = RawMetadata::default();
+    meta.title = tag.title().map(|s| fix_encoding(s.to_owned()));
+    meta.artist = tag.artist().map(|s| fix_encoding(s.to_owned()));
+    meta.album = tag.album().map(|s| fix_encoding(s.to_owned()));
+    meta.year = tag.year().and_then(|y| u32::try_from(y).ok());
+    meta.track_number = tag.track();
+    meta.genre = tag.genre().map(|s: &str| fix_encoding(s.to_owned()));
+
+    Ok(meta)
+}
+
+fn extract_tags(tags: &[symphonia::core::meta::Tag], meta: &mut RawMetadata) {
+    for tag in tags {
+        let value = fix_encoding(tag.value.to_string());
+        if let Some(key) = tag.std_key {
+            match key {
+                StandardTagKey::TrackTitle => {
+                    if meta.title.is_none() {
+                        meta.title = Some(value);
+                    }
+                }
+                StandardTagKey::Artist | StandardTagKey::Performer => {
+                    if meta.artist.is_none() {
+                        meta.artist = Some(value);
+                    }
+                }
+                StandardTagKey::Album => {
+                    if meta.album.is_none() {
+                        meta.album = Some(value);
+                    }
+                }
+                StandardTagKey::TrackNumber => {
+                    if meta.track_number.is_none() {
+                        meta.track_number = value.parse().ok();
+                    }
+                }
+                StandardTagKey::Date | StandardTagKey::OriginalDate => {
+                    if meta.year.is_none() {
+                        meta.year = value[..4.min(value.len())].parse().ok();
+                    }
+                }
+                StandardTagKey::Genre => {
+                    if meta.genre.is_none() {
+                        meta.genre = Some(value);
+                    }
+                }
+                _ => {}
+            }
+        }
+    }
+}
+
+/// Heuristic to fix mojibake (CP1251 bytes interpreted as Latin-1/Windows-1252).
+fn fix_encoding(s: String) -> String {
+    let bytes: Vec<u8> = s
+        .chars()
+        .map(|c| c as u32)
+        .filter(|&c| c <= 255)
+        .map(|c| c as u8)
+        .collect();
+
+    if bytes.len() != s.chars().count() {
+        return s;
+    }
+
+    let has_mojibake = bytes.iter().any(|&b| b >= 0xC0);
+    if !has_mojibake {
+        return s;
+    }
+
+    let (decoded, _, errors) = encoding_rs::WINDOWS_1251.decode(&bytes);
+    if errors {
+        return s;
+    }
+
+    decoded.into_owned()
+}