//! End-to-end SSO over HTTP: the real Cot application, a real PostgreSQL database and a fake
//! OpenID provider. One test function because the instance configuration is process-wide.
#[path = "support/fake_oidc.rs"]
mod fake_oidc;
mod support;
use cot::{
    AppBuilder,
    config::{DatabaseConfig, ProjectConfig},
    db::query,
    project::RegisterAppsContext,
    test::TestServerBuilder,
};
use fake_oidc::{CLIENT_ID, CLIENT_SECRET, Scenario};
use meguri::{
    access::{self, Config},
    identity::{self, BootstrapPasswords, SyncOptions},
    models::{ExternalIdentityRow, UserRow},
    oidc,
    web::MeguriApp,
};
use reqwest::{Client, Response, StatusCode, redirect::Policy};
use serde_json::{Value, json};
use support::IsolatedDatabase;

struct TestProject {
    database: String,
}
impl cot::Project for TestProject {
    fn config(&self, _: &str) -> cot::Result<ProjectConfig> {
        Ok(ProjectConfig::builder()
            .debug(false)
            .database(DatabaseConfig::builder().url(self.database.clone()).build())
            .build())
    }
    fn register_apps(&self, apps: &mut AppBuilder, _: &RegisterAppsContext) {
        apps.register_with_views(MeguriApp, "");
    }
}

fn cookies(response: &Response) -> Vec<String> {
    response
        .headers()
        .get_all("set-cookie")
        .iter()
        .map(|v| v.to_str().unwrap().to_owned())
        .collect()
}
fn cookie_value(response: &Response, name: &str) -> Option<String> {
    cookies(response).iter().find_map(|c| {
        let value = c.strip_prefix(&format!("{name}="))?.split(';').next()?;
        (!value.is_empty()).then(|| value.to_owned())
    })
}
fn location(response: &Response) -> String {
    response
        .headers()
        .get("location")
        .expect("redirect location")
        .to_str()
        .unwrap()
        .to_owned()
}
fn claims(subject: &str, name: &str, groups: &[&str]) -> Value {
    json!({
        "sub":subject,"preferred_username":name,"name":format!("{name} Person"),
        "email":format!("{name}@corp.test"),"groups":groups
    })
}

struct Harness {
    client: Client,
    base: String,
    idp: fake_oidc::Server,
}
impl Harness {
    async fn begin(&self) -> (String, String) {
        let response = self
            .client
            .get(format!("{}/api/oidc/login", self.base))
            .send()
            .await
            .unwrap();
        assert!(response.status().is_redirection(), "{}", response.status());
        let flow = cookies(&response)
            .into_iter()
            .find(|c| c.starts_with("meguri_oidc="))
            .unwrap();
        for attribute in ["HttpOnly", "SameSite=Lax", "Path=/api/oidc", "Max-Age=600"] {
            assert!(flow.contains(attribute), "{flow}");
        }
        let state = flow["meguri_oidc=".len()..].split(';').next().unwrap();
        (location(&response), state.to_owned())
    }
    async fn callback(&self, query: &str, cookie: Option<&str>) -> Response {
        let mut request = self
            .client
            .get(format!("{}/api/oidc/callback?{query}", self.base));
        if let Some(cookie) = cookie {
            request = request.header("cookie", format!("meguri_oidc={cookie}"));
        }
        request.send().await.unwrap()
    }
    async fn attempt(&self, scenario: Scenario) -> Response {
        let (url, state) = self.begin().await;
        let code = self.idp.authorize(&url, scenario);
        self.callback(&format!("code={code}&state={state}"), Some(&state))
            .await
    }
    async fn session(&self, token: &str) -> Value {
        self.client
            .get(format!("{}/api/session", self.base))
            .header("cookie", format!("meguri_session={token}"))
            .send()
            .await
            .unwrap()
            .json()
            .await
            .unwrap()
    }
    async fn signed_in(&self, response: &Response) -> String {
        assert!(response.status().is_redirection());
        assert_eq!(location(response), "/", "{:?}", cookies(response));
        cookie_value(response, "meguri_session").expect("session cookie")
    }
    fn refused(&self, response: &Response, code: &str) -> String {
        assert!(response.status().is_redirection());
        let target = location(response);
        assert!(
            target.starts_with(&format!("/?login_error={code}&ref=")),
            "{target}"
        );
        assert!(
            cookie_value(response, "meguri_session").is_none(),
            "a refused sign-in never sets a session"
        );
        target.split("ref=").nth(1).unwrap().to_owned()
    }
}

#[cot::e2e_test]
#[ignore = "requires MEGURI_TEST_DATABASE_URL and CREATEDB"]
async fn sso_login_over_http_validates_tokens_maps_groups_and_never_leaks_a_session() {
    let iso = IsolatedDatabase::new().await;
    let idp = fake_oidc::Server::start().await;
    let project = TestProject {
        database: iso.url().await,
    };
    let server = TestServerBuilder::new(project).start().await;
    let base = server.url();
    // The process-wide settings can only be known once both servers have addresses.
    // SAFETY: this binary has a single test function; nothing else reads the environment.
    unsafe {
        std::env::set_var("MEGURI_PUBLIC_URL", &base);
    }
    let config = Config::parse(&format!(
        r#"
oidc: {{issuer: '{}', client_id: {CLIENT_ID}}}
instance_admin_groups: ['/meguri/admins']
workspaces:
  - {{key: payments, name: Payments, admin_groups: ['/payments/leads'], member_groups: ['/payments/team']}}
  - {{key: search, name: Search, admin_groups: ['/search/leads'], member_groups: ['/search/team']}}
"#,
        idp.issuer()
    ))
    .unwrap();
    access::install(config.clone());
    oidc::install(oidc::Settings {
        config: config.oidc.clone().unwrap(),
        client_secret: CLIENT_SECRET.into(),
        redirect_uri: format!("{base}/api/oidc/callback"),
    });
    identity::sync_config(
        &iso.store,
        &config,
        SyncOptions {
            passwords: BootstrapPasswords::Derived,
            now: chrono::Utc::now(),
            allow_disable_all: false,
        },
    )
    .await
    .unwrap();
    let h = Harness {
        client: Client::builder().redirect(Policy::none()).build().unwrap(),
        base: base.clone(),
        idp,
    };
    let users = || async { UserRow::objects_count(&iso).await };

    // The login screen offers SSO only; password sign-in is switched off for this instance.
    let session: Value = h
        .client
        .get(format!("{base}/api/session"))
        .send()
        .await
        .unwrap()
        .json()
        .await
        .unwrap();
    assert_eq!(session["auth"], json!({"oidc":true,"password":false}));
    assert!(session["user"].is_null());
    let password = h
        .client
        .post(format!("{base}/api/login"))
        .header("origin", &base)
        .json(&json!({"username":"anyone","password":"anything-at-all"}))
        .send()
        .await
        .unwrap();
    assert_eq!(password.status(), StatusCode::UNAUTHORIZED);
    // Registration and workspace creation no longer exist.
    for (path, expected) in [("/api/register", StatusCode::NOT_FOUND)] {
        let response = h
            .client
            .post(format!("{base}{path}"))
            .header("origin", &base)
            .json(&json!({}))
            .send()
            .await
            .unwrap();
        assert_eq!(response.status(), expected, "{path}");
    }

    // Happy path: an employee of Payments signs in and gets exactly that.
    let (url, _) = h.begin().await;
    let url = reqwest::Url::parse(&url).unwrap();
    assert_eq!(url.path(), "/realms/corp/protocol/openid-connect/auth");
    let query: std::collections::HashMap<_, _> = url.query_pairs().into_owned().collect();
    assert_eq!(query["redirect_uri"], format!("{base}/api/oidc/callback"));
    assert!(query["state"].len() >= 32 && query["nonce"].len() >= 32);
    let response = h
        .attempt(Scenario::new(claims(
            "u-1",
            "carol",
            &["/payments/team", "/other"],
        )))
        .await;
    let token = h.signed_in(&response).await;
    assert!(
        cookies(&response)
            .iter()
            .any(|c| c.starts_with("meguri_session=")
                && c.contains("HttpOnly")
                && c.contains("SameSite=Lax"))
    );
    assert!(
        cookies(&response)
            .iter()
            .any(|c| c.starts_with("meguri_oidc=;") && c.contains("Max-Age=0")),
        "the one-time flow cookie is cleared"
    );
    let session = h.session(&token).await;
    assert_eq!(session["user"]["username"], "carol");
    assert_eq!(session["user"]["email"], "carol@corp.test");
    assert_eq!(session["user"]["instance_admin"], false);
    assert_eq!(session["user"]["has_password"], false);
    let workspaces: Value = h
        .client
        .get(format!("{base}/api/workspaces"))
        .header("cookie", format!("meguri_session={token}"))
        .send()
        .await
        .unwrap()
        .json()
        .await
        .unwrap();
    assert_eq!(workspaces["workspaces"].as_array().unwrap().len(), 1);
    assert_eq!(workspaces["workspaces"][0]["key"], "payments");
    // The administration API answers 403 to an ordinary employee.
    let admin = h
        .client
        .get(format!("{base}/api/admin/overview"))
        .header("cookie", format!("meguri_session={token}"))
        .send()
        .await
        .unwrap();
    assert_eq!(admin.status(), StatusCode::FORBIDDEN);
    assert_eq!(users().await, 1);

    // Instance administrators and workspace leads come from their groups.
    let response = h
        .attempt(Scenario::new(claims("u-2", "root", &["/meguri/admins"])))
        .await;
    let admin_token = h.signed_in(&response).await;
    assert_eq!(
        h.session(&admin_token).await["user"]["instance_admin"],
        true
    );
    let overview: Value = h
        .client
        .get(format!("{base}/api/admin/overview"))
        .header("cookie", format!("meguri_session={admin_token}"))
        .send()
        .await
        .unwrap()
        .json()
        .await
        .unwrap();
    assert_eq!(overview["workspaces"].as_array().unwrap().len(), 2);
    assert_eq!(overview["config"]["oidc_issuer"], idp_issuer(&h));

    // Groups can come from userinfo when the ID token does not carry them.
    let mut scenario =
        Scenario::new(json!({"sub":"u-3","preferred_username":"lena","email":"lena@corp.test"}));
    scenario.userinfo = Some(json!({"sub":"u-3","groups":["/search/leads"]}));
    let response = h.attempt(scenario).await;
    let lena = h.signed_in(&response).await;
    assert_eq!(h.session(&lena).await["user"]["username"], "lena");
    assert_eq!(h.idp.state.lock().unwrap().userinfo_requests, 1);

    // Unmapped users and a provider that sends no groups get the same explanation and no account.
    let before = users().await;
    let reference = h.refused(
        &h.attempt(Scenario::new(claims("u-4", "stranger", &["/unknown"])))
            .await,
        "no_access",
    );
    assert_eq!(reference.len(), 8);
    h.refused(
        &h.attempt(Scenario::new(
            json!({"sub":"u-5","preferred_username":"nogroups"}),
        ))
        .await,
        "no_access",
    );
    assert_eq!(users().await, before);

    // Everything that can be wrong with a token or callback is refused without a session.
    let mut wrong_issuer = Scenario::new(claims("u-6", "mallory", &["/payments/team"]));
    wrong_issuer.issuer = Some("https://evil.example/realms/corp".into());
    let mut wrong_audience = Scenario::new(claims("u-6", "mallory", &["/payments/team"]));
    wrong_audience.audience = Some(json!("another-client"));
    let mut expired = Scenario::new(claims("u-6", "mallory", &["/payments/team"]));
    expired.expires_in = -600;
    let mut wrong_nonce = Scenario::new(claims("u-6", "mallory", &["/payments/team"]));
    wrong_nonce.nonce = Some("replayed-nonce".into());
    let mut bad_signature = Scenario::new(claims("u-6", "mallory", &["/payments/team"]));
    bad_signature.corrupt_signature = true;
    for scenario in [
        wrong_issuer,
        wrong_audience,
        expired,
        wrong_nonce,
        bad_signature,
    ] {
        h.refused(&h.attempt(scenario).await, "failed");
    }
    let mut broken = Scenario::new(claims("u-6", "mallory", &["/payments/team"]));
    broken.token_status = 500;
    h.refused(&h.attempt(broken).await, "failed");
    assert!(
        !query!(ExternalIdentityRow,$subject=="u-6".to_owned())
            .exists(&iso.store.db)
            .await
            .unwrap()
    );

    // Flow protections: state cookie binding, one-time use, missing and foreign state.
    let good = || Scenario::new(claims("u-7", "dave", &["/payments/team"]));
    let (url, state) = h.begin().await;
    let code = h.idp.authorize(&url, good());
    h.refused(
        &h.callback(
            &format!("code={code}&state={state}"),
            Some("0".repeat(64).as_str()),
        )
        .await,
        "failed",
    );
    let (url, state) = h.begin().await;
    let code = h.idp.authorize(&url, good());
    h.refused(
        &h.callback(&format!("code={code}&state={state}"), None)
            .await,
        "failed",
    );
    let (url, state) = h.begin().await;
    let code = h.idp.authorize(&url, good());
    h.signed_in(
        &h.callback(&format!("code={code}&state={state}"), Some(&state))
            .await,
    )
    .await;
    let code = h.idp.authorize(&url, good());
    h.refused(
        &h.callback(&format!("code={code}&state={state}"), Some(&state))
            .await,
        "failed",
    );
    h.refused(
        &h.callback("error=access_denied&state=x", Some("x")).await,
        "failed",
    );
    h.refused(&h.callback("", None).await, "failed");

    // A user whose groups were revoked is refused at the next sign-in and loses access at once.
    let response = h
        .attempt(Scenario::new(claims("u-1", "carol", &["/search/team"])))
        .await;
    h.signed_in(&response).await;
    let response = h
        .attempt(Scenario::new(claims("u-1", "carol", &["/unknown"])))
        .await;
    h.refused(&response, "no_access");
    let row = query!(UserRow,$username=="carol".to_owned())
        .get(&iso.store.db)
        .await
        .unwrap()
        .unwrap();
    let id = row.id;
    assert!(
        !query!(meguri::models::WorkspaceMemberRow,$user_id==id)
            .exists(&iso.store.db)
            .await
            .unwrap()
    );
    drop(h);
    server.close().await;
    iso.drop().await;
}

fn idp_issuer(h: &Harness) -> String {
    h.idp.issuer()
}

trait Count {
    async fn objects_count(iso: &IsolatedDatabase) -> usize;
}
impl Count for UserRow {
    async fn objects_count(iso: &IsolatedDatabase) -> usize {
        use cot::db::Model;
        UserRow::objects().all(&iso.store.db).await.unwrap().len()
    }
}