#![allow(clippy::unwrap_used)]
//! Session durability tests: persistent archive, hint-keyword ranking,
//! per-signal windowed counts, and audit truncation.

use std::collections::HashMap;
use std::time::Duration;

use tidaldb::TidalDb;
use tidaldb::schema::{
    AgentPolicy, DecaySpec, EntityId, EntityKind, SchemaBuilder, Timestamp, Window,
};
use tidaldb::session::MAX_AUDIT_ENTRIES;

fn test_schema() -> tidaldb::schema::Schema {
    let mut builder = SchemaBuilder::new();

    for sig in &["view", "like", "reward", "skip"] {
        let _ = builder
            .signal(
                sig,
                EntityKind::Item,
                DecaySpec::Exponential {
                    half_life: Duration::from_secs(7 * 24 * 3600),
                },
            )
            .windows(&[Window::OneHour, Window::TwentyFourHours])
            .velocity(false)
            .add();
    }

    let _ = builder.session_policy(
        "default_policy",
        AgentPolicy {
            allowed_signals: vec!["reward".to_string(), "view".to_string()],
            denied_signals: vec!["skip".to_string()],
            max_session_duration: Duration::from_secs(3600),
            max_signals_per_session: 10_000,
        },
    );

    builder.build().unwrap()
}

// ── Test 1: Archived session readable after close and reopen ────────────────

#[test]
fn archived_session_readable_after_close_and_reopen() {
    let dir = tempfile::tempdir().unwrap();
    let schema = test_schema();

    let session_id;
    let written;
    {
        let db = TidalDb::builder()
            .with_data_dir(dir.path())
            .with_schema(schema.clone())
            .open()
            .unwrap();

        let handle = db
            .start_session(1, "agent-a", "default_policy", HashMap::new())
            .unwrap();
        session_id = handle.id;
        let ts = Timestamp::now();

        for i in 1u64..=3 {
            let mut meta = HashMap::new();
            meta.insert("title".to_string(), format!("item-{i}"));
            db.write_item_with_metadata(EntityId::new(i), &meta)
                .unwrap();
        }

        db.session_signal(&handle, "reward", EntityId::new(1), 1.0, ts, None)
            .unwrap();
        db.session_signal(&handle, "view", EntityId::new(2), 0.5, ts, None)
            .unwrap();

        let summary = db.close_session(handle).unwrap();
        written = summary.signals_written;

        db.close().unwrap();
    }

    // Reopen — snapshot must be readable from storage.
    {
        let db = TidalDb::builder()
            .with_data_dir(dir.path())
            .with_schema(schema)
            .open()
            .unwrap();

        let snap = db.session_snapshot(session_id).unwrap();
        assert_eq!(
            snap.signals_written, written,
            "signals_written survives reopen"
        );
        assert_eq!(snap.signals_written, 2);
        assert_eq!(snap.signals_rejected, 0);

        db.close().unwrap();
    }
}

// ── Test 2: Hint keywords boost matching items ───────────────────────────────

#[test]
fn hint_keywords_boost_matching_items() {
    let db = TidalDb::builder()
        .ephemeral()
        .with_schema(test_schema())
        .open()
        .unwrap();

    // Write 5 jazz items and 5 rock items.
    for i in 1u64..=5 {
        let mut meta = HashMap::new();
        meta.insert("genre".to_string(), "jazz".to_string());
        meta.insert("title".to_string(), format!("jazz-track-{i}"));
        db.write_item_with_metadata(EntityId::new(i), &meta)
            .unwrap();
    }
    for i in 6u64..=10 {
        let mut meta = HashMap::new();
        meta.insert("genre".to_string(), "rock".to_string());
        meta.insert("title".to_string(), format!("rock-track-{i}"));
        db.write_item_with_metadata(EntityId::new(i), &meta)
            .unwrap();
    }

    let handle = db
        .start_session(1, "agent-a", "default_policy", HashMap::new())
        .unwrap();
    let session_id = handle.id;
    let ts = Timestamp::now();

    // Signal with annotation hinting jazz preference.
    db.session_signal(
        &handle,
        "reward",
        EntityId::new(1),
        1.0,
        ts,
        Some("jazz fusion acoustic".to_string()),
    )
    .unwrap();

    // Query FOR SESSION.
    let query = tidaldb::query::retrieve::RetrieveBuilder::new(
        EntityKind::Item,
        tidaldb::query::retrieve::ProfileRef::new("hot"),
    )
    .limit(10)
    .for_session(session_id)
    .build()
    .unwrap();
    let results = db.retrieve(&query).unwrap();

    assert!(!results.items.is_empty(), "should return results");
    assert!(
        results.session_snapshot.is_some(),
        "FOR SESSION query must attach session snapshot"
    );

    // Jazz items (1–5) should appear in results (session hint matched metadata).
    let jazz_count = results
        .items
        .iter()
        .filter(|r| r.entity_id.as_u64() <= 5)
        .count();
    assert!(
        jazz_count > 0,
        "at least one jazz item should appear in FOR SESSION results"
    );

    db.close_session(handle).unwrap();
    db.close().unwrap();
}

// ── Test 3: Per-signal windowed counts in snapshot ───────────────────────────

#[test]
fn per_signal_snapshot_shows_windowed_counts() {
    let db = TidalDb::builder()
        .ephemeral()
        .with_schema(test_schema())
        .open()
        .unwrap();

    let mut meta = HashMap::new();
    meta.insert("title".to_string(), "item-1".to_string());
    db.write_item_with_metadata(EntityId::new(1), &meta)
        .unwrap();

    let handle = db
        .start_session(2, "agent-b", "default_policy", HashMap::new())
        .unwrap();
    let session_id = handle.id;
    let ts = Timestamp::now();

    // Write 5 "reward" signals.
    for _ in 0..5 {
        db.session_signal(&handle, "reward", EntityId::new(1), 1.0, ts, None)
            .unwrap();
    }

    // Write 3 "view" signals.
    for _ in 0..3 {
        db.session_signal(&handle, "view", EntityId::new(1), 0.5, ts, None)
            .unwrap();
    }

    let snap = db.session_snapshot(session_id).unwrap();

    assert!(
        snap.signals.contains_key("reward"),
        "reward should appear in signals map"
    );
    assert!(
        snap.signals.contains_key("view"),
        "view should appear in signals map"
    );

    let reward = &snap.signals["reward"];
    assert_eq!(
        reward.window_1h, 5,
        "reward window_1h should count 5 signals"
    );
    assert!(
        reward.decay_score > 0.0,
        "reward decay_score should be positive"
    );

    let view = &snap.signals["view"];
    assert_eq!(view.window_1h, 3, "view window_1h should count 3 signals");

    db.close_session(handle).unwrap();
    db.close().unwrap();
}

// ── Test 4: Audit truncation marker ─────────────────────────────────────────

#[test]
fn audit_truncation_marker_set_when_cap_exceeded() {
    let db = TidalDb::builder()
        .ephemeral()
        .with_schema(test_schema())
        .open()
        .unwrap();

    let mut meta = HashMap::new();
    meta.insert("title".to_string(), "item-1".to_string());
    db.write_item_with_metadata(EntityId::new(1), &meta)
        .unwrap();

    // Use a policy with a very large signal cap so it doesn't interfere.
    let handle = db
        .start_session(3, "agent-c", "default_policy", HashMap::new())
        .unwrap();
    let session_id = handle.id;
    let ts = Timestamp::now();

    // Write MAX_AUDIT_ENTRIES + 1 signals (all "reward" which is allowed).
    for _ in 0..=MAX_AUDIT_ENTRIES {
        let _ = db.session_signal(&handle, "reward", EntityId::new(1), 1.0, ts, None);
    }

    // audit_truncated flag is visible in the live snapshot.
    let snap = db.session_snapshot(session_id).unwrap();
    assert!(
        snap.audit_truncated,
        "audit_truncated should be true after exceeding MAX_AUDIT_ENTRIES"
    );

    // session_audit() returns the capped entries (MAX_AUDIT_ENTRIES).
    let entries = db.session_audit(session_id).unwrap();
    assert_eq!(
        entries.len(),
        MAX_AUDIT_ENTRIES,
        "audit log capped at MAX_AUDIT_ENTRIES"
    );

    db.close_session(handle).unwrap();
    db.close().unwrap();
}

// ── Test 5: Annotation timestamps preserved in snapshot ─────────────────────

#[test]
fn annotation_timestamps_preserved() {
    let db = TidalDb::builder()
        .ephemeral()
        .with_schema(test_schema())
        .open()
        .unwrap();

    let mut meta = HashMap::new();
    meta.insert("title".to_string(), "item-1".to_string());
    db.write_item_with_metadata(EntityId::new(1), &meta)
        .unwrap();

    let handle = db
        .start_session(4, "agent-d", "default_policy", HashMap::new())
        .unwrap();
    let session_id = handle.id;
    let ts = Timestamp::now();

    db.session_signal(
        &handle,
        "reward",
        EntityId::new(1),
        1.0,
        ts,
        Some("piano solo".to_string()),
    )
    .unwrap();

    let snap = db.session_snapshot(session_id).unwrap();
    assert_eq!(snap.annotations.len(), 1);
    let (ann_ts, ann_text) = &snap.annotations[0];
    assert!(*ann_ts > 0, "annotation timestamp should be non-zero");
    assert_eq!(ann_text, "piano solo");

    db.close_session(handle).unwrap();
    db.close().unwrap();
}

// ── Test 6: Active session state restored after crash ────────────────────────

/// Proves that an active (never-closed) session is restored from the WAL
/// journal after a simulated crash. The "crash" is simulated by dropping
/// the `TidalDb` without calling `close_session()` — the WAL has a
/// `SessionStart` and N `SessionSignal` records but no `SessionClose`,
/// so on reopen the session must appear as active with all signals intact.
#[test]
fn active_session_state_restored_after_crash() {
    let dir = tempfile::tempdir().unwrap();
    let schema = test_schema();

    let session_id;
    {
        let db = TidalDb::builder()
            .with_data_dir(dir.path())
            .with_schema(schema.clone())
            .open()
            .unwrap();

        // Write an item so session signals have a valid target.
        let mut meta = HashMap::new();
        meta.insert("title".to_string(), "item-1".to_string());
        db.write_item_with_metadata(EntityId::new(1), &meta)
            .unwrap();

        let handle = db
            .start_session(42, "agent-crash", "default_policy", HashMap::new())
            .unwrap();
        session_id = handle.id;
        let ts = Timestamp::now();

        // Write 4 "reward" signals and 3 "view" signals (7 total).
        for _ in 0..4 {
            db.session_signal(&handle, "reward", EntityId::new(1), 1.0, ts, None)
                .unwrap();
        }
        for _ in 0..3 {
            db.session_signal(&handle, "view", EntityId::new(1), 0.5, ts, None)
                .unwrap();
        }

        // Verify signals are live before "crash".
        let snap_before = db.session_snapshot(session_id).unwrap();
        assert_eq!(snap_before.signals_written, 7);

        // Simulate crash: drop the db without calling close_session().
        // The Drop impl flushes the WAL, but the session was never archived.
        drop(db);
    }

    // Reopen — the session should be restored as active from the WAL journal.
    {
        let db = TidalDb::builder()
            .with_data_dir(dir.path())
            .with_schema(schema)
            .open()
            .unwrap();

        // The session must appear in active_sessions().
        let active = db.active_sessions();
        let restored = active
            .iter()
            .find(|info| info.id == session_id)
            .expect("session should be restored as active after crash");
        assert_eq!(
            restored.user_id, 42,
            "restored session should have the original user_id"
        );
        assert_eq!(
            restored.signals_written, 7,
            "all 7 signals should be replayed from WAL"
        );

        // Snapshot must contain per-signal-type data.
        let snap = db.session_snapshot(session_id).unwrap();
        assert_eq!(
            snap.signals_written, 7,
            "snapshot signals_written must match total replayed signals"
        );

        let reward = snap
            .signals
            .get("reward")
            .expect("reward signal type should exist in restored snapshot");
        assert_eq!(
            reward.window_1h, 4,
            "reward window_1h should count 4 replayed signals"
        );
        assert!(
            reward.decay_score > 0.0,
            "reward decay_score should be positive after replay"
        );

        let view = snap
            .signals
            .get("view")
            .expect("view signal type should exist in restored snapshot");
        assert_eq!(
            view.window_1h, 3,
            "view window_1h should count 3 replayed signals"
        );
        assert!(
            view.decay_score > 0.0,
            "view decay_score should be positive after replay"
        );

        // Entity 1 should appear in signaled_entities.
        assert!(
            snap.signaled_entities.contains(&1),
            "entity 1 should be in signaled_entities after replay"
        );

        db.close().unwrap();
    }
}

// ── Test 6: Session metadata survives crash recovery ─────────────────────────

/// Verifies that `start_session` metadata (e.g. `{"tool": "planner"}`) is
/// rehydrated from the storage start record during WAL replay, so that
/// `session_snapshot().metadata` is populated after a crash.
#[test]
fn metadata_survives_crash() {
    let dir = tempfile::tempdir().unwrap();
    let schema = test_schema();

    let session_id;
    {
        let db = TidalDb::builder()
            .with_data_dir(dir.path())
            .with_schema(schema.clone())
            .open()
            .unwrap();

        let mut meta = HashMap::new();
        meta.insert("tool".to_string(), "planner".to_string());
        meta.insert("context".to_string(), "daily-feed".to_string());

        let handle = db
            .start_session(10, "agent-meta", "default_policy", meta)
            .unwrap();
        session_id = handle.id;

        // Write a signal so the WAL has a SessionSignal record too.
        let mut item_meta = HashMap::new();
        item_meta.insert("title".to_string(), "item-1".to_string());
        db.write_item_with_metadata(EntityId::new(1), &item_meta)
            .unwrap();
        let ts = Timestamp::now();
        db.session_signal(&handle, "reward", EntityId::new(1), 1.0, ts, None)
            .unwrap();

        // Simulate crash: drop without close_session().
        drop(db);
    }

    // Reopen — metadata must be present in the restored active session.
    {
        let db = TidalDb::builder()
            .with_data_dir(dir.path())
            .with_schema(schema)
            .open()
            .unwrap();

        let active = db.active_sessions();
        assert!(
            active.iter().any(|info| info.id == session_id),
            "session must be restored as active after crash"
        );

        let snap = db.session_snapshot(session_id).unwrap();
        assert_eq!(
            snap.metadata.get("tool").map(String::as_str),
            Some("planner"),
            "tool metadata must survive crash recovery"
        );
        assert_eq!(
            snap.metadata.get("context").map(String::as_str),
            Some("daily-feed"),
            "context metadata must survive crash recovery"
        );

        db.close().unwrap();
    }
}

// ── Test 7: Preference annotations survive crash recovery ────────────────────

/// Verifies that session signal annotations ("more jazz today") are replayed
/// from the WAL during crash recovery, so that `SessionContext::keywords` is
/// populated for FOR SESSION ranking after a restart.
#[test]
fn annotations_survive_crash() {
    let dir = tempfile::tempdir().unwrap();
    let schema = test_schema();

    let session_id;
    {
        let db = TidalDb::builder()
            .with_data_dir(dir.path())
            .with_schema(schema.clone())
            .open()
            .unwrap();

        let handle = db
            .start_session(11, "agent-ann", "default_policy", HashMap::new())
            .unwrap();
        session_id = handle.id;

        let mut item_meta = HashMap::new();
        item_meta.insert("genre".to_string(), "jazz".to_string());
        db.write_item_with_metadata(EntityId::new(1), &item_meta)
            .unwrap();
        let ts = Timestamp::now();

        // Write two annotated signals.
        db.session_signal(
            &handle,
            "reward",
            EntityId::new(1),
            1.0,
            ts,
            Some("more jazz today".to_string()),
        )
        .unwrap();
        db.session_signal(
            &handle,
            "view",
            EntityId::new(1),
            0.5,
            ts,
            Some("acoustic vibes".to_string()),
        )
        .unwrap();

        // Simulate crash.
        drop(db);
    }

    // Reopen — annotations must be present so FOR SESSION ranking can use them.
    {
        let db = TidalDb::builder()
            .with_data_dir(dir.path())
            .with_schema(schema)
            .open()
            .unwrap();

        let active = db.active_sessions();
        assert!(
            active.iter().any(|info| info.id == session_id),
            "session must be restored as active after crash"
        );

        let snap = db.session_snapshot(session_id).unwrap();
        assert_eq!(
            snap.annotations.len(),
            2,
            "both annotations must be replayed from WAL"
        );

        let texts: Vec<&str> = snap.annotations.iter().map(|(_, s)| s.as_str()).collect();
        assert!(
            texts.contains(&"more jazz today"),
            "jazz annotation must survive crash recovery"
        );
        assert!(
            texts.contains(&"acoustic vibes"),
            "acoustic annotation must survive crash recovery"
        );

        db.close().unwrap();
    }
}

// ── Test 8: WAL replay preserves signal counts exactly ───────────────────────

/// Property-like correctness test: write exactly K signals of one type into
/// an active session, "crash" (drop without close_session), reopen, and
/// verify the replayed count is exactly K — not K-1, not K+1.
///
/// This directly tests the acceptance criterion from the roadmap:
/// "WAL replay of session signals restores SessionSignalState accumulators
/// correctly."
#[test]
fn wal_replay_restores_signal_counts_exactly() {
    let dir = tempfile::tempdir().unwrap();
    let schema = test_schema();

    const K: u64 = 5;
    let session_id;
    {
        let db = TidalDb::builder()
            .with_data_dir(dir.path())
            .with_schema(schema.clone())
            .open()
            .unwrap();

        let mut meta = HashMap::new();
        meta.insert("title".to_string(), "target".to_string());
        db.write_item_with_metadata(EntityId::new(99), &meta)
            .unwrap();

        let handle = db
            .start_session(7, "agent-replay", "default_policy", HashMap::new())
            .unwrap();
        session_id = handle.id;
        let ts = Timestamp::now();

        // Write exactly K "reward" signals, all targeting the same entity.
        for _ in 0..K {
            db.session_signal(&handle, "reward", EntityId::new(99), 1.0, ts, None)
                .unwrap();
        }

        // Sanity check before "crash".
        let snap = db.session_snapshot(session_id).unwrap();
        assert_eq!(snap.signals_written, K);
        assert_eq!(snap.signals["reward"].window_1h, K);

        // Drop without close_session — session left active in WAL.
        drop(db);
    }

    // Reopen and verify exact replay.
    {
        let db = TidalDb::builder()
            .with_data_dir(dir.path())
            .with_schema(schema)
            .open()
            .unwrap();

        // Session must be active (not closed — no SessionClose in WAL).
        let active = db.active_sessions();
        assert!(
            active.iter().any(|info| info.id == session_id),
            "session must be restored as active"
        );

        let snap = db.session_snapshot(session_id).unwrap();

        // The critical assertion: exact signal count after WAL replay.
        assert_eq!(
            snap.signals_written, K,
            "total signals_written must be exactly {K} after replay"
        );

        let reward = snap
            .signals
            .get("reward")
            .expect("reward signal type must exist after replay");
        assert_eq!(
            reward.window_1h, K,
            "reward window_1h must be exactly {K} after replay"
        );

        // Only one entity was signaled.
        assert_eq!(
            snap.signaled_entities.len(),
            1,
            "exactly one entity should appear in signaled_entities"
        );
        assert_eq!(
            snap.signaled_entities[0], 99,
            "signaled entity should be 99"
        );

        // Decay score should be positive (signals were recent).
        assert!(
            reward.decay_score > 0.0,
            "decay_score must be positive for recently replayed signals"
        );

        db.close().unwrap();
    }
}