use musicfs_cache::{VirtualTree, ROOT_INODE};
use musicfs_cas::{CasConfig, CasStore};
use musicfs_core::{HealthStatus, OriginId, OriginType, RealPath};
use musicfs_origins::{HealthMonitor, LocalOrigin, OriginRegistry};
use musicfs_test_utils::{FaultyOrigin, FailMode};
use std::collections::HashMap;
use std::io::ErrorKind;
use std::path::{Path, PathBuf};
use std::sync::Arc;
use std::time::{Duration, Instant};
use tempfile::TempDir;

fn setup_test_file(dir: &TempDir, name: &str, content: &[u8]) -> PathBuf {
    let path = dir.path().join(name);
    std::fs::write(&path, content).unwrap();
    path
}

async fn setup_cas(dir: &Path) -> CasStore {
    CasStore::open(CasConfig {
        chunks_dir: dir.join("chunks"),
        max_size: 100 * 1024 * 1024,
        shard_levels: 2,
    })
    .await
    .unwrap()
}

fn create_faulty_origin(id: &str, dir: &TempDir, mode: FailMode) -> Arc<FaultyOrigin> {
    let inner = Arc::new(LocalOrigin::new(OriginId::from(id), dir.path().to_path_buf()));
    Arc::new(FaultyOrigin::new(inner, mode))
}

#[tokio::test]
async fn test_sqlite_integrity_check_detects_corruption() {
    todo!("Issue 2.4: Implement Database::open_with_integrity_check()")
}

#[tokio::test]
async fn test_tantivy_corruption_triggers_rebuild() {
    todo!("Issue 2.4: Implement SearchIndex::open_with_recovery()")
}

#[tokio::test]
async fn test_sled_corruption_triggers_repair() {
    todo!("Issue 3.5: Implement sled recovery in CasStore::open()")
}

#[tokio::test]
async fn test_cas_put_handles_enospc() {
    let dir = TempDir::new().unwrap();
    let store = CasStore::open(CasConfig {
        chunks_dir: dir.path().join("chunks"),
        max_size: 100,
        shard_levels: 2,
    })
    .await
    .unwrap();

    let large_data = vec![0u8; 1000];
    let result = store.put(&large_data).await;
    
    assert!(result.is_err(), "Issue 2.8: CasStore should pre-check space and reject oversized write");
}

#[test]
fn test_poisoned_tree_lock_returns_eio_not_panic() {
    use std::sync::{Arc, RwLock};
    use std::thread;

    let lock = Arc::new(RwLock::new(42));
    let lock_clone = lock.clone();

    let handle = thread::spawn(move || {
        let _guard = lock_clone.write().unwrap();
        panic!("writer panic");
    });

    let _ = handle.join();

    let result = lock.read();
    assert!(result.is_ok(), "Issue 2.9: Lock access after panic should return EIO, not poison error");
}

#[test]
fn test_parking_lot_rwlock_survives_panic() {
    use parking_lot::RwLock;
    use std::sync::Arc;
    use std::thread;

    let tree = Arc::new(RwLock::new(VirtualTree::new()));
    let tree_clone = tree.clone();

    let handle = thread::spawn(move || {
        let _guard = tree_clone.write();
        panic!("writer panic");
    });

    let _ = handle.join();

    assert!(tree.read().get(ROOT_INODE).is_some(), "parking_lot RwLock should survive writer panic");
}

#[tokio::test]
async fn test_failover_on_primary_death() {
    let primary_dir = TempDir::new().unwrap();
    let backup_dir = TempDir::new().unwrap();
    setup_test_file(&primary_dir, "test.txt", b"primary");
    setup_test_file(&backup_dir, "test.txt", b"backup");

    let primary = create_faulty_origin("primary", &primary_dir, FailMode::ReturnError(ErrorKind::ConnectionRefused));
    let backup = create_faulty_origin("backup", &backup_dir, FailMode::Healthy);

    let mut thresholds = HashMap::new();
    thresholds.insert(OriginType::Local, 1);
    let monitor = Arc::new(HealthMonitor::new(Duration::from_secs(30)).with_per_type_thresholds(thresholds));
    let registry = Arc::new(OriginRegistry::new(monitor.clone()));

    registry.register(primary.clone(), 1);
    registry.register(backup.clone(), 2);

    monitor.check_now(&OriginId::from("primary")).await;
    monitor.check_now(&OriginId::from("backup")).await;

    assert!(registry.health().is_unhealthy(&OriginId::from("primary")));
    assert!(registry.health().is_healthy(&OriginId::from("backup")));

    let path = RealPath {
        origin_id: OriginId::from("backup"),
        path: PathBuf::from("/test.txt"),
    };
    let candidates = registry.route_all(&path);
    assert_eq!(candidates.len(), 1);
    assert_eq!(candidates[0].id(), &OriginId::from("backup"));
}

#[tokio::test]
async fn test_origin_recovery_resumes_routing() {
    let dir = TempDir::new().unwrap();
    setup_test_file(&dir, "test.txt", b"content");

    let faulty = create_faulty_origin("recovering", &dir, FailMode::ReturnError(ErrorKind::ConnectionRefused));

    let mut thresholds = HashMap::new();
    thresholds.insert(OriginType::Local, 1);
    let monitor = Arc::new(HealthMonitor::new(Duration::from_secs(30)).with_per_type_thresholds(thresholds));
    monitor.add_origin(faulty.clone());

    monitor.check_now(&OriginId::from("recovering")).await;
    assert_eq!(monitor.get_state(&OriginId::from("recovering")).unwrap().status, HealthStatus::Unhealthy);

    faulty.set_mode(FailMode::Healthy);
    monitor.check_now(&OriginId::from("recovering")).await;

    assert_eq!(monitor.get_state(&OriginId::from("recovering")).unwrap().status, HealthStatus::Healthy);
    assert_eq!(monitor.get_state(&OriginId::from("recovering")).unwrap().consecutive_failures, 0);
}

#[tokio::test]
async fn test_local_origin_health_check_has_timeout() {
    let dir = TempDir::new().unwrap();
    setup_test_file(&dir, "test.txt", b"content");

    let slow = create_faulty_origin("slow", &dir, FailMode::TimeoutMs(5_000));

    let monitor = Arc::new(HealthMonitor::new(Duration::from_secs(30)));
    monitor.add_origin(slow.clone());

    let start = Instant::now();
    monitor.check_now(&OriginId::from("slow")).await;
    let elapsed = start.elapsed();

    assert!(elapsed < Duration::from_secs(2), 
        "Issue 4.2.1: Health check should timeout in <2s, took {:?}", elapsed);
    
    let state = monitor.get_state(&OriginId::from("slow")).unwrap();
    assert_eq!(state.status, HealthStatus::Unhealthy);
}

#[tokio::test]
async fn test_health_checks_run_in_parallel() {
    let slow1_dir = TempDir::new().unwrap();
    let slow2_dir = TempDir::new().unwrap();
    let slow3_dir = TempDir::new().unwrap();

    let slow1 = create_faulty_origin("slow1", &slow1_dir, FailMode::TimeoutMs(200));
    let slow2 = create_faulty_origin("slow2", &slow2_dir, FailMode::TimeoutMs(200));
    let slow3 = create_faulty_origin("slow3", &slow3_dir, FailMode::TimeoutMs(200));

    let monitor = Arc::new(HealthMonitor::new(Duration::from_secs(30)));
    monitor.add_origin(slow1);
    monitor.add_origin(slow2);
    monitor.add_origin(slow3);

    let start = Instant::now();
    monitor.check_all().await;
    let elapsed = start.elapsed();

    assert!(elapsed < Duration::from_millis(350), "Issue 4.2.2: check_all() should run in parallel (sequential would take ~600ms), took {:?}", elapsed);
}

#[tokio::test]
async fn test_tantivy_survives_uncommitted_crash() {
    todo!("Issue 5.2: Implement tantivy crash recovery test")
}

#[tokio::test]
async fn test_fd_exhaustion_handling() {
    todo!("Issue 5.3: Implement fd exhaustion test with rlimit")
}

#[tokio::test]
async fn test_corrupt_chunk_auto_refetched() {
    let dir = TempDir::new().unwrap();
    let origin_dir = TempDir::new().unwrap();
    setup_test_file(&origin_dir, "test.flac", b"original audio data");

    let store = setup_cas(dir.path()).await;
    let data = b"chunk data";
    let hash = store.put(data).await.unwrap();

    let hex = hash.as_hex();
    let chunk_path = dir.path().join("chunks").join(&hex[0..2]).join(&hex[2..4]).join(&hex);
    let mut corrupted = std::fs::read(&chunk_path).unwrap();
    corrupted[0] = corrupted[0].wrapping_add(1);
    std::fs::write(&chunk_path, &corrupted).unwrap();

    let result = store.get(&hash).await;
    
    assert!(result.is_ok(), "Issue 6.4: Corrupted chunk should be auto-refetched from origin");
}

#[tokio::test]
async fn test_missing_chunk_triggers_origin_fetch() {
    todo!("Issue 6.4: Implement missing chunk origin fetch")
}

#[tokio::test]
async fn test_passthrough_mode_when_cache_disk_dead() {
    todo!("Issue 6.6: Implement passthrough mode")
}

#[test]
fn test_systemd_service_has_execstoppost() {
    let service_path = std::path::Path::new("../../../systemd/musicfs.service");
    if !service_path.exists() {
        panic!("Issue 3.7: systemd/musicfs.service does not exist");
    }
    
    let content = std::fs::read_to_string(service_path).unwrap();
    assert!(content.contains("ExecStopPost") || content.contains("fusermount"), 
            "Issue 3.7: Service file should have ExecStopPost with fusermount for cleanup");
}