use shanty_db::entities::download_queue::DownloadStatus;
use shanty_db::{Database, queries};
use shanty_dl::backend::{AudioFormat, BackendConfig, DownloadBackend, DownloadResult, DownloadTarget, SearchResult};
use shanty_dl::error::DlResult;
use shanty_dl::queue::{run_queue, download_single};
use tempfile::TempDir;

/// Mock backend for testing without yt-dlp.
struct MockBackend {
    /// If true, downloads will fail.
    should_fail: bool,
}

impl MockBackend {
    fn new(should_fail: bool) -> Self {
        Self { should_fail }
    }
}

impl DownloadBackend for MockBackend {
    async fn check_available(&self) -> DlResult<()> {
        Ok(())
    }

    async fn search(&self, query: &str) -> DlResult<Vec<SearchResult>> {
        Ok(vec![SearchResult {
            url: format!("https://example.com/{}", query.replace(' ', "_")),
            title: query.to_string(),
            artist: Some("Test Artist".to_string()),
            duration: Some(180.0),
            source: "mock".to_string(),
        }])
    }

    async fn download(
        &self,
        target: &DownloadTarget,
        config: &BackendConfig,
    ) -> DlResult<DownloadResult> {
        if self.should_fail {
            return Err(shanty_dl::DlError::DownloadFailed("mock failure".into()));
        }

        let title = match target {
            DownloadTarget::Url(u) => u.clone(),
            DownloadTarget::Query(q) => q.clone(),
        };

        let file_name = format!("{}.{}", title.replace(' ', "_"), config.format);
        let file_path = config.output_dir.join(&file_name);
        std::fs::write(&file_path, b"fake audio data").unwrap();

        Ok(DownloadResult {
            file_path,
            title,
            artist: Some("Test Artist".into()),
            duration: Some(180.0),
            source_url: "https://example.com/test".into(),
        })
    }
}

async fn test_db() -> Database {
    Database::new("sqlite::memory:")
        .await
        .expect("failed to create test database")
}

#[tokio::test]
async fn test_queue_process_success() {
    let db = test_db().await;
    let dir = TempDir::new().unwrap();
    let backend = MockBackend::new(false);

    let config = BackendConfig {
        output_dir: dir.path().to_owned(),
        format: AudioFormat::Opus,
        cookies_path: None,
    };

    // Enqueue an item
    queries::downloads::enqueue(db.conn(), "Test Song", None, "mock")
        .await
        .unwrap();

    // Process queue
    let stats = run_queue(db.conn(), &backend, &config, false).await.unwrap();
    assert_eq!(stats.downloads_attempted, 1);
    assert_eq!(stats.downloads_completed, 1);
    assert_eq!(stats.downloads_failed, 0);

    // Verify status in DB
    let items = queries::downloads::list(db.conn(), Some(DownloadStatus::Completed))
        .await
        .unwrap();
    assert_eq!(items.len(), 1);
}

#[tokio::test]
async fn test_queue_process_failure() {
    let db = test_db().await;
    let dir = TempDir::new().unwrap();
    let backend = MockBackend::new(true);

    let config = BackendConfig {
        output_dir: dir.path().to_owned(),
        format: AudioFormat::Opus,
        cookies_path: None,
    };

    queries::downloads::enqueue(db.conn(), "Failing Song", None, "mock")
        .await
        .unwrap();

    let stats = run_queue(db.conn(), &backend, &config, false).await.unwrap();
    assert_eq!(stats.downloads_attempted, 1);
    assert_eq!(stats.downloads_failed, 1);

    // Check it's marked as failed
    let items = queries::downloads::list(db.conn(), Some(DownloadStatus::Failed))
        .await
        .unwrap();
    assert_eq!(items.len(), 1);
    assert!(items[0].error_message.is_some());
}

#[tokio::test]
async fn test_queue_dry_run() {
    let db = test_db().await;
    let dir = TempDir::new().unwrap();
    let backend = MockBackend::new(false);

    let config = BackendConfig {
        output_dir: dir.path().to_owned(),
        format: AudioFormat::Opus,
        cookies_path: None,
    };

    queries::downloads::enqueue(db.conn(), "Dry Run Song", None, "mock")
        .await
        .unwrap();

    let stats = run_queue(db.conn(), &backend, &config, true).await.unwrap();
    assert_eq!(stats.downloads_attempted, 1);
    assert_eq!(stats.downloads_skipped, 1);
    assert_eq!(stats.downloads_completed, 0);

    // No files should exist
    let entries: Vec<_> = std::fs::read_dir(dir.path()).unwrap().collect();
    assert!(entries.is_empty());
}

#[tokio::test]
async fn test_download_single_success() {
    let dir = TempDir::new().unwrap();
    let backend = MockBackend::new(false);

    let config = BackendConfig {
        output_dir: dir.path().to_owned(),
        format: AudioFormat::Mp3,
        cookies_path: None,
    };

    download_single(
        &backend,
        DownloadTarget::Query("Test Song".into()),
        &config,
        false,
    )
    .await
    .unwrap();

    // File should exist
    let entries: Vec<_> = std::fs::read_dir(dir.path())
        .unwrap()
        .filter_map(|e| e.ok())
        .collect();
    assert_eq!(entries.len(), 1);
}

#[tokio::test]
async fn test_queue_retry() {
    let db = test_db().await;

    // Enqueue and manually fail an item
    let item = queries::downloads::enqueue(db.conn(), "Retry Song", None, "mock")
        .await
        .unwrap();
    queries::downloads::update_status(db.conn(), item.id, DownloadStatus::Failed, Some("oops"))
        .await
        .unwrap();

    // Retry it
    queries::downloads::retry_failed(db.conn(), item.id)
        .await
        .unwrap();

    // Should be pending again with retry_count = 1
    let pending = queries::downloads::list(db.conn(), Some(DownloadStatus::Pending))
        .await
        .unwrap();
    assert_eq!(pending.len(), 1);
    assert_eq!(pending[0].retry_count, 1);
}

#[tokio::test]
async fn test_wanted_item_status_updated_on_download() {
    use shanty_db::entities::wanted_item::{ItemType, WantedStatus};

    let db = test_db().await;
    let dir = TempDir::new().unwrap();
    let backend = MockBackend::new(false);

    let config = BackendConfig {
        output_dir: dir.path().to_owned(),
        format: AudioFormat::Opus,
        cookies_path: None,
    };

    // Create a wanted item
    let wanted = queries::wanted::add(db.conn(), ItemType::Track, "Wanted Song", None, None, None, None)
        .await
        .unwrap();
    assert_eq!(wanted.status, WantedStatus::Wanted);

    // Enqueue download linked to the wanted item
    queries::downloads::enqueue(db.conn(), "Wanted Song", Some(wanted.id), "mock")
        .await
        .unwrap();

    // Process queue
    run_queue(db.conn(), &backend, &config, false).await.unwrap();

    // Wanted item should now be Downloaded
    let updated = queries::wanted::get_by_id(db.conn(), wanted.id)
        .await
        .unwrap();
    assert_eq!(updated.status, WantedStatus::Downloaded);
}