package repository

import (
	"butterfliu/internal/model"
	"database/sql"
)

// SongDetail is a DTO for API responses with joined artist/album names.
// Kept here temporarily for backward compatibility with service layer.
// Consider moving to model package in future refactoring.
type SongDetail = model.SongDetail

type LibraryRepository struct {
	db *sql.DB
}

func NewLibraryRepository(db *sql.DB) *LibraryRepository {
	return &LibraryRepository{db: db}
}

func (r *LibraryRepository) GetAll() ([]model.Library, error) {
	rows, err := r.db.Query("SELECT id, name, path, COALESCE(created_at, '1970-01-01T00:00:00Z'), COALESCE(updated_at, '1970-01-01T00:00:00Z') FROM libraries")
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	libraries := []model.Library{}
	for rows.Next() {
		var lib model.Library
		if err := rows.Scan(&lib.ID, &lib.Name, &lib.Path, &lib.CreatedAt, &lib.UpdatedAt); err != nil {
			return nil, err
		}
		libraries = append(libraries, lib)
	}

	return libraries, nil
}

func (r *LibraryRepository) GetByID(id int) (model.Library, error) {
	row := r.db.QueryRow("SELECT id, name, path, COALESCE(created_at, '1970-01-01T00:00:00Z'), COALESCE(updated_at, '1970-01-01T00:00:00Z') FROM libraries WHERE id = ?", id)
	var lib model.Library
	if err := row.Scan(&lib.ID, &lib.Name, &lib.Path, &lib.CreatedAt, &lib.UpdatedAt); err != nil {
		return model.Library{}, err
	}
	return lib, nil
}

func (r *LibraryRepository) Create(name, path string) (model.Library, error) {
	result, err := r.db.Exec("INSERT INTO libraries (name, path) VALUES (?, ?)", name, path)
	if err != nil {
		return model.Library{}, err
	}

	id, err := result.LastInsertId()
	if err != nil {
		return model.Library{}, err
	}

	return model.Library{
		ID:   int(id),
		Name: name,
		Path: path,
	}, nil
}

func (r *LibraryRepository) UpdateName(id int, name string) error {
	_, err := r.db.Exec("UPDATE libraries SET name = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?", name, id)
	return err
}

func (r *LibraryRepository) UpdatePath(id int, path string) error {
	_, err := r.db.Exec("UPDATE libraries SET path = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?", path, id)
	return err
}

func (r *LibraryRepository) Delete(id int) error {
	tx, err := r.db.Begin()
	if err != nil {
		return err
	}
	defer tx.Rollback()

	// Delete the library — CASCADE removes media_files and songs automatically
	_, err = tx.Exec("DELETE FROM libraries WHERE id = ?", id)
	if err != nil {
		return err
	}

	// Clean up orphan albums (no songs reference them)
	_, err = tx.Exec(`
		DELETE FROM albums WHERE id NOT IN (
			SELECT DISTINCT album_id FROM songs WHERE album_id IS NOT NULL
		)
	`)
	if err != nil {
		return err
	}

	// Clean up orphan artists (no songs and no albums reference them)
	_, err = tx.Exec(`
		DELETE FROM artists WHERE id NOT IN (
			SELECT DISTINCT artist_id FROM songs WHERE artist_id IS NOT NULL
			UNION
			SELECT DISTINCT artist_id FROM albums WHERE artist_id IS NOT NULL
		)
	`)
	if err != nil {
		return err
	}

	return tx.Commit()
}

func (r *LibraryRepository) GetSongsByLibraryWithDetails(libraryID int) ([]SongDetail, error) {
	rows, err := r.db.Query(`
		SELECT s.id, s.title, a.name as artist_name, al.title as album_title, s.duration, mf.path
		FROM songs s
		INNER JOIN media_files mf ON s.media_file_id = mf.id
		INNER JOIN artists a ON s.artist_id = a.id
		INNER JOIN albums al ON s.album_id = al.id
		WHERE mf.library_id = ?
		ORDER BY s.title
	`, libraryID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	songs := []SongDetail{}
	for rows.Next() {
		var song SongDetail
		if err := rows.Scan(&song.ID, &song.Title, &song.Artist, &song.Album, &song.Duration, &song.Path); err != nil {
			return nil, err
		}
		songs = append(songs, song)
	}
	return songs, nil
}

func (r *LibraryRepository) GetMediaFileByPath(path string) (model.MediaFile, error) {
	row := r.db.QueryRow(`
		SELECT id, path, library_id, 
		       COALESCE(file_size, 0), COALESCE(format, ''), 
		       COALESCE(bit_rate, 0), COALESCE(sample_rate, 0),
		       COALESCE(created_at, '1970-01-01T00:00:00Z'), 
		       COALESCE(updated_at, '1970-01-01T00:00:00Z')
		FROM media_files WHERE path = ?
	`)
	var mediaFile model.MediaFile
	if err := row.Scan(
		&mediaFile.ID, &mediaFile.Path, &mediaFile.LibraryID,
		&mediaFile.FileSize, &mediaFile.Format,
		&mediaFile.BitRate, &mediaFile.SampleRate,
		&mediaFile.CreatedAt, &mediaFile.UpdatedAt,
	); err != nil {
		return model.MediaFile{}, err
	}
	return mediaFile, nil
}

func (r *LibraryRepository) CreateMediaFile(path string, libraryID int) (model.MediaFile, error) {
	result, err := r.db.Exec("INSERT INTO media_files (path, library_id) VALUES (?, ?)", path, libraryID)
	if err != nil {
		return model.MediaFile{}, err
	}

	id, err := result.LastInsertId()
	if err != nil {
		return model.MediaFile{}, err
	}

	return model.MediaFile{
		ID:        int(id),
		Path:      path,
		LibraryID: libraryID,
	}, nil
}

func (r *LibraryRepository) GetArtistByName(name string) (model.Artist, error) {
	row := r.db.QueryRow("SELECT id, name FROM artists WHERE name = ?", name)
	var artist model.Artist
	if err := row.Scan(&artist.ID, &artist.Name); err != nil {
		return model.Artist{}, err
	}
	return artist, nil
}

func (r *LibraryRepository) CreateArtist(name string) (model.Artist, error) {
	result, err := r.db.Exec("INSERT INTO artists (name) VALUES (?)", name)
	if err != nil {
		return model.Artist{}, err
	}

	id, err := result.LastInsertId()
	if err != nil {
		return model.Artist{}, err
	}

	return model.Artist{
		ID:   int(id),
		Name: name,
	}, nil
}

func (r *LibraryRepository) GetAlbumByTitleAndArtist(title string, artistID int) (model.Album, error) {
	row := r.db.QueryRow(`
		SELECT id, title, artist_id, COALESCE(cover, ''), COALESCE(year, 0)
		FROM albums WHERE title = ? AND artist_id = ?
	`)
	var album model.Album
	if err := row.Scan(&album.ID, &album.Title, &album.ArtistID, &album.Cover, &album.Year); err != nil {
		return model.Album{}, err
	}
	return album, nil
}

func (r *LibraryRepository) CreateAlbum(title string, artistID int) (model.Album, error) {
	result, err := r.db.Exec("INSERT INTO albums (title, artist_id) VALUES (?, ?)", title, artistID)
	if err != nil {
		return model.Album{}, err
	}

	id, err := result.LastInsertId()
	if err != nil {
		return model.Album{}, err
	}

	return model.Album{
		ID:       int(id),
		Title:    title,
		ArtistID: artistID,
	}, nil
}

func (r *LibraryRepository) CreateSong(title string, artistID, albumID, duration, mediaFileID int) (model.Song, error) {
	result, err := r.db.Exec(
		"INSERT INTO songs (title, artist_id, album_id, duration, media_file_id) VALUES (?, ?, ?, ?, ?)",
		title, artistID, albumID, duration, mediaFileID,
	)
	if err != nil {
		return model.Song{}, err
	}

	id, err := result.LastInsertId()
	if err != nil {
		return model.Song{}, err
	}

	return model.Song{
		ID:          int(id),
		Title:       title,
		ArtistID:    artistID,
		AlbumID:     albumID,
		Duration:    duration,
		MediaFileID: mediaFileID,
	}, nil
}

func (r *LibraryRepository) GetArtists() ([]model.Artist, error) {
	rows, err := r.db.Query("SELECT id, name FROM artists")
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	artists := []model.Artist{}
	for rows.Next() {
		var artist model.Artist
		if err := rows.Scan(&artist.ID, &artist.Name); err != nil {
			return nil, err
		}
		artists = append(artists, artist)
	}
	return artists, nil
}

func (r *LibraryRepository) GetAlbums() ([]model.Album, error) {
	rows, err := r.db.Query("SELECT id, title, artist_id FROM albums")
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	albums := []model.Album{}
	for rows.Next() {
		var album model.Album
		if err := rows.Scan(&album.ID, &album.Title, &album.ArtistID); err != nil {
			return nil, err
		}
		albums = append(albums, album)
	}
	return albums, nil
}