package persistence

import (
	"context"
	"database/sql"
	"slices"

	. "github.com/Masterminds/squirrel"
	"github.com/deluan/rest"
	"github.com/navidrome/navidrome/log"
	"github.com/navidrome/navidrome/model"
	"github.com/navidrome/navidrome/utils/slice"
)

type playlistTrackRepository struct {
	sqlRepository
	playlistId   string
	playlist     *model.Playlist
	playlistRepo *playlistRepository
}

type dbPlaylistTrack struct {
	dbMediaFile
	*model.PlaylistTrack `structs:",flatten"`
}

func (t *dbPlaylistTrack) PostScan() error {
	if err := t.dbMediaFile.PostScan(); err != nil {
		return err
	}
	t.PlaylistTrack.MediaFile = *t.dbMediaFile.MediaFile
	t.PlaylistTrack.MediaFile.ID = t.MediaFileID
	return nil
}

type dbPlaylistTracks []dbPlaylistTrack

func (t dbPlaylistTracks) toModels() model.PlaylistTracks {
	return slice.Map(t, func(trk dbPlaylistTrack) model.PlaylistTrack {
		return *trk.PlaylistTrack
	})
}

func (r *playlistRepository) Tracks(ctx context.Context, playlistId string, refreshSmartPlaylist bool) model.PlaylistTrackRepository {
	p := &playlistTrackRepository{}
	p.playlistRepo = r
	p.playlistId = playlistId
	p.db = r.db
	p.tableName = "playlist_tracks"
	p.registerModel(&model.PlaylistTrack{}, map[string]filterFunc{
		"missing":    booleanFilter,
		"library_id": libraryIdFilter,
	})
	p.setSortMappings(
		map[string]string{
			"id":           "playlist_tracks.id",
			"artist":       "order_artist_name",
			"album_artist": "order_album_artist_name",
			"album":        "order_album_name, album_id, disc_number, track_number, order_artist_name, " + naturalSort("f.title"),
			"title":        "order_title",
			"random":       "random()",
			// To make sure these fields will be whitelisted
			"duration": "duration",
			"year":     "year",
			"bpm":      "bpm",
			"channels": "channels",
		},
		"f") // TODO I don't like this solution, but I won't change it now as it's not the focus of BFR.

	pls, err := r.Get(ctx, playlistId)
	if err != nil {
		log.Warn(ctx, "Error getting playlist's tracks", "playlistId", playlistId, err)
		return nil
	}
	if refreshSmartPlaylist {
		r.refreshSmartPlaylist(ctx, pls)
	}
	p.playlist = pls
	return p
}

func (r *playlistTrackRepository) CountAll(ctx context.Context, options ...model.QueryOptions) (int64, error) {
	query := Select().
		Join("media_file f on f.id = media_file_id").
		Where(Eq{"playlist_id": r.playlistId})
	query = r.applyLibraryFilter(ctx, query, "f")
	return r.count(ctx, query, options...)
}

func (r *playlistTrackRepository) Count(ctx context.Context, options ...rest.QueryOptions) (int64, error) {
	query := Select().
		LeftJoin("media_file f on f.id = media_file_id").
		Where(Eq{"playlist_id": r.playlistId})
	query = r.applyLibraryFilter(ctx, query, "f")
	return r.count(ctx, query, r.parseRestOptions(ctx, options...))
}

func (r *playlistTrackRepository) Read(ctx context.Context, id string) (*model.PlaylistTrack, error) {
	userID := loggedUser(ctx).ID
	sel := r.newSelect(ctx).
		LeftJoin("annotation on ("+
			"annotation.item_id = media_file_id"+
			" AND annotation.item_type = 'media_file'"+
			" AND annotation.user_id = '"+userID+"')").
		Columns(
			"coalesce(starred, 0) as starred",
			"coalesce(play_count, 0) as play_count",
			"coalesce(rating, 0) as rating",
			"starred_at",
			"play_date",
			"rated_at",
			"f.*",
			"playlist_tracks.*",
		).
		Join("media_file f on f.id = media_file_id").
		Where(And{Eq{"playlist_id": r.playlistId}, Eq{"playlist_tracks.id": id}})
	sel = r.applyLibraryFilter(ctx, sel, "f")
	var trk dbPlaylistTrack
	err := r.queryOne(ctx, sel, &trk)
	return trk.PlaylistTrack, err
}

func (r *playlistTrackRepository) GetAll(ctx context.Context, options ...model.QueryOptions) (model.PlaylistTracks, error) {
	tracks, err := r.playlistRepo.loadTracks(ctx, r.newSelect(ctx, options...), r.playlistId)
	if err != nil {
		return nil, err
	}
	return tracks, err
}

func (r *playlistTrackRepository) GetCursor(ctx context.Context, options ...model.QueryOptions) (model.PlaylistTrackCursor, error) {
	sel := r.playlistRepo.tracksQuery(ctx, r.newSelect(ctx, options...), r.playlistId)
	cursor, err := queryWithStableResults[dbPlaylistTrack](ctx, r.sqlRepository, sel)
	if err != nil {
		return nil, err
	}
	tracks := wrapCursor(cursor, func(t dbPlaylistTrack) *model.PlaylistTrack {
		return t.PlaylistTrack
	})
	return model.PlaylistTrackCursor(hydrateCursor(tracks, func(batch []model.PlaylistTrack) {
		hydratePlaylistTrackArtwork(ctx, r.db, batch)
	})), nil
}

// GetMediaFileIDs returns the tracks' song ids, for callers that need every id but no track data.
func (r *playlistTrackRepository) GetMediaFileIDs(ctx context.Context, options ...model.QueryOptions) ([]string, error) {
	query := r.newSelect(ctx, options...).Columns("media_file_id").
		Join("media_file f on f.id = media_file_id").
		Where(Eq{"playlist_id": r.playlistId})
	query = r.applyLibraryFilter(ctx, query, "f")
	var ids []string
	if err := r.queryAllSlice(ctx, query, &ids); err != nil {
		return nil, err
	}
	return ids, nil
}

func (r *playlistTrackRepository) GetAlbumIDs(ctx context.Context, options ...model.QueryOptions) ([]string, error) {
	query := r.newSelect(ctx, options...).Columns("distinct mf.album_id").
		Join("media_file mf on mf.id = media_file_id").
		Where(Eq{"playlist_id": r.playlistId})
	query = r.applyLibraryFilter(ctx, query, "mf")
	var ids []string
	err := r.queryAllSlice(ctx, query, &ids)
	if err != nil {
		return nil, err
	}
	return ids, nil
}

func (r *playlistTrackRepository) ReadAll(ctx context.Context, options ...rest.QueryOptions) ([]model.PlaylistTrack, error) {
	return r.GetAll(ctx, r.parseRestOptions(ctx, options...))
}

func (r *playlistTrackRepository) Add(ctx context.Context, mediaFileIds []string) (int, error) {
	if len(mediaFileIds) > 0 {
		log.Debug(ctx, "Adding songs to playlist", "playlistId", r.playlistId, "mediaFileIds", mediaFileIds)
	} else {
		return 0, nil
	}

	// Get next pos (ID) in playlist
	sq := r.newSelect(ctx).Columns("max(id) as max").Where(Eq{"playlist_id": r.playlistId})
	var res struct{ Max sql.NullInt32 }
	if err := r.queryOne(ctx, sq, &res); err != nil {
		return 0, err
	}

	return r.playlistRepo.addTracks(ctx, r.playlistId, int(res.Max.Int32+1), mediaFileIds)
}

// Insert adds tracks before the 1-based position pos, shifting the following entries down; a
// position past the end appends. Callers must run it in a transaction.
func (r *playlistTrackRepository) Insert(ctx context.Context, mediaFileIds []string, pos int) (int, error) {
	if len(mediaFileIds) == 0 {
		return 0, nil
	}
	pos = max(pos, 1)
	n := len(mediaFileIds)
	// Negate while shifting, so no intermediate row hits the unique (playlist_id, id) index.
	_, err := r.executeSQL(ctx, Expr(`UPDATE playlist_tracks SET id = -(id + ?) WHERE playlist_id = ? AND id >= ?`, n, r.playlistId, pos))
	if err != nil {
		return 0, err
	}
	res, err := r.executeSQL(ctx, Expr(`UPDATE playlist_tracks SET id = -id WHERE playlist_id = ? AND id < 0`, r.playlistId))
	if err != nil {
		return 0, err
	}
	if res == 0 {
		return r.Add(ctx, mediaFileIds)
	}
	inserted, err := r.playlistRepo.addTracks(ctx, r.playlistId, pos, mediaFileIds)
	if err != nil || inserted == n {
		return inserted, err
	}
	// The shift above reserved a slot per requested id, so ids dropped by keepAccessible
	// leave a hole. Close it.
	return inserted, r.playlistRepo.renumber(ctx, r.playlistId)
}

func (r *playlistTrackRepository) addMediaFileIds(ctx context.Context, cond Sqlizer) (int, error) {
	sq := Select("id").From("media_file").Where(cond).OrderBy("album_artist, album, release_date, disc_number, track_number")
	var ids []string
	err := r.queryAllSlice(ctx, sq, &ids)
	if err != nil {
		log.Error(ctx, "Error getting tracks to add to playlist", err)
		return 0, err
	}
	return r.Add(ctx, ids)
}

func (r *playlistTrackRepository) AddAlbums(ctx context.Context, albumIds []string) (int, error) {
	return r.addMediaFileIds(ctx, Eq{"album_id": albumIds})
}

func (r *playlistTrackRepository) AddArtists(ctx context.Context, artistIds []string) (int, error) {
	// Match by album-artist participation, not the deprecated album_artist_id
	// column, which only holds the first album artist.
	return r.addMediaFileIds(ctx, ParticipantIDFilter("media_file", artistIds, model.RoleAlbumArtist))
}

func (r *playlistTrackRepository) AddDiscs(ctx context.Context, discs []model.DiscID) (int, error) {
	if len(discs) == 0 {
		return 0, nil
	}
	var clauses Or
	for _, d := range discs {
		clauses = append(clauses, And{Eq{"album_id": d.AlbumID}, Eq{"release_date": d.ReleaseDate}, Eq{"disc_number": d.DiscNumber}})
	}
	return r.addMediaFileIds(ctx, clauses)
}

// deleteChunkSize keeps each DELETE under SQLITE_MAX_VARIABLE_NUMBER, matching addTracks.
const deleteChunkSize = 200

func (r *playlistTrackRepository) Delete(ctx context.Context, ids ...string) error {
	for chunk := range slices.Chunk(ids, deleteChunkSize) {
		if err := r.delete(ctx, And{Eq{"playlist_id": r.playlistId}, Eq{"id": chunk}}); err != nil {
			return err
		}
	}

	return r.playlistRepo.renumber(ctx, r.playlistId)
}

func (r *playlistTrackRepository) DeleteAll(ctx context.Context) error {
	err := r.delete(ctx, Eq{"playlist_id": r.playlistId})
	if err != nil {
		return err
	}

	return r.playlistRepo.renumber(ctx, r.playlistId)
}

// Reorder moves a track from pos to newPos, shifting other tracks accordingly. newPos is clamped
// to the playlist; a pos outside it is ErrNotFound, since shifting around it would leave a gap.
func (r *playlistTrackRepository) Reorder(ctx context.Context, pos int, newPos int) error {
	var res struct{ Max sql.NullInt32 }
	if err := r.queryOne(ctx, r.newSelect(ctx).Columns("max(id) as max").Where(Eq{"playlist_id": r.playlistId}), &res); err != nil {
		return err
	}
	last := int(res.Max.Int32)
	if pos < 1 || pos > last {
		return model.ErrNotFound
	}
	newPos = min(max(newPos, 1), last)
	if pos == newPos {
		return nil
	}
	pid := r.playlistId

	// Step 1: Move the source track out of the way (temporary sentinel value)
	_, err := r.executeSQL(ctx, Expr(
		`UPDATE playlist_tracks SET id = -999999 WHERE playlist_id = ? AND id = ?`, pid, pos))
	if err != nil {
		return err
	}

	// Step 2: Shift the affected range using negative values to avoid unique constraint violations
	if pos < newPos {
		_, err = r.executeSQL(ctx, Expr(
			`UPDATE playlist_tracks SET id = -(id - 1) WHERE playlist_id = ? AND id > ? AND id <= ?`,
			pid, pos, newPos))
	} else {
		_, err = r.executeSQL(ctx, Expr(
			`UPDATE playlist_tracks SET id = -(id + 1) WHERE playlist_id = ? AND id >= ? AND id < ?`,
			pid, newPos, pos))
	}
	if err != nil {
		return err
	}

	// Step 3: Flip the shifted range back to positive
	_, err = r.executeSQL(ctx, Expr(
		`UPDATE playlist_tracks SET id = -id WHERE playlist_id = ? AND id < 0 AND id != -999999`, pid))
	if err != nil {
		return err
	}

	// Step 4: Place the source track at its new position
	_, err = r.executeSQL(ctx, Expr(
		`UPDATE playlist_tracks SET id = ? WHERE playlist_id = ? AND id = -999999`, newPos, pid))
	return err
}

var _ model.PlaylistTrackRepository = (*playlistTrackRepository)(nil)