// Package coverart finds and fetches album cover artwork.
//
// Two-layer model: a directory-walking sidecar lookup (cover.jpg / folder.jpg
// next to the audio files) and a MusicBrainz Cover Art Archive (MBCAA)
// fallback for albums with an MBID but no sidecar. The Enricher orchestrates
// the two; the API and Subsonic packages reuse the sidecar helper directly.
package coverart

import (
	"context"
	"os"
	"path/filepath"

	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
)

// SidecarNames is the lookup order for cover art living next to audio files.
// Matches common library conventions: cover.* wins over folder.*; JPEG wins
// over PNG when both are present.
var SidecarNames = []string{
	"cover.jpg", "cover.jpeg", "cover.png",
	"folder.jpg", "folder.jpeg", "folder.png",
}

// FindSidecar returns the absolute path to a sidecar cover image in
// albumDir, or "" when none of the conventional names are present as a
// regular file. Directories named like sidecar files are skipped.
func FindSidecar(albumDir string) string {
	for _, name := range SidecarNames {
		candidate := filepath.Join(albumDir, name)
		info, err := os.Stat(candidate)
		if err != nil || info.IsDir() {
			continue
		}
		return candidate
	}
	return ""
}

// ResolveAlbumPath returns the on-disk path to an album's cover image,
// preferring the explicit album.cover_art_path when set and the file
// exists, falling back to a sidecar (cover.jpg / folder.jpg) next to the
// first track in the album's directory. "" means no art was found.
//
// Shared by internal/api/media.go (browser endpoint) and
// internal/subsonic/stream.go (Subsonic endpoint); they were byte-identical
// duplicates before extraction.
func ResolveAlbumPath(ctx context.Context, q *dbq.Queries, album dbq.Album) string {
	if album.CoverArtPath != nil && *album.CoverArtPath != "" {
		if _, err := os.Stat(*album.CoverArtPath); err == nil {
			return *album.CoverArtPath
		}
	}
	tracks, err := q.ListTracksByAlbum(ctx, dbq.ListTracksByAlbumParams{AlbumID: album.ID})
	if err != nil || len(tracks) == 0 {
		return ""
	}
	return FindSidecar(filepath.Dir(tracks[0].FilePath))
}