feat: initial implementation of metadata aggregator

- gRPC service with MusicBrainz provider - PostgreSQL schema with migrations - Service layer with database-first caching - Repository pattern for data access - YAML configuration support - Research documentation for 17 music metadata projects
2026-04-28 16:27:14 +02:00
commit a1f6701bac
163 changed files with 95884 additions and 0 deletions
@@ -0,0 +1,226 @@
+package postgres
+
+import (
+	"context"
+	"errors"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"github.com/metadata-agregator/internal/domain"
+	"github.com/metadata-agregator/internal/repository"
+)
+
+type TrackRepository struct {
+	pool *pgxpool.Pool
+}
+
+func NewTrackRepository(pool *pgxpool.Pool) *TrackRepository {
+	return &TrackRepository{pool: pool}
+}
+
+func (r *TrackRepository) GetByID(ctx context.Context, id string) (*domain.Track, error) {
+	query := `
+		SELECT id, title, duration_ms, isrc, explicit, source, source_id
+		FROM tracks
+		WHERE id = $1`
+
+	track, err := r.scanTrack(ctx, query, id)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := r.loadExternalIDs(ctx, track); err != nil {
+		return nil, err
+	}
+
+	return track, nil
+}
+
+func (r *TrackRepository) GetByExternalID(ctx context.Context, source, sourceID string) (*domain.Track, error) {
+	query := `
+		SELECT t.id, t.title, t.duration_ms, t.isrc, t.explicit, t.source, t.source_id
+		FROM tracks t
+		JOIN track_external_ids e ON t.id = e.track_id
+		WHERE e.source = $1 AND e.source_id = $2`
+
+	track, err := r.scanTrack(ctx, query, source, sourceID)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := r.loadExternalIDs(ctx, track); err != nil {
+		return nil, err
+	}
+
+	return track, nil
+}
+
+func (r *TrackRepository) GetByISRC(ctx context.Context, isrc string) (*domain.Track, error) {
+	query := `
+		SELECT id, title, duration_ms, isrc, explicit, source, source_id
+		FROM tracks
+		WHERE isrc = $1`
+
+	track, err := r.scanTrack(ctx, query, isrc)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := r.loadExternalIDs(ctx, track); err != nil {
+		return nil, err
+	}
+
+	return track, nil
+}
+
+func (r *TrackRepository) GetByAlbumID(ctx context.Context, albumID string) ([]domain.Track, error) {
+	query := `
+		SELECT t.id, t.title, t.duration_ms, t.isrc, t.explicit, t.source, t.source_id,
+		       at.disc_number, at.track_number
+		FROM tracks t
+		JOIN album_tracks at ON t.id = at.track_id
+		JOIN album_external_ids ae ON at.album_id = ae.album_id
+		WHERE ae.source_id = $1
+		ORDER BY at.disc_number, at.track_number`
+
+	rows, err := r.pool.Query(ctx, query, albumID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var tracks []domain.Track
+	for rows.Next() {
+		var (
+			track      domain.Track
+			durationMs *int
+			isrc       *string
+			explicit   *bool
+			source     string
+			sourceID   *string
+		)
+
+		err := rows.Scan(
+			&track.ID, &track.Title, &durationMs, &isrc, &explicit,
+			&source, &sourceID, &track.DiscNumber, &track.TrackNumber,
+		)
+		if err != nil {
+			return nil, err
+		}
+
+		if durationMs != nil {
+			track.DurationMs = *durationMs
+		}
+		track.ISRC = derefString(isrc)
+		if explicit != nil {
+			track.Explicit = *explicit
+		}
+
+		tracks = append(tracks, track)
+	}
+
+	return tracks, rows.Err()
+}
+
+func (r *TrackRepository) Save(ctx context.Context, track *domain.Track) error {
+	tx, err := r.pool.Begin(ctx)
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback(ctx)
+
+	var source, sourceID string
+	if len(track.ExternalIDs) > 0 {
+		source = track.ExternalIDs[0].Source
+		sourceID = track.ExternalIDs[0].SourceID
+	}
+
+	query := `
+		INSERT INTO tracks (id, title, duration_ms, isrc, explicit, source, source_id)
+		VALUES ($1, $2, $3, $4, $5, $6, $7)
+		ON CONFLICT (id) DO UPDATE SET
+			title = EXCLUDED.title,
+			duration_ms = EXCLUDED.duration_ms,
+			isrc = EXCLUDED.isrc,
+			explicit = EXCLUDED.explicit,
+			updated_at = now()`
+
+	_, err = tx.Exec(ctx, query,
+		track.ID, track.Title, track.DurationMs, nullString(track.ISRC),
+		track.Explicit, source, sourceID)
+	if err != nil {
+		return err
+	}
+
+	for _, ext := range track.ExternalIDs {
+		extQuery := `
+			INSERT INTO track_external_ids (track_id, source, source_id, url)
+			VALUES ($1, $2, $3, $4)
+			ON CONFLICT (track_id, source, source_id) DO UPDATE SET
+				url = EXCLUDED.url,
+				fetched_at = now()`
+
+		_, err = tx.Exec(ctx, extQuery, track.ID, ext.Source, ext.SourceID, nullString(ext.URL))
+		if err != nil {
+			return err
+		}
+	}
+
+	return tx.Commit(ctx)
+}
+
+func (r *TrackRepository) scanTrack(ctx context.Context, query string, args ...any) (*domain.Track, error) {
+	row := r.pool.QueryRow(ctx, query, args...)
+
+	var (
+		track      domain.Track
+		durationMs *int
+		isrc       *string
+		explicit   *bool
+		source     string
+		sourceID   *string
+	)
+
+	err := row.Scan(
+		&track.ID, &track.Title, &durationMs, &isrc, &explicit, &source, &sourceID,
+	)
+	if errors.Is(err, pgx.ErrNoRows) {
+		return nil, repository.ErrNotFound
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	if durationMs != nil {
+		track.DurationMs = *durationMs
+	}
+	track.ISRC = derefString(isrc)
+	if explicit != nil {
+		track.Explicit = *explicit
+	}
+
+	return &track, nil
+}
+
+func (r *TrackRepository) loadExternalIDs(ctx context.Context, track *domain.Track) error {
+	query := `SELECT source, source_id, url FROM track_external_ids WHERE track_id = $1`
+
+	rows, err := r.pool.Query(ctx, query, track.ID)
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		var ext domain.ExternalID
+		var url *string
+		if err := rows.Scan(&ext.Source, &ext.SourceID, &url); err != nil {
+			return err
+		}
+		ext.URL = derefString(url)
+		track.ExternalIDs = append(track.ExternalIDs, ext)
+	}
+
+	return rows.Err()
+}