ライブラリ・再生・削除を追加（Range 配信、パスの安全確認、共有ファイル名規則）

internal/store/store.go

@@ -111,6 +111,36 @@ func (s *Store) GetJob(ctx context.Context, id int64) (Job, error) {
 	return scanJob(s.pool.QueryRow(ctx, `SELECT `+jobColumns+` FROM download_jobs WHERE id=$1`, id))
 }
 
+func (s *Store) GetSucceededJob(ctx context.Context, id int64) (Job, error) {
+	return scanJob(s.pool.QueryRow(ctx, `SELECT `+jobColumns+` FROM download_jobs WHERE id=$1 AND status='succeeded'`, id))
+}
+
+func (s *Store) ListSucceededJobs(ctx context.Context, limit int) ([]Job, error) {
+	if limit <= 0 {
+		return nil, errors.New("limit must be positive")
+	}
+	rows, err := s.pool.Query(ctx, `SELECT `+jobColumns+` FROM download_jobs
+		WHERE status='succeeded' ORDER BY finished_at DESC NULLS LAST, id DESC LIMIT $1`, limit)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var jobs []Job
+	for rows.Next() {
+		job, err := scanJob(rows)
+		if err != nil {
+			return nil, err
+		}
+		jobs = append(jobs, job)
+	}
+	return jobs, rows.Err()
+}
+
+func (s *Store) DeleteSucceededJob(ctx context.Context, id int64) error {
+	tag, err := s.pool.Exec(ctx, `DELETE FROM download_jobs WHERE id=$1 AND status='succeeded'`, id)
+	return transitionResult(tag.RowsAffected(), err)
+}
+
 // Retry は失敗・中断されたジョブの実行時情報を消して再投入する。
 func (s *Store) Retry(ctx context.Context, id int64) error {
 	tag, err := s.pool.Exec(ctx, `UPDATE download_jobs SET status='queued', phase=NULL,