Subsonic: browsing endpoints (getMusicFolders, getIndexes, getMusicDirectory, getGenres, getArtists/Artist, getAlbum, getSong, getVideos/VideoInfo, getArtistInfo/2, getAlbumInfo/2, getSimilarSongs/2, getTopSongs)

internal/subsonic/folders.go

@@ -0,0 +1,98 @@
+package subsonic
+
+import (
+	"database/sql"
+	"strconv"
+
+	"git.noroutes.net/NoRoutes/vibetunes/internal/database"
+)
+
+// folderMap resolves between VibeSonic's opaque music-folder IDs and the
+// small sequential integers the Subsonic protocol expects for
+// musicFolderId (the official XSD types it as xs:int, and some clients
+// build folder-picker UIs assuming small integers). The mapping is
+// derived fresh per request from folder creation order, which is stable
+// as long as folders aren't deleted/recreated — acceptable for how
+// rarely music folders change.
+type folderMap struct {
+	folders  []*database.MusicFolder
+	toInt    map[string]int
+	toFolder map[int]*database.MusicFolder
+}
+
+func loadFolderMap(db *sql.DB) (*folderMap, error) {
+	folders, err := database.ListMusicFolders(db)
+	if err != nil {
+		return nil, err
+	}
+	fm := &folderMap{
+		folders:  folders,
+		toInt:    make(map[string]int, len(folders)),
+		toFolder: make(map[int]*database.MusicFolder, len(folders)),
+	}
+	for i, f := range folders {
+		id := i + 1
+		fm.toInt[f.ID] = id
+		fm.toFolder[id] = f
+	}
+	return fm, nil
+}
+
+func (fm *folderMap) IntID(folderID string) string {
+	return strconv.Itoa(fm.toInt[folderID])
+}
+
+func (fm *folderMap) ByIntID(s string) *database.MusicFolder {
+	n, err := strconv.Atoi(s)
+	if err != nil {
+		return nil
+	}
+	return fm.toFolder[n]
+}
+
+// Allowed returns the folders a user may see: every folder, unless the
+// user has an explicit restriction list configured.
+func (fm *folderMap) Allowed(db *sql.DB, user *database.User) ([]*database.MusicFolder, error) {
+	allowedIDs, err := database.AllowedMusicFolderIDs(db, user.ID)
+	if err != nil {
+		return nil, err
+	}
+	if len(allowedIDs) == 0 {
+		return fm.folders, nil
+	}
+	set := make(map[string]bool, len(allowedIDs))
+	for _, id := range allowedIDs {
+		set[id] = true
+	}
+	var out []*database.MusicFolder
+	for _, f := range fm.folders {
+		if set[f.ID] {
+			out = append(out, f)
+		}
+	}
+	return out, nil
+}
+
+// UserCanSeeFolder reports whether user is allowed to see folderID,
+// given their restriction list (empty = unrestricted).
+func UserCanSeeFolder(db *sql.DB, user *database.User, folderID string) (bool, error) {
+	allowedIDs, err := database.AllowedMusicFolderIDs(db, user.ID)
+	if err != nil {
+		return false, err
+	}
+	if len(allowedIDs) == 0 {
+		return true, nil
+	}
+	for _, id := range allowedIDs {
+		if id == folderID {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+// UserCanSeeMediaFile reports whether user is allowed to see a song
+// belonging to the given music folder (per their folder restriction).
+func UserCanSeeMediaFile(db *sql.DB, user *database.User, mediaFile *database.MediaFile) (bool, error) {
+	return UserCanSeeFolder(db, user, mediaFile.MusicFolderID)
+}