implement playlist wrapper functions

gspotify/auth.go

@@ -23,6 +23,7 @@ var (
 		sptauth.ScopeUserLibraryRead,
 		sptauth.ScopePlaylistModifyPublic,
 		sptauth.ScopePlaylistModifyPrivate,
+		sptauth.ScopePlaylistReadPrivate,
 		sptauth.ScopePlaylistReadCollaborative,
 		sptauth.ScopeUserLibraryModify,
 		sptauth.ScopeUserLibraryRead,

gspotify/get.go

@@ -0,0 +1,83 @@
+package gspotify
+
+import (
+	"context"
+
+	"github.com/zmb3/spotify/v2"
+)
+
+type Playlist struct {
+	SnapshotID string
+	Tracks     []spotify.PlaylistTrack
+}
+
+type Playable struct {
+	ID   spotify.ID
+	Name string
+	Type string
+}
+
+var (
+	playlistCache map[spotify.ID]*Playlist = make(map[spotify.ID]*Playlist)
+	Client        *spotify.Client
+	ctx           = context.Background()
+)
+
+func getPlaylistTracks(trackPage *spotify.PlaylistTrackPage) ([]spotify.PlaylistTrack, error) {
+	tracks := make([]spotify.PlaylistTrack, 0)
+	addTracks := func() {
+		tracks = append(tracks, trackPage.Tracks...)
+	}
+	addTracks()
+	for page := 1; ; page++ {
+		if perr := Client.NextPage(ctx, trackPage); perr == spotify.ErrNoMorePages {
+			break
+		} else if perr != nil {
+			return nil, perr
+		}
+		addTracks()
+	}
+	return tracks, nil
+}
+
+func GetPlaylist(playlistId spotify.ID) (*Playlist, error) {
+	if fp, err := Client.GetPlaylist(ctx, playlistId); err != nil {
+		return nil, err
+	} else {
+		if _, ok := playlistCache[fp.ID]; !ok || playlistCache[fp.ID].SnapshotID != fp.SnapshotID {
+			if tracks, err := getPlaylistTracks(&fp.Tracks); err != nil {
+				return nil, err
+			} else {
+				p := &Playlist{
+					SnapshotID: fp.SnapshotID,
+					Tracks:     tracks,
+				}
+				playlistCache[fp.ID] = p
+				return p, nil
+			}
+		} else {
+			return playlistCache[fp.ID], nil
+		}
+	}
+}
+
+func CurrentUserAllPlaylists() ([]spotify.SimplePlaylist, error) {
+	playlists := make([]spotify.SimplePlaylist, 0)
+	if spage, err := Client.CurrentUsersPlaylists(ctx); err != nil {
+		return nil, err
+	} else {
+		addPlaylists := func() {
+			playlists = append(playlists, spage.Playlists...)
+		}
+		addPlaylists()
+		for page := 1; ; page++ {
+			if perr := Client.NextPage(ctx, spage); perr == spotify.ErrNoMorePages {
+				break
+			} else if perr != nil {
+				return nil, perr
+			}
+			addPlaylists()
+		}
+		return playlists, nil
+	}
+}