sync playlists between spotify and navidrome

internal/playlist/navidrome.go

@@ -28,6 +28,7 @@ type NavidromePlaylist struct {
 }
 
 type NavidromeTrack struct {
+	ID              string  `json:"id"` // position ID within the playlist or id of the song. See MediaFileID
 	Title           string  `json:"title"`
 	Artist          string  `json:"artist"`
 	ArtistID        string  `json:"artistId"`
@@ -65,7 +66,6 @@ type NavidromeTrack struct {
 type NavidromePlaylistTrack struct {
 	NavidromeTrack
 
-	ID          string `json:"id"`          // position ID within the playlist
 	MediaFileID string `json:"mediaFileId"` // the actual song ID
 }
 
@@ -168,6 +168,25 @@ func (c *NavidromeClient) getPlaylistTracks(playlistID string) ([]NavidromePlayl
 	return tracks, nil
 }
 
+func (c *NavidromeClient) GetSongBySpotifyID(spotifyID string) ([]NavidromeTrack, error) {
+	// https://navi.kapelle.org/api/song?_end=100&_order=ASC&_sort=title&_start=0&spotifyid=0NhcaHA0cyJyhk3g8tUsZP&missing=false
+	params := url.Values{
+		"spotifyid": {spotifyID},
+	}
+	var songs []NavidromeTrack
+	err := c.getList("/api/song", params, &songs)
+	if err != nil {
+		return nil, err
+	}
+
+	return songs, nil
+}
+
+func (c *NavidromeClient) AddTracks(playlistID string, songIDs []string) error {
+	body := map[string]interface{}{"ids": songIDs}
+	return c.request(http.MethodPost, "/api/playlist/"+playlistID+"/tracks", body, nil)
+}
+
 func (c *NavidromeClient) getList(path string, extra url.Values, dest any) error {
 	const pageSize = 500
 	var all []json.RawMessage
@@ -207,7 +226,7 @@ func (c *NavidromeClient) getList(path string, extra url.Values, dest any) error
 	return json.Unmarshal(merged, dest)
 }
 
-func (c *NavidromeClient) request(method, path string, body interface{}, dest interface{}) error {
+func (c *NavidromeClient) request(method, path string, body any, dest any) error {
 	httpResp, err := c.do(method, path, body)
 	if err != nil {
 		return err

internal/playlist/spotify.go

@@ -8,16 +8,12 @@ import (
 	"net/http"
 	"net/url"
 	"strings"
+	"sync"
+	"time"
 )
 
 const spotifyAPIBase = "https://api.spotify.com/v1"
 
-type SpotifyTokenResponse struct {
-	AccessToken string `json:"access_token"`
-	TokenType   string `json:"token_type"`
-	ExpiresIn   int    `json:"expires_in"`
-}
-
 type SpotifyPlaylist struct {
 	Name        string `json:"name"`
 	Description string `json:"description"`
@@ -51,50 +47,46 @@ type SpotifyTrack struct {
 	} `json:"external_ids"`
 }
 
-func GetSpotifyAccessToken(clientID, clientSecret string) (string, error) {
-	creds := base64.StdEncoding.EncodeToString([]byte(clientID + ":" + clientSecret))
-
-	data := url.Values{}
-	data.Set("grant_type", "client_credentials")
-
-	req, err := http.NewRequest("POST", "https://accounts.spotify.com/api/token",
-		strings.NewReader(data.Encode()))
-	if err != nil {
-		return "", err
-	}
-	req.Header.Set("Authorization", "Basic "+creds)
-	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
-
-	resp, err := http.DefaultClient.Do(req)
-	if err != nil {
-		return "", err
-	}
-	defer resp.Body.Close()
-
-	body, _ := io.ReadAll(resp.Body)
-	if resp.StatusCode != http.StatusOK {
-		return "", fmt.Errorf("auth failed (%d): %s", resp.StatusCode, body)
-	}
-
-	var token SpotifyTokenResponse
-	if err := json.Unmarshal(body, &token); err != nil {
-		return "", err
-	}
-	return token.AccessToken, nil
+type SpotifyClient struct {
+	clientID     string
+	clientSecret string
+	token        string
+	mu           sync.Mutex
+	httpClient   *http.Client
 }
 
-func GetPlaylist(token, playlistID string) (*SpotifyPlaylist, error) {
+type spotifyTokenResponse struct {
+	AccessToken string `json:"access_token"`
+	TokenType   string `json:"token_type"`
+	ExpiresIn   int    `json:"expires_in"`
+}
+
+func NewSpotifyClient(clientID, clientSecret string) (*SpotifyClient, error) {
+	c := &SpotifyClient{
+		clientID:     clientID,
+		clientSecret: clientSecret,
+		httpClient:   &http.Client{Timeout: 30 * time.Second},
+	}
+
+	if err := c.renewToken(); err != nil {
+		return nil, err
+	}
+
+	return c, nil
+}
+
+func (c *SpotifyClient) GetPlaylist(playlistID string) (*SpotifyPlaylist, error) {
 	// TODO: handle rate limit
 	// TODO: handle request limits
+
 	reqURL := fmt.Sprintf("%s/playlists/%s", spotifyAPIBase, playlistID)
 
 	req, err := http.NewRequest("GET", reqURL, nil)
 	if err != nil {
 		return nil, err
 	}
-	req.Header.Set("Authorization", "Bearer "+token)
 
-	resp, err := http.DefaultClient.Do(req)
+	resp, err := c.do(req)
 	if err != nil {
 		return nil, err
 	}
@@ -111,3 +103,60 @@ func GetPlaylist(token, playlistID string) (*SpotifyPlaylist, error) {
 	}
 	return &playlist, nil
 }
+
+func (c *SpotifyClient) renewToken() error {
+	creds := base64.StdEncoding.EncodeToString([]byte(c.clientID + ":" + c.clientSecret))
+
+	data := url.Values{}
+	data.Set("grant_type", "client_credentials")
+
+	req, err := http.NewRequest("POST", "https://accounts.spotify.com/api/token",
+		strings.NewReader(data.Encode()))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Authorization", "Basic "+creds)
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	body, _ := io.ReadAll(resp.Body)
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("auth failed (%d): %s", resp.StatusCode, body)
+	}
+
+	var token spotifyTokenResponse
+	if err := json.Unmarshal(body, &token); err != nil {
+		return err
+	}
+
+	c.token = token.AccessToken
+
+	return nil
+}
+
+func (c *SpotifyClient) do(req *http.Request) (*http.Response, error) {
+	resp, err := c.doOnce(req)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode == http.StatusUnauthorized {
+		resp.Body.Close()
+		if err := c.renewToken(); err != nil {
+			return nil, err
+		}
+		return c.doOnce(req)
+	}
+	return resp, nil
+}
+
+func (c *SpotifyClient) doOnce(req *http.Request) (*http.Response, error) {
+	c.mu.Lock()
+	req.Header.Set("Authorization", "Bearer "+c.token)
+	c.mu.Unlock()
+	return c.httpClient.Do(req)
+}