WIP playlist sync

internal/playlist/spotify.go

@@ -0,0 +1,113 @@
+package playlist
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+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"`
+	Public      bool   `json:"public"`
+	Images      []struct {
+		Url    string `json:"url"`
+		Height int    `json:"height"`
+		Width  int    `json:"width"`
+	} `json:"images"`
+	Items struct {
+		Limit  int `json:"limit"`
+		Offset int `json:"offset"`
+		Total  int `json:"total"`
+		Items  []struct {
+			Item SpotifyTrack `json:"item"`
+		} `json:"items"`
+	} `json:"items"`
+	ExternalURLs struct {
+		Spotify string `json:"spotify"`
+	} `json:"external_urls"`
+}
+
+type SpotifyTrack struct {
+	ID      string `json:"id"`
+	Name    string `json:"name"`
+	Artists []struct {
+		Name string `json:"name"`
+	} `json:"artists"`
+	ExternalIDs struct {
+		Isrc string `json:"isrc"`
+	} `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
+}
+
+func GetPlaylist(token, 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)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	body, _ := io.ReadAll(resp.Body)
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("API error (%d): %s", resp.StatusCode, body)
+	}
+
+	var playlist SpotifyPlaylist
+	if err := json.Unmarshal(body, &playlist); err != nil {
+		return nil, err
+	}
+	return &playlist, nil
+}