v6.1

backend/songlink.go

@@ -0,0 +1,150 @@
+package backend
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+type SongLinkClient struct {
+	client           *http.Client
+	lastAPICallTime  time.Time
+	apiCallCount     int
+	apiCallResetTime time.Time
+}
+
+type SongLinkURLs struct {
+	TidalURL  string `json:"tidal_url"`
+	DeezerURL string `json:"deezer_url"`
+	AmazonURL string `json:"amazon_url"`
+}
+
+func NewSongLinkClient() *SongLinkClient {
+	return &SongLinkClient{
+		client: &http.Client{
+			Timeout: 30 * time.Second,
+		},
+		apiCallResetTime: time.Now(),
+	}
+}
+
+func (s *SongLinkClient) GetAllURLsFromSpotify(spotifyTrackID string) (*SongLinkURLs, error) {
+	// Rate limiting: max 10 requests per minute (song.link API limit)
+	now := time.Now()
+	if now.Sub(s.apiCallResetTime) >= time.Minute {
+		s.apiCallCount = 0
+		s.apiCallResetTime = now
+	}
+
+	// If we've hit the limit, wait until the next minute
+	if s.apiCallCount >= 9 {
+		waitTime := time.Minute - now.Sub(s.apiCallResetTime)
+		if waitTime > 0 {
+			fmt.Printf("Rate limit reached, waiting %v...\n", waitTime.Round(time.Second))
+			time.Sleep(waitTime)
+			s.apiCallCount = 0
+			s.apiCallResetTime = time.Now()
+		}
+	}
+
+	// Add delay between requests (7 seconds to be safe)
+	if !s.lastAPICallTime.IsZero() {
+		timeSinceLastCall := now.Sub(s.lastAPICallTime)
+		minDelay := 7 * time.Second
+		if timeSinceLastCall < minDelay {
+			waitTime := minDelay - timeSinceLastCall
+			fmt.Printf("Rate limiting: waiting %v...\n", waitTime.Round(time.Second))
+			time.Sleep(waitTime)
+		}
+	}
+
+	// Decode base64 API URL
+	spotifyBase, _ := base64.StdEncoding.DecodeString("aHR0cHM6Ly9vcGVuLnNwb3RpZnkuY29tL3RyYWNrLw==")
+	spotifyURL := fmt.Sprintf("%s%s", string(spotifyBase), spotifyTrackID)
+
+	apiBase, _ := base64.StdEncoding.DecodeString("aHR0cHM6Ly9hcGkuc29uZy5saW5rL3YxLWFscGhhLjEvbGlua3M/dXJsPQ==")
+	apiURL := fmt.Sprintf("%s%s", string(apiBase), url.QueryEscape(spotifyURL))
+
+	req, err := http.NewRequest("GET", apiURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+
+	fmt.Println("Getting streaming URLs from song.link...")
+
+	// Retry logic for rate limit errors
+	maxRetries := 3
+	var resp *http.Response
+	for i := 0; i < maxRetries; i++ {
+		resp, err = s.client.Do(req)
+		if err != nil {
+			return nil, fmt.Errorf("failed to get URLs: %w", err)
+		}
+
+		// Update rate limit tracking
+		s.lastAPICallTime = time.Now()
+		s.apiCallCount++
+
+		if resp.StatusCode == 429 {
+			resp.Body.Close()
+			if i < maxRetries-1 {
+				waitTime := 15 * time.Second
+				fmt.Printf("Rate limited by API, waiting %v before retry...\n", waitTime)
+				time.Sleep(waitTime)
+				continue
+			}
+			return nil, fmt.Errorf("API rate limit exceeded after %d retries", maxRetries)
+		}
+
+		if resp.StatusCode != 200 {
+			resp.Body.Close()
+			return nil, fmt.Errorf("API returned status %d", resp.StatusCode)
+		}
+
+		break
+	}
+	defer resp.Body.Close()
+
+	var songLinkResp struct {
+		LinksByPlatform map[string]struct {
+			URL string `json:"url"`
+		} `json:"linksByPlatform"`
+	}
+	if err := json.NewDecoder(resp.Body).Decode(&songLinkResp); err != nil {
+		return nil, fmt.Errorf("failed to decode response: %w", err)
+	}
+
+	urls := &SongLinkURLs{}
+
+	// Extract Tidal URL
+	if tidalLink, ok := songLinkResp.LinksByPlatform["tidal"]; ok && tidalLink.URL != "" {
+		urls.TidalURL = tidalLink.URL
+		fmt.Printf("✓ Tidal URL found\n")
+	}
+
+	// Extract Deezer URL
+	if deezerLink, ok := songLinkResp.LinksByPlatform["deezer"]; ok && deezerLink.URL != "" {
+		urls.DeezerURL = deezerLink.URL
+		fmt.Printf("✓ Deezer URL found\n")
+	}
+
+	// Extract Amazon URL
+	if amazonLink, ok := songLinkResp.LinksByPlatform["amazonMusic"]; ok && amazonLink.URL != "" {
+		amazonURL := amazonLink.URL
+		// Convert album URL to track URL if needed
+		if len(amazonURL) > 0 {
+			urls.AmazonURL = amazonURL
+			fmt.Printf("✓ Amazon URL found\n")
+		}
+	}
+
+	// Check if at least one URL was found
+	if urls.TidalURL == "" && urls.DeezerURL == "" && urls.AmazonURL == "" {
+		return nil, fmt.Errorf("no streaming URLs found")
+	}
+
+	return urls, nil
+}