add lyric fetching

lrc.go

@@ -0,0 +1,166 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+type LRCLibResponse struct {
+	SyncedLyrics string `json:"syncedLyrics"`
+	PlainLyrics  string `json:"plainLyrics"`
+}
+
+func TrackDuration(path string) (int, error) {
+	cmd := exec.Command(
+		"ffprobe",
+		"-v", "error",
+		"-show_entries", "format=duration",
+		"-of", "default=noprint_wrappers=1:nokey=1",
+		path,
+	)
+
+	var out bytes.Buffer
+	var stderr bytes.Buffer
+	cmd.Stdout = &out
+	cmd.Stderr = &stderr
+
+	if err := cmd.Run(); err != nil {
+		return 0, fmt.Errorf("ffprobe error: %w (%s)", err, stderr.String())
+	}
+
+	raw := strings.TrimSpace(out.String())
+	if raw == "" {
+		return 0, fmt.Errorf("empty duration output from ffprobe")
+	}
+
+	flt, err := strconv.ParseFloat(raw, 64)
+	if err != nil {
+		return 0, fmt.Errorf("parse duration: %w (raw=%q)", err, raw)
+	}
+
+	return int(flt + 0.5), nil // round to nearest second
+}
+
+// DownloadAlbumLyrics downloads synced lyrics (LRC format) for each track in the album directory.
+// Assumes metadata is already final (tags complete).
+func DownloadAlbumLyrics(albumDir string) error {
+	err := filepath.Walk(albumDir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil
+		}
+
+		ext := strings.ToLower(filepath.Ext(info.Name()))
+		if ext != ".mp3" && ext != ".flac" {
+			return nil
+		}
+
+		// Skip if LRC already exists next to the file
+		lrcPath := strings.TrimSuffix(path, ext) + ".lrc"
+		if _, err := os.Stat(lrcPath); err == nil {
+			fmt.Println("→ Skipping (already has lyrics):", filepath.Base(path))
+			return nil
+		}
+
+		// Read metadata
+		md, err := readTags(path)
+		if err != nil {
+			fmt.Println("Skipping (unable to read tags):", path, "error:", err)
+			return nil
+		}
+		if md.Title == "" || md.Artist == "" || md.Album == "" {
+			fmt.Println("Skipping (missing metadata):", path)
+			return nil
+		}
+
+		duration, _ := TrackDuration(path)
+
+		lyrics, err := fetchLRCLibLyrics(md.Artist, md.Title, md.Album, duration)
+		if err != nil {
+			fmt.Println("No lyrics found:", md.Artist, "-", md.Title)
+			return nil
+		}
+
+		// Write .lrc file
+		if err := os.WriteFile(lrcPath, []byte(lyrics), 0644); err != nil {
+			return fmt.Errorf("writing lrc file for %s: %w", path, err)
+		}
+
+		fmt.Println("→ Downloaded lyrics:", filepath.Base(lrcPath))
+		return nil
+	})
+
+	return err
+}
+
+// fetchLRCLibLyrics calls the LRCLIB API and returns synced lyrics if available.
+func fetchLRCLibLyrics(artist, title, album string, duration int) (string, error) {
+
+	url := fmt.Sprintf(
+		"https://lrclib.net/api/get?artist_name=%s&track_name=%s&album_name=%s&duration=%d",
+		urlEncode(artist), urlEncode(title), urlEncode(album), duration,
+	)
+
+	resp, err := http.Get(url)
+	if err != nil {
+		return "", fmt.Errorf("lrclib fetch error: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("lrclib returned status %d", resp.StatusCode)
+	}
+
+	bodyBytes, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("reading lrclib response: %w", err)
+	}
+
+	var out LRCLibResponse
+	if err := json.Unmarshal(bodyBytes, &out); err != nil {
+		return "", fmt.Errorf("parsing lrclib json: %w", err)
+	}
+
+	if out.SyncedLyrics != "" {
+		return out.SyncedLyrics, nil
+	}
+
+	// If no syncedLyrics, fallback to plain
+	if out.PlainLyrics != "" {
+		// Convert plain text to a fake LRC wrapper
+		return plainToLRC(out.PlainLyrics), nil
+	}
+
+	return "", fmt.Errorf("no lyrics found")
+}
+
+// URL escape helper
+func urlEncode(s string) string {
+	r := strings.ReplaceAll(s, " ", "+")
+	return r
+}
+
+// Convert plaintext lyrics to a basic unsynced LRC (fallback)
+func plainToLRC(plain string) string {
+	lines := strings.Split(plain, "\n")
+	var out strings.Builder
+
+	for _, line := range lines {
+		// LRC format with [00:00.00] prefix when no timing exists
+		out.WriteString("[00:00.00] ")
+		out.WriteString(strings.TrimSpace(line))
+		out.WriteByte('\n')
+	}
+
+	return out.String()
+}