From 4f1137e1625c75aa0b0499e03ccc16e90e497043 Mon Sep 17 00:00:00 2001
From: Chigozirim Igweamaka <cgzirim@gmail.com>
Date: Wed, 9 Jul 2025 12:35:08 +0100
Subject: [PATCH] feat: add downloadYTaudio2 function to download YouTube audio
 using yt-dlp CLI

---
 server/spotify/youtube.go | 95 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)

diff --git a/server/spotify/youtube.go b/server/spotify/youtube.go
index 51d5d04..e62fb51 100644
--- a/server/spotify/youtube.go
+++ b/server/spotify/youtube.go
@@ -4,6 +4,13 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"log/slog"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"song-recognition/utils"
+
+	ytdlib "github.com/kkdai/youtube/v2"
 
 	"errors"
 	"io"
@@ -215,3 +222,91 @@ func ytSearch(searchTerm string, limit int) (results []*SearchResult, err error)
 
 	return results, nil
 }
+
+// downloadYTaudio1 downloads audio from a YouTube video using the github.com/kkdai/youtube library.
+func downloadYTaudio1(id, outputFilePath string) (string, error) {
+	logger := utils.GetLogger()
+
+	dir := filepath.Dir(outputFilePath)
+	if stat, err := os.Stat(dir); err != nil || !stat.IsDir() {
+		logger.Error("Invalid directory for output file", slog.Any("error", err))
+		return "", errors.New("output directory does not exist or is not a directory")
+	}
+
+	client := ytdlib.Client{}
+	video, err := client.GetVideo(id)
+	if err != nil {
+		logger.Error("Error getting YouTube video", slog.Any("error", err))
+		return "", err
+	}
+
+	/*
+		itag code: 140, container: m4a, content: audio, bitrate: 128k
+		change the FindByItag parameter to 139 if you want smaller files (but with a bitrate of 48k)
+		https://gist.github.com/sidneys/7095afe4da4ae58694d128b1034e01e2
+	*/
+	formats := video.Formats.Itag(140)
+
+	/* in some cases, when attempting to download the audio
+	using the library github.com/kkdai/youtube,
+	the download fails (and shows the file size as 0 bytes)
+	until the second or third attempt. */
+	var fileSize int64
+	file, err := os.Create(outputFilePath)
+	if err != nil {
+		logger.Error("Error creating file", slog.Any("error", err))
+		return "", err
+	}
+
+	for fileSize == 0 {
+		stream, _, err := client.GetStream(video, &formats[0])
+		if err != nil {
+			logger.Error("Error getting stream", slog.Any("error", err))
+			return "", err
+		}
+
+		if _, err = io.Copy(file, stream); err != nil {
+			logger.Error("Error copying stream to file", slog.Any("error", err))
+			return "", err
+		}
+
+		fileSize, _ = GetFileSize(outputFilePath)
+	}
+	defer file.Close()
+
+	return outputFilePath + "m4a", nil
+}
+
+// downloadYTaudio2 downloads audio from a YouTube video using yt-dlp command line tool.
+func downloadYTaudio2(videoURL, outputFilePath string) (string, error) {
+	logger := utils.GetLogger()
+
+	dir := filepath.Dir(outputFilePath)
+	if stat, err := os.Stat(dir); err != nil || !stat.IsDir() {
+		logger.Error("Invalid directory for output file", slog.Any("error", err))
+		return "", errors.New("output directory does not exist or is not a directory")
+	}
+
+	_, err := exec.LookPath("yt-dlp")
+	if err != nil {
+		logger.Error("yt-dlp not found in PATH", slog.Any("error", err))
+		return "", errors.New("yt-dlp is not installed or not in PATH")
+	}
+
+	audioFmt := "wav"
+	cmd := exec.Command(
+		"yt-dlp",
+		"-f", "bestaudio",
+		"--extract-audio",
+		"--audio-format", audioFmt,
+		"-o", outputFilePath,
+		videoURL,
+	)
+
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		logger.Error("yt-dlp command failed", slog.String("output", string(output)), slog.Any("error", err))
+		return "", err
+	}
+	return outputFilePath + "." + audioFmt, nil
+}