import os
import subprocess
import time
from concurrent.futures import ThreadPoolExecutor, as_completed

def convert_file(input_path, output_path):
    command = [
        'ffmpeg',
        '-y',  # 自動覆蓋現有文件
        '-i', input_path,
        '-acodec', 'libmp3lame',
        '-b:a', '192k',
        output_path
    ]
    try:
        subprocess.run(command, check=True, stderr=subprocess.PIPE, timeout=300)  # 5分鐘超時
        return f"Converted: {output_path}"
    except subprocess.CalledProcessError as e:
        return f"Error converting {input_path}: {e.stderr.decode()}"
    except subprocess.TimeoutExpired:
        return f"Timeout converting {input_path}"

def convert_aac_to_mp3(input_dir, output_dir):
    start_time = time.time()
    total_files = 0
    processed_files = 0
    converted_files = 0

    with ThreadPoolExecutor(max_workers=os.cpu_count()) as executor:
        futures = []

        for root, _, files in os.walk(input_dir):
            for filename in files:
                if filename.lower().endswith('.aac'):
                    total_files += 1
                    input_path = os.path.join(root, filename)
                    rel_path = os.path.relpath(root, input_dir)
                    output_filename = os.path.splitext(filename)[0] + '.mp3'
                    output_path = os.path.join(output_dir, rel_path, output_filename)
                    
                    os.makedirs(os.path.dirname(output_path), exist_ok=True)
                    
                    futures.append(executor.submit(convert_file, input_path, output_path))

        for future in as_completed(futures):
            result = future.result()
            print(result)
            processed_files += 1
            if "Converted" in result:
                converted_files += 1
            print(f"Progress: {processed_files}/{total_files} files processed")

    end_time = time.time()
    print(f"\nConversion completed.")
    print(f"Total files: {total_files}")
    print(f"Converted files: {converted_files}")
    print(f"Failed conversions: {total_files - converted_files}")
    print(f"Total time: {end_time - start_time:.2f} seconds")

input_dir = input("請輸入包含 AAC 文件的目錄路徑: ")
output_dir = input("請輸入 MP3 文件的輸出目錄路徑: ")
convert_aac_to_mp3(input_dir, output_dir)