import os


def remove_lf(text: str) -> str:
    texts = [i.lstrip() for i in text.replace("\\n", "\n").splitlines()]
    return ''.join(texts)


def process_m3t(m3t_path):
    lines = []
    line_num = 0
    for line in open(m3t_path, "r", encoding="utf-8"):
        line = line.strip()
        line = line.replace('\u200b', '')  # 移除零宽空格
        if line_num == 0:
            line = line.lstrip("\ufeff")  # 移除可能的BOM
        line_num += 1
        if line.startswith("●") or line.startswith("△") or line.startswith("○"):
            if line.startswith("○ NAME:"):
                lines.append(line)
                continue
            data = line[1:].strip()
            ndata = remove_lf(data)
            if data != ndata:
                print(f"{m3t_path}:{line_num}: {data} -> {ndata}")
                line = line[0] + " " + ndata
        lines.append(line)
    return lines


def save_lines(m3t_path, lines):
    with open(m3t_path, "w", encoding="utf-8") as f:
        for line in lines:
            f.write(line + "\n")


def process_m3t_file(m3t_path, target_path=None):
    lines = process_m3t(m3t_path)
    if target_path is None:
        save_lines(m3t_path, lines)
    else:
        os.makedirs(os.path.dirname(target_path), exist_ok=True)
        save_lines(target_path, lines)


def recursive_process_m3t(m3t_path, target_path=None, ext=".txt"):
    for root, dirs, files in os.walk(m3t_path):
        for file in files:
            if not file.lower().endswith(ext):
                continue
            full_path = os.path.join(root, file)
            output_path = None
            if target_path is not None:
                output_path = os.path.join(target_path, file)
            process_m3t_file(full_path, output_path)


if __name__ == "__main__":
    from argparse import ArgumentParser
    parser = ArgumentParser(description="Post-process M3T files.")
    parser.add_argument("m3t_path", help="Path to M3T file/directory.")
    parser.add_argument("target_path", nargs="?", default=None, help="Path to save processed M3T file/directory. If not specified, overwrite original files.")
    parser.add_argument("--ext", default=".txt", help="File extension to process in directory mode.")
    args = parser.parse_args()
    if os.path.isdir(args.m3t_path):
        recursive_process_m3t(args.m3t_path, args.target_path, args.ext)
    else:
        process_m3t_file(args.m3t_path, args.target_path)