import re
import os
import math


ELLIPSIS = re.compile(r'\.{3,}')
ELLIPSIS_ZH = re.compile(r'…+')
HYPHEN_ZH = re.compile(r'—+')
HALF_FULL_MAP = (
    (',', '，'),
    ('.', '。'),
    ('!', '！'),
    ('?', '？'),
    ('~', '～'),
    ('(', '（'),
    (')', '）'),
    (':', '：'),
    (';', '；'),
    ('-', '—'),
    ('ー', '—'),
    ('&', '＆'),
    ('%', '％'),
    ('・', '·'),
)
MIXED_RULE1 = re.compile(r'[，。、]+([…—～]+)')
MIXED_RULE2 = re.compile(r'([…—～]+)[，。、]+')
MIXED_RULE3 = re.compile(f'([…—～])[…—～]+')
# 平假名
HIRAGANA = re.compile(r'[\u3040-\u309F]+')
# 片假名
KATAKANA = re.compile(r'[\u30A0-\u30FF]+')
# 狗屎wamsoft在scn里拉的指令
SCN_SPECIAL = re.compile(r'(%(?:[^%;]*;|r)|#[0-9a-fA-F]{6,8};)')


def process_line(data: str) -> str:
    # 使用省略号替换连续的点
    data = ELLIPSIS.sub(lambda m: '…' * math.ceil(len(m.group(0)) / 3), data)
    for half, full in HALF_FULL_MAP:
        data = data.replace(half, full)
    #，。、和…—~混用
    data = MIXED_RULE1.sub(lambda m: m.group(1), data)
    data = MIXED_RULE2.sub(lambda m: m.group(1), data)
    # 混用时…—~只保留一个
    data = MIXED_RULE3.sub(lambda m: m.group(1) * len(m.group(0)), data)
    # 省略号和破折号统一只留一对
    data = ELLIPSIS_ZH.sub('……', data)
    data = HYPHEN_ZH.sub('——', data)
    # 删除所有平假名
    data = HIRAGANA.sub('', data)
    # 删除所有片假名
    data = KATAKANA.sub('', data)
    data = data.replace('！？', '？！')
    data = data.replace('。」', '」')
    return data


def process_scn_line(data: str) -> str:
    parts = SCN_SPECIAL.split(data)
    for i in range(len(parts)):
        if i % 2 == 0:
            parts[i] = process_line(parts[i])
            # 特殊处理 。%command;」
            if i > 0 and parts[i].startswith('」'):
                while parts[i - 2].endswith('。'):
                    parts[i - 2] = parts[i - 2][:-1]
    return ''.join(parts)


def process_m3t(m3t_path, scn=False):
    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("△"):
            data = line[1:].strip()
            if scn:
                ndata = process_scn_line(data)
            else:
                ndata = process_line(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, dry_run=False, scn=False):
    lines = process_m3t(m3t_path, scn)
    if not dry_run:
        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, dry_run=False, scn=False):
    for root, dirs, files in os.walk(m3t_path):
        for file in files:
            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, dry_run, scn)


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("-d", "--dry-run", action="store_true", help="Only show changes without saving.")
    parser.add_argument("--scn", action="store_true", help="Process SCN lines with special rules.")
    args = parser.parse_args()
    if os.path.isdir(args.m3t_path):
        recursive_process_m3t(args.m3t_path, args.target_path, args.dry_run, args.scn)
    else:
        process_m3t_file(args.m3t_path, args.target_path, args.dry_run, args.scn)