"""修复 wechat_bot.py 的字节级损坏。

损坏形态：个别字节被就地替换成 0x3f（'?'），字节长度不变，行结构完好。
因此可以用 git HEAD 版本做参照：把损坏行里的 0x3f 当通配符，在 HEAD 里找
长度相同、其余字节全部一致的唯一候选行来还原。

默认只报告不写入；加 --write 才真正落盘。
"""

import subprocess
import sys


def load_head() -> bytes:
    return subprocess.run(
        ["git", "show", "HEAD:wechat_rpa/wechat_bot.py"],
        capture_output=True,
        check=True,
        cwd="..",
    ).stdout


def is_valid(line: bytes) -> bool:
    try:
        line.decode("utf-8")
        return True
    except UnicodeDecodeError:
        return False


def candidates(broken: bytes, pool: dict) -> list:
    """在同长度的候选里找出「除 0x3f 位置外完全一致」的行。"""
    found = []
    for other in pool.get(len(broken), ()):  # 长度相同才可能是同一行
        if all(
            b == o or b == 0x3F
            for b, o in zip(broken, other)
        ):
            found.append(other)
    return found


def main():
    write = "--write" in sys.argv
    current = open("wechat_bot.py", "rb").read()
    head = load_head()

    cur_lines = current.split(b"\n")
    head_lines = head.split(b"\n")

    pool = {}
    for line in head_lines:
        pool.setdefault(len(line), []).append(line)

    broken_idx = [i for i, line in enumerate(cur_lines) if not is_valid(line)]
    print(f"总行数 {len(cur_lines)}，损坏行 {len(broken_idx)}")

    repaired = list(cur_lines)
    fixed = unresolved = ambiguous = 0
    unresolved_lines = []
    for i in broken_idx:
        found = set(candidates(cur_lines[i], pool))
        if len(found) == 1:
            repaired[i] = found.pop()
            fixed += 1
        elif len(found) > 1:
            ambiguous += 1
            unresolved_lines.append((i, cur_lines[i], len(found)))
        else:
            unresolved += 1
            unresolved_lines.append((i, cur_lines[i], 0))

    print(f"可唯一还原 {fixed}，歧义 {ambiguous}，HEAD 里找不到 {unresolved}")
    if unresolved_lines:
        print("\n需要人工确认的行（最多列 40 条）：")
        for i, line, n in unresolved_lines[:40]:
            print(f"  第 {i + 1} 行 候选={n}: {line.decode('utf-8', 'replace')!r}")

    if not write:
        print("\n（只报告，未写入。加 --write 才落盘）")
        return

    out = b"\n".join(repaired)
    open("wechat_bot.py", "wb").write(out)
    print(f"\n已写回 {len(out)} 字节")


if __name__ == "__main__":
    main()