#!/usr/bin/env python3
# dev/gofmt_keep_crlf.py
#
# 运行 gofmt -w，但保留文件原始行尾（CRLF / LF），避免 gofmt 把 CRLF 文件整文件
# 重写成 LF 造成的万行级 diff 污染。
#
# 用法：
#   python dev/gofmt_keep_crlf.py <file1> [file2 ...]
#   git diff --name-only | grep '\.go$' | xargs python dev/gofmt_keep_crlf.py
#
# 实现要点：先把源文件按 LF 写入临时副本交给 gofmt，gofmt 输出也是 LF；
# 若原文件是 CRLF，再把输出整体换回 CRLF 写回，从而只保留真实的格式化改动。
import os
import sys
import subprocess

GOFMT = r"C:/Program Files/Go/bin/gofmt"


def fmt_one(path):
    with open(path, "rb") as f:
        data = f.read()
    crlf = b"\r\n" in data

    tmp = path + ".gofmt.tmp"
    with open(tmp, "wb") as f:
        f.write(data.replace(b"\r\n", b"\n"))
    try:
        r = subprocess.run([GOFMT, "-w", tmp], capture_output=True)
        if r.returncode != 0:
            sys.stderr.write(
                "gofmt FAILED on %s:\n%s\n" % (path, r.stderr.decode("utf-8", "replace"))
            )
            return False
        with open(tmp, "rb") as f:
            out = f.read()
    finally:
        try:
            os.remove(tmp)
        except OSError:
            pass

    if crlf:
        out = out.replace(b"\r\n", b"\n").replace(b"\n", b"\r\n")
    with open(path, "wb") as f:
        f.write(out)
    return True


def main():
    files = [a for a in sys.argv[1:] if a.strip()]
    if not files:
        sys.stderr.write("usage: gofmt_keep_crlf.py <file> [file ...]\n")
        return 2
    ok = True
    for p in files:
        if not fmt_one(p):
            ok = False
    return 0 if ok else 1


if __name__ == "__main__":
    sys.exit(main())