"""Patch the `English` column of `Data\\Misc\\Strings.dat` with simplified Chinese.

Reads the byte-exact file (single byte code page), replaces only the value that
follows `Id = "<id>"` and `English = "..."`, and writes GB2312 double byte text.
The original is preserved next to it as `Strings.dat.orig` (once).
"""

import argparse
import os
import re
import sys

from cn_strings import CN_STRINGS

DEFAULT_GAME = r"F:\steam\steamapps\common\The I of the Dragon"


def patch(raw, mapping):
    done, missing = [], []
    for sid, cn in mapping.items():
        enc = cn.encode("gb2312")
        pat = re.compile(
            rb'(Id\s*=\s*"' + re.escape(sid.encode("latin1")) + rb'"'
            rb'\s*[\r\n]+\s*English\s*=\s*")(?:[^"\\]|\\.)*(")'
        )
        new, n = pat.subn(lambda m: m.group(1) + enc + m.group(2), raw, count=1)
        if n:
            raw = new
            done.append(sid)
        else:
            missing.append(sid)
    return raw, done, missing


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--game", default=DEFAULT_GAME)
    ap.add_argument("--file", default=None)
    ap.add_argument("--restore", action="store_true")
    args = ap.parse_args()

    path = args.file or os.path.join(args.game, "Data", "Misc", "Strings.dat")
    bak = path + ".orig"

    if args.restore:
        if os.path.exists(bak):
            open(path, "wb").write(open(bak, "rb").read())
            print("restored", path)
        else:
            print("no backup at", bak)
        return

    if not os.path.exists(bak):
        open(bak, "wb").write(open(path, "rb").read())
        print("backup ->", bak)

    raw = open(path, "rb").read()
    out, done, missing = patch(raw, CN_STRINGS)
    open(path, "wb").write(out)
    print("patched %d/%d strings (%d bytes)" % (len(done), len(CN_STRINGS), len(out)))
    if missing:
        print("MISSING:", missing, file=sys.stderr)
        sys.exit(2)


if __name__ == "__main__":
    main()