#!/usr/bin/env python3
"""Conservatively set BepInEx ValheimWebMap settings without removing other keys."""
import os
import re
import sys
from pathlib import Path

path = Path(sys.argv[1])
port = sys.argv[2]
if not port.isdigit() or not 1 <= int(port) <= 65535:
    raise SystemExit("Invalid port")
path.parent.mkdir(parents=True, exist_ok=True)
original = path.read_text(encoding="utf-8") if path.exists() else ""
if "\x00" in original:
    raise SystemExit("Unexpected NUL in config")
lines = original.splitlines(keepends=True)
sections = {}
section = None
for ix, line in enumerate(lines):
    m = re.match(r"^\s*\[([^\]]+)\]\s*$", line.strip())
    if m:
        section = m.group(1).casefold()
        if section in sections:
            raise SystemExit("Duplicate section; refusing to edit")
        sections[section] = ix

settings = {"web": {"Port": port, "Host": "*"},
            "history": {"TrackSessions": "false", "TrackDeaths": "false"}}
for name, options in settings.items():
    if name not in sections:
        if lines and not lines[-1].endswith("\n"):
            lines[-1] += "\n"
        lines.extend([f"\n[{name.capitalize()}]\n"] + [f"{key} = {value}\n" for key, value in options.items()])
        continue
    start = sections[name]
    end = next((ix for ix in sorted(sections.values()) if ix > start), len(lines))
    region = lines[start + 1:end]
    for key, value in options.items():
        matches = [ix for ix, line in enumerate(region) if re.match(rf"^\s*{re.escape(key)}\s*=", line, flags=re.I)]
        if len(matches) > 1:
            raise SystemExit(f"Duplicate setting {name}.{key}; refusing to edit")
        if matches:
            region[matches[0]] = f"{key} = {value}\n"
        else:
            region.append(f"{key} = {value}\n")
    lines[start + 1:end] = region
    # positions after this section have moved; recalculate before next section
    sections = {}
    for ix, line in enumerate(lines):
        m = re.match(r"^\s*\[([^\]]+)\]\s*$", line.strip())
        if m:
            sections[m.group(1).casefold()] = ix
result = "".join(lines)
if result != original:
    tmp = path.with_name(path.name + ".ansible-tmp")
    with tmp.open("w", encoding="utf-8") as f:
        f.write(result)
        f.flush()
        os.fsync(f.fileno())
    os.chmod(tmp, 0o640)
    os.replace(tmp, path)
print("changed" if result != original else "unchanged")