#!/usr/bin/env python3
"""Check on the test server that a balance change goes live with tools/server_update.py alone (Adrian, 2026-11-09):
the server loads the update's data instead of the copy in its jar, `/reload` picks up a changed file while it runs,
and without the update the jar's copy is used again.

Usage: tools/check_server_update.py     (needs eula.txt from tools/selftest.py --accept-eula)
"""
import json
import subprocess
import sys
import time
import zipfile
from io import BytesIO
from pathlib import Path

from mcserver import ROOT, SERVER, Server, eula_accepted, prepare

ZIP = SERVER / "config/cobblesurvival/datapack.zip"
TUNING = "data/cobblesurvival/tuning/server.json"
LEVEL = "world-update-check"
FLAT = {"level-name": LEVEL, "level-type": "minecraft:flat",
        "generator-settings": '{"layers":[{"block":"minecraft:stone","height":4}],"biome":"minecraft:plains"}'}


def expect(line, *parts):
    missing = [p for p in parts if p not in line]
    if missing:
        sys.exit(f"expected {missing} in: {line}")
    print(f"ok: {line.strip()}")


def set_boss_evs(value):
    with zipfile.ZipFile(ZIP) as z:
        items = [(i, z.read(i.filename)) for i in z.infolist()]
    out = BytesIO()
    with zipfile.ZipFile(out, "w", zipfile.ZIP_DEFLATED) as z:
        for info, content in items:
            if info.filename == TUNING:
                content = json.dumps(json.loads(content) | {"boss_evs": value}).encode()
            z.writestr(info, content)
    part = ZIP.with_name(ZIP.name + ".part")
    part.write_bytes(out.getvalue())
    part.replace(ZIP)  # as an update does, with the server running


def main():
    if not eula_accepted():
        sys.exit("build/server/eula.txt does not accept the Minecraft EULA yet (see tools/selftest.py --accept-eula).")
    args_file = prepare()
    subprocess.run([sys.executable, str(ROOT / "tools/server_update.py"), "--install", str(SERVER), "--level", LEVEL, "--force"], check=True)
    try:
        with Server(args_file, FLAT, stdout_name="update-check-stdout.log") as server:
            server.wait_ready()
            first = server.command("cobblesurvival data")
            expect(first, "data server;", "boss_evs 170;")
            set_boss_evs(150)
            server.command("reload")
            for _ in range(60):
                time.sleep(2)
                line = server.command("cobblesurvival data")
                if "boss_evs 150" in line:
                    break
            expect(line, "data server;", "boss_evs 150;")
            server.stop()
        ZIP.unlink()
        with Server(args_file, FLAT, stdout_name="update-check-stdout.log") as server:
            server.wait_ready()
            expect(server.command("cobblesurvival data"), "data jar;", "boss_evs 170;")
            server.stop()
    finally:
        ZIP.unlink(missing_ok=True)
    print("SERVER UPDATE CHECK PASSED")


if __name__ == "__main__":
    main()