"""Fail when generated build metadata has drifted from .build_number."""

from __future__ import annotations

import ast
import json
from pathlib import Path


ROOT = Path(__file__).resolve().parents[1]


def backend_build_number() -> str:
    tree = ast.parse((ROOT / "backend/app/build_info.py").read_text(encoding="utf-8-sig"))
    for node in tree.body:
        if isinstance(node, ast.Assign) and any(
            isinstance(target, ast.Name) and target.id == "BUILD_NUMBER" for target in node.targets
        ):
            return str(ast.literal_eval(node.value))
    raise RuntimeError("backend/app/build_info.py does not define BUILD_NUMBER")


def main() -> None:
    expected = (ROOT / ".build_number").read_text(encoding="utf-8-sig").strip()
    package = json.loads((ROOT / "frontend/package.json").read_text(encoding="utf-8"))
    package_lock = json.loads((ROOT / "frontend/package-lock.json").read_text(encoding="utf-8"))
    values = {
        "backend/app/build_info.py": backend_build_number(),
        "frontend/package.json": str(package.get("version") or ""),
        "frontend/package-lock.json": str(package_lock.get("version") or ""),
        "frontend/package-lock.json root package": str(package_lock.get("packages", {}).get("", {}).get("version") or ""),
    }
    drifted = {name: value for name, value in values.items() if value != expected}
    if drifted:
        details = ", ".join(f"{name}={value!r}" for name, value in drifted.items())
        raise SystemExit(f"Build metadata differs from .build_number ({expected!r}): {details}")
    print(f"Build metadata is synchronized: {expected}")


if __name__ == "__main__":
    main()