#!/usr/bin/env python3
"""Sync the canonical observability CSS to the Flask-served static path.

The project keeps the design-system source at:
  static/css/observability-system.css

Production Flask static serving currently exposes:
  web/static/css/observability-system.css

This helper keeps the two files byte-identical so deploys do not regress into
"HTML links the CSS but /static/css/observability-system.css is 404/stale".
"""

from __future__ import annotations

import shutil
from pathlib import Path


ROOT = Path(__file__).resolve().parents[1]
SOURCE = ROOT / "static/css/observability-system.css"
TARGET = ROOT / "web/static/css/observability-system.css"


def main() -> int:
    if not SOURCE.exists():
        print(f"ERROR: missing source CSS: {SOURCE.relative_to(ROOT)}")
        return 1

    TARGET.parent.mkdir(parents=True, exist_ok=True)
    source_bytes = SOURCE.read_bytes()
    target_bytes = TARGET.read_bytes() if TARGET.exists() else b""

    if source_bytes == target_bytes:
        print("Observability CSS sync: already in sync")
        print(f"- source: {SOURCE.relative_to(ROOT)}")
        print(f"- target: {TARGET.relative_to(ROOT)}")
        return 0

    shutil.copyfile(SOURCE, TARGET)
    print("Observability CSS sync: synced")
    print(f"- source: {SOURCE.relative_to(ROOT)}")
    print(f"- target: {TARGET.relative_to(ROOT)}")
    print(f"- bytes: {len(source_bytes)}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())