#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""Shared cache invalidation marker for the PChome growth opportunity API."""

from __future__ import annotations

import time
from pathlib import Path

_BASE_DIR = Path(__file__).resolve().parents[1]
_CACHE_MARKER_FILE = _BASE_DIR / "data" / "pchome_growth_cache_epoch.txt"
_MEMORY_EPOCH = 0.0


def get_pchome_growth_cache_epoch() -> float:
    """Return the newest known invalidation epoch across workers."""
    global _MEMORY_EPOCH
    try:
        raw = _CACHE_MARKER_FILE.read_text(encoding="utf-8").strip()
        file_epoch = float(raw or 0)
    except (OSError, ValueError):
        file_epoch = 0.0
    _MEMORY_EPOCH = max(_MEMORY_EPOCH, file_epoch)
    return _MEMORY_EPOCH


def mark_pchome_growth_cache_stale() -> float:
    """Invalidate cached PChome growth opportunities in every worker."""
    global _MEMORY_EPOCH
    epoch = time.time()
    _MEMORY_EPOCH = max(_MEMORY_EPOCH, epoch)
    try:
        _CACHE_MARKER_FILE.parent.mkdir(parents=True, exist_ok=True)
        _CACHE_MARKER_FILE.write_text(f"{epoch:.6f}", encoding="utf-8")
    except OSError:
        pass
    return _MEMORY_EPOCH