"""
Periodic cloud check-in. Runs every 6 hours as an asyncio background task.
If cloud is unreachable, falls back to last known state + grace period.
"""
import asyncio
import json
import logging
import os
from datetime import datetime, timedelta, timezone
from pathlib import Path

import httpx


from config import settings
from middleware.license_check import license_state

logger = logging.getLogger(__name__)

SYNC_INTERVAL_SECONDS = 6 * 60 * 60  # 6 hours
STATE_FILE = Path(__file__).parent.parent / "license_state.json"


def _load_persisted_state():
    if STATE_FILE.exists():
        try:
            data = json.loads(STATE_FILE.read_text())
            license_state.update(data)
            logger.info("Loaded persisted license state: %s", data)
        except Exception as e:
            logger.warning("Could not load license state file: %s", e)


def _persist_state():
    try:
        STATE_FILE.write_text(json.dumps(license_state))
    except Exception as e:
        logger.warning("Could not persist license state: %s", e)


async def _sync_once():
    if not settings.SITE_ID or not settings.CLOUD_URL:
        logger.debug("No SITE_ID/CLOUD_URL configured — skipping cloud sync")
        return

    try:
        async with httpx.AsyncClient(timeout=10) as client:
            resp = await client.post(
                f"{settings.CLOUD_URL}/api/sites/heartbeat",
                json={"site_id": settings.SITE_ID},
            )
            resp.raise_for_status()
            data = resp.json()
            license_state["licensed"] = data.get("licensed", True)
            license_state["locked"] = data.get("locked", False)
            license_state["expires_at"] = data.get("expires_at")
            license_state["last_sync"] = datetime.now(timezone.utc).isoformat()
            license_state["sync_failed"] = False
            _persist_state()
            logger.info("Cloud sync OK: %s", data)
    except Exception as e:
        logger.warning("Cloud sync failed: %s", e)
        license_state["sync_failed"] = True
        # Check grace period
        last_sync_str = license_state.get("last_sync")
        if last_sync_str:
            last_sync = datetime.fromisoformat(last_sync_str)
            grace_expires = last_sync + timedelta(hours=settings.LICENSE_GRACE_HOURS)
            if datetime.now(timezone.utc) > grace_expires:
                logger.error("License grace period expired — marking as unlicensed")
                license_state["licensed"] = False


async def _sync_loop():
    _load_persisted_state()
    while True:
        await _sync_once()
        await asyncio.sleep(SYNC_INTERVAL_SECONDS)


async def start_cloud_sync() -> asyncio.Task:
    task = asyncio.create_task(_sync_loop())
    return task