"""
Kontrola plán vs. skutečnost po uzavření 15min slotu.

Pravidla a dedup INSERT drží ems.fn_plan_actual_slot_guard_site / fn_plan_actual_slot_guard_all_active
(repeatable R__076). Python jen zavolá funkci a pošle Discord podle vrácených alertů.
"""

from __future__ import annotations

import logging
from datetime import datetime, timezone
from typing import Any

import asyncpg
from zoneinfo import ZoneInfo

from app.db_json import fetch_json
from services.notification_service import notify_plan_vs_actual_fatal

logger = logging.getLogger(__name__)

_PRAGUE = ZoneInfo("Europe/Prague")


def _interval_start_utc(value: Any) -> datetime:
    if isinstance(value, datetime):
        if value.tzinfo is None:
            return value.replace(tzinfo=timezone.utc)
        return value.astimezone(timezone.utc)
    if isinstance(value, str):
        s = value.replace("Z", "+00:00")
        dt = datetime.fromisoformat(s)
        if dt.tzinfo is None:
            return dt.replace(tzinfo=timezone.utc)
        return dt.astimezone(timezone.utc)
    raise TypeError(f"expected datetime or str for interval_start, got {type(value)!r}")


def _slot_label_prague(interval_start: datetime) -> str:
    loc = interval_start.astimezone(_PRAGUE)
    return loc.strftime("%Y-%m-%d %H:%M") + " Europe/Prague"


async def _dispatch_site_result(site_payload: dict[str, Any]) -> None:
    if site_payload.get("error") == "unknown_site":
        logger.warning("plan_actual_slot_guard: unknown site_id=%s", site_payload.get("site_id"))
        return
    site_code = str(site_payload.get("site_code") or site_payload.get("site_id") or "")
    alerts = site_payload.get("alerts")
    if not isinstance(alerts, list):
        return
    for alert in alerts:
        if not isinstance(alert, dict):
            continue
        if not alert.get("notify"):
            continue
        interval_start = _interval_start_utc(alert["interval_start"])
        reason_code = str(alert.get("reason_code") or "")
        detail = str(alert.get("detail") or "")
        plan_grid_w = int(alert.get("plan_grid_w") or 0)
        actual_grid_w = int(alert.get("actual_grid_w") or 0)
        deviation_grid_w = int(alert.get("deviation_grid_w") or 0)
        slot_label = _slot_label_prague(interval_start)
        await notify_plan_vs_actual_fatal(
            site_code=site_code,
            slot_label=slot_label,
            interval_start_utc=interval_start,
            plan_grid_w=plan_grid_w,
            actual_grid_w=actual_grid_w,
            deviation_grid_w=deviation_grid_w,
            reason_code=reason_code,
            detail=detail,
        )
        logger.warning(
            "[site=%s] plan_actual fatal %s slot=%s: %s",
            site_payload.get("site_id"),
            reason_code,
            interval_start.isoformat(),
            detail,
        )


async def run_plan_actual_slot_guard_for_all_active_sites(
    pool: asyncpg.Pool,
    *,
    now: datetime | None = None,
) -> None:
    """Scheduler: jeden dotaz přes aktivní lokality (SQL dedup + klasifikace)."""
    async with pool.acquire() as conn:
        try:
            if now is not None:
                raw = await fetch_json(
                    conn,
                    "SELECT ems.fn_plan_actual_slot_guard_all_active($1::timestamptz)",
                    now,
                )
            else:
                raw = await fetch_json(conn, "SELECT ems.fn_plan_actual_slot_guard_all_active()")
        except Exception:
            logger.exception("plan_actual_slot_guard fn_plan_actual_slot_guard_all_active failed")
            return
        if raw is None:
            return
        if not isinstance(raw, list):
            logger.warning("plan_actual_slot_guard: unexpected payload type %s", type(raw))
            return
        for site_payload in raw:
            if not isinstance(site_payload, dict):
                continue
            try:
                await _dispatch_site_result(site_payload)
            except Exception:
                logger.exception(
                    "plan_actual_slot_guard site=%s failed",
                    site_payload.get("site_id"),
                )