from datetime import UTC, datetime, timedelta

import httpx
from fastapi import APIRouter, Depends, HTTPException, Query, status
from sqlalchemy.ext.asyncio import AsyncSession

from app.auth.deps import get_current_user
from app.database import get_db
from app.models.user import User
from app.schemas.settings import (
    FeatureSettingsResponse,
    FeatureSettingsUpdate,
    PlannerWeatherResponse,
    ServicePricingSettingsResponse,
    ServicePricingSettingsUpdate,
    SiteSettingsResponse,
    SiteSettingsUpdate,
)
from app.services import settings as settings_service
from app.services.settings import FeatureSettingsSchemaOutdatedError, ServicePricingSchemaOutdatedError

router = APIRouter(prefix="/settings", tags=["Settings"])
PLANNER_WEATHER_URL = "https://api.open-meteo.com/v1/forecast"
PLANNER_WEATHER_TTL = timedelta(hours=1)
PLANNER_WEATHER_CACHE = {
    "fetched_at": datetime.min.replace(tzinfo=UTC),
    "weather": {},
}


async def _load_planner_weather_snapshot() -> tuple[datetime, dict[str, dict[str, int]]]:
    fetched_at = PLANNER_WEATHER_CACHE["fetched_at"]
    cached_weather = PLANNER_WEATHER_CACHE["weather"]
    now = datetime.now(UTC)

    if cached_weather and now - fetched_at < PLANNER_WEATHER_TTL:
        return fetched_at, cached_weather

    try:
        async with httpx.AsyncClient(timeout=5.0) as client:
            response = await client.get(
                PLANNER_WEATHER_URL,
                params={
                    "latitude": -36.85,
                    "longitude": 174.77,
                    "daily": "weathercode,temperature_2m_max,temperature_2m_min",
                    "timezone": "Pacific/Auckland",
                    "forecast_days": 16,
                    "past_days": 14,
                },
            )
            response.raise_for_status()
            payload = response.json()
    except httpx.HTTPError:
        if cached_weather:
            return fetched_at, cached_weather
        raise

    next_weather: dict[str, dict[str, int]] = {}
    daily = payload.get("daily") or {}
    dates = daily.get("time") or []
    codes = daily.get("weathercode") or []
    highs = daily.get("temperature_2m_max") or []
    lows = daily.get("temperature_2m_min") or []

    for index, date_key in enumerate(dates):
        if index >= len(codes) or index >= len(highs) or index >= len(lows):
            continue
        next_weather[date_key] = {
            "code": int(codes[index]),
            "max": round(highs[index]),
            "min": round(lows[index]),
        }

    fetched_at = now
    PLANNER_WEATHER_CACHE["fetched_at"] = fetched_at
    PLANNER_WEATHER_CACHE["weather"] = next_weather
    return fetched_at, next_weather


def _filter_planner_weather(
    weather: dict[str, dict[str, int]],
    start_date: str | None,
    end_date: str | None,
) -> dict[str, dict[str, int]]:
    if not start_date and not end_date:
        return weather

    filtered: dict[str, dict[str, int]] = {}
    for key, value in weather.items():
        if start_date and key < start_date:
            continue
        if end_date and key > end_date:
            continue
        filtered[key] = value
    return filtered


@router.get("", response_model=SiteSettingsResponse)
async def get_settings(db: AsyncSession = Depends(get_db)):
    """Get site settings singleton."""
    row = await settings_service.get_settings(db)
    if row is None:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Site settings have not been configured yet. Run seed.py to initialise.",
        )
    return SiteSettingsResponse.model_validate(row)


@router.put("", response_model=SiteSettingsResponse)
async def update_settings(
    data: SiteSettingsUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Create or update site settings singleton (auth required)."""
    row = await settings_service.upsert_settings(db, data)
    return SiteSettingsResponse.model_validate(row)


@router.get("/features", response_model=FeatureSettingsResponse)
async def get_feature_settings(db: AsyncSession = Depends(get_db)):
    snapshot = await settings_service.get_feature_settings_snapshot(db)
    return FeatureSettingsResponse(
        bookings_enabled=snapshot.bookings_enabled,
        walks_enabled=snapshot.walks_enabled,
        messages_enabled=snapshot.messages_enabled,
        two_factor_enabled=snapshot.two_factor_enabled,
        audit_history_enabled=snapshot.audit_history_enabled,
        experiments_enabled=snapshot.experiments_enabled,
    )


@router.put("/features", response_model=FeatureSettingsResponse)
async def update_feature_settings(
    data: FeatureSettingsUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    del current_user
    try:
        snapshot = await settings_service.update_feature_settings_snapshot(db, data)
    except FeatureSettingsSchemaOutdatedError as exc:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail=str(exc))
    return FeatureSettingsResponse(
        bookings_enabled=snapshot.bookings_enabled,
        walks_enabled=snapshot.walks_enabled,
        messages_enabled=snapshot.messages_enabled,
        two_factor_enabled=snapshot.two_factor_enabled,
        audit_history_enabled=snapshot.audit_history_enabled,
        experiments_enabled=snapshot.experiments_enabled,
    )


@router.get("/pricing", response_model=ServicePricingSettingsResponse)
async def get_service_pricing(db: AsyncSession = Depends(get_db)):
    snapshot = await settings_service.get_service_pricing_snapshot(db)
    return ServicePricingSettingsResponse(service_pricing=snapshot)


@router.put("/pricing", response_model=ServicePricingSettingsResponse)
async def update_service_pricing(
    data: ServicePricingSettingsUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    del current_user
    try:
        snapshot = await settings_service.update_service_pricing_snapshot(
            db,
            service_pricing=data.service_pricing,
        )
    except ServicePricingSchemaOutdatedError as exc:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail=str(exc))
    return ServicePricingSettingsResponse(service_pricing=snapshot)


@router.get("/planner-weather", response_model=PlannerWeatherResponse)
async def get_planner_weather(
    start_date: str | None = Query(default=None),
    end_date: str | None = Query(default=None),
    current_user: User = Depends(get_current_user),
):
    del current_user

    for value, label in ((start_date, "start_date"), (end_date, "end_date")):
        if not value:
            continue
        try:
            datetime.strptime(value, "%Y-%m-%d")
        except ValueError as exc:
            raise HTTPException(
                status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
                detail=f"{label} must use YYYY-MM-DD format.",
            ) from exc

    fetched_at, weather = await _load_planner_weather_snapshot()
    return PlannerWeatherResponse(
        fetched_at=fetched_at,
        weather=_filter_planner_weather(weather, start_date, end_date),
    )