from fastapi import APIRouter, Depends, HTTPException, Query
from pydantic import BaseModel
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from datetime import datetime, timedelta
import asyncio
import urllib.request
import urllib.parse
import urllib.error
import json

from app.database import get_db
from app.models.settings import Settings
from app.config import settings as app_settings
from app.routers.auth import get_current_session

router = APIRouter()

_cache: dict = {}


class GeoSearchResult(BaseModel):
    name: str
    state: str
    country: str
    lat: float
    lon: float


def _fetch_json(url: str) -> dict:
    with urllib.request.urlopen(url, timeout=10) as resp:
        return json.loads(resp.read().decode())


@router.get("/search", response_model=list[GeoSearchResult])
async def search_locations(
    q: str = Query(..., min_length=1, max_length=100),
    current_user: Settings = Depends(get_current_session)
):
    api_key = app_settings.OPENWEATHERMAP_API_KEY
    if not api_key:
        raise HTTPException(status_code=500, detail="Weather API key not configured")

    try:
        loop = asyncio.get_running_loop()
        url = f"https://api.openweathermap.org/geo/1.0/direct?q={urllib.parse.quote(q)}&limit=5&appid={api_key}"
        results = await loop.run_in_executor(None, _fetch_json, url)

        return [
            {
                "name": r.get("name", ""),
                "state": r.get("state", ""),
                "country": r.get("country", ""),
                "lat": r.get("lat"),
                "lon": r.get("lon"),
            }
            for r in results
        ]
    except urllib.error.URLError:
        raise HTTPException(status_code=502, detail="Geocoding service unavailable")
    except (KeyError, json.JSONDecodeError):
        raise HTTPException(status_code=502, detail="Invalid geocoding data")


@router.get("/")
async def get_weather(
    db: AsyncSession = Depends(get_db),
    current_user: Settings = Depends(get_current_session)
):
    # Get settings
    result = await db.execute(select(Settings))
    settings_row = result.scalar_one_or_none()
    city = settings_row.weather_city if settings_row else None
    lat = settings_row.weather_lat if settings_row else None
    lon = settings_row.weather_lon if settings_row else None

    if not city and (lat is None or lon is None):
        raise HTTPException(status_code=400, detail="No weather location configured")

    # Build cache key from coordinates or city
    use_coords = lat is not None and lon is not None
    cache_key = f"{lat},{lon}" if use_coords else city

    # Check cache
    now = datetime.now()
    if _cache.get("expires_at") and now < _cache["expires_at"] and _cache.get("cache_key") == cache_key:
        return _cache["data"]

    api_key = app_settings.OPENWEATHERMAP_API_KEY
    if not api_key:
        raise HTTPException(status_code=500, detail="Weather API key not configured")

    try:
        loop = asyncio.get_running_loop()

        # Build query params based on coordinates or city name
        if use_coords:
            location_params = f"lat={lat}&lon={lon}"
        else:
            location_params = f"q={urllib.parse.quote(city)}"

        current_url = f"https://api.openweathermap.org/data/2.5/weather?{location_params}&units=metric&appid={api_key}"
        forecast_url = f"https://api.openweathermap.org/data/2.5/forecast?{location_params}&units=metric&cnt=8&appid={api_key}"

        current_data, forecast_data = await asyncio.gather(
            loop.run_in_executor(None, _fetch_json, current_url),
            loop.run_in_executor(None, _fetch_json, forecast_url),
        )

        rain_chance = 0
        for item in forecast_data.get("list", []):
            pop = item.get("pop", 0)
            if pop > rain_chance:
                rain_chance = pop

        weather_result = {
            "temp": round(current_data["main"]["temp"]),
            "temp_min": round(current_data["main"]["temp_min"]),
            "temp_max": round(current_data["main"]["temp_max"]),
            "description": current_data["weather"][0]["description"],
            "rain_chance": round(rain_chance * 100),
            "sunrise": current_data["sys"]["sunrise"],
            "sunset": current_data["sys"]["sunset"],
            "city": current_data["name"],
        }

        # Cache for 1 hour
        _cache["data"] = weather_result
        _cache["expires_at"] = now + timedelta(hours=1)
        _cache["cache_key"] = cache_key

        return weather_result

    except urllib.error.URLError:
        raise HTTPException(status_code=502, detail="Weather service unavailable")
    except (KeyError, json.JSONDecodeError):
        raise HTTPException(status_code=502, detail="Invalid weather data")