import json
import os
from typing import Dict, Any

import requests
from .metrics import CACHE_HITS_TOTAL, CACHE_MISSES_TOTAL, OPENMETEO_CALLS_TOTAL

API_URL = "https://geocoding-api.open-meteo.com/v1/search"
CITIES = ["Tel Aviv", "Beersheba", "Jerusalem", "Szeged"]

CACHE_FILE = os.environ.get("CACHE_FILE", "coordinates_cache.json")


def _fetch_coordinates(city: str) -> Dict[str, Any]:
    OPENMETEO_CALLS_TOTAL.labels(city=city).inc()

    params = {"name": city, "count": 1}
    r = requests.get(API_URL, params=params, timeout=10)
    r.raise_for_status()
    data = r.json()

    if "results" not in data or not data["results"]:
        raise ValueError(f"No results found for {city}")

    result = data["results"][0]
    return {
        "name": result.get("name"),
        "latitude": result.get("latitude"),
        "longitude": result.get("longitude"),
        "country": result.get("country"),
    }


def _load_cache() -> Dict[str, Any] | None:
    if os.path.exists(CACHE_FILE):
        with open(CACHE_FILE, "r", encoding="utf-8") as f:
            return json.load(f)
    return None


def _save_cache(data: Dict[str, Any]) -> None:
    with open(CACHE_FILE, "w", encoding="utf-8") as f:
        json.dump(data, f, indent=2)


def get_all_coordinates() -> Dict[str, Any]:
    cached = _load_cache()
    
    # Check if all cities from CITIES list are in cache
    if cached and all(city in cached for city in CITIES):
        CACHE_HITS_TOTAL.inc()
        # Filter cache to only include cities from CITIES list
        filtered_data = {city: cached[city] for city in CITIES}
        return {"source": "cache", "data": filtered_data}

    CACHE_MISSES_TOTAL.inc()
    
    # Fetch missing cities
    results = cached if cached else {}
    for city in CITIES:
        if city not in results:
            results[city] = _fetch_coordinates(city)
    
    _save_cache(results)
    # Return only cities from CITIES list
    filtered_data = {city: results[city] for city in CITIES}
    return {"source": "open-meteo", "data": filtered_data}


def get_coordinates_for_city(city: str) -> Dict[str, Any]:
    cached = _load_cache()
    if cached and city in cached:
        CACHE_HITS_TOTAL.inc()
        return {"source": "cache", "data": cached[city]}

    CACHE_MISSES_TOTAL.inc()

    result = _fetch_coordinates(city)

    # Update cache with the new city
    if cached is None:
        cached = {}
    cached[city] = result
    _save_cache(cached)

    return {"source": "open-meteo", "data": result}