import geoip2.database
from pathlib import Path
from django.db import connection
from django.core.cache import cache
import logging

# Configure logging
logger = logging.getLogger(__name__)

# GeoLite2 database paths
CITY_DB_PATH = Path("utils/country_city_db/GeoLite2-City.mmdb")

# Special coordinates
SPECIAL_COORDINATES = [
    (32.616565, 44.03462),
    (51.5287718, -0.2416802),
    (40.3947021, 49.78492),
    (55.751199, 37.614706),
    (48.8589466, 2.2769956),
    (40.4381311, -3.8196194),
    (-6.2295712, 106.759478),
    (33.6158004, 72.8059198)
]

def get_location_by_coordinates_optimized(lat, lon):
    """
    Optimized version with special coordinates handling.
    Handles special coordinates correctly before geo lookup.
    """
    try:
        # Quick validation
        if not lat or not lon:
            return None

        lat, lon = float(lat), float(lon)

        # Check if coordinates are in special list - should use IP detection instead
        for special_lat, special_lon in SPECIAL_COORDINATES:
            if abs(lat - special_lat) < 0.001 and abs(lon - special_lon) < 0.001:
                # These coordinates should use IP detection, not geo lookup
                # Return None to trigger fallback to original method
                logger.debug(f"Special coordinate detected: ({lat}, {lon}) - skipping geo lookup")
                return None

        # Simple cache key
        cache_key = f'geo_{round(lat, 2)}_{round(lon, 2)}'

        # Try cache first (no exception handling for speed)
        cached_result = cache.get(cache_key)
        if cached_result is not None:
            return cached_result

        # Simple bounding box (larger range for better coverage)
        lat_range = 3.0  # ~330km
        lon_range = 3.0

        lat_min = lat - lat_range
        lat_max = lat + lat_range
        lon_min = lon - lon_range
        lon_max = lon + lon_range

        # Simplified query - remove population filter for better accuracy
        with connection.cursor() as cursor:
            cursor.execute("""
                WITH bounded_cities AS (
                    SELECT name, country_code, latitude, longitude
                    FROM geonames_city
                    WHERE feature_class = 'P'
                      AND latitude BETWEEN %s AND %s
                      AND longitude BETWEEN %s AND %s
                ),
                distance_calc AS (
                    SELECT name, country_code,
                           (6371 * acos(least(1, greatest(-1,
                            cos(radians(%s)) * cos(radians(latitude)) *
                            cos(radians(longitude) - radians(%s)) +
                            sin(radians(%s)) * sin(radians(latitude))
                           )))) AS distance
                    FROM bounded_cities
                )
                SELECT name, country_code
                FROM distance_calc
                WHERE distance <= 300
                ORDER BY distance
                LIMIT 1
            """, [lat_min, lat_max, lon_min, lon_max, lat, lon, lat])

            result = cursor.fetchone()

            if result:
                name, country_code = result
                response = {
                    'status': 'success',
                    'city': name,
                    'countryCode': country_code
                }

                # Cache for 24 hours
                cache.set(cache_key, response, 86400)
                return response
            else:
                # Cache None for 1 hour
                cache.set(cache_key, None, 3600)
                return None

    except Exception:
        # Fallback to original method on any error
        return get_location_by_coordinates_original(lat, lon)


def get_location_by_coordinates_original(lat, lon):
    """Original implementation as fallback"""
    try:
        with connection.cursor() as cursor:
            cursor.execute("""
                WITH distance_calc AS (
                    SELECT name, country_code, latitude, longitude,
                           (6371 * acos(least(1, greatest(-1, cos(radians(%s)) * cos(radians(latitude)) *
                            cos(radians(longitude) - radians(%s)) +
                            sin(radians(%s)) * sin(radians(latitude)))))) AS distance
                    FROM geonames_city
                    WHERE feature_class = 'P'
                )
                SELECT name, country_code, distance
                FROM distance_calc
                WHERE distance <= 300
                ORDER BY distance
                LIMIT 1
            """, [lat, lon, lat])

            result = cursor.fetchone()

            if result:
                name, country_code, distance = result
                return {
                    'status': 'success',
                    'city': name,
                    'countryCode': country_code
                }
        return None

    except Exception:
        return None


def get_location_by_coordinates(lat, lon):
    """
    Main function with smart fallback strategy.
    Try optimized first, fallback to original if needed.
    """
    # Try optimized version first
    result = get_location_by_coordinates_optimized(lat, lon)

    # If optimized fails, use original as fallback
    if result is None:
        result = get_location_by_coordinates_original(lat, lon)

    return result

def get_location_by_ip(ip):
    """Get location from IP using MaxMind MMDB file directly"""
    try:
        if not CITY_DB_PATH.exists():
            return None

        with geoip2.database.Reader(CITY_DB_PATH) as reader:
            response = reader.city(ip)
            if response and response.city and response.country:
                return {
                    'status': 'success',
                    'countryCode': response.country.iso_code,
                    'city': response.city.name
                }
        return None

    except Exception:
        return None