/**
 * @ai-summary Google Maps client for station discovery
 * @ai-context Searches for gas stations and caches results
 */

import axios from 'axios';
import { env } from '../../../../core/config/environment';
import { logger } from '../../../../core/logging/logger';
import { cacheService } from '../../../../core/config/redis';
import { GooglePlacesResponse, GooglePlace } from './google-maps.types';
import { Station } from '../../domain/stations.types';

export class GoogleMapsClient {
  private readonly apiKey = env.GOOGLE_MAPS_API_KEY;
  private readonly baseURL = 'https://maps.googleapis.com/maps/api/place';
  private readonly cacheTTL = 3600; // 1 hour

  async searchNearbyStations(
    latitude: number,
    longitude: number,
    radius: number = 5000
  ): Promise<Station[]> {
    const cacheKey = `stations:${latitude.toFixed(4)},${longitude.toFixed(4)},${radius}`;
    
    try {
      // Check cache
      const cached = await cacheService.get<Station[]>(cacheKey);
      if (cached) {
        logger.debug('Station search cache hit', { latitude, longitude });
        return cached;
      }

      // Search Google Places
      logger.info('Searching Google Places for stations', { latitude, longitude, radius });
      
      const response = await axios.get<GooglePlacesResponse>(
        `${this.baseURL}/nearbysearch/json`,
        {
          params: {
            location: `${latitude},${longitude}`,
            radius,
            type: 'gas_station',
            key: this.apiKey
          }
        }
      );

      if (response.data.status !== 'OK' && response.data.status !== 'ZERO_RESULTS') {
        throw new Error(`Google Places API error: ${response.data.status}`);
      }

      // Transform results
      const stations = response.data.results.map(place => 
        this.transformPlaceToStation(place, latitude, longitude)
      );

      // Cache results
      await cacheService.set(cacheKey, stations, this.cacheTTL);

      return stations;
    } catch (error) {
      logger.error('Station search failed', { error, latitude, longitude });
      throw error;
    }
  }

  private transformPlaceToStation(place: GooglePlace, searchLat: number, searchLng: number): Station {
    // Calculate distance from search point
    const distance = this.calculateDistance(
      searchLat,
      searchLng,
      place.geometry.location.lat,
      place.geometry.location.lng
    );

    // Generate photo URL if available
    let photoUrl: string | undefined;
    if (place.photos && place.photos.length > 0) {
      photoUrl = `https://maps.googleapis.com/maps/api/place/photo?maxwidth=400&photo_reference=${place.photos[0].photo_reference}&key=${this.apiKey}`;
    }

    return {
      id: place.place_id,
      placeId: place.place_id,
      name: place.name,
      address: place.vicinity,
      latitude: place.geometry.location.lat,
      longitude: place.geometry.location.lng,
      distance,
      isOpen: place.opening_hours?.open_now,
      rating: place.rating,
      photoUrl
    };
  }

  private calculateDistance(lat1: number, lon1: number, lat2: number, lon2: number): number {
    const R = 6371e3; // Earth's radius in meters
    const φ1 = lat1 * Math.PI / 180;
    const φ2 = lat2 * Math.PI / 180;
    const Δφ = (lat2 - lat1) * Math.PI / 180;
    const Δλ = (lon2 - lon1) * Math.PI / 180;

    const a = Math.sin(Δφ/2) * Math.sin(Δφ/2) +
              Math.cos(φ1) * Math.cos(φ2) *
              Math.sin(Δλ/2) * Math.sin(Δλ/2);
    const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

    return Math.round(R * c); // Distance in meters
  }
}

export const googleMapsClient = new GoogleMapsClient();