<?php
defined('BASEPATH') or exit('No direct script access allowed');

/**
 * Google Maps helper.
 * All Google Maps API calls from the backend should go through here so that
 * the API key lives only on the server (via constants configured in setting.php).
 */

if (!function_exists('maps_get_api_key')) {
    /**
     * Resolve the Maps API key from environment/constant.
     *
     * @return string
     */
    function maps_get_api_key()
    {
        if (defined('google_maps_api') && google_maps_api !== '') {
            return google_maps_api;
        }
        if (defined('GOOGLE_MAPS_API_KEY') && GOOGLE_MAPS_API_KEY !== '') {
            return GOOGLE_MAPS_API_KEY;
        }
        return '';
    }
}

if (!function_exists('maps_http_get_json')) {
    /**
     * Internal helper to issue a GET request and decode JSON.
     *
     * @param string $url
     * @return array|null
     */
    function maps_http_get_json($url)
    {
        $ctx = stream_context_create(array(
            'http' => array(
                'method' => 'GET',
                'timeout' => 10,
            ),
        ));
        $raw = @file_get_contents($url, false, $ctx);
        if ($raw === false) {
            log_message('error', 'Maps helper: HTTP request failed for URL: ' . $url);
            return null;
        }
        $data = json_decode($raw, true);
        if (!is_array($data)) {
            log_message('error', 'Maps helper: JSON decode failed for URL: ' . $url);
            return null;
        }
        return $data;
    }
}

if (!function_exists('maps_directions')) {
    /**
     * Call Google Directions API for a simple origin/destination pair.
     *
     * @param float $originLat
     * @param float $originLng
     * @param float $destLat
     * @param float $destLng
     * @param string $mode
     * @return array|null
     */
    function maps_directions($originLat, $originLng, $destLat, $destLng, $mode = 'driving')
    {
        $key = maps_get_api_key();
        if ($key === '') {
            log_message('error', 'Maps helper: GOOGLE_MAPS_API_KEY not set');
            return null;
        }
        $params = http_build_query(array(
            'origin' => $originLat . ',' . $originLng,
            'destination' => $destLat . ',' . $destLng,
            'mode' => $mode,
            'units' => 'metric',
            'key' => $key,
        ));
        $url = 'https://maps.googleapis.com/maps/api/directions/json?' . $params;
        return maps_http_get_json($url);
    }
}

if (!function_exists('maps_geocode')) {
    /**
     * Reverse geocode a lat/lng using Google Geocoding API.
     *
     * @param float $lat
     * @param float $lng
     * @return array|null
     */
    function maps_geocode($lat, $lng)
    {
        $key = maps_get_api_key();
        if ($key === '') {
            log_message('error', 'Maps helper: GOOGLE_MAPS_API_KEY not set for geocode');
            return null;
        }
        $params = http_build_query(array(
            'latlng' => $lat . ',' . $lng,
            'key' => $key,
        ));
        $url = 'https://maps.googleapis.com/maps/api/geocode/json?' . $params;
        return maps_http_get_json($url);
    }
}