<?php
header('Content-Type: application/json; charset=utf-8');
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: POST, GET, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type');

// Handle preflight requests
if ($_SERVER['REQUEST_METHOD'] == 'OPTIONS') {
    exit(0);
}

include_once 'includes/db.php';

// Function to calculate distance between two points using Haversine formula
function calculateDistance($lat1, $lon1, $lat2, $lon2) {
    $earthRadius = 6371; // Earth's radius in kilometers
    
    $dLat = deg2rad($lat2 - $lat1);
    $dLon = deg2rad($lon2 - $lon1);
    
    $a = sin($dLat/2) * sin($dLat/2) + cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * sin($dLon/2) * sin($dLon/2);
    $c = 2 * atan2(sqrt($a), sqrt(1-$a));
    
    return $earthRadius * $c;
}

// Get user location from request
$input = json_decode(file_get_contents('php://input'), true);

if (!isset($input['lat']) || !isset($input['lng'])) {
    echo json_encode([
        'success' => false,
        'message' => 'الرجاء توفير الإحداثيات'
    ]);
    exit;
}

$userLat = floatval($input['lat']);
$userLng = floatval($input['lng']);

try {
    // Get all branches from database
    $sql = "SELECT id, name, address, phone, lat, lng FROM branches WHERE lat IS NOT NULL AND lng IS NOT NULL";
    $result = $conn->query($sql);
    
    if ($result->num_rows == 0) {
        echo json_encode([
            'success' => false,
            'message' => 'لا توجد فروع متاحة حالياً'
        ]);
        exit;
    }
    
    $nearestBranch = null;
    $minDistance = PHP_FLOAT_MAX;
    
    // Calculate distance to each branch
    while ($branch = $result->fetch_assoc()) {
        $distance = calculateDistance(
            $userLat, 
            $userLng, 
            floatval($branch['lat']), 
            floatval($branch['lng'])
        );
        
        if ($distance < $minDistance) {
            $minDistance = $distance;
            $nearestBranch = $branch;
            $nearestBranch['distance'] = round($distance, 2);
        }
    }
    
    if ($nearestBranch) {
        echo json_encode([
            'success' => true,
            'branch' => [
                'name' => $nearestBranch['name'],
                'address' => $nearestBranch['address'],
                'phone' => $nearestBranch['phone'],
                'distance' => $nearestBranch['distance']
            ]
        ]);
    } else {
        echo json_encode([
            'success' => false,
            'message' => 'لم يتم العثور على فروع قريبة'
        ]);
    }
    
} catch (Exception $e) {
    echo json_encode([
        'success' => false,
        'message' => 'حدث خطأ في النظام'
    ]);
}

$conn->close();
?>