<?php
require_once __DIR__ . '/../helpers.php';
runAuth();

/**
 * List Businesses
 * POST: { lat?: float, lng?: float }
 * Returns nearest 50 businesses sorted by distance.
 */

function haversineDistance(float $lat1, float $lng1, float $lat2, float $lng2): float {
    $R = 3959; // Earth radius in miles
    $dLat = deg2rad($lat2 - $lat1);
    $dLng = deg2rad($lng2 - $lng1);
    $a = sin($dLat / 2) ** 2 +
         cos(deg2rad($lat1)) * cos(deg2rad($lat2)) *
         sin($dLng / 2) ** 2;
    $a = max(0, min(1, $a));
    $c = 2 * asin(sqrt($a));
    return $R * $c;
}

try {
    $data = readJsonBody();
    $userLat = (float) ($data['lat'] ?? 0);
    $userLng = (float) ($data['lng'] ?? 0);
    $hasUserLocation = ($userLat != 0 && $userLng != 0);

    $rows = queryTimed("
        SELECT
            b.ID, b.Name, b.ParentBusinessID,
            (SELECT COUNT(*) FROM Businesses c WHERE c.ParentBusinessID = b.ID) AS ChildCount,
            a.Latitude AS AddressLat, a.Longitude AS AddressLng,
            a.City AS AddressCity, a.Line1 AS AddressLine1
        FROM Businesses b
        LEFT JOIN Addresses a ON b.AddressID = a.ID
        WHERE (b.IsDemo = 0 OR b.IsDemo IS NULL)
          AND (b.IsPrivate = 0 OR b.IsPrivate IS NULL)
          AND (b.ParentBusinessID IS NULL OR b.ParentBusinessID = 0)
        ORDER BY b.Name
    ");

    $businesses = [];
    foreach ($rows as $r) {
        $bizLat = (float) ($r['AddressLat'] ?? 0);
        $bizLng = (float) ($r['AddressLng'] ?? 0);

        $distance = 99999;
        if ($hasUserLocation && $bizLat != 0 && $bizLng != 0) {
            $distance = haversineDistance($userLat, $userLng, $bizLat, $bizLng);
        }

        $businesses[] = [
            'BusinessID' => (int) $r['ID'],
            'Name' => $r['Name'],
            'HasChildren' => ((int) $r['ChildCount']) > 0,
            'City' => $r['AddressCity'] ?? '',
            'Line1' => $r['AddressLine1'] ?? '',
            'Latitude' => $bizLat,
            'Longitude' => $bizLng,
            'DistanceMiles' => $distance,
        ];
    }

    // Sort by distance if user location provided
    if ($hasUserLocation) {
        usort($businesses, fn($a, $b) => $a['DistanceMiles'] <=> $b['DistanceMiles']);
    }

    // Limit to 50
    $businesses = array_slice($businesses, 0, 50);

    jsonResponse([
        'OK' => true,
        'ERROR' => '',
        'VERSION' => 'businesses_list_v5',
        'BUSINESSES' => $businesses,
        'Businesses' => $businesses,
    ]);

} catch (Exception $e) {
    apiAbort(['OK' => false, 'ERROR' => 'server_error', 'DETAIL' => $e->getMessage()]);
}