<?php
header('Content-Type: application/json; charset=utf-8');
require_once __DIR__ . '/../../connect.php'; // Includes db connection

$zone_name = filterRequest('zone_name');
$latitude = filterRequest('latitude');
$longitude = filterRequest('longitude');
$radius_meters = filterRequest('radius_meters');
$country_code = filterRequest('country_code');
$priority = filterRequest('priority') ?? 1;

if (empty($zone_name) || empty($latitude) || empty($longitude) || empty($radius_meters) || empty($country_code)) {
    echo json_encode(["status" => "error", "message" => "Missing required fields"]);
    exit;
}

try {
    // 1. Check for overlapping zones
    // Using Haversine formula directly in SQL to find any zone where distance < (new_radius + existing_radius)
    $sql = "
        SELECT id, zone_name, radius_meters, 
        (
            6371000 * acos(
                cos(radians(:new_lat)) * cos(radians(latitude)) * 
                cos(radians(longitude) - radians(:new_lng)) + 
                sin(radians(:new_lat)) * sin(radians(latitude))
            )
        ) AS distance_meters
        FROM geofence_zones
        WHERE is_active = 1 AND country_code = :country_code
        HAVING distance_meters < (radius_meters + :new_radius)
        LIMIT 1
    ";

    $stmt = $con->prepare($sql);
    $stmt->bindValue(':new_lat', (float) $latitude);
    $stmt->bindValue(':new_lng', (float) $longitude);
    $stmt->bindValue(':new_radius', (int) $radius_meters, PDO::PARAM_INT);
    $stmt->bindValue(':country_code', $country_code);
    $stmt->execute();

    $overlapping_zone = $stmt->fetch(PDO::FETCH_ASSOC);

    if ($overlapping_zone) {
        echo json_encode([
            "status" => "error",
            "message" => "Zone overlaps with existing zone: " . $overlapping_zone['zone_name'],
            "overlap_details" => $overlapping_zone
        ]);
        exit;
    }

    // 2. Insert new zone
    $insert_sql = "INSERT INTO geofence_zones (zone_name, latitude, longitude, radius_meters, priority, country_code) 
                   VALUES (:zone_name, :lat, :lng, :radius, :priority, :country)";
    
    $insert_stmt = $con->prepare($insert_sql);
    $insert_stmt->bindValue(':zone_name', $zone_name);
    $insert_stmt->bindValue(':lat', (float) $latitude);
    $insert_stmt->bindValue(':lng', (float) $longitude);
    $insert_stmt->bindValue(':radius', (int) $radius_meters, PDO::PARAM_INT);
    $insert_stmt->bindValue(':priority', (int) $priority, PDO::PARAM_INT);
    $insert_stmt->bindValue(':country', $country_code);
    $insert_stmt->execute();

    echo json_encode([
        "status" => "success",
        "message" => "Geofence zone added successfully",
        "zone_id" => $con->lastInsertId()
    ]);

} catch (Exception $e) {
    error_log("Error adding geofence zone: " . $e->getMessage());
    echo json_encode(["status" => "error", "message" => "Server error"]);
}
?>