<?php

// CONFIG
$PIXEL_ID     = '128124764529976';
$ACCESS_TOKEN = 'EAAevkFHhd0oBPsvcVnHzuTEruMOONyXU4eCjSCmDn6r3qEhVljmxX4LHaoLpap6Y0menQjJDzkTJ8wy5NpDRI0u2U8GcZBSxEopsXXzNcI8fYf9QFCIrtQBMZC8yi38siEfFhZASHa1KvBKVcIWe5yTvRQ7GzWF7ojkZBTFFqs9MddbMjtjjqCqreAZAn4ZCccPgZDZD';
$GRAPH_VER    = 'v21.0';

// Helpers
function sha256_lower($v){ $v = trim(mb_strtolower($v ?? '')); return $v ? hash('sha256',$v) : null; }
function read_cookie($n){ return $_COOKIE[$n] ?? null; }
function client_ip(){
  $cf  = $_SERVER['HTTP_CF_CONNECTING_IP'] ?? null;
  $xff = $_SERVER['HTTP_X_FORWARDED_FOR'] ?? null;
  $xri = $_SERVER['HTTP_X_REAL_IP'] ?? null;
  $rem = $_SERVER['REMOTE_ADDR'] ?? null;
  if ($xff && strpos($xff, ',') !== false) { $xff = trim(explode(',', $xff)[0]); }
  foreach ([$cf,$xff,$xri,$rem] as $ip) {
    if ($ip && filter_var($ip, FILTER_VALIDATE_IP)) return $ip;
  }
  return null;
}

// Input
$input    = file_get_contents('php://input');
$data     = json_decode($input, true) ?: [];
$event_id = $data['event_id'] ?? null;
$events   = $data['events'] ?? [];
$page_url = $data['page_url'] ?? null;
$now      = time();

// user_data
$user_data = array_filter([
  'client_ip_address' => client_ip(),
  'client_user_agent' => $_SERVER['HTTP_USER_AGENT'] ?? null,
  'fbc'               => read_cookie('_fbc'),
  'fbp'               => read_cookie('_fbp'),
  // 'em' => [ sha256_lower($logged_in_email) ],
  // 'ph' => [ sha256_lower($logged_in_phone) ],
]);

$event_source_url = $page_url ?: ($_SERVER['HTTP_REFERER'] ?? (
  (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS']==='on' ? 'https' : 'http') .
  '://' . $_SERVER['HTTP_HOST'] . ($_SERVER['REQUEST_URI'] ?? '/')
));

// Build events
$server_events = [];
foreach ($events as $e) {
  $server_events[] = [
    'event_name'       => $e['name'] ?? '',
    'event_time'       => $now,
    'event_id'         => $event_id,
    'action_source'    => 'website',
    'event_source_url' => $event_source_url,
    'user_data'        => $user_data,
    'custom_data'      => $e['params'] ?? []
  ];
}

$payload = ['data' => $server_events];
//$payload['test_event_code'] = 'TEST38806';

$endpoint = "https://graph.facebook.com/{$GRAPH_VER}/{$PIXEL_ID}/events?access_token=" . urlencode($ACCESS_TOKEN);

$ch = curl_init($endpoint);
curl_setopt_array($ch, [
  CURLOPT_POST => true,
  CURLOPT_HTTPHEADER => ['Content-Type: application/json'],
  CURLOPT_POSTFIELDS => json_encode($payload, JSON_UNESCAPED_UNICODE),
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_TIMEOUT => 10,
]);
$response  = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

header('Content-Type: application/json');
echo json_encode(['ok' => $http_code >= 200 && $http_code < 300, 'status' => $http_code]);