<?php

require __DIR__ . '/../vendor/autoload.php';

use Curl\MultiCurl;

// List of pages to fetch.
$urls = [
    'https://httpbin.org/status/503',
    'https://httpbin.org/status/200',
    'https://httpbin.org/status/401',
    'https://httpbin.org/delay/3',
    'https://httpbin.org/status/201',
    'https://httpbin.org/delay/1',
    'https://httpbin.org/status/500',
    'https://httpbin.org/status/504',
];

$request_stats = [
    'all' => [],
    'successful' => [],
    'errors' => [],
    'completed' => [],
    'not_completed' => [],
];

$multi_curl = new MultiCurl();
$multi_curl->setConcurrency(2);

foreach ($urls as $url) {
    // Queue requests.
    $request = $multi_curl->addGet($url);

    // Track all requests queued.
    $request_stats['all'][] = $request->url;
}

// Track successful requests.
$multi_curl->success(function ($instance) use (&$request_stats, $multi_curl) {
    $request_stats['successful'][] = $instance->url;

    // Optionally, stop additional requests based on some condition (e.g. stop
    // after a number of successful requests).
    if (count($request_stats['successful']) >= 3) {
        $multi_curl->stop();
    }
});

// Track requests that errored.
$multi_curl->error(function ($instance) use (&$request_stats) {
    $request_stats['errors'][] = $instance->url;
});

// Track requests that completed.
$multi_curl->complete(function ($instance) use (&$request_stats) {
    $request_stats['completed'][] = $instance->url;
});

$multi_curl->start();

// Determine urls not completed.
$request_stats['not_completed'] = array_diff($request_stats['all'], $request_stats['completed']);

// Display results.
var_dump($request_stats);

// $ php multi_curl_track_success_urls.php
// array(5) {
//   ["all"]=>
//   array(8) {
//     [0]=>
//     string(30) "https://httpbin.org/status/503"
//     [1]=>
//     string(30) "https://httpbin.org/status/200"
//     [2]=>
//     string(30) "https://httpbin.org/status/401"
//     [3]=>
//     string(27) "https://httpbin.org/delay/3"
//     [4]=>
//     string(30) "https://httpbin.org/status/201"
//     [5]=>
//     string(27) "https://httpbin.org/delay/1"
//     [6]=>
//     string(30) "https://httpbin.org/status/500"
//     [7]=>
//     string(30) "https://httpbin.org/status/504"
//   }
//   ["successful"]=>
//   array(3) {
//     [0]=>
//     string(30) "https://httpbin.org/status/200"
//     [1]=>
//     string(27) "https://httpbin.org/delay/3"
//     [2]=>
//     string(30) "https://httpbin.org/status/201"
//   }
//   ["errors"]=>
//   array(2) {
//     [0]=>
//     string(30) "https://httpbin.org/status/503"
//     [1]=>
//     string(30) "https://httpbin.org/status/401"
//   }
//   ["completed"]=>
//   array(5) {
//     [0]=>
//     string(30) "https://httpbin.org/status/200"
//     [1]=>
//     string(30) "https://httpbin.org/status/503"
//     [2]=>
//     string(30) "https://httpbin.org/status/401"
//     [3]=>
//     string(27) "https://httpbin.org/delay/3"
//     [4]=>
//     string(30) "https://httpbin.org/status/201"
//   }
//   ["not_completed"]=>
//   array(3) {
//     [5]=>
//     string(27) "https://httpbin.org/delay/1"
//     [6]=>
//     string(30) "https://httpbin.org/status/500"
//     [7]=>
//     string(30) "https://httpbin.org/status/504"
//   }
// }