<?php
// Simple API rate limiter simulation
function callExternalApi($data) {
    // Simulate API call
    echo "API call with data: " . json_encode($data) . "<br>";
    return ["status" => "success", "message" => "Data processed"];
}

$apiRequests = [
    ["user" => "user1", "action" => "update"],
    ["user" => "user2", "action" => "create"],
    ["user" => "user3", "action" => "delete"],
    ["user" => "user4", "action" => "read"],
    ["user" => "user5", "action" => "update"],
];

$requestsPerSecond = 2; // Maximum 2 requests per second
$i = 0;

while ($i < count($apiRequests)) {
    $batchStart = microtime(true);
    $batchCount = 0;
    
    // Process up to $requestsPerSecond requests in this batch
    while ($i < count($apiRequests) && $batchCount < $requestsPerSecond) {
        $result = callExternalApi($apiRequests[$i]);
        $i++;
        $batchCount++;
    }
    
    // Calculate time spent on this batch
    $batchTime = microtime(true) - $batchStart;
    
    // If we processed quickly, wait until 1 second has passed
    if ($batchTime < 1 && $i < count($apiRequests)) {
        $waitTime = 1 - $batchTime;
        echo "Rate limiting: waiting " . number_format($waitTime, 2) . " seconds...<br>";
        // In a real application, you would use sleep() or usleep()
        // sleep($waitTime); // Uncomment in real usage
    }
}

echo "All API requests completed.";
?>

<?php
// Simple web crawler simulation
function getLinksFromPage($url) {
    // In a real crawler, this would parse HTML and extract links
    // Here we're just simulating with fixed data
    $pageData = [
        "https://example.com/" => [
            "https://example.com/about",
            "https://example.com/products"
        ],
        "https://example.com/about" => [
            "https://example.com/team",
            "https://example.com/history"
        ],
        "https://example.com/products" => [
            "https://example.com/products/1",
            "https://example.com/products/2"
        ],
        // Other pages have no outgoing links
        "https://example.com/team" => [],
        "https://example.com/history" => [],
        "https://example.com/products/1" => [],
        "https://example.com/products/2" => []
    ];
    
    echo "Crawling: $url<br>";
    return isset($pageData[$url]) ? $pageData[$url] : [];
}

// Initialize with starting URL
$startUrl = "https://example.com/";
$urlsToVisit = [$startUrl];
$visitedUrls = [];
$maxPages = 10; // Safety limit
$pagesVisited = 0;

// Continue until no more URLs or we hit the limit
while (!empty($urlsToVisit) && $pagesVisited < $maxPages) {
    // Get the next URL to process
    $currentUrl = array_shift($urlsToVisit);
    
    // Skip if already visited
    if (in_array($currentUrl, $visitedUrls)) {
        continue;
    }
    
    // Add to visited set
    $visitedUrls[] = $currentUrl;
    $pagesVisited++;
    
    // Get links from this page
    $links = getLinksFromPage($currentUrl);
    
    // Add new links to our queue
    foreach ($links as $link) {
        if (!in_array($link, $visitedUrls) && !in_array($link, $urlsToVisit)) {
            $urlsToVisit[] = $link;
        }
    }
}

echo "Crawler finished after visiting $pagesVisited pages.";
?>