<?php

$data_time_start = microtime(true);

$analytics_enable_tail = false;
$analytics_post = null;

function deduce_user_agent() {
    $real_agent=$_SERVER['HTTP_USER_AGENT'];

    if(preg_match('/(Googlebot|\w*Google\w*)/', $real_agent, $match)) {
        return "bot/google/" . $match[1];
    }
    elseif(preg_match('/(Mozilla|Chrome|Chromium)/', $real_agent, $match)) {
        return "user/" . $match[1];
    }
    else {
        return "unidentified";
    }
}

function analytics_is_user() {
    return preg_match('/^user/', deduce_user_agent());
}

register_shutdown_function(function() {
    $data_end_time = microtime(true);

    global $data_time_start;
    global $analytics_adapter;

    global $REQUEST_PATH;
    global $REQUEST_QUERY;

    global $analytics_enable_tail;

    $data_time_end = microtime(true);

    $http_referer = 'magic';
    if(isset($_SERVER['HTTP_REFERER'])) {
        $http_referer = parse_url($_SERVER['HTTP_REFERER'], PHP_URL_HOST);
    }

    $referrer = $REQUEST_QUERY['referer'] ?? $REQUEST_QUERY['ref'] ?? $http_referer;

    $compute_time = $data_time_end - $data_time_start;

    $analytics_adapter->log_path_access($REQUEST_PATH,
        deduce_user_agent(),
        $referrer,
        $compute_time);

    if($analytics_enable_tail) {
        echo "<!-- Total page time was: " . $compute_time . " -->";
    }

    if(isset($analytics_post)) {
        $analytics_post->increment_counter("compute_time", $compute_time);

        if(analytics_is_user()) {
            $analytics_post->increment_counter("views");
        }
    }
});

?>