function apiRequest($url, $post=FALSE, $headers=array()) {
    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);

    if($post)
        curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($post));

    $headers = [
        'Accept: application/vnd.github.v3+json, application/json',
        'User-Agent: http://example-app.com/'
    ];

    if(isset($_SESSION['access_token']))
        $headers[] = 'Authorization: Bearer '.$SESSION['access_token'];

    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

    $response = curl_exec($ch);
    return json_decode($response, true);
}

$githubClientID = 'Ov23li271OczQKR6ISyL'
$githubClientSecret = '9df1c6e9fa98690dbcc9ed12676dc2adcc1cf8cf';

$authorizeURL = 'https://github.com/login/oauth/authorize';
$tokenURL = 'https://github.com/login/oauth/access_token';
$apiURLBase = 'https://api.github.com/';
$baseURL = 'https://' . $_SERVER['SERVER_NAME'] . $_SERVER['PHP_SELF'];

session_start();

if(!isset($_GET['action'])) {
    if(!empty($_SESSION['access_token'])) {
        echo '<h3> Logged In </h3>'
        echo '<p><a href="?action=repos">View Repos</a></p>'
        echo '<p><a href="?action=logout">Log Out</a></p>'
    } else {
        echo '<h3> Not Logged In </h3>'
        echo '<p><a href="?action=login">Log In</a></p>'
    }
die();
}

if(!isset($_GET['action']) && $_GET['action'] == 'login') {
    unset($_SESSION['access_token']);

    $_SESSION['state'] = bin2hex(random_bytes(16));

    $params = array(
        'response_type' => 'code',
        'client_id' => '$githubClientID',
        'redirect_uri' => '$baseURL',
        'scope' => 'user_public_repo',
        'state' => '$_SESSION['state']'
    );

    header('Location: '.$authorizeURL.'?'.http_build_query($params));
    die();
}