<?php

use Lrf141\OAuth2\Client\Provider\Mastodon;

session_start();

$provider = new Mastodon([
    'clientId' => '',
    'clientSecret' => '',
    'redirectUri' => 'redirect url',
    'instance' => 'https://mstdn.jp',
    'scope' => 'read write follow',
]);


if (!isset($_GET['code'])) {

    $authUrl = $provider->getAuthorizationUrl();

    $_SESSION['oauth2state'] = $provider->getState();
    header('Location: '.$authUrl);
    exit;

// Check given state against previously stored one to mitigate CSRF attack
} elseif (empty($_GET['state']) || ($_GET['state'] !== $_SESSION['oauth2state'])) {

    unset($_SESSION['oauth2state']);
    exit('Invalid state');

} else {

    // Try to get an access token (using the authorization code grant)
    $token = $provider->getAccessToken('authorization_code', [
        'code' => $_GET['code']
    ]);
    
    // Optional: Now you have a token you can look up a users profile data
    try {
    
        $user = $provider->getResourceOwner($token);
       
        echo $user->getName();
        
    } catch(Exception $e) {
       
       
        exit('Oh dear...');
    }


    echo $token->getToken();
}