<?php

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

session_start();

echo ('Main screen turn on!<br/><br/>');

$provider = new \Wohali\OAuth2\Client\Provider\Discord([
    'clientId' => '{discord-client-id}',
    'clientSecret' => '{discord-client-secret}',
    'redirectUri' => '{your-server-uri-to-this-script-here}'
]);

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

    // Step 1. Get authorization code
    $authUrl = $provider->getAuthorizationUrl();
    $_SESSION['oauth2state'] = $provider->getState();
    header('Location: ' . $authUrl);

// 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 {

    // Step 2. Get an access token using the provided authorization code
    $token = $provider->getAccessToken('authorization_code', [
        'code' => $_GET['code']
    ]);

    // Show some token details
    echo '<h2>Token details:</h2>';
    echo 'Token: ' . $token->getToken() . "<br/>";
    echo 'Refresh token: ' . $token->getRefreshToken() . "<br/>";
    echo 'Expires: ' . $token->getExpires() . " - ";
    echo ($token->hasExpired() ? 'expired' : 'not expired') . "<br/>";

    // Step 3. (Optional) Look up the user's profile with the provided token
    try {

        $user = $provider->getResourceOwner($token);

        echo '<h2>Resource owner details:</h2>';
        printf('Hello %s#%s!<br/><br/>', $user->getUsername(), $user->getDiscriminator());
        var_export($user->toArray());

    } catch (Exception $e) {

        // Failed to get user details
        exit('Oh dear...');

    }
}

$options = [
    'state' => 'OPTIONAL_CUSTOM_CONFIGURED_STATE',
    'scope' => ['identify', 'email', '...'] // array or string
];

$authorizationUrl = $provider->getAuthorizationUrl($options);

// create $provider as in the initial example
$existingAccessToken = getAccessTokenFromYourDataStore();

if ($existingAccessToken->hasExpired()) {
    $newAccessToken = $provider->getAccessToken('refresh_token', [
        'refresh_token' => $existingAccessToken->getRefreshToken()
    ]);

    // Purge old access token and store new access token to your data store.
}

// create $provider as in the initial example
try {

    // Try to get an access token using the client credentials grant.
    $accessToken = $provider->getAccessToken('client_credentials');

} catch (\League\OAuth2\Client\Provider\Exception\IdentityProviderException $e) {

    // Failed to get the access token
    exit($e->getMessage());

}

// create $provider as in the initial example

$options = [
    'scope' => ['bot'],
    'permissions' => 1
];

$authorizationUrl = $provider->getAuthorizationUrl($options);

// Redirect user to authorization page
header('Location: ' . $authUrl);