<?php

class InstagramGraphLogin {

    /*
     * Facebook Object
     */
    private $fb;

    /*
     * Facebook helper
     */
    private $fbHelper;

    /*
     * Facebook Permissions
     */
    private $permissions = ['instagram_basic', 'manage_pages'];

    /**
     * Instantiates a new Facebook class object, Facebook Helper
     *
     */
    public function __construct() {
	$this->fb = new \Facebook\Facebook([
	    'app_id' => FACEBOOK_APP_ID,
	    'app_secret' => FACEBOOK_APP_SECRET,
	    'default_graph_version' => 'v3.3',
	]);
	$this->fbHelper = $this->fb->getRedirectLoginHelper();
    }

    /**
     * Get Login Url for your Application
     *
     */
    public function getLoginUrl() {
	return $this->fbHelper->getLoginUrl(INSTAGRAM_GRAPH_REDIRECT_URL, $this->permissions);
    }

    /**
     * returns an AccessToken.
     *
     *
     * @return AccessToken|null|false
     *
     * @throws FacebookSDKException
     */
    public function getAccessToken() {
	try {
	    $accessToken = $this->fbHelper->getAccessToken();
	} catch (Facebook\Exceptions\FacebookResponseException $e) {
	    // When Graph returns an error
	    error_log('Graph returned an error: ' . $e->getMessage());
	    return false;
	} catch (Facebook\Exceptions\FacebookSDKException $e) {
	    // When validation fails or other local issues
	    error_log('Facebook SDK returned an error: ' . $e->getMessage());
	    return false;
	}

	if (!isset($accessToken)) {
	    if ($this->fbHelper->getError()) {
		$error = "Error: " . $this->fbHelper->getError() . "\n";
		$error .= "Error Code: " . $this->fbHelper->getErrorCode() . "\n";
		$error .= "Error Reason: " . $this->fbHelper->getErrorReason() . "\n";
		$error .= "Error Description: " . $this->fbHelper->getErrorDescription() . "\n";

		error_log($error);
		return false;
	    } else {
		error_log('Bad request');
		return false;
	    }
	    return false;
	}

	// Logged in
	$accessTokenValue = $accessToken->getValue();

	// The OAuth 2.0 client handler helps us manage access tokens
	$oAuth2Client = $this->fb->getOAuth2Client();

	// Get the access token metadata from /debug_token
	$tokenMetadata = $oAuth2Client->debugToken($accessToken);

	// Validation (these will throw FacebookSDKException's when they fail)
	$tokenMetadata->validateAppId(FACEBOOK_APP_ID);
	// If you know the user ID this access token belongs to, you can validate it here
	//$tokenMetadata->validateUserId('123');
	$tokenMetadata->validateExpiration();

	if (!$accessToken->isLongLived()) {
	    // Exchanges a short-lived access token for a long-lived one
	    try {
		$accessToken = $oAuth2Client->getLongLivedAccessToken($accessToken);
	    } catch (Facebook\Exceptions\FacebookSDKException $e) {
		error_log("<p>Error getting long-lived access token: " . $e->getMessage() . "</p>\n\n");
	    }

	    $accessTokenValue = ($accessToken->getValue());
	}

	return $accessTokenValue;
    }

    /**
     * returns Connected Instagram IDs
     *
     *
     * @return array|false
     *
     * @throws FacebookSDKException
     */
    public function getConnectedInstagramID($accessToken) {
	try {
	    $response = $this->fb->get('/me/accounts', $accessToken);
	} catch (\Facebook\Exceptions\FacebookResponseException $e) {
	    // When Graph returns an error
	    error_log('Graph returned an error: ' . $e->getMessage());
	    return false;
	} catch (\Facebook\Exceptions\FacebookSDKException $e) {
	    // When validation fails or other local issues
	    error_log('Facebook SDK returned an error: ' . $e->getMessage());
	    return false;
	}

	$decodedData = json_decode($response->getBody());

	$connectedAccountIDs = [];

	foreach ($decodedData->data as $key => $item) {
	    $pageID = $item->id;
	    try {
		$connectedAccountResponse = $this->fb->get('/' . $pageID . '?fields=connected_instagram_account,instagram_business_account', $accessToken);
		$decodedConnectedAccountData = json_decode($connectedAccountResponse->getBody());

		if (!empty($decodedConnectedAccountData->instagram_business_account)) {
		    $connectedAccountIDs[] = $decodedConnectedAccountData->instagram_business_account->id;
		} else if (!empty($decodedConnectedAccountData->connected_instagram_account)) {
		    $connectedAccountIDs[] = $decodedConnectedAccountData->connected_instagram_account->id;
		}
	    } catch (\Facebook\Exceptions\FacebookResponseException $e) {
		// When Graph returns an error
		error_log('Graph returned an error: ' . $e->getMessage());
		return false;
	    } catch (\Facebook\Exceptions\FacebookSDKException $e) {
		// When validation fails or other local issues
		error_log('Facebook SDK returned an error: ' . $e->getMessage());
		return false;
	    }
	}

	return $connectedAccountIDs;
    }

    /**
     * returns User Info for Connected Instagram IDs
     *
     *
     * @return array|false
     *
     * @throws FacebookSDKException
     */
    public function getUserInfo() {
	$accessToken = $this->getAccessToken();

	$connectedInstagramIDs = $this->getConnectedInstagramID($accessToken);

	$instagramuserInfo = [];

	if (!empty($connectedInstagramIDs)) {
	    foreach ($connectedInstagramIDs as $key => $value) {
		try {
		    // Get the \Facebook\GraphNodes\GraphUser object for the current user.
		    // If you provided a 'default_access_token', the '{access-token}' is optional.
		    $response = $this->fb->get('/'.$value.'?fields=name,biography,username,ig_id,followers_count,follows_count,media_count,profile_picture_url,website', $accessToken);

		    $decodedData = json_decode($response->getBody());

		    $instagramuserInfo[] = $decodedData;
		} catch (\Facebook\Exceptions\FacebookResponseException $e) {
		    // When Graph returns an error
		    error_log('Graph returned an error: ' . $e->getMessage());
		    return false;
		} catch (\Facebook\Exceptions\FacebookSDKException $e) {
		    // When validation fails or other local issues
		    error_log('Facebook SDK returned an error: ' . $e->getMessage());
		    return false;
		}
	    }
	}

	return ["userInfo" => $instagramuserInfo, "accessToken" => $accessToken];
    }

}

?>