<?php
namespace Sakura;

use \PayPal\Api\Amount;
use \PayPal\Api\Details;
use \PayPal\Api\Item;
use \PayPal\Api\ItemList;
use \PayPal\Api\Payer;
use \PayPal\Api\Payment;
use \PayPal\Api\PaymentExecution;
use \PayPal\Api\RedirectUrls;
use \PayPal\Api\Transaction;

/**
 * Sakura PayPal API wrapper.
 * 
 * @package Sakura
 * @author Kamil Rakowski <admin@krakow.pw>
 * @author Julian van de Groep <me@flash.moe>
 */
class Payments
{
    /**
     * Container for the PayPal API
     * 
     * @var \PayPal\Rest\ApiContext
     */
    private static $paypal;

    /**
     * Initialise the wrapper.
     * 
     * @return bool Always true.
     */
    public static function init()
    {

        // Set PayPal object
        try {
            self::$paypal = new \PayPal\Rest\ApiContext(
                new \PayPal\Auth\OAuthTokenCredential(
                    Config::get('paypal_client_id'),
                    Config::get('paypal_secret')
                )
            );
        } catch (\Exception $e) {
            return false;
        }

        // Set the configuration
        self::$paypal->setConfig([
            'mode' => Config::get('paypal_mode'),
        ]);

        return true;
    }

    /**
     * Create a new transaction.
     * 
     * @param float $total The total amount of money.
     * @param string $itemName The name of the item being purchased.
     * @param string $transDescription The description of the item.
     * @param string $returnUrl The URL that PayPal will redirect back to.
     * 
     * @return bool|null|string If successful; the PayPal approval link.
     */
    public static function createTransaction($total, $itemName, $transDescription, $returnUrl)
    {

        // Create the payer object
        $payer = new Payer();

        // Set the method
        $payer->setPaymentMethod('paypal');

        // Create the item
        $item = new Item();

        // Set the item details
        $item->setName($itemName)
            ->setCurrency('EUR')
            ->setQuantity(1)
            ->setPrice($total);

        // Create itemlist
        $list = new ItemList();

        // Add the items
        $list->setItems([$item]);

        // Create details
        $details = new Details();

        // Set details
        $details->setSubtotal($total);

        // Create amount
        $amount = new Amount();

        // Set amount data
        $amount->setCurrency('EUR')
            ->setTotal($total)
            ->setDetails($details);

        // Create transaction
        $trans = new Transaction();

        // Set transaction data
        $trans->setAmount($amount)
            ->setItemList($list)
            ->setDescription($transDescription)
            ->setInvoiceNumber(uniqid());

        // Create redirect url object
        $redir = new RedirectUrls();

        // Set redirect url data
        $redir->setReturnUrl($returnUrl . '?mode=finish&success=true')
            ->setCancelUrl($returnUrl . '?mode=finish&success=false');

        // Create payment object
        $payment = new Payment();

        // Set payment data (finally)
        $payment->setIntent('sale')
            ->setPayer($payer)
            ->setRedirectUrls($redir)
            ->setTransactions([$trans]);

        // Try to create payment
        try {
            $payment->create(self::$paypal);
        } catch (\Exception $ex) {
            return false;
        }

        // Return the approval link if everything is gucci
        return $payment->getApprovalLink();
    }

    /**
     * Complete the PayPal transaction.
     * 
     * @param string $paymentId ID of the payment.
     * @param string $payerId ID of the payer.
     * 
     * @return bool Success indicator.
     */
    public static function completeTransaction($paymentId, $payerId)
    {

        // Attempt to get the payment
        $payment = Payment::get($paymentId, self::$paypal);

        // Create payment execution object
        $execute = new PaymentExecution();

        // Set the payer ID
        $execute->setPayerId($payerId);

        // Attempt to charge the fucker
        try {
            $payment->execute($execute, self::$paypal);
        } catch (\Exception $ex) {
            return false;
        }

        // If everything was cute return true
        return true;
    }
}