<?php

/**
 * Custom PayU gateway for Acadlix.
 *
 * IMPORTANT:
 * This is NOT the PayU PHP SDK.
 * No third-party PayU library is bundled or loaded.
 *
 * @package Acadlix
 */

namespace Yuvayana\Acadlix\Common\Payments\Gateways;

use Yuvayana\Acadlix\Common\Models\Order;

defined('ABSPATH') || exit();

use Yuvayana\Acadlix\Common\Payments\PaymentGatewayInterface;
use WP_REST_Response;
use WP_Error;
use Exception;

// Prevent class re-declaration when another plugin loads a class with the same FQCN.
if (!class_exists(__NAMESPACE__ . '\\PayU')) {
  class PayU implements PaymentGatewayInterface
  {
    const CONNECTION_TIMEOUT = 30;
    const REDIRECT_URL_SANDBOX = 'https://test.payu.in';
    const REDIRECT_URL_LIVE = 'https://secure.payu.in';
    const API_URL_SANDBOX = 'https://test.payu.in';
    const API_URL_LIVE = 'https://info.payu.in';
    protected bool $is_payu_active;
    protected string $payu_url;
    protected string $redirect_url;
    protected bool $sandbox;
    protected string $merchant_key;
    protected string $salt;
    protected float $amount;
    protected string $currency;
    protected array $billing_info;

    public function __construct()
    {
      $this->sandbox = acadlix()->helper()->acadlix_get_option('acadlix_payu_sandbox') === 'yes';
      $this->payu_url = $this->sandbox ? self::API_URL_SANDBOX : self::API_URL_LIVE;
      $this->redirect_url = $this->sandbox ? self::REDIRECT_URL_SANDBOX : self::REDIRECT_URL_LIVE;
      $this->merchant_key = acadlix()->helper()->acadlix_get_option('acadlix_payu_merchant_key');
      $this->salt = acadlix()->helper()->acadlix_get_option('acadlix_payu_salt');
      $this->is_payu_active = acadlix()->helper()->acadlix_get_option('acadlix_payu_active') === 'yes';
    }

    public function is_payu_active()
    {
      if ($this->is_payu_active && $this->merchant_key && $this->salt) {
        return true;
      }
      return false;
    }
    public function setAmount(float $amount): self
    {
      $this->amount = $amount;
      return $this;
    }

    public function setCurrency(string $currency): self
    {
      $this->currency = $currency;
      return $this;
    }

    public function setBillingInfo(array $billing_info): self
    {
      $this->billing_info = $billing_info;
      return $this;
    }

    protected function verifyPayment($payu_order_id)
    {
      $command = 'verify_payment';

      $hash_str = "{$this->merchant_key}|{$command}|{$payu_order_id}|{$this->salt}";
      $hash = strtolower(hash('sha512', $hash_str)); // generate hash for verify payment request

      $data = [
        'key' => $this->merchant_key,
        'command' => $command,
        'var1' => $payu_order_id,
        'hash' => $hash,
      ];
      $response = wp_remote_post(
        $this->payu_url . '/merchant/postservice?form=2',
        [
          'body' => $data,
          'timeout' => self::CONNECTION_TIMEOUT,
        ]
      );

      if (is_wp_error($response)) {
        throw new Exception(esc_html($response->get_error_message()));
      }

      $result = wp_remote_retrieve_body($response);
      $result = json_decode($result);

      $status_code = wp_remote_retrieve_response_code($response);

      if ($status_code < 200 || $status_code > 299) {
        throw new Exception(esc_html($result->error_description));
      }

      if (isset($result->status) && 1 === $result->status) {
        return $result->transaction_details->$payu_order_id;
      }

      if (isset($result->msg)) {
        $error = trim($result->msg);
        throw new Exception(esc_html($error));
      }
      throw new Exception('Something went wrong. Please try again later.');
    }

    protected function returnUrl($txn_id)
    {
      $args = [
        'token' => $txn_id,
        'nonce' => wp_create_nonce('acadlix_payment_nonce'),
      ];
      return add_query_arg($args, esc_url(get_permalink(acadlix()->helper()->acadlix_get_option('acadlix_thankyou_page_id'))));
    }

    protected function cancelUrl($txn_id)
    {
      $args = [
        'cancelled' => true,
      ];
      return add_query_arg($args, $this->returnUrl($txn_id));
    }


    protected function getOutputField()
    {
      $first_name = $this->billing_info['first_name'] ?? '';
      $last_name = $this->billing_info['last_name'] ?? '';
      $email = $this->billing_info['email'] ?? '';
      $phone = $this->billing_info['phone'] ?? '';
      $address = $this->billing_info['address'] ?? '';
      $city = $this->billing_info['city'] ?? '';
      $country = $this->billing_info['country'] ?? '';
      $zipcode = $this->billing_info['zipcode'] ?? '';

      $udf1 = PHP_VERSION;
      $udf2 = acadlix()->isDev ? '1.0.0' : ACADLIX_VERSION;
      $udf3 = 'ACADLIX LMS COURSE';
      $udf4 = home_url('/');
      $udf5 = 'ACADLIX Pay';

      $txnid = substr(hash('sha256', wp_rand() . microtime()), 0, 20);
      $str = "{$this->merchant_key}|{$txnid}|{$this->amount}|Product Info|{$first_name}|{$email}|{$udf1}|{$udf2}|{$udf3}|{$udf4}|{$udf5}||||||{$this->salt}";
      $hash = strtolower(hash('sha512', $str));

      $return_url = $this->returnUrl($txnid);
      $cancel_url = $this->cancelUrl($txnid);
      return [
        'key' => $this->merchant_key,
        'txnid' => $txnid,
        'amount' => $this->amount,
        'productinfo' => 'Product Info',
        'firstname' => $first_name,
        'lastname' => $last_name,
        'address1' => $address,
        'city' => $city,
        'country' => $country,
        'zipcode' => $zipcode,
        'email' => $email,
        'phone' => $phone,
        'surl' => $return_url,
        'furl' => $cancel_url,
        'hash' => $hash,
        'udf1' => $udf1,
        'udf2' => $udf2,
        'udf3' => $udf3,
        'udf4' => $udf4,
        'udf5' => $udf5,
      ];
    }

    public function getOrder($payu_txn_id)
    {
      $order_meta = acadlix()->model()->orderMeta()
        ->where("meta_key", "payu_txn_id")
        ->where("meta_value", $payu_txn_id)
        ->first();
      return $order_meta
        ? acadlix()->model()->order()->find($order_meta->order_id)
        : null;
    }

    protected function successOrder($order)
    {
      if (!$order) {
        throw new Exception('Order not found');
      }
      $order->success_order();
      $message = "Order status updated to success";
      $order->createActivityLog($message);

      if ($order->order_items()->count() > 0) {
        foreach ($order->order_items as $item) {
          $cart = acadlix()->model()->courseCart()
            ->where("user_id", $order->user_id)
            ->where("item_id", $item->item_id)
            ->where("type", $item->type)
            ->first();
          if ($cart) {
            $cart->delete();
          }
        }
      }
      return ['success' => true, 'message' => 'Order captured successfully'];
    }

    public function failedOrder($order, $message = ''): array
    {
      if (!$order) {
        throw new Exception('Order not found');
      }
      $order->failed_order();
      $message = "Order status updated to failed";
      $order->createActivityLog($message);

      $order->updateOrCreateMeta('failure_reason', $message);
      return ['success' => true, 'message' => $message];
    }

    public function processOrder(): array|object|null
    {
      if (!$this->is_payu_active()) {
        throw new Exception("PayU is not active");
      }

      if ($this->currency !== "INR") {
        throw new Exception("PayU only supports INR");
      }

      $body['payu_url'] = "{$this->redirect_url}/_payment";
      $body['payu_data'] = $this->getOutputField();
      return $body;
    }

    public function verifyWebhook(array $data): WP_REST_Response|WP_Error
    {
      try {
        if (!$this->is_payu_active()) {
          throw new Exception("PayU is not active");
        }
        $payload = $data['stream'] ?? '';

        if (!$payload) {
          throw new Exception("PayU payload not found");
        }
        parse_str($payload, $post_array);
        $txn_id = $post_array["txnid"];
        $order = $this->getOrder($txn_id);
        if (null === $order) {
          exit;
        }
        $response = $this->orderCapture($txn_id);
        return new WP_REST_Response($response, 200);

      } catch (Exception $e) {
        exit;
      }
    }

    protected function orderCapture($payu_txn_id)
    {
      try {
        if (!$payu_txn_id) {
          throw new Exception('PayU txn id not found');
        }

        $order = $this->getOrder($payu_txn_id);
        if (!$order) {
          throw new Exception('Order not found');
        }

        if ($order->status == Order::STATUS_SUCCESS) {
          return ['success' => true, 'message' => 'Order already processed'];
        }

        $payu_payment = $this->verifyPayment($payu_txn_id);
        if ($payu_payment->txnid !== $payu_txn_id) {
          return;
        }

        if (isset($payu_payment->status)) {
          $transaction_status = $payu_payment->status;
          if ('success' === $transaction_status) {
            return $this->successOrder($order);
          } elseif (isset($payu_payment->error_Message)) {
            return $this->failedOrder($order, $payu_payment->error_Message);
          }
        }
        return;
      } catch (Exception $e) {
        throw new Exception(esc_html($e->getMessage()));
      }

    }

    public function verifyOrder($payu_txn_id): void
    {
      try {
        if (!$this->is_payu_active()) {
          throw new Exception("PayU is not active");
        }
        if (!$payu_txn_id) {
          throw new Exception('PayU txn id not found');
        }
        $this->orderCapture($payu_txn_id);
      } catch (Exception $e) {
        return;
      }
    }

  }
} // end if class_exists