<?php
defined('ABSPATH') || exit;

/**
 * Core payment processing functions for Redsys gateway
 */
class EB_Redsys_Payment_Functions {

    private static $instance = null;
    private $api;

    public static function get_instance() {
        if (null === self::$instance) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    private function __construct() {
        // Initialize Redsys API
        require_once EB_REDSYS_PATH . 'includes/api/apiRedsysFinal.php';
        $this->api = new RedsysAPI();
    }

    /**
     * Process standard payment
     */
    public function process_standard_payment($booking_data) {
        try {
            $params = $this->prepare_payment_params($booking_data);
            return $this->send_payment_request($params);
        } catch (Exception $e) {
            $this->log_error($e->getMessage());
            return false;
        }
    }

    /**
     * Process future dated payment
     */
    public function process_future_payment($booking_data) {
        try {
            $params = $this->prepare_payment_params($booking_data);
            
            // Add future payment parameters
            $params['DS_MERCHANT_TRANSACTIONTYPE'] = 'L'; // Deferred payment
            $params['DS_MERCHANT_DATEFRECUENCY'] = '1'; // Daily
            $params['DS_MERCHANT_CHARGEEXPIRYDATE'] = date('d/m/Y', strtotime($booking_data['check_in_date']));
            
            return $this->send_payment_request($params);
        } catch (Exception $e) {
            $this->log_error($e->getMessage());
            return false;
        }
    }

    /**
     * Process subscription payment
     */
    public function process_subscription_payment($booking_data) {
        try {
            $params = $this->prepare_payment_params($booking_data);
            
            // Add subscription parameters
            $params['DS_MERCHANT_TRANSACTIONTYPE'] = 'L'; 
            $params['DS_MERCHANT_COF_INI'] = 'S'; // Initial recurring payment
            $params['DS_MERCHANT_COF_TYPE'] = 'R'; // Recurring payment type
            
            return $this->send_payment_request($params);
        } catch (Exception $e) {
            $this->log_error($e->getMessage());
            return false;
        }
    }

    /**
     * Process subsequent subscription payment
     */
    public function process_subscription_renewal($booking_data, $reference_id) {
        try {
            $params = $this->prepare_payment_params($booking_data);
            
            // Add subsequent payment parameters
            $params['DS_MERCHANT_TRANSACTIONTYPE'] = '0';
            $params['DS_MERCHANT_IDENTIFIER'] = $reference_id;
            $params['DS_MERCHANT_DIRECTPAYMENT'] = 'true';
            
            return $this->send_payment_request($params);
        } catch (Exception $e) {
            $this->log_error($e->getMessage());
            return false;
        }
    }

    /**
     * Prepare common payment parameters
     */
    private function prepare_payment_params($booking_data) {
        return array(
            'DS_MERCHANT_AMOUNT' => $this->format_amount($booking_data['amount']),
            'DS_MERCHANT_ORDER' => $this->generate_order_number($booking_data['booking_id']),
            'DS_MERCHANT_MERCHANTCODE' => get_option('eb_redsys_merchant_code'),
            'DS_MERCHANT_CURRENCY' => '978', // EUR
            'DS_MERCHANT_TERMINAL' => get_option('eb_redsys_terminal'),
            'DS_MERCHANT_MERCHANTURL' => $this->get_notification_url($booking_data['booking_id']),
            'DS_MERCHANT_URLOK' => $this->get_return_url($booking_data['booking_id'], 'success'),
            'DS_MERCHANT_URLKO' => $this->get_return_url($booking_data['booking_id'], 'failure')
        );
    }

    /**
     * Send payment request to Redsys
     */
    private function send_payment_request($params) {
        $version = "HMAC_SHA256_V1";
        $key = get_option('eb_redsys_encryption_key');
        
        // Create merchant parameters
        $merchant_params = $this->api->createMerchantParameters($params);
        
        // Create merchant signature
        $signature = $this->api->createMerchantSignature($key, $merchant_params);
        
        return array(
            'endpoint' => $this->get_endpoint(),
            'params' => array(
                'Ds_SignatureVersion' => $version,
                'Ds_MerchantParameters' => $merchant_params,
                'Ds_Signature' => $signature
            )
        );
    }

    /**
     * Process Redsys notification
     */
    public function process_notification($data) {
        try {
            $key = get_option('eb_redsys_encryption_key');
            $merchant_params = $data['Ds_MerchantParameters'];
            $signature = $data['Ds_Signature'];
            
            // Validate signature
            if (!$this->api->check_signature($merchant_params, $signature, $key)) {
                throw new Exception('Invalid signature');
            }
            
            // Decode parameters
            $decoded_params = $this->api->decodeMerchantParameters($merchant_params);
            
            // Check response code
            $response_code = $decoded_params['Ds_Response'];
            if ($response_code < 100) {
                // Payment successful
                $order_id = $this->extract_booking_id($decoded_params['Ds_Order']);
                $transaction_id = $decoded_params['Ds_AuthorisationCode'];
                
                // Store card reference for future payments if available
                if (isset($decoded_params['Ds_Merchant_Identifier'])) {
                    $this->store_card_reference(
                        $order_id, 
                        $decoded_params['Ds_Merchant_Identifier']
                    );
                }
                
                return array(
                    'success' => true,
                    'booking_id' => $order_id,
                    'transaction_id' => $transaction_id
                );
            }
            
            throw new Exception("Payment failed with code: $response_code");
            
        } catch (Exception $e) {
            $this->log_error($e->getMessage());
            return array('success' => false, 'error' => $e->getMessage());
        }
    }

    /**
     * Store card reference for future payments
     */
    private function store_card_reference($booking_id, $reference) {
        update_post_meta($booking_id, '_redsys_card_reference', $reference);
    }

    /**
     * Get stored card reference
     */
    public function get_card_reference($booking_id) {
        return get_post_meta($booking_id, '_redsys_card_reference', true);
    }

    /**
     * Get Redsys endpoint based on mode
     */
    private function get_endpoint() {
        return (get_option('eb_redsys_test_mode') === 'yes')
            ? 'https://sis-t.redsys.es:25443/sis/realizarPago'
            : 'https://sis.redsys.es/sis/realizarPago';
    }

    /**
     * Format amount for Redsys (in cents)
     */
    private function format_amount($amount) {
        return number_format($amount * 100, 0, '', '');
    }

    /**
     * Generate unique order number
     */
    private function generate_order_number($booking_id) {
        return sprintf('%010d', $booking_id) . date('is');
    }

    /**
     * Get notification URL
     */
    private function get_notification_url($booking_id) {
        return add_query_arg(array(
            'eb-api' => 'redsys',
            'booking_id' => $booking_id
        ), home_url('/'));
    }

    /**
     * Get return URL
     */
    private function get_return_url($booking_id, $result) {
        return add_query_arg(array(
            'booking_id' => $booking_id,
            'result' => $result
        ), eb_get_checkout_url());
    }

    /**
     * Extract booking ID from order number
     */
    private function extract_booking_id($order_number) {
        return intval(substr($order_number, 0, 10));
    }

    /**
     * Log error message
     */
    private function log_error($message) {
        if (function_exists('eb_log')) {
            eb_log('Redsys Error: ' . $message);
        }
    }
}

// Initialize payment functions
function eb_redsys_payment() {
    return EB_Redsys_Payment_Functions::get_instance();
}