<?php
/**
 * Customer Sync to Business Central
 *
 * @package WooBusinessCentral
 */

// Prevent direct access
if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

/**
 * Class WBC_Customer_Sync
 *
 * Handles syncing customers from WooCommerce to Business Central.
 */
class WBC_Customer_Sync {

    /**
     * Get or create a customer in Business Central
     *
     * Lookup priority:
     * 1. If NIF provided → search BC by taxRegistrationNumber, create if not found
     * 2. If no NIF → use configured default customer number
     *
     * @param WC_Order $order WooCommerce order.
     * @return string|WP_Error BC customer number or error.
     */
    public function get_or_create_customer( $order ) {
        $nif = $order->get_meta( '_nif' );
        $user_id = $order->get_user_id();

        // No NIF → use default customer number
        if ( empty( $nif ) ) {
            $default_customer = get_option( 'wbc_default_customer_number', '' );

            if ( empty( $default_customer ) ) {
                return new WP_Error( 'wbc_no_nif_no_default', __( 'Order has no NIF and no default customer number is configured.', 'woo-business-central' ) );
            }

            WBC_Logger::info( 'CustomerSync', 'No NIF provided, using default customer', array(
                'order_id'        => $order->get_id(),
                'customer_number' => $default_customer,
            ) );

            return $default_customer;
        }

        WBC_Logger::debug( 'CustomerSync', 'Getting or creating customer by NIF', array(
            'nif' => $nif,
        ) );

        // Check cached BC customer number for this user
        if ( $user_id ) {
            $cached_customer_number = get_user_meta( $user_id, '_wbc_bc_customer_number', true );
            if ( ! empty( $cached_customer_number ) ) {
                $exists = $this->verify_customer_exists( $cached_customer_number );
                if ( $exists ) {
                    WBC_Logger::debug( 'CustomerSync', 'Using cached BC customer', array(
                        'customer_number' => $cached_customer_number,
                    ) );
                    return $cached_customer_number;
                }
            }
        }

        // Search BC for customer with this NIF
        $existing = $this->find_customer_by_nif( $nif );

        if ( is_wp_error( $existing ) ) {
            return $existing;
        }

        if ( $existing ) {
            $customer_number = $existing['number'];

            if ( $user_id ) {
                update_user_meta( $user_id, '_wbc_bc_customer_id', $existing['id'] );
                update_user_meta( $user_id, '_wbc_bc_customer_number', $customer_number );
            }

            WBC_Logger::info( 'CustomerSync', 'Found existing BC customer by NIF', array(
                'nif'             => $nif,
                'customer_number' => $customer_number,
            ) );

            return $customer_number;
        }

        // Create new customer in BC with NIF
        $new_customer = $this->create_customer( $order );

        if ( is_wp_error( $new_customer ) ) {
            return $new_customer;
        }

        $customer_number = $new_customer['number'];

        if ( $user_id ) {
            update_user_meta( $user_id, '_wbc_bc_customer_id', $new_customer['id'] );
            update_user_meta( $user_id, '_wbc_bc_customer_number', $customer_number );
        }

        WBC_Logger::info( 'CustomerSync', 'Created new BC customer with NIF', array(
            'nif'             => $nif,
            'customer_number' => $customer_number,
        ) );

        return $customer_number;
    }

    /**
     * Find customer in BC by NIF (taxRegistrationNumber)
     *
     * @param string $nif Tax registration number (NIF/CIF/NIE).
     * @return array|false|WP_Error Customer data, false if not found, or error.
     */
    private function find_customer_by_nif( $nif ) {
        $filter = "taxRegistrationNumber eq '" . WBC_API_Client::escape_odata_string( $nif ) . "'";
        $result = WBC_API_Client::get_customers( $filter );

        if ( is_wp_error( $result ) ) {
            return $result;
        }

        $customers = isset( $result['value'] ) ? $result['value'] : array();

        if ( empty( $customers ) ) {
            return false;
        }

        return $customers[0];
    }

    /**
     * Verify a customer exists in BC
     *
     * @param string $customer_number BC customer number.
     * @return bool Whether the customer exists.
     */
    private function verify_customer_exists( $customer_number ) {
        $filter = "number eq '" . WBC_API_Client::escape_odata_string( $customer_number ) . "'";
        $result = WBC_API_Client::get_customers( $filter );

        if ( is_wp_error( $result ) ) {
            return false;
        }

        $customers = isset( $result['value'] ) ? $result['value'] : array();

        return ! empty( $customers );
    }

    /**
     * Create a new customer in BC
     *
     * @param WC_Order $order WooCommerce order.
     * @return array|WP_Error Created customer data or error.
     */
    private function create_customer( $order ) {
        // Build customer data from order
        $customer_data = $this->build_customer_data( $order );

        WBC_Logger::debug( 'CustomerSync', 'Creating new customer in BC', array(
            'data' => $customer_data,
        ) );

        $result = WBC_API_Client::create_customer( $customer_data );

        if ( is_wp_error( $result ) ) {
            WBC_Logger::error( 'CustomerSync', 'Failed to create customer in BC', array(
                'error' => $result->get_error_message(),
                'data'  => $customer_data,
            ) );
            return $result;
        }

        return $result;
    }

    /**
     * Build customer data from WC order
     *
     * @param WC_Order $order WooCommerce order.
     * @return array Customer data for BC API.
     */
    private function build_customer_data( $order ) {
        // Get billing info
        $first_name = $order->get_billing_first_name();
        $last_name = $order->get_billing_last_name();
        $company = $order->get_billing_company();

        // Determine display name and type
        if ( ! empty( $company ) ) {
            $display_name = $company;
            $type = 'Company';
        } else {
            $display_name = trim( $first_name . ' ' . $last_name );
            $type = 'Person';
        }

        // Build address
        $address_line1 = $order->get_billing_address_1();
        $address_line2 = $order->get_billing_address_2();

        if ( ! empty( $address_line2 ) ) {
            $address_line1 .= ', ' . $address_line2;
        }

        // Map country code
        $country = $order->get_billing_country();

        // Build customer payload
        $customer_data = array(
            'displayName'  => substr( $display_name, 0, 100 ), // BC has max length
            'type'         => $type,
            'email'        => $order->get_billing_email(),
        );

        // Add NIF as tax registration number
        $nif = $order->get_meta( '_nif' );
        if ( ! empty( $nif ) ) {
            $customer_data['taxRegistrationNumber'] = $nif;
        }

        // Add optional fields if present
        $phone = $order->get_billing_phone();
        if ( ! empty( $phone ) ) {
            $customer_data['phoneNumber'] = substr( $phone, 0, 30 );
        }

        if ( ! empty( $address_line1 ) ) {
            $customer_data['addressLine1'] = substr( $address_line1, 0, 100 );
        }

        $city = $order->get_billing_city();
        if ( ! empty( $city ) ) {
            $customer_data['city'] = substr( $city, 0, 30 );
        }

        $state = $order->get_billing_state();
        if ( ! empty( $state ) ) {
            $customer_data['state'] = substr( $state, 0, 30 );
        }

        $postcode = $order->get_billing_postcode();
        if ( ! empty( $postcode ) ) {
            $customer_data['postalCode'] = substr( $postcode, 0, 20 );
        }

        if ( ! empty( $country ) ) {
            $customer_data['country'] = $country;
        }

        // Add currency if available
        $currency = $order->get_currency();
        if ( ! empty( $currency ) ) {
            $customer_data['currencyCode'] = $currency;
        }

        return $customer_data;
    }

    /**
     * Update customer in BC with WC order data
     *
     * @param string   $customer_id BC customer ID.
     * @param WC_Order $order       WooCommerce order.
     * @return array|WP_Error Updated customer data or error.
     */
    public function update_customer( $customer_id, $order ) {
        $customer_data = $this->build_customer_data( $order );

        WBC_Logger::debug( 'CustomerSync', 'Updating customer in BC', array(
            'customer_id' => $customer_id,
            'data'        => $customer_data,
        ) );

        $result = WBC_API_Client::patch( '/customers(' . $customer_id . ')', $customer_data );

        if ( is_wp_error( $result ) ) {
            WBC_Logger::error( 'CustomerSync', 'Failed to update customer in BC', array(
                'error'       => $result->get_error_message(),
                'customer_id' => $customer_id,
            ) );
        }

        return $result;
    }
}