formipay/includes/Shipping/FlatRate.php

<?php
namespace Formipay\Shipping;
use Formipay\Traits\SingletonTrait;
use Formipay\Shipping\Shipping;

if ( ! defined( 'ABSPATH' ) ) exit;

class FlatRate extends Shipping {

    use SingletonTrait;

    private $shipping_method = 'flat_rate';

    protected function __construct() {

        parent::__construct();

        // Register flat rate as a form-level shipping method
        add_filter( 'formipay/form-settings/tab:shipping/method',     [$this, 'add_shipping_method'], 15 );
        add_filter( 'formipay/form-settings/tab:shipping',            [$this, 'add_shipping_settings'], 15 );

        // Add to order details
        add_filter( 'formipay/order/order-details',                 [$this, 'add_shipping_to_order_details'], 99, 3 );

    }

    public function add_shipping_method($shipping_methods){

        $shipping_methods['flat_rate'] = [
            'method' => __( 'Flat Rate', 'formipay' ),
        ];

        return $shipping_methods;

    }

    /**
     * Add flat rate settings to form shipping configuration
     * These fields are shown when "Flat Rate" is selected as the shipping method
     */
    public function add_shipping_settings($fields) {

        // Get global currencies configuration
        $global_currencies = get_global_currency_array();

        // Basic flat rate fields (type and label)
        $flat_rate_fields = array(
            $this->shipping_method.'_group' => array(
                'type' => 'group_title',
                'label' => __( 'Flat Rate Setup', 'formipay' ),
                'description' => __( 'Configure flat rate shipping cost for this form', 'formipay' ),
                'dependency' => array(
                    'key' => 'shipping_enabled',
                    'value' => 'flat_rate'
                ),
                'group' => 'started'
            ),
            $this->shipping_method.'_type' => array(
                'type' => 'select',
                'label' => __( 'Type', 'formipay' ),
                'options' => array(
                    'fixed' => __( 'Fixed Amount', 'formipay' ),
                    'percentage' => __( 'Percentage of Order Total', 'formipay' )
                ),
                'value' => 'fixed',
                'dependency' => array(
                    'key' => 'shipping_enabled',
                    'value' => 'flat_rate'
                ),
            ),
        );

        // Add per-currency amount fields
        foreach ($global_currencies as $currency) {
            // Get the currency code (first part of triple) - this is used for meta key suffix
            $currency_code = formipay_get_currency_data_by_value($currency['currency'], 'symbol');

            $step = ($currency['decimal_digits'] ?? 2) > 0 ? pow(10, -($currency['decimal_digits'] ?? 2)) : 1;
            $is_last = ($currency === end($global_currencies));

            $flat_rate_fields[$this->shipping_method.'_amount_'.$currency_code] = array(
                'type' => 'number',
                'label' => sprintf(__( 'Amount (%s)', 'formipay' ), $currency_code),
                'description' => $is_last ? __( 'Shipping cost for this form (not per-product)', 'formipay' ) : '',
                'step' => $step,
                'min' => 0,
                'placeholder' => $is_last ? __( 'Enter Amount...', 'formipay' ) : __( 'Auto', 'formipay' ),
                'dependency' => array(
                    'key' => 'shipping_enabled',
                    'value' => 'flat_rate'
                ),
                'group' => $is_last ? 'ended' : null,
            );
        }

        // Merge fields into the main fields array
        foreach($flat_rate_fields as $key => $value){
            $fields[$key] = $value;
        }

        return $fields;

    }

    /**
     * Add shipping cost to order details
     *
     * @param array $details Order details array
     * @param int $form_id Product/form ID
     * @param array $order_data Order data from submission
     * @return array Updated order details
     */
    public function add_shipping_to_order_details( $details, $form_id, $order_data ) {

        if ( formipay_get_post_meta($form_id, 'product_type') == 'physical' && formipay_get_post_meta($form_id, 'shipping_method') == 'flat_rate' ) {

            $flat_rate_type = formipay_get_post_meta($form_id, 'flat_rate_type');
            $flat_rate_label = formipay_get_post_meta($form_id, 'flat_rate_label');

            // Get the selected currency from request (same way Order class does it)
            $currency = isset($_REQUEST['currency']) ? sanitize_text_field( wp_unslash($_REQUEST['currency']) ) : (string) formipay_default_currency('code');

            // Get flat rate amount - check for currency-specific first, then fallback to base
            $flat_rate_amount = formipay_get_post_meta($form_id, 'flat_rate_amount_' . $currency);
            if (empty($flat_rate_amount)) {
                $flat_rate_amount = formipay_get_post_meta($form_id, 'flat_rate_amount');
            }

            $amount = floatval( formipay_price_format($flat_rate_amount) );

            // For percentage-based, calculate from actual product price paid
            if ( $flat_rate_type == 'percentage' ) {
                // Find the actual product price from order details (already currency-aware)
                $product_price = 0;
                foreach ($details as $item) {
                    if (isset($item['context']) && $item['context'] == 'product') {
                        // Use the first product's amount (already in selected currency)
                        $product_price = floatval($item['amount']);
                        break;
                    }
                }

                // If no product found in details, fallback to lookup by currency
                if ($product_price == 0) {
                    $regular_key = 'setting_product_price_regular_' . $currency;
                    $sale_key = 'setting_product_price_sale_' . $currency;
                    $regular_price = formipay_get_post_meta($form_id, $regular_key);
                    $sale_price = formipay_get_post_meta($form_id, $sale_key);
                    $product_price = ($sale_price !== '' && $sale_price !== null) ? floatval($sale_price) : floatval($regular_price);
                }

                $calculate = $product_price * $amount / 100;
                $amount = floatval($calculate);
            }

            $details[] = [
                'item'      => $flat_rate_label,
                'amount'    => $amount,
                'subtotal'  => $amount
            ];

        }

        return $details;

    }

}