WooCommerce Live Currency Rates: Auto-Update Toman Prices from a USD Base Price

<?php
/**
 * Plugin Name: Toman Live Pricing
 * Description: Recalculates WooCommerce prices from a USD base price using EZRate live rates.
 */
defined('ABSPATH') || exit;

// Put the key in wp-config.php:  define('EZRATE_KEY', '…');
const TLP_MARGIN = 0.15;      // 15%
const TLP_STEP = 10000;       // round up to 10,000 Toman
const TLP_MIN_CHANGE = 0.01;  // 1%
const TLP_MAX_JUMP = 0.06;    // 6% per run without review

add_action('woocommerce_product_options_pricing', function () {
    woocommerce_wp_text_input([
        'id' => '_tlp_base_usd', 'label' => 'Base price (USD)',
        'data_type' => 'price', 'desc_tip' => true,
        'description' => 'The Toman price is recalculated automatically from this value.',
    ]);
});

add_action('woocommerce_admin_process_product_object', function (WC_Product $p) {
    if (isset($_POST['_tlp_base_usd'])) {
        $p->update_meta_data('_tlp_base_usd', wc_clean(wp_unslash($_POST['_tlp_base_usd'])));
    }
});

function tlp_usd(): ?array {
    if ($hit = get_transient('tlp_usd')) {
        return $hit;
    }
    $res = wp_remote_get('https://api.ezrate.me/v1/rates/usd', [
        'headers' => ['X-API-Key' => EZRATE_KEY], 'timeout' => 10,
    ]);
    if (is_wp_error($res) || wp_remote_retrieve_response_code($res) !== 200) {
        return null;
    }
    $usd = json_decode(wp_remote_retrieve_body($res), true)['data'] ?? null;
    if ($usd) {
        set_transient('tlp_usd', $usd, MINUTE_IN_SECONDS);
    }
    return $usd;
}

register_activation_hook(__FILE__, function () {
    if (! wp_next_scheduled('tlp_reprice')) {
        wp_schedule_event(time() + 60, 'tlp_30min', 'tlp_reprice');
    }
});
register_deactivation_hook(__FILE__, fn () => wp_clear_scheduled_hook('tlp_reprice'));
add_filter('cron_schedules', fn ($s) => $s + ['tlp_30min' => ['interval' => 1800, 'display' => 'Every 30 minutes']]);

add_action('tlp_reprice', function () {
    $usd = tlp_usd();
    if (! $usd || ! empty($usd['low_sources'])) {
        return;                                    // no data or thin data: keep prices
    }
    $ids = wc_get_products(['limit' => -1, 'return' => 'ids', 'meta_key' => '_tlp_base_usd', 'meta_compare' => 'EXISTS']);
    foreach ($ids as $id) {
        $p = wc_get_product($id);
        $base = (float) $p->get_meta('_tlp_base_usd');
        if ($base <= 0) continue;
        $new = (int) (ceil($base * $usd['sell'] * (1 + TLP_MARGIN) / TLP_STEP) * TLP_STEP);
        $old = (float) $p->get_regular_price();
        $delta = $old > 0 ? $new / $old - 1 : 1;
        if (abs($delta) < TLP_MIN_CHANGE) continue;
        if ($old > 0 && abs($delta) > TLP_MAX_JUMP) {
            $p->update_meta_data('_tlp_pending', $new);   // review in admin
            $p->save();
            continue;
        }
        $p->set_regular_price((string) $new);
        $p->update_meta_data('_tlp_last', sprintf('%s @ %s', $usd['sell'], $usd['updated_at']));
        $p->save();
    }
});