<?php
namespace ToDownload\Fulfillment;

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

use ToDownload\Data\Orders;
use ToDownload\Licenses\Licenses;
use ToDownload\Sellers\Pricing;
use ToDownload\Support\Token;

final class EmailDelivery {
    private const META_SELLER_MEMBERSHIP_TIER = '_ToDownload_seller_membership_tier';

    private static ?EmailDelivery $instance = null;

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

    private function __construct() {
        add_action('ToDownload_after_order_complete', [$this, 'send_order_email'], 10, 1);
    }

    public function send_order_email(int $order_id): void {
        $order = Orders::get_order($order_id);
        if (!$order) {
            return;
        }
        if (($order['status'] ?? '') !== 'complete') {
            return;
        }

        // Best-effort idempotency guard (prevents accidental duplicate emails).
        $marker = 'ToDownload_email_sent:downloads';
        if (Orders::order_notes_contain($order_id, $marker)) {
            return;
        }

        $customer = Orders::get_customer((int) ($order['customer_id'] ?? 0));
        $to = $customer ? sanitize_email((string) ($customer['email'] ?? '')) : '';
        if (!$to || !is_email($to)) {
            return;
        }

        $items = Orders::get_order_items($order_id);
        if (empty($items)) {
            return;
        }

        $attachments = $this->get_email_attachments($order_id, $items);
        $attachments = (array) apply_filters('ToDownload_order_email_attachments', $attachments, $order_id, $order, $customer, $items);

        $order_public_id = Orders::order_public_id($order_id);
        $ref = $order_public_id !== '' ? substr($order_public_id, -8) : '';
        $subject = $ref !== ''
            ? sprintf(
                /* translators: %s is a non-sensitive order reference */
                __('Your downloads are ready (Order %s)', '2download-connector'),
                $ref
            )
            : __('Your downloads are ready', '2download-connector');
        $subject = (string) apply_filters('ToDownload_order_email_subject', $subject, $order_id, $order, $customer, $items);

        $html = $this->build_email_html($order_id, $order, $customer, $items);
        $html = (string) apply_filters('ToDownload_order_email_body_html', $html, $order_id, $order, $customer, $items);

        $headers = [
            'Content-Type: text/html; charset=UTF-8',
        ];
        $headers = (array) apply_filters('ToDownload_order_email_headers', $headers, $order_id, $order, $customer, $items);

        $sent = wp_mail($to, $subject, $html, $headers, $attachments);
        if ($sent) {
            Orders::append_order_note($order_id, $marker);
        }
    }

    /**
     * Resend the completed-order email (receipt + download links).
     *
     * @return bool true if wp_mail reported success
     */
    public function resend_order_email(int $order_id): bool {
        $order = Orders::get_order($order_id);
        if (!$order) {
            return false;
        }
        if (($order['status'] ?? '') !== 'complete') {
            return false;
        }

        $customer = Orders::get_customer((int) ($order['customer_id'] ?? 0));
        $to = $customer ? sanitize_email((string) ($customer['email'] ?? '')) : '';
        if (!$to || !is_email($to)) {
            return false;
        }

        $items = Orders::get_order_items($order_id);
        if (empty($items)) {
            return false;
        }

        $attachments = $this->get_email_attachments($order_id, $items);
        $attachments = (array) apply_filters('ToDownload_order_email_attachments', $attachments, $order_id, $order, $customer, $items);

        $order_public_id = Orders::order_public_id($order_id);
        $ref = $order_public_id !== '' ? substr($order_public_id, -8) : '';
        $subject = $ref !== ''
            ? sprintf(
                /* translators: %s is a non-sensitive order reference */
                __('Your downloads are ready (Order %s)', '2download-connector'),
                $ref
            )
            : __('Your downloads are ready', '2download-connector');
        $subject = (string) apply_filters('ToDownload_order_email_subject', $subject, $order_id, $order, $customer, $items);

        $html = $this->build_email_html($order_id, $order, $customer, $items);
        $html = (string) apply_filters('ToDownload_order_email_body_html', $html, $order_id, $order, $customer, $items);

        $headers = [
            'Content-Type: text/html; charset=UTF-8',
        ];
        $headers = (array) apply_filters('ToDownload_order_email_headers', $headers, $order_id, $order, $customer, $items);

        $sent = wp_mail($to, $subject, $html, $headers, $attachments);
        Orders::append_order_note($order_id, 'ToDownload_email_resent:downloads');
        return (bool) $sent;
    }

    private function get_email_attachments(int $order_id, array $items): array {
        $max_bytes = (int) apply_filters('ToDownload_order_email_attachment_max_bytes', 10 * 1024 * 1024, $order_id, $items);
        if ($max_bytes < 0) {
            $max_bytes = 0;
        }

        $paths = [];
        foreach ($items as $it) {
            $download_id = (int) ($it['download_id'] ?? 0);
            if (!$download_id) {
                continue;
            }

            // Only attach the actual purchased file (not previews).
            $file_id = (int) get_post_meta($download_id, '_ToDownload_file_attachment_id', true);
            if (!$file_id) {
                continue;
            }
            $path = get_attached_file($file_id);
            if (!$path || !is_string($path)) {
                continue;
            }
            if (!file_exists($path) || !is_readable($path)) {
                continue;
            }

            if ($max_bytes > 0) {
                $size = @filesize($path);
                if (is_int($size) && $size > $max_bytes) {
                    continue;
                }
            } else {
                // Max bytes 0 disables attachments entirely.
                continue;
            }

            // Avoid duplicate attachments.
            $paths[$path] = true;
        }

        return array_keys($paths);
    }

    private function build_email_html(int $order_id, array $order, ?array $customer, array $items): string {
        $first = $customer ? (string) ($customer['first_name'] ?? '') : '';
        $name = trim($first);

        $greeting = $name !== ''
            /* translators: %s = customer name */
            ? sprintf(__('Hi %s,', '2download-connector'), esc_html($name))
            : esc_html__('Hi,', '2download-connector');

        $total = isset($order['total']) ? number_format((float) $order['total'], 2) : '0.00';
        $currency = isset($order['currency']) ? (string) $order['currency'] : 'USD';

        $lines = [];
        $lines[] = '<div style="font-family:Arial,Helvetica,sans-serif;font-size:14px;line-height:1.5">';
        $lines[] = '<p>' . $greeting . '</p>';
        $receipt_url = '';
        $settings = get_option('ToDownload_settings', []);
        if (is_array($settings)) {
            $receipt_url = (string) ($settings['success_url'] ?? '');
        }
        if ($receipt_url === '') {
            $receipt_url = home_url('/');
        }
        $customer_email = $customer ? sanitize_email((string) ($customer['email'] ?? '')) : '';
        if ($customer_email !== '' && is_email($customer_email)) {
            $order_public_id = Orders::order_public_id((int) $order_id);
            $receipt_url = add_query_arg([
                'ToDownload_order' => $order_public_id,
                'ToDownload_receipt_token' => Token::receipt_token($order_public_id, $customer_email),
            ], $receipt_url);
        }

        $account_url = '';
        if ($customer_email !== '' && is_email($customer_email)) {
            $account_page_id = is_array($settings) ? (int) ($settings['account_page_id'] ?? 0) : 0;
            if ($account_page_id <= 0) {
                $account_page_id = (int) get_option('ToDownload_account_page_id');
            }
            $account_base = $account_page_id > 0 ? (string) get_permalink($account_page_id) : '';
            if ($account_base === '') {
                $account_base = home_url('/');
            }
            $email_token = Token::email_lookup_token($customer_email);
            if ($email_token !== '') {
                $account_url = (string) add_query_arg([
                    'ToDownload_email' => $customer_email,
                    'ToDownload_email_token' => $email_token,
                ], $account_base);
            }
        }

        $lines[] = '<p>' . esc_html__('Thanks for your purchase! Your downloads are ready.', '2download-connector') . '</p>';
        $lines[] = '<p><strong>' . esc_html__('Receipt:', '2download-connector') . '</strong> <a href="' . esc_url($receipt_url) . '">' . esc_html__('View receipt', '2download-connector') . '</a></p>';
        if ($account_url !== '') {
            $lines[] = '<p><strong>' . esc_html__('Account:', '2download-connector') . '</strong> <a href="' . esc_url($account_url) . '">' . esc_html__('View your purchases', '2download-connector') . '</a></p>';
        }

        if (class_exists('ZipArchive')) {
            $all_link = DownloadDelivery::generate_download_all_link($order_id);
            $lines[] = '<p><a href="' . esc_url($all_link) . '">' . esc_html__('Download all (.zip)', '2download-connector') . '</a></p>';
        }

        $settings = get_option('ToDownload_settings', []);
        if (!is_array($settings)) {
            $settings = [];
        }
        $show_license = $this->order_is_seller_membership_purchase($items, $settings);
        if ($show_license) {
            Licenses::ensure_for_order($order_id);
        }

        $lines[] = '<ul>';
        foreach ($items as $it) {
            $download_id = (int) ($it['download_id'] ?? 0);
            if (!$download_id) {
                continue;
            }
            $title = get_the_title($download_id);
            $link = DownloadDelivery::generate_link($order_id, $download_id);

            $extra = '';
            if ($show_license) {
                $license = Licenses::get_for_item($order_id, $download_id);
                $extra = $license !== '' ? ('<br /><small>' . esc_html__('License:', '2download-connector') . ' <code>' . esc_html($license) . '</code></small>') : '';
            }

            $lines[] = '<li><a href="' . esc_url($link) . '">' . esc_html((string) $title) . '</a>' . $extra . '</li>';
        }
        $lines[] = '</ul>';

        $public_ref = Orders::order_public_id((int) $order_id);
        $ref_label = $public_ref !== '' ? substr($public_ref, -8) : '';
        $lines[] = '<p><strong>' . esc_html__('Order reference:', '2download-connector') . '</strong> ' . esc_html($ref_label) . '<br />';
        $lines[] = '<strong>' . esc_html__('Total:', '2download-connector') . '</strong> ' . esc_html($currency) . ' ' . esc_html($total) . '</p>';

		$lines[] = '<p>' . esc_html__('Tip: save this email. You can always come back to the receipt link above to re-download.', '2download-connector') . '</p>';

        $lines[] = '<p>' . esc_html__('— 2Download', '2download-connector') . '</p>';
        $lines[] = '</div>';

        return implode("\n", $lines);
    }

    private function order_is_seller_membership_purchase(array $items, array $settings): bool {
        if (count($items) !== 1) {
            return false;
        }
        $it = $items[0] ?? null;
        if (!is_array($it)) {
            return false;
        }
        $download_id = (int) ($it['download_id'] ?? 0);
        if ($download_id <= 0) {
            return false;
        }

        $tier = sanitize_key((string) get_post_meta($download_id, self::META_SELLER_MEMBERSHIP_TIER, true));
        if ($tier === Pricing::TIER_PRO || $tier === Pricing::TIER_STUDIO) {
            return true;
        }

        $pro_id = (int) ($settings['seller_plan_pro_product_id'] ?? 0);
        $studio_id = (int) ($settings['seller_plan_studio_product_id'] ?? 0);
        if ($studio_id > 0 && $download_id === $studio_id) {
            return true;
        }
        if ($pro_id > 0 && $download_id === $pro_id) {
            return true;
        }

        return false;
    }
}