<?php
/**
 * Email preview & resend.
 *
 * @package AdminPowerups
 */

namespace SmartWP\AdminPowerups\Modules\EmailPreview;

use Automattic\WooCommerce\Internal\Admin\EmailPreview\EmailPreview;
use SmartWP\AdminPowerups\Modules\AbstractModule;
use SmartWP\AdminPowerups\Support\Assets;
use SmartWP\AdminPowerups\Support\Cleanup;
use SmartWP\AdminPowerups\Support\Orders;
use SmartWP\AdminPowerups\Support\WooEmails;
use SmartWP\AdminPowerups\Support\Str;
use WC_Order;
use WP_Error;
use WP_REST_Request;
use WP_REST_Server;

defined( 'ABSPATH' ) || exit;

/**
 * Resend Processing and Completed emails from the order's Order actions menu, and preview or
 * test-send any order email using a real order (WooCommerce's own preview only uses sample data).
 * Rendering goes through WooCommerce's EmailPreview with the real order swapped in, so the result
 * matches what WooCommerce sends. Nothing on the order changes when previewing or testing.
 *
 * @since 1.0.0
 */
class Module extends AbstractModule {

	/**
	 * User meta holding the times of a user's recent test sends (one row per send).
	 */
	const SENDS_META = '_apwc_email_preview_sends';

	/**
	 * Test sends are counted over this many seconds.
	 */
	const SEND_WINDOW = 600;

	/**
	 * {@inheritDoc}
	 */
	public function id() {
		return 'email-preview';
	}

	/**
	 * {@inheritDoc}
	 */
	public function title() {
		return __( 'Email preview & resend', 'admin-powerups-for-woocommerce' );
	}

	/**
	 * {@inheritDoc}
	 */
	public function description() {
		return __( 'Resend order emails from the order page, and preview or test any email with a real order.', 'admin-powerups-for-woocommerce' );
	}

	/**
	 * {@inheritDoc}
	 */
	public function category() {
		return 'emails';
	}

	/**
	 * {@inheritDoc}
	 */
	public function location() {
		return __( 'Order actions, Preview & test tab', 'admin-powerups-for-woocommerce' );
	}

	/**
	 * {@inheritDoc}
	 */
	public function icon() {
		return 'eye';
	}

	/**
	 * {@inheritDoc}
	 */
	public function autoload_settings() {
		return false;
	}

	/**
	 * {@inheritDoc}
	 *
	 * @return array<int, array<string, mixed>>
	 */
	public function data() {
		return array_merge(
			parent::data(),
			array(
				Cleanup::user_meta( 'test-sends', self::SENDS_META, __( 'Test send times', 'admin-powerups-for-woocommerce' ), __( 'When each person sent test emails in the last 10 minutes, to limit how many they can send.', 'admin-powerups-for-woocommerce' ), 'cache' ),
			)
		);
	}

	/**
	 * {@inheritDoc}
	 */
	public function unmet_requirement() {
		// WooCommerce's previewer is an internal class: check it's still there rather than trust the version.
		return class_exists( EmailPreview::class ) ? '' : __( 'Needs WooCommerce’s email preview, which isn’t available on this site.', 'admin-powerups-for-woocommerce' );
	}

	/**
	 * {@inheritDoc}
	 */
	public function shortcut() {
		return 'preview';
	}

	/**
	 * {@inheritDoc}
	 */
	public function views() {
		return array( 'preview' => __( 'Preview & test', 'admin-powerups-for-woocommerce' ) );
	}

	/**
	 * Emails offered in the Order actions menu.
	 *
	 * @since 1.0.0
	 * @return string[]
	 */
	public static function order_action_emails() {
		/**
		 * Filter which emails get a "Resend …" entry in the order's Order actions menu.
		 * WooCommerce already offers the invoice ("Send order details to customer") and "Resend new
		 * order notification". Only emails in `apwc_resendable_emails` are used.
		 *
		 * @since 1.0.0
		 * @param string[] $ids Email IDs.
		 */
		$ids = (array) apply_filters( 'apwc_order_resend_emails', array( 'customer_processing_order', 'customer_completed_order' ) );
		return array_values( array_intersect( $ids, WooEmails::resendable() ) );
	}

	/**
	 * {@inheritDoc}
	 */
	public function boot() {
		add_filter( 'woocommerce_order_actions', array( $this, 'order_actions' ), 20, 2 );
		foreach ( self::order_action_emails() as $id ) {
			add_action(
				'woocommerce_order_action_apwc_resend_' . $id,
				function ( $order ) use ( $id ) {
					$this->resend_from_order( $id, $order );
				}
			);
		}
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
	}

	/**
	 * Add "Resend …" to Order actions.
	 *
	 * @since 1.0.0
	 * @param array<string, string> $actions Actions.
	 * @param WC_Order|null         $order   Order (WooCommerce 8.1+).
	 * @return array<string, string>
	 */
	public function order_actions( $actions, $order = null ) {
		foreach ( self::order_action_emails() as $id ) {
			$email = WooEmails::get( $id );
			// Manual emails (e.g. "Order details") are never "enabled" in WooCommerce but can always be sent.
			if ( $email && ( $email->is_enabled() || $email->is_manual() ) ) {
				/* translators: %s: email title, e.g. "Processing order". */
				$actions[ 'apwc_resend_' . $id ] = sprintf( __( 'Resend “%s” email', 'admin-powerups-for-woocommerce' ), $email->get_title() );
			}
		}
		return $actions;
	}

	/**
	 * Run an order action resend and leave a note.
	 *
	 * @since 1.0.0
	 * @param string   $id    Email ID.
	 * @param WC_Order $order Order.
	 * @return void
	 */
	public function resend_from_order( $id, $order ) {
		if ( ! $order instanceof WC_Order || ! current_user_can( 'edit_shop_orders' ) ) {
			return;
		}
		$result = WooEmails::resend( $id, $order );
		$order->add_order_note(
			is_wp_error( $result )
				? $result->get_error_message()
				/* translators: 1: email title, 2: staff name. */
				: sprintf( __( '“%1$s” email resent manually by %2$s.', 'admin-powerups-for-woocommerce' ), WooEmails::title( $id ), wp_get_current_user()->display_name ),
			0,
			true
		);
	}

	/* ------------------------------------------------------------------ Preview & test tab */

	/**
	 * {@inheritDoc}
	 *
	 * @param string $view View ID.
	 */
	public function enqueue_view_assets( $view ) {
		wp_enqueue_script( 'apwc-email-preview', Assets::url( 'assets/js/email-preview.js' ), array( 'wp-api-fetch', 'wp-i18n' ), Assets::ver( 'assets/js/email-preview.js' ), true );
		wp_set_script_translations( 'apwc-email-preview', 'admin-powerups-for-woocommerce' );
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param string $view View ID.
	 */
	public function render_view( $view ) {
		$emails  = WooEmails::titles( true );
		$latest  = wc_get_orders(
			array(
				'limit'   => 1,
				'orderby' => 'date',
				'order'   => 'DESC',
				'return'  => 'ids',
				'type'    => 'shop_order',
				'status'  => array_keys( wc_get_order_statuses() ),
			)
		);
		$example = $latest ? wc_get_order( (int) $latest[0] ) : null;
		$me      = wp_get_current_user()->user_email;
		include __DIR__ . '/views/preview.php';
	}

	/**
	 * REST routes.
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public function register_routes() {
		$args = array(
			'email' => array(
				'type'     => 'string',
				'required' => true,
			),
			'order' => array(
				'type'     => 'string',
				'required' => true,
			),
		);
		register_rest_route(
			'apwc/v1',
			'/email-preview/render',
			array(
				'methods'             => WP_REST_Server::CREATABLE,
				'callback'            => array( $this, 'rest_render' ),
				'permission_callback' => static fn() => current_user_can( 'manage_woocommerce' ),
				'args'                => $args,
			)
		);
		register_rest_route(
			'apwc/v1',
			'/email-preview/send',
			array(
				'methods'             => WP_REST_Server::CREATABLE,
				'callback'            => array( $this, 'rest_send' ),
				'permission_callback' => static fn() => current_user_can( 'manage_woocommerce' ),
				'args'                => $args + array(
					'to' => array(
						'type'     => 'string',
						'required' => true,
					),
				),
			)
		);
	}

	/**
	 * Find an order by number or ID ("#12817" works too). See Orders::find_by_number().
	 *
	 * @since 1.0.0
	 * @param string $term Order number.
	 * @return WC_Order|null
	 */
	public static function find_order( $term ) {
		return Orders::find_by_number( (string) $term );
	}

	/**
	 * Render an email for a real order with WooCommerce's previewer.
	 *
	 * @since 1.0.0
	 * @param string   $id    Email ID.
	 * @param WC_Order $order Order.
	 * @return array{html: string, raw: string, subject: string, email: \WC_Email}|WP_Error
	 */
	public function build( $id, WC_Order $order ) {
		$email = WooEmails::get( $id );
		if ( ! $email || WooEmails::is_account_email( $id ) || ! class_exists( EmailPreview::class ) ) {
			return new WP_Error( 'apwc_bad_email', __( 'Pick an order email.', 'admin-powerups-for-woocommerce' ), array( 'status' => 400 ) );
		}
		$use_order = static fn() => $order;
		add_filter( 'woocommerce_email_preview_dummy_order', $use_order, PHP_INT_MAX );
		WC()->payment_gateways();
		WC()->shipping();
		ob_start();
		try {
			// WooCommerce's previewer sets the email up for the order (object, placeholders). We render it
			// ourselves: its render() adds sample-data filters (fake downloads, forced shipping address,
			// placeholder images) meant for its dummy order, which would make a real order's email wrong.
			$preview = wc_get_container()->get( EmailPreview::class );
			$preview->set_email_type( get_class( $email ) );
			$mail = clone $preview->get_email();
			$mail->setup_locale();
			// Raw content is what WC_Email::send() expects (it styles and filters it itself); the
			// preview shows the styled version, with plain text wrapped so it reads as sent.
			$raw     = $mail->get_content();
			$content = 'plain' === $mail->get_email_type()
				? '<pre style="word-wrap: break-word; white-space: pre-wrap;">' . esc_html( $raw ) . '</pre>'
				: $raw;
			/** This filter is documented in woocommerce/includes/emails/class-wc-email.php */
			$html    = apply_filters( 'woocommerce_mail_content', $mail->style_inline( $content ) ); // phpcs:ignore WooCommerce.Commenting.CommentHooks.MissingSinceComment, WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- WooCommerce's own hook, fired as WC_Email::send() would so the preview matches.
			$subject = $mail->get_subject();
			$mail->restore_locale();
		} catch ( \Throwable $e ) {
			ob_end_clean();
			remove_filter( 'woocommerce_email_preview_dummy_order', $use_order, PHP_INT_MAX );
			return new WP_Error( 'apwc_render_failed', __( 'WooCommerce couldn’t build this email for that order.', 'admin-powerups-for-woocommerce' ), array( 'status' => 500 ) );
		}
		ob_end_clean();
		remove_filter( 'woocommerce_email_preview_dummy_order', $use_order, PHP_INT_MAX );
		return array(
			'html'    => (string) $html,
			'raw'     => (string) $raw,
			'subject' => wp_specialchars_decode( (string) $subject ),
			'email'   => $mail,
		);
	}

	/**
	 * POST /email-preview/render.
	 *
	 * @since 1.0.0
	 * @param WP_REST_Request $request Request.
	 * @return \WP_REST_Response|WP_Error
	 */
	public function rest_render( WP_REST_Request $request ) {
		$order = self::find_order( (string) $request['order'] );
		if ( ! $order ) {
			return new WP_Error( 'apwc_no_order', __( 'No order with that number.', 'admin-powerups-for-woocommerce' ), array( 'status' => 404 ) );
		}
		$built = $this->build( sanitize_key( (string) $request['email'] ), $order );
		if ( is_wp_error( $built ) ) {
			return $built;
		}
		return rest_ensure_response(
			array(
				'subject' => $built['subject'],
				'html'    => $built['html'],
				/* translators: 1: order number, 2: customer email. */
				'context' => sprintf( __( 'Order #%1$s · normally goes to %2$s', 'admin-powerups-for-woocommerce' ), $order->get_order_number(), $built['email']->is_customer_email() ? $order->get_billing_email() : $built['email']->get_recipient() ),
			)
		);
	}

	/**
	 * Mail headers without Cc and Bcc lines. Folded lines (starting with a space or tab) are joined
	 * to the header above first, and header names are read the way wp_mail() reads them, so a
	 * copy can't hide in a continuation line or behind leading whitespace.
	 *
	 * @since 1.0.0
	 * @param string|string[] $headers Headers as a string or one header per entry.
	 * @return string|string[] Same shape as given.
	 */
	public static function without_copies( $headers ) {
		$is_list = is_array( $headers );
		$text    = $is_list ? implode( "\r\n", Str::scalars( $headers ) ) : (string) $headers;
		$text    = (string) preg_replace( '/(?:\r\n|\n|\r)[ \t]+/', ' ', $text );
		$lines   = array();
		foreach ( (array) preg_split( '/\r\n|\n|\r/', $text ) as $line ) {
			$line = (string) $line;
			$name = strtolower( trim( explode( ':', trim( $line ), 2 )[0] ) );
			if ( '' !== trim( $line ) && ( ! str_contains( $line, ':' ) || ! in_array( $name, array( 'cc', 'bcc' ), true ) ) ) {
				$lines[] = $line;
			}
		}
		if ( $is_list ) {
			return $lines;
		}
		return $lines ? implode( "\r\n", $lines ) . "\r\n" : '';
	}

	/**
	 * Count a test send for a user, or refuse it when they've sent too many lately. Each send adds
	 * its own meta row first and then counts, so requests running side by side can't both slip
	 * under the limit.
	 *
	 * @since 1.0.0
	 * @param int $user_id User.
	 * @return string|WP_Error This send's meta value (to give the slot back if nothing is sent).
	 */
	private function take_send_slot( $user_id ) {
		/**
		 * Filter how many test emails one user may send from Preview & test in ten minutes.
		 *
		 * @since 1.0.0
		 * @param int $limit Sends per ten minutes (default 10; at least 1).
		 * @param int $user_id User.
		 */
		$limit = max( 1, (int) apply_filters( 'apwc_email_preview_send_limit', 10, $user_id ) );
		$now   = time();
		$mine  = $now . ':' . wp_generate_password( 12, false );
		add_user_meta( $user_id, self::SENDS_META, $mine );
		$recent = 0;
		foreach ( (array) get_user_meta( $user_id, self::SENDS_META, false ) as $value ) {
			$time = (int) strtok( (string) $value, ':' );
			if ( $time <= $now - self::SEND_WINDOW ) {
				delete_user_meta( $user_id, self::SENDS_META, $value );
			} else {
				++$recent;
			}
		}
		if ( $recent > $limit ) {
			delete_user_meta( $user_id, self::SENDS_META, $mine );
			/* translators: %d: number of test emails. */
			return new WP_Error( 'apwc_too_many_tests', sprintf( _n( 'You can send %d test email every 10 minutes. Try again in a few minutes.', 'You can send %d test emails every 10 minutes. Try again in a few minutes.', $limit, 'admin-powerups-for-woocommerce' ), $limit ), array( 'status' => 429 ) );
		}
		return $mine;
	}

	/**
	 * POST /email-preview/send: send the rendered email to one address, marked as a test.
	 *
	 * @since 1.0.0
	 * @param WP_REST_Request $request Request.
	 * @return \WP_REST_Response|WP_Error
	 */
	public function rest_send( WP_REST_Request $request ) {
		$to = sanitize_email( (string) $request['to'] );
		if ( ! is_email( $to ) ) {
			return new WP_Error( 'apwc_bad_to', __( 'Enter one valid email address to send the test to.', 'admin-powerups-for-woocommerce' ), array( 'status' => 400 ) );
		}
		$order = self::find_order( (string) $request['order'] );
		if ( ! $order ) {
			return new WP_Error( 'apwc_no_order', __( 'No order with that number.', 'admin-powerups-for-woocommerce' ), array( 'status' => 404 ) );
		}
		$email_id = sanitize_key( (string) $request['email'] );
		if ( WooEmails::is_account_email( $email_id ) ) {
			return new WP_Error( 'apwc_bad_email', __( 'Pick an order email.', 'admin-powerups-for-woocommerce' ), array( 'status' => 400 ) );
		}
		$slot = $this->take_send_slot( get_current_user_id() );
		if ( is_wp_error( $slot ) ) {
			return $slot;
		}
		$built = $this->build( $email_id, $order );
		if ( is_wp_error( $built ) ) {
			// Nothing was sent: this attempt doesn't use up the allowance.
			delete_user_meta( get_current_user_id(), self::SENDS_META, $slot );
			return $built;
		}
		$email            = $built['email'];
		$email->recipient = $to;
		$sender           = get_current_user_id();
		// Mark the Email log entry of this send as a test (it can't be resent to the customer) and
		// record who sent it.
		$as_test = static function ( $row ) use ( $sender ) {
			if ( is_array( $row ) ) {
				$row['is_test'] = 1;
				$row['sent_by'] = $sender;
			}
			return $row;
		};
		// A test goes only to the address given: drop every To, Cc and Bcc other code adds (Email
		// recipients, other plugins), in the headers WooCommerce hands to wp_mail() and again on the
		// mailer itself, after everything else had its turn.
		$only_to     = static function ( $params ) use ( $to ) {
			if ( is_array( $params ) ) {
				$params[0] = $to;
				$params[3] = self::without_copies( $params[3] ?? '' );
			}
			return $params;
		};
		$only_mailer = static function ( $mailer ) use ( $to ) {
			if ( $mailer instanceof \PHPMailer\PHPMailer\PHPMailer ) {
				$mailer->clearAllRecipients();
				$mailer->addAddress( $to );
			}
		};
		add_filter( 'apwc_email_log_entry', $as_test, PHP_INT_MAX );
		add_filter( 'woocommerce_mail_callback_params', $only_to, PHP_INT_MAX - 1 ); // Before the Email log reads them (PHP_INT_MAX).
		add_action( 'phpmailer_init', $only_mailer, PHP_INT_MAX );
		try {
			$sent = $email->send( $to, $built['subject'], $built['raw'], self::without_copies( (string) $email->get_headers() ), $email->get_attachments() );
		} finally {
			remove_filter( 'apwc_email_log_entry', $as_test, PHP_INT_MAX );
			remove_filter( 'woocommerce_mail_callback_params', $only_to, PHP_INT_MAX - 1 );
			remove_action( 'phpmailer_init', $only_mailer, PHP_INT_MAX );
		}
		if ( ! $sent ) {
			return new WP_Error( 'apwc_not_sent', __( 'The test email couldn’t be sent. Check that your site can send email.', 'admin-powerups-for-woocommerce' ), array( 'status' => 500 ) );
		}
		/* translators: %s: email address. */
		return rest_ensure_response( array( 'message' => sprintf( __( 'Test sent to %s.', 'admin-powerups-for-woocommerce' ), $to ) ) );
	}
}