<?php
/**
 * Weekly email digest (opt-in).
 *
 * @package Unbreak
 */

namespace Unbreak\Admin;

use Unbreak\Check\StatusPolicy;
use Unbreak\Data\LinkQuery;
use Unbreak\Install\Schema;
use Unbreak\Queue\Jobs;
use Unbreak\Support\Clock;
use Unbreak\Support\Settings;

defined( 'ABSPATH' ) || exit;

/**
 * Sends one email a week to the site admin address, only when new broken links appeared.
 */
final class Digest {

	public const HOOK      = 'unbreak_weekly_digest';
	public const LAST_SENT = 'unbreak_digest_last_sent';

	/**
	 * Register hooks.
	 */
	public function register(): void {
		add_action( self::HOOK, array( $this, 'handle' ) );
		if ( Jobs::is_background_context() ) {
			add_action( 'action_scheduler_init', array( $this, 'sync_schedule' ) );
		}
	}

	/**
	 * Schedule or unschedule the weekly job to match the setting.
	 */
	public function sync_schedule(): void {
		if ( ! function_exists( 'as_has_scheduled_action' ) ) {
			return;
		}
		$scheduled = as_has_scheduled_action( self::HOOK, array(), Jobs::GROUP );
		if ( Settings::get( 'email_digest' ) && ! $scheduled ) {
			if ( ! get_option( self::LAST_SENT ) ) {
				update_option( self::LAST_SENT, Clock::now(), false );
			}
			as_schedule_recurring_action( Clock::now() + WEEK_IN_SECONDS, WEEK_IN_SECONDS, self::HOOK, array(), Jobs::GROUP );
		} elseif ( ! Settings::get( 'email_digest' ) && $scheduled ) {
			Jobs::cancel( self::HOOK );
		}
	}

	/**
	 * Action Scheduler callback.
	 */
	public function handle(): void {
		$this->send();
	}

	/**
	 * Send the digest if there are new problems since the last one.
	 *
	 * @return bool Whether an email was sent.
	 */
	public function send(): bool {
		if ( ! Settings::get( 'email_digest' ) ) {
			return false;
		}
		$since = (int) get_option( self::LAST_SENT, 0 );
		$new   = $this->new_problems( $since );
		if ( empty( $new ) ) {
			return false;
		}

		$lines = array(
			/* translators: 1: number of links, 2: site name. */
			sprintf( _n( '%1$d new broken link was found on %2$s:', '%1$d new broken links were found on %2$s:', count( $new ), 'unbreak' ), count( $new ), wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES ) ),
			'',
		);
		$query = new LinkQuery();
		$locs  = $query->locations( array_map( 'intval', wp_list_pluck( $new, 'id' ) ) );
		foreach ( array_slice( $new, 0, 100 ) as $link ) {
			$lines[] = sprintf( '- %s (%s%s)', $link->url, self::status_label( (string) $link->status ), $link->http_code ? ' ' . $link->http_code : '' );
			foreach ( array_slice( $locs[ (int) $link->id ] ?? array(), 0, 3 ) as $loc ) {
				/* translators: %s: where the link appears (post title, menu, widget). */
				$lines[] = '    ' . sprintf( __( 'in: %s', 'unbreak' ), $loc['title'] );
			}
		}
		$lines[] = '';
		$lines[] = __( 'Review and fix them here:', 'unbreak' ) . ' ' . admin_url( 'tools.php?page=unbreak' );
		$lines[] = '';
		$lines[] = __( 'You receive this email because the weekly digest is enabled in Unbreak settings.', 'unbreak' );

		/* translators: %s: site name. */
		$subject = sprintf( __( '[%s] New broken links found', 'unbreak' ), wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES ) );
		$sent    = wp_mail( (string) get_option( 'admin_email' ), $subject, implode( "\n", $lines ) );
		if ( $sent ) {
			update_option( self::LAST_SENT, Clock::now(), false );
		}
		return (bool) $sent;
	}

	/**
	 * Translated label for a problem status.
	 *
	 * @param string $status Status slug.
	 */
	public static function status_label( string $status ): string {
		$labels = array(
			'broken'       => __( 'Broken', 'unbreak' ),
			'server_error' => __( 'Server error', 'unbreak' ),
			'timeout'      => __( 'Timeout', 'unbreak' ),
			'ssl_error'    => __( 'SSL error', 'unbreak' ),
		);
		return $labels[ $status ] ?? $status;
	}

	/**
	 * Links that turned into a confirmed problem since a timestamp.
	 *
	 * @param int $since Timestamp.
	 * @return array<int,object>
	 */
	public function new_problems( int $since ): array {
		global $wpdb;
		$table    = Schema::table( 'links' );
		$statuses = StatusPolicy::problem_statuses();
		$in       = implode( ',', array_fill( 0, count( $statuses ), '%s' ) );
		$params   = array_merge( array( $table ), $statuses, array( Clock::to_mysql( $since ) ) );
		// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared,WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare,WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber -- $in only holds %s placeholders generated above.
		return (array) $wpdb->get_results( $wpdb->prepare( "SELECT id, url, status, http_code FROM %i WHERE dismissed = 0 AND status IN ({$in}) AND status_changed_at > %s ORDER BY status_changed_at DESC LIMIT 500", $params ) );
	}
}