<?php
/**
 * Weekly or monthly SEO health email.
 *
 * @package OrbitstemSEO
 */

namespace Orbitstem\SEO\Monitor;

use Orbitstem\SEO\Core\Settings;
use Orbitstem\SEO\Diagnostics\Issues;
use Orbitstem\SEO\Diagnostics\Tables;

defined( 'ABSPATH' ) || exit;

/**
 * A short, plain email sent from the site itself (wp_mail, no outside
 * service) to the admin address: what was fixed, what changed, what needs
 * attention. Off by default; checked once a day.
 */
class HealthEmail {

	const LAST = 'orbitstem_seo_health_last';

	/**
	 * Settings.
	 *
	 * @var Settings
	 */
	private $settings;

	/**
	 * Issues.
	 *
	 * @var Issues
	 */
	private $issues;

	/**
	 * Constructor.
	 *
	 * @param Settings $settings Settings.
	 * @param Issues   $issues   Issues.
	 */
	public function __construct( Settings $settings, Issues $issues ) {
		$this->settings = $settings;
		$this->issues   = $issues;
	}

	/**
	 * Registers hooks.
	 */
	public function register() {
		add_action( 'orbitstem_seo_daily', array( $this, 'maybe_send' ) );
		add_action( 'update_option_' . Settings::OPTION, array( $this, 'on_settings' ), 10, 2 );
	}

	/**
	 * Switching the email on or changing how often starts a new period, so the
	 * first report never covers the months it was off.
	 *
	 * @param mixed $old_value Old settings.
	 * @param mixed $value     New settings.
	 */
	public function on_settings( $old_value, $value ) {
		$was = is_array( $old_value ) && isset( $old_value['health_email'] ) ? $old_value['health_email'] : 'off';
		$is  = is_array( $value ) && isset( $value['health_email'] ) ? $value['health_email'] : 'off';
		if ( $was !== $is ) {
			delete_option( self::LAST );
		}
	}

	/**
	 * Sends when a week or a month has passed since the last email.
	 *
	 * @return bool Whether an email was sent.
	 */
	public function maybe_send() {
		$frequency = $this->settings->get( 'health_email' );
		if ( 'off' === $frequency ) {
			delete_option( self::LAST );
			return false;
		}
		$last  = (int) get_option( self::LAST, 0 );
		$every = 'monthly' === $frequency ? 30 * DAY_IN_SECONDS : 7 * DAY_IN_SECONDS;
		if ( ! $last ) {
			update_option( self::LAST, time(), false ); // First period starts now.
			return false;
		}
		if ( time() - $last < $every - HOUR_IN_SECONDS ) {
			return false;
		}
		$sent = $this->send( $last );
		update_option( self::LAST, time(), false );
		return $sent;
	}

	/**
	 * Builds and sends the email for the period since a time.
	 *
	 * @param int $since Unix time.
	 * @return bool
	 */
	public function send( $since ) {
		$report = $this->report( $since );
		$name   = wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES );
		/* translators: %s: site name */
		return wp_mail( (string) get_option( 'admin_email' ), sprintf( __( '[%s] Your SEO health report', 'orbitstem-seo' ), $name ), $report );
	}

	/**
	 * The email text.
	 *
	 * @param int $since Unix time.
	 * @return string
	 */
	public function report( $since ) {
		global $wpdb;
		$from    = gmdate( 'Y-m-d H:i:s', (int) $since );
		$fixed   = 0;
		$changes = 0;
		$events  = array();
		if ( Tables::v3_ready() ) {
			// phpcs:disable WordPress.DB.DirectDatabaseQuery
			$fixed   = (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM %i WHERE created_at >= %s AND fixer IN ('redirected_links','redirect_chains','broken_links','outdated_links','orphan_links') AND status = 'applied'", Tables::changes(), $from ) );
			$changes = (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM %i WHERE created_at >= %s AND fixer NOT IN ('site_event') AND status = 'applied'", Tables::changes(), $from ) ); // Changes undone since do not count.
			$events  = $wpdb->get_col( $wpdb->prepare( "SELECT summary FROM %i WHERE created_at >= %s AND fixer = 'site_event' ORDER BY id DESC LIMIT 10", Tables::changes(), $from ) );
			// phpcs:enable
		}
		$summary = $this->issues->summary();
		$lines   = array(
			/* translators: 1: site name, 2: start date */
			sprintf( __( 'SEO health for %1$s since %2$s', 'orbitstem-seo' ), wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES ), wp_date( get_option( 'date_format' ), (int) $since ) ),
			'',
			__( 'Fixed', 'orbitstem-seo' ),
			/* translators: %d: number of repairs */
			'- ' . sprintf( _n( '%d link or redirect repaired.', '%d links or redirects repaired.', $fixed, 'orbitstem-seo' ), $fixed ),
			/* translators: %d: number of recorded changes */
			'- ' . sprintf( _n( '%d SEO change recorded (each can be undone).', '%d SEO changes recorded (each can be undone).', $changes, 'orbitstem-seo' ), $changes ),
			'',
		);
		if ( $events ) {
			$lines[] = __( 'Site updates', 'orbitstem-seo' );
			foreach ( $events as $event ) {
				$lines[] = '- ' . $event;
			}
			$lines[] = '';
		}
		$lines[] = __( 'Needs attention', 'orbitstem-seo' );
		/* translators: 1: errors, 2: warnings */
		$lines[] = '- ' . sprintf( __( 'Errors: %1$d. Warnings: %2$d.', 'orbitstem-seo' ), (int) $summary['error'], (int) $summary['warning'] );
		foreach ( array_slice( (array) $summary['top'], 0, 3 ) as $top ) {
			$lines[] = '- ' . ( isset( $top['title'] ) ? $top['title'] : '' ) . ( isset( $top['count'] ) ? ' (' . (int) $top['count'] . ')' : '' );
		}
		if ( ! $summary['error'] && ! $summary['warning'] ) {
			$lines[] = '- ' . __( 'Nothing urgent. Well done.', 'orbitstem-seo' );
		}
		$lines[] = '';
		$lines[] = admin_url( 'admin.php?page=orbitstem-seo' );
		$lines[] = '';
		$lines[] = __( 'You get this email because "SEO health email" is on in Orbitstem SEO > Settings > Checks & history.', 'orbitstem-seo' );
		return implode( "\n", $lines );
	}
}