<?php
/**
 * The Client Monitor: checks sites and lists what needs attention.
 *
 * @package TurtleReport
 */

namespace TurtleReport\Attention;

use TurtleReport\Profiles\Profile;
use TurtleReport\Profiles\ProfileRepository;
use TurtleReport\Settings\Settings;
use TurtleReport\Support\Periods;

defined( 'ABSPATH' ) || exit;

/**
 * Runs the checks (once a day from the background job, or on demand from
 * the Client Monitor screen) and builds what the screen shows.
 */
final class Monitor {

	/** A check older than this is run again when the screen opens. */
	const STALE_AFTER = 20 * HOUR_IN_SECONDS;

	/**
	 * Sites.
	 *
	 * @var ProfileRepository
	 */
	private $sites;

	/**
	 * Alerts.
	 *
	 * @var AlertStore
	 */
	private $store;

	/**
	 * Numbers.
	 *
	 * @var Data
	 */
	private $data;

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

	/**
	 * Constructor.
	 *
	 * @param ProfileRepository $sites    Sites.
	 * @param AlertStore        $store    Alerts.
	 * @param Data              $data     Numbers.
	 * @param Settings          $settings Settings.
	 */
	public function __construct( ProfileRepository $sites, AlertStore $store, Data $data, Settings $settings ) {
		$this->sites    = $sites;
		$this->store    = $store;
		$this->data     = $data;
		$this->settings = $settings;
	}

	/**
	 * Whether the monitor is switched on in Settings.
	 *
	 * @return bool
	 */
	public function enabled() {
		return (bool) $this->settings->get( 'monitor_enabled' );
	}

	/**
	 * The alert store.
	 *
	 * @return AlertStore
	 */
	public function store() {
		return $this->store;
	}

	/**
	 * Whether a site has anything the monitor can check.
	 *
	 * @param Profile $site Site.
	 * @return bool
	 */
	public static function checkable( Profile $site ) {
		return ( $site->wants( Profile::SECTION_SEARCH ) && '' !== (string) $site->gsc_site )
			|| ( ( $site->wants( Profile::SECTION_CONVERSIONS ) || $site->wants( Profile::SECTION_TRAFFIC ) ) && '' !== (string) $site->ga_property );
	}

	/**
	 * Checks one site now.
	 *
	 * @param Profile $site Site.
	 * @param int     $now  Timestamp.
	 * @return array The site's record.
	 */
	public function check( Profile $site, $now = 0 ) {
		$period   = Periods::last_days( 28 );
		$detector = new Detector( $this->data, Rules::get( (string) $this->settings->get( 'monitor_sensitivity' ) ) );
		try {
			$result = $detector->detect( $site, $period, $this->store->open_ids( $site->id ) );
		} catch ( \Throwable $e ) {
			// A bug or a removed report costs this site's check, not everyone's.
			$result = array(
				'findings' => array(),
				'errors'   => array(
					Detector::SEARCH    => __( 'This client couldn\'t be checked because of an unexpected error.', 'turtlereport' ),
					Detector::ANALYTICS => __( 'This client couldn\'t be checked because of an unexpected error.', 'turtlereport' ),
				),
				'sources'  => array(),
			);
		}
		return $this->store->reconcile( $site->id, $result, $period, $now );
	}

	/**
	 * Checks every site (the daily background job), longest-unchecked first.
	 *
	 * Stops after a time budget so a big agency doesn't run WP-Cron past its
	 * limit; sites left over are checked first the next day, or when someone
	 * opens the Client Monitor.
	 *
	 * @return int Sites checked.
	 */
	public function check_all() {
		if ( ! $this->enabled() ) {
			return 0;
		}
		$sites = array_values( $this->sites->all() );
		$this->store->keep_only(
			array_map(
				static function ( $s ) {
					return $s->id;
				},
				$sites
			)
		);
		$checked = array();
		foreach ( $sites as $site ) {
			$checked[ $site->id ] = $this->store->site( $site->id )['checked'];
		}
		usort(
			$sites,
			static function ( $a, $b ) use ( $checked ) {
				return $checked[ $a->id ] <=> $checked[ $b->id ];
			}
		);

		/**
		 * Filters how many seconds the daily Client Monitor check may run.
		 *
		 * @param int $seconds Default 150.
		 */
		$budget = (int) apply_filters( 'turtlereport_attention_time_budget', 150 );
		$start  = microtime( true );
		$n      = 0;
		foreach ( $sites as $site ) {
			if ( ! self::checkable( $site ) ) {
				continue;
			}
			if ( $n && microtime( true ) - $start > $budget ) {
				break;
			}
			$this->check( $site );
			++$n;
		}
		return $n;
	}

	/**
	 * Everything the Client Monitor screen shows.
	 *
	 * @param Profile[] $sites Sites to include (all, for administrators).
	 * @return array{alerts:array[],sites:array[],stale:string[],checked:int}
	 */
	public function payload( array $sites ) {
		$alerts  = array();
		$list    = array();
		$stale   = array();
		$checked = 0;
		$now     = time();
		foreach ( $sites as $site ) {
			if ( ! self::checkable( $site ) ) {
				continue;
			}
			$rec = $this->store->site( $site->id );
			if ( $rec['checked'] < $now - self::STALE_AFTER ) {
				$stale[] = $site->id;
			}
			$checked           = max( $checked, $rec['checked'] );
			$list[ $site->id ] = array(
				'id'      => $site->id,
				'name'    => $site->display_name(),
				'checked' => $rec['checked'],
				'errors'  => array_values( array_unique( array_map( 'strval', $rec['errors'] ) ) ),
			);
			foreach ( $rec['alerts'] as $alert ) {
				$alerts[] = Presenter::present( $alert, $site );
			}
		}
		$order = array(
			AlertStore::ACTIVE   => 0,
			AlertStore::SNOOZED  => 1,
			AlertStore::HANDLED  => 2,
			AlertStore::RESOLVED => 3,
		);
		usort(
			$alerts,
			static function ( $a, $b ) use ( $order ) {
				$state = $order[ $a['state'] ] <=> $order[ $b['state'] ];
				if ( 0 !== $state ) {
					return $state;
				}
				$severity = ( 'high' === $b['severity'] ) <=> ( 'high' === $a['severity'] );
				return 0 !== $severity ? $severity : strnatcasecmp( $a['siteName'], $b['siteName'] );
			}
		);
		return array(
			'alerts'  => $alerts,
			'sites'   => array_values( $list ),
			'stale'   => $stale,
			'checked' => $checked,
		);
	}
}