<?php
/**
 * Moves a report run through build, review, hold and send.
 *
 * @package TurtleReport
 */

namespace TurtleReport\Email;

use TurtleReport\Delivery\DeliveryRepository;
use TurtleReport\Delivery\Notifier;
use TurtleReport\Delivery\Readiness;
use TurtleReport\Delivery\RunRepository;
use TurtleReport\Policy\Options;
use TurtleReport\Profiles\Profile;
use TurtleReport\Profiles\ProfileRepository;
use TurtleReport\Support\ErrorText;

defined( 'ABSPATH' ) || exit;

/**
 * The run pipeline: builds the report for the run's period, checks it, waits for
 * review or holds it when the client asks for that, works out the recipients and
 * hands the run to RecipientSender. Safe to call again at any point.
 */
final class RunProcessor {

	/** Builds of a held report, the first included, while Google is temporarily unavailable. */
	const HOLD_CHECKS = 3;

	/**
	 * Site storage.
	 *
	 * @var ProfileRepository
	 */
	private $sites;

	/**
	 * Mailer.
	 *
	 * @var ReportMailer
	 */
	private $mailer;

	/**
	 * Status log per client.
	 *
	 * @var EmailLog
	 */
	private $log;

	/**
	 * Audience resolver.
	 *
	 * @var Recipients
	 */
	private $recipients;

	/**
	 * Runs.
	 *
	 * @var RunRepository
	 */
	private $runs;

	/**
	 * Per-recipient deliveries.
	 *
	 * @var DeliveryRepository
	 */
	private $deliveries;

	/**
	 * Tells administrators about reports to review or that are held.
	 *
	 * @var Notifier|null
	 */
	private $notifier;

	/**
	 * Sends to recipients.
	 *
	 * @var RecipientSender
	 */
	private $sender;

	/**
	 * Constructor.
	 *
	 * @param ProfileRepository  $sites      Site storage.
	 * @param ReportMailer       $mailer     Mailer.
	 * @param EmailLog           $log        Status log.
	 * @param Recipients         $recipients Audience resolver.
	 * @param RunRepository      $runs       Runs.
	 * @param DeliveryRepository $deliveries Deliveries.
	 * @param Notifier|null      $notifier   Notifier.
	 * @param RecipientSender    $sender     Sends to recipients.
	 */
	public function __construct( ProfileRepository $sites, ReportMailer $mailer, EmailLog $log, Recipients $recipients, RunRepository $runs, DeliveryRepository $deliveries, ?Notifier $notifier, RecipientSender $sender ) {
		$this->sites      = $sites;
		$this->mailer     = $mailer;
		$this->log        = $log;
		$this->recipients = $recipients;
		$this->runs       = $runs;
		$this->deliveries = $deliveries;
		$this->notifier   = $notifier;
		$this->sender     = $sender;
	}

	/**
	 * Moves a run forward: build and check it, wait for review, hold it, or send.
	 *
	 * Safe to call again at any point; it carries on where the run is.
	 *
	 * @param int   $run_id Run ID.
	 * @param int   $now    Unix time.
	 * @param array $opts   force (send even if blocked), approved (a reviewer approved it), rebuild (fetch the numbers again).
	 * @return array|null The run afterwards.
	 */
	public function process( $run_id, $now = null, array $opts = array() ) {
		$now  = null === $now ? time() : (int) $now;
		$opts = array_merge(
			array(
				'force'    => false,
				'approved' => false,
				'rebuild'  => false,
			),
			$opts
		);
		$run  = $this->runs->find( $run_id );
		if ( ! $run || in_array( $run['status'], array( RunRepository::SENT, RunRepository::CANCELLED ), true ) ) {
			return $run;
		}
		$site = $this->sites->find( $run['site_id'] );
		if ( ! $site ) {
			$this->runs->update( $run['id'], array( 'status' => RunRepository::CANCELLED ) );
			return $this->runs->find( $run['id'] );
		}
		$meta = (array) $run['meta'];

		try {
			// Build (or rebuild) the numbers. Once recipients exist, they're never rebuilt, so a retry sends what the others got.
			$started = (bool) $this->deliveries->for_run( $run['id'] );
			// An approved run keeps the numbers the reviewer saw.
			$refresh = ! $opts['approved'] && ( $opts['rebuild'] || in_array( $run['status'], array( RunRepository::HELD, RunRepository::PREPARING ), true ) );
			if ( ! $started && ( null === $run['snapshot'] || $refresh ) ) {
				$prep   = $this->mailer->builder()->prepare( $site, RunRepository::period( $run ), null, wp_date( 'Y-m-d', $now ) );
				$fields = array(
					'snapshot'  => array(
						'data' => $prep['data'],
						'full' => $prep['full'],
					),
					'readiness' => $prep['readiness']['level'],
					'checks'    => $prep['readiness'],
					'attempts'  => (int) $run['attempts'] + 1,
				);
				// Reviewer edits win over fresh automatic insights.
				if ( empty( $run['reviewed_at'] ) && empty( $meta['insights_edited'] ) ) {
					$fields['insights'] = $prep['insights'];
				}
				$this->runs->update( $run['id'], $fields );
				$run = $this->runs->find( $run['id'] );
			}

			if ( ! $started && ! $opts['approved'] && empty( $run['reviewed_at'] ) && Options::MODE_REVIEW === $site->delivery['mode'] && RunRepository::KIND_SCHEDULED === $run['kind'] ) {
				$this->runs->update(
					$run['id'],
					array(
						'status'     => RunRepository::REVIEW,
						'next_check' => 0,
					)
				);
				$run = $this->runs->find( $run['id'] );
				$this->notify( $site, $run, 'review' );
				return $run;
			}

			$blocked = Readiness::BLOCKED === $run['readiness'];
			if ( ! $started && $blocked && ! $opts['force'] && Options::INCOMPLETE_HOLD === $site->delivery['incomplete'] ) {
				$temporary = ! empty( $run['checks']['temporary'] );
				$again     = $temporary && (int) $run['attempts'] < self::HOLD_CHECKS;
				$this->runs->update(
					$run['id'],
					array(
						'status'     => RunRepository::HELD,
						'next_check' => $again ? $now + HOUR_IN_SECONDS : 0,
					)
				);
				$run = $this->runs->find( $run['id'] );
				if ( ! $again ) {
					$this->notify( $site, $run, 'held' );
					$this->log->update( $site->id, array( 'last_error' => __( 'Held: the report was incomplete. Review it on the Email deliveries screen.', 'turtlereport' ) ) );
				}
				return $run;
			}

			if ( ! $started ) {
				$to = $this->recipients->addresses( $site );
				if ( ! $to ) {
					$this->runs->update(
						$run['id'],
						array(
							'status' => RunRepository::FAILED,
							'meta'   => array_merge( $meta, array( 'error' => __( 'Nobody to send to: no one can view this site yet and no other people or addresses are chosen.', 'turtlereport' ) ) ),
						)
					);
					$this->log->update(
						$site->id,
						array(
							'last_error' => __( 'Nobody to send to: no one can view this site yet and no other people or addresses are chosen.', 'turtlereport' ),
							'last_count' => 0,
						)
					);
					return $this->runs->find( $run['id'] );
				}
				$this->deliveries->ensure( $run['id'], $site->id, $to );
			}
			$this->runs->transition( $run['id'], array( RunRepository::PREPARING, RunRepository::HELD, RunRepository::REVIEW, RunRepository::RETRYING, RunRepository::PARTIAL, RunRepository::FAILED, RunRepository::SENDING ), RunRepository::SENDING );
			return $this->sender->send_pending( $site, $this->runs->find( $run['id'] ), $now );
		} catch ( \Throwable $e ) {
			// A bug or a fatal problem in one report must not stop the queue.
			$this->runs->update(
				$run['id'],
				array(
					'meta' => array_merge( $meta, array( 'error' => ErrorText::from( $e, 500 ) ) ),
				)
			);
			/* translators: %s: error message. */
			$this->log->update( $site->id, array( 'last_error' => sprintf( __( 'The report couldn\'t be prepared: %s', 'turtlereport' ), ErrorText::from( $e ) ) ) );
			return $this->runs->find( $run['id'] );
		}
	}

	/**
	 * Tells administrators once per run that it needs them.
	 *
	 * @param Profile $site Site.
	 * @param array   $run  Run.
	 * @param string  $why  review or held.
	 * @return void
	 */
	private function notify( Profile $site, array $run, $why ) {
		$meta = (array) $run['meta'];
		$flag = 'notified_' . $why;
		if ( ! empty( $meta[ $flag ] ) || ! $this->notifier ) {
			return;
		}
		$this->notifier->notify( $site, $run, $why );
		$meta[ $flag ] = time();
		$this->runs->update( $run['id'], array( 'meta' => $meta ) );
	}
}