<?php

namespace RoosterLMS\Notify;

use RoosterLMS\Content\CourseRepository;
use RoosterLMS\Core\Clock;
use RoosterLMS\Core\Settings;
use RoosterLMS\Data\Db;
use RoosterLMS\Data\SqlPart;
use RoosterLMS\Data\Transaction;
use RoosterLMS\Domain\Actor;
use RoosterLMS\Domain\DomainError;
use RoosterLMS\Domain\ErrorCode;
use RoosterLMS\Domain\Services;
use RoosterLMS\I18n\Format;
use RoosterLMS\I18n\Language;
use RoosterLMS\I18n\Providers;
use RoosterLMS\I18n\Switcher;
use RoosterLMS\Orgs\StaffStatus;

defined( 'ABSPATH' ) || exit;

final class Notifier {

	private const MAX_TRIES = 3;

	private const BACKOFF = array( 5, 30, 120 );

	private const LEASE = 900;

	private static array $new_users = array();

	public function queue( NotificationKey $key, int $recipient_id, int $org_id, array $payload, Actor $actor ): void {
		if ( $actor->is_import() || $recipient_id <= 0 || ! self::enabled( $key ) ) {
			return;
		}
		if ( NotificationKey::JOB_ROLE_CHANGED === $key && isset( self::$new_users[ $recipient_id ] ) ) {
			return;
		}
		$payload = self::clean( $payload );
		$due     = null;
		Transaction::run(
			static function () use ( $key, $recipient_id, $org_id, $payload, &$due ): void {
			Services::people()->lock( $recipient_id );
				if ( $org_id > 0 ) {
					$member = Db::row( 'SELECT left_at FROM %i WHERE org_id = %d AND user_id = %d FOR UPDATE', Db::table( 'org_members' ), $org_id, $recipient_id );
					if ( null === $member || null !== $member['left_at'] ) {
						return;
					}
				}
				if ( NotificationKey::WELCOME === $key && null !== Db::value( 'SELECT id FROM %i WHERE recipient_id = %d AND notif_key = %s AND status = %d LIMIT 1 FOR UPDATE', Db::table( 'notifications' ), $recipient_id, $key->value, NotificationStatus::SENT->value ) ) {
					return;
				}
				$now  = Transaction::now();
				$open = Db::row( 'SELECT id, payload, send_after FROM %i WHERE recipient_id = %d AND notif_key = %s AND org_id = %d AND open_slot = 1 FOR UPDATE', Db::table( 'notifications' ), $recipient_id, $key->value, $org_id );
				if ( null === $open ) {
					$send_after = $key->is_digest() ? gmdate( 'Y-m-d H:i:s', (int) strtotime( $now . ' UTC' ) + self::delay( $key ) ) : $now;
					Db::query(

							"INSERT INTO %i (recipient_id, notif_key, org_id, open_slot, lang, payload, first_change_at, send_after, status, tries) VALUES (%d, %s, %d, 1, '', %s, %s, %s, %d, 0)",
							Db::table( 'notifications' ),
							$recipient_id,
							$key->value,
							$org_id,
							(string) wp_json_encode( (object) $payload ),
							$now,
							$send_after,
							NotificationStatus::PENDING->value

					);
					$due = $send_after;
					return;
				}
				$old    = json_decode( (string) $open['payload'], true );
				$merged = self::merge( $key, is_array( $old ) ? $old : array(), $payload );
				if ( wp_json_encode( (object) $merged ) !== wp_json_encode( (object) ( is_array( $old ) ? $old : array() ) ) ) {
					Db::query( 'UPDATE %i SET payload = %s WHERE id = %d', Db::table( 'notifications' ), (string) wp_json_encode( (object) $merged ), (int) $open['id'] );
				}
				$due = (string) $open['send_after'];
			}
		);
		if ( null !== $due ) {
			$at = (int) strtotime( $due . ' UTC' );
			Transaction::after_commit(
				static function () use ( $at ): void {
					NotifyJobs::schedule( $at );
				}
			);
		}
	}

	public function send_due( int $limit = 50, int $budget = 20 ): array {
		$out      = array(
			'sent'    => 0,
			'skipped' => 0,
			'failed'  => 0,
		);
		$deadline = microtime( true ) + max( 1, $budget );
		if ( \RoosterLMS\Messages\QuietHours::active() ) {
			$this->hold_quiet();
		}
		$ids = array_map( 'intval', Db::col( 'SELECT id FROM %i WHERE status = %d AND send_after <= %s ORDER BY send_after, id LIMIT %d /* outside-tx */', Db::table( 'notifications' ), NotificationStatus::PENDING->value, Clock::now(), max( 1, $limit ) ) );
		foreach ( $ids as $id ) {
			if ( microtime( true ) >= $deadline ) {
				break;
			}
			$row = $this->claim( $id );
			if ( null === $row ) {
				continue;
			}
			$key     = NotificationKey::from( (string) $row['notif_key'] );
			$payload = $this->deliverable( $key, $row );
			if ( null === $payload ) {
				$this->finish( $id, NotificationStatus::SKIPPED );
				\RoosterLMS\Messages\MessageLog::notification( $id, $key, (int) $row['recipient_id'], $row, NotificationStatus::SKIPPED, '' );
				++$out['skipped'];
				continue;
			}
			$recipient = (int) $row['recipient_id'];
			$org_id    = (int) $row['org_id'];
			$lang      = $this->language_of( $recipient, $org_id );
			$message   = $this->compose( $key, $recipient, $org_id, $lang, $payload, false );
			$user      = get_userdata( $recipient );
			if ( null === $message || ! $user instanceof \WP_User ) {
				$this->finish( $id, NotificationStatus::SKIPPED );
				\RoosterLMS\Messages\MessageLog::notification( $id, $key, $recipient, $row, NotificationStatus::SKIPPED, $lang );
				++$out['skipped'];
				continue;
			}
			$tracked = \RoosterLMS\Messages\MessageLog::prepare_notification( $id, $key, $recipient, (string) $user->user_email, $lang );
			$html    = $tracked > 0 ? \RoosterLMS\Messages\Tracking::instrument( $message['html'], $tracked ) : $message['html'];
			if ( $this->mail( (string) $user->user_email, $message['subject'], $html, $org_id, $lang, (array) ( $message['attachments'] ?? array() ), (array) ( $message['headers'] ?? array() ), $recipient ) ) {
				$this->finish( $id, NotificationStatus::SENT, $lang );
				\RoosterLMS\Messages\MessageLog::notification( $id, $key, $recipient, $row, NotificationStatus::SENT, $lang, (string) $user->user_email, $tracked );
				++$out['sent'];
				$key_value = $key->value;
				do_action( 'rooster_lms_notification_sent', $id, $key_value, $recipient );
				continue;
			}
			$tries = (int) $row['tries'] + 1;
			if ( $tries >= self::MAX_TRIES ) {
				$this->finish( $id, NotificationStatus::FAILED );
				\RoosterLMS\Messages\MessageLog::notification( $id, $key, $recipient, $row, NotificationStatus::FAILED, $lang, (string) $user->user_email, $tracked );
				++$out['failed'];
				continue;
			}
			if ( $tracked > 0 ) {
				\RoosterLMS\Messages\MessageLog::mark( $tracked, \RoosterLMS\Messages\LogState::FAILED, 'retry' );
			}
			$this->retry( $id, $key, $recipient, $org_id, self::BACKOFF[ $tries - 1 ] ?? 120 );
			++$out['failed'];
		}
		return $out;
	}

	public function preview( NotificationKey $key, int $recipient_id, int $org_id, string $lang, array $payload = array() ): array {
		$lang    = '' !== Language::normalize( $lang ) ? Language::normalize( $lang ) : $this->language_of( $recipient_id, $org_id );
		$payload = self::clean( $payload );
		if ( ! isset( $payload['course_ids'] ) && NotificationKey::JOB_ROLE_CHANGED !== $key && ! $key->is_live() && ! $key->is_offer() ) {
			$payload['course_ids'] = array_map( static fn( array $c ): int => $c['course_id'], Services::syllabus()->for_member( $org_id, $recipient_id, $lang ) );
		}
		return $this->compose( $key, $recipient_id, $org_id, $lang, $payload, true ) ?? array(
			'subject' => '',
			'html'    => '',
		);
	}

	public function record_history( NotificationKey $key, int $recipient_id, int $org_id, string $at, NotificationStatus $status, Actor $actor ): void {
		if ( ! $actor->is_trusted() ) {
			DomainError::raise( ErrorCode::FORBIDDEN );
		}
		if ( $recipient_id <= 0 || ! in_array( $status, array( NotificationStatus::SENT, NotificationStatus::SKIPPED ), true ) ) {
			DomainError::raise( ErrorCode::INVALID );
		}
		Transaction::run(
			static function () use ( $key, $recipient_id, $org_id, $at, $status ): void {
			$found = Db::value( 'SELECT id FROM %i WHERE recipient_id = %d AND notif_key = %s AND org_id = %d AND open_slot IS NULL AND status = %d AND first_change_at = %s LIMIT 1 FOR UPDATE', Db::table( 'notifications' ), $recipient_id, $key->value, $org_id, $status->value, $at );
				if ( null !== $found ) {
					return;
				}
				if ( NotificationStatus::SENT === $status ) {
					Db::query( "INSERT INTO %i (recipient_id, notif_key, org_id, open_slot, lang, payload, first_change_at, send_after, sent_at, status, tries) VALUES (%d, %s, %d, NULL, '', '{}', %s, %s, %s, %d, 0)", Db::table( 'notifications' ), $recipient_id, $key->value, $org_id, $at, $at, $at, $status->value );
				} else {
					Db::query( "INSERT INTO %i (recipient_id, notif_key, org_id, open_slot, lang, payload, first_change_at, send_after, status, tries) VALUES (%d, %s, %d, NULL, '', '{}', %s, %s, %d, 0)", Db::table( 'notifications' ), $recipient_id, $key->value, $org_id, $at, $at, $status->value );
				}
			}
		);
	}

	public static function mark_new_user( int $user_id ): void {
		self::$new_users[ $user_id ] = true;
	}

	public function delete_user( int $user_id ): int {
		return Db::query( 'DELETE FROM %i WHERE recipient_id = %d', Db::table( 'notifications' ), $user_id );
	}

	public function next_due(): ?string {
		return Db::value( 'SELECT MIN(send_after) FROM %i WHERE status = %d /* outside-tx */', Db::table( 'notifications' ), NotificationStatus::PENDING->value );
	}

	public static function enabled( NotificationKey $key ): bool {
		if ( '' !== $key->setting() && true !== Settings::get( $key->setting() ) ) {
			return false;
		}
		return \RoosterLMS\Messages\TemplateRepository::key_enabled( $key );
	}

	public static function delay( NotificationKey $key ): int {
		$seconds = (int) Settings::get( 'notify_delay_minutes' ) * MINUTE_IN_SECONDS;
		return max( 0, (int) apply_filters( 'rooster_lms_notification_delay', $seconds, $key->value ) );
	}

	private function claim( int $id ): ?array {
		return Transaction::run(
			static function () use ( $id ): ?array {
			$now = Transaction::now();
				$row = Db::row( 'SELECT * FROM %i WHERE id = %d AND status = %d FOR UPDATE', Db::table( 'notifications' ), $id, NotificationStatus::PENDING->value );
				if ( null === $row || (string) $row['send_after'] > $now ) {
					return null;
				}
				$lease = gmdate( 'Y-m-d H:i:s', (int) strtotime( $now . ' UTC' ) + self::LEASE );
				Db::query( 'UPDATE %i SET open_slot = NULL, send_after = %s WHERE id = %d', Db::table( 'notifications' ), $lease, $id );
				return $row;
			}
		);
	}

	private function deliverable( NotificationKey $key, array $row ): ?array {
		$recipient = (int) $row['recipient_id'];
		$org_id    = (int) $row['org_id'];
		$payload   = json_decode( (string) $row['payload'], true );
		$payload   = self::clean( is_array( $payload ) ? $payload : array() );
		if ( ! self::enabled( $key ) || ! get_userdata( $recipient ) instanceof \WP_User ) {
			return null;
		}
		if ( $org_id > 0 ) {
			$member = Services::member_repo()->get( $org_id, $recipient );
			if ( null === $member || ! $member->is_current() || StaffStatus::ACTIVE !== StaffStatus::effective( $member, Clock::org_today( $org_id ) ) ) {
				return null;
			}
			if ( NotificationKey::JOB_ROLE_CHANGED === $key && (int) ( $payload['from'] ?? 0 ) === $member->job_role_id ) {
				return null;
			}
		}
		if ( $key->is_grading() ) {
			return \RoosterLMS\Messages\GradingNotice::deliverable( $recipient, $payload );
		}
		if ( $key->is_report() ) {
			return \RoosterLMS\Messages\QuizReportNotice::deliverable( $key, $recipient, $payload );
		}
		if ( $key->is_staff() ) {
			$taught                = array_values( array_intersect( (array) ( $payload['course_ids'] ?? array() ), Services::course_staff()->course_ids_of( $recipient ) ) );
			$payload['course_ids'] = $taught;
			return array() === $taught || array() === (array) ( $payload['learner_ids'] ?? array() ) ? null : $payload;
		}
		if ( NotificationKey::PROGRAMME_CHANGED === $key ) {
			$welcome = Db::value( 'SELECT id FROM %i WHERE recipient_id = %d AND notif_key = %s AND status = %d AND sent_at >= %s LIMIT 1 /* outside-tx */', Db::table( 'notifications' ), $recipient, NotificationKey::WELCOME->value, NotificationStatus::SENT->value, (string) $row['first_change_at'] );
			if ( null !== $welcome ) {
				return null;
			}
		}
		if ( $key->is_live() ) {
			return \RoosterLMS\Live\Notices\LiveNotices::deliverable( $key, $recipient, $payload );
		}
		if ( ( NotificationKey::PLAN_EXPIRING === $key || NotificationKey::PLAN_STATUS === $key ) && ! \RoosterLMS\S1b\PlanNotices::deliverable( $key, $payload ) ) {
			return null;
		}
		if ( $key->is_offer() ) {
			return \RoosterLMS\Earlier\EarlierService::deliverable( $recipient, $payload );
		}
		if ( NotificationKey::ANNOUNCEMENT === $key ) {
			$live = array_keys( \RoosterLMS\Account\AnnouncementRepository::published( (array) ( $payload['announcement_ids'] ?? array() ) ) );
			if ( array() === $live ) {
				return null;
			}
			$payload['announcement_ids'] = $live;
		}
		if ( isset( $payload['course_ids'] ) ) {
			$granted = $this->granted( $recipient, $org_id, $payload['course_ids'] );
			$keep    = NotificationKey::UNENROLLED_BULK === $key ? array_values( array_diff( $payload['course_ids'], $granted ) ) : $granted;
			if ( array() === $keep ) {
				return null;
			}
			$payload['course_ids'] = $keep;
		}
		return $payload;
	}

	private function granted( int $user_id, int $org_id, array $course_ids ): array {
		$course_ids = CourseRepository::ids( $course_ids );
		if ( array() === $course_ids ) {
			return array();
		}
		global $wpdb;
		$sql = SqlPart::of(
			'SELECT DISTINCT course_id FROM %i WHERE user_id = %d AND course_id IN (' . implode( ',', array_fill( 0, count( $course_ids ), '%d' ) ) . ') AND revoked_at IS NULL /* outside-tx */',
			array_merge( array( Db::table( 'grants' ), $user_id ), $course_ids )
		);
		if ( $org_id > 0 ) {
			$sql = $sql->add( SqlPart::of( ' AND org_id = %d', $org_id ) );
		}
		$have = array_map( 'intval', Db::col( $sql ) );
		return array_values( array_intersect( $course_ids, $have ) );
	}

	public function language_of( int $user_id, int $org_id ): string {
		$lang = Language::normalize( (string) Db::value( 'SELECT lang FROM %i WHERE user_id = %d /* outside-tx */', Db::table( 'people' ), $user_id ) );
		if ( '' === $lang && $org_id > 0 ) {
			$lang = Language::normalize( (string) Services::org_repo()->get( $org_id )?->lang );
		}
		return '' !== $lang ? $lang : Providers::current()->default_language();
	}

	private function compose( NotificationKey $key, int $user_id, int $org_id, string $lang, array $payload, bool $preview ): ?array {
		$user = get_userdata( $user_id );
		if ( ! $user instanceof \WP_User ) {
			return null;
		}
		if ( $key->is_live() ) {
			return \RoosterLMS\Live\Notices\NoticeMail::message( $key->value, $user, $lang, (array) ( $payload['live'] ?? array() ) );
		}
		if ( $key->is_offer() ) {
			return \RoosterLMS\Earlier\EarlierMail::message( $user, $lang, $payload, $preview );
		}
		if ( NotificationKey::INVITATION === $key ) {
			return $preview ? \RoosterLMS\Invitations\InvitationMail::preview( $user, $lang ) : null;
		}
		$template = \RoosterLMS\Messages\NotifierBridge::template_for( $key );
		if ( $key->is_grading() ) {
			return null === $template ? null : \RoosterLMS\Messages\GradingNotice::message( $template, $user, $lang, $payload );
		}
		if ( $key->is_report() ) {
			return \RoosterLMS\Messages\QuizReportNotice::message( $key, $user, $lang, $payload );
		}
		if ( $key->is_staff() ) {
			return null === $template ? null : \RoosterLMS\Messages\NotifierBridge::staff_digest( $template, $key, $user, $lang, $payload );
		}
		return Switcher::with(
			$lang,
			function () use ( $key, $user, $org_id, $lang, $payload, $preview, $template ): ?array {
				$syllabus = Services::syllabus();
				$courses  = array_map( 'intval', (array) ( $payload['course_ids'] ?? array() ) );
				$site     = wp_specialchars_decode( (string) get_bloginfo( 'name' ), ENT_QUOTES );
				$org      = $org_id > 0 ? Services::org_repo()->get( $org_id ) : null;
				$company  = null === $org ? '' : \RoosterLMS\Orgs\OrgBranding::of( $org, $lang, (int) $user->ID )->name;
				$first    = '' !== (string) $user->first_name ? (string) $user->first_name : (string) $user->display_name;
				$font     = 'font-family:Arial,Helvetica,sans-serif;';
				/* translators: %s: the recipient's first name. */
				$h = '<h2 style="' . $font . 'margin:0 0 16px;font-size:20px;color:#1d2327;">' . esc_html( sprintf( __( 'Hello %s,', 'rooster-lms' ), $first ) ) . '</h2>';
				switch ( $key ) {
					case NotificationKey::WELCOME:
						$list = $syllabus->for_member( $org_id, (int) $user->ID, $lang );
						/* translators: %s: site name. */
						$subject = sprintf( __( 'Welcome to %s: your courses', 'rooster-lms' ), $site );
						$intro   = '' !== $company
							/* translators: 1: organisation name, 2: site name. */
							? sprintf( __( '%1$s has registered you on %2$s. Below are the courses assigned to you, in the order we recommend you follow them.', 'rooster-lms' ), $company, $site )
							/* translators: %s: site name. */
							: sprintf( __( 'You have been registered on %s. Below are the courses assigned to you, in the order we recommend you follow them.', 'rooster-lms' ), $site );
						break;
					case NotificationKey::PROGRAMME_CHANGED:
						$list    = $syllabus->for_member( $org_id, (int) $user->ID, $lang, $courses );
						$subject = __( 'New in your training programme', 'rooster-lms' );
						$intro   = __( 'New courses have been added to your training programme:', 'rooster-lms' );
						break;
					case NotificationKey::JOB_ROLE_CHANGED:
						$names   = Services::job_role_repo()->names( array( (int) ( $payload['from'] ?? 0 ), (int) ( $payload['to'] ?? 0 ) ), $lang );
						$to_name = $names[ (int) ( $payload['to'] ?? 0 ) ] ?? '';
						$new     = $this->new_for_role( $org_id, (int) $user->ID, (int) ( $payload['from'] ?? 0 ) );
						$list    = array() === $new ? array() : $syllabus->for_member( $org_id, (int) $user->ID, $lang, $new );
						$subject = __( 'Your job role has changed', 'rooster-lms' );
						$intro   = '' !== $to_name
							/* translators: %s: the new job role. */
							? sprintf( __( 'Your job role is now %s.', 'rooster-lms' ), $to_name ) . ( array() === $list ? '' : ' ' . __( 'These courses are new in your training programme:', 'rooster-lms' ) )
							: __( 'Your job role has changed.', 'rooster-lms' );
						$preview = true;
						break;
					case NotificationKey::QUIZ_REGRADED:
						$list    = $this->regraded_list( (int) $user->ID, (array) ( $payload['attempt_ids'] ?? array() ), $lang );
						$subject = __( 'Your quiz result has been updated', 'rooster-lms' );
						$intro   = __( 'The answer key of a quiz you took was corrected, and your result was recalculated:', 'rooster-lms' );
						break;
					case NotificationKey::RESULTS_RELEASED:
						$list    = $this->regraded_list( (int) $user->ID, (array) ( $payload['attempt_ids'] ?? array() ), $lang );
						$subject = __( 'Your exam results have been published', 'rooster-lms' );
						$intro   = __( 'The results of an exam you took have been published:', 'rooster-lms' );
						break;
					case NotificationKey::ANNOUNCEMENT:
						$list    = self::announcement_list( (array) ( $payload['announcement_ids'] ?? array() ) );
						$subject = 1 === count( $list ) ? (string) $list[0]['title'] : __( 'New announcements', 'rooster-lms' );
						$intro   = _n( 'There is an announcement for you:', 'There are announcements for you:', max( 1, count( $list ) ), 'rooster-lms' );
						break;
					case NotificationKey::PLAN_EXPIRING:
					case NotificationKey::PLAN_STATUS:
						$message = \RoosterLMS\S1b\PlanNotices::message( $key, (int) $user->ID, $org_id, $lang, $payload );
						$list    = $message['list'];
						$subject = $message['subject'];
						$intro   = $message['intro'];
						break;
					case NotificationKey::PLACEMENT_CHANGED:
					case NotificationKey::PROMOTION_COMPLETED:
						$list    = $syllabus->for_courses( (int) $user->ID, $courses, $lang );
						$subject = NotificationKey::PLACEMENT_CHANGED === $key ? __( 'Your placement has changed', 'rooster-lms' ) : __( 'You have moved up', 'rooster-lms' );
						$intro   = NotificationKey::PLACEMENT_CHANGED === $key ? __( 'You have a new placement. These are your courses now:', 'rooster-lms' ) : __( 'Your new school year has started. These are your courses now:', 'rooster-lms' );
						break;
					case NotificationKey::ENROLLED_BULK:
						$list = $syllabus->for_courses( (int) $user->ID, $courses, $lang );
						/* translators: %d: number of courses. */
						$subject = sprintf( _n( 'You have been enrolled in %d course', 'You have been enrolled in %d courses', max( 1, count( $list ) ), 'rooster-lms' ), max( 1, count( $list ) ) );
						$intro   = __( 'You now have access to:', 'rooster-lms' );
						break;
					default:
						$list = $syllabus->for_courses( (int) $user->ID, $courses, $lang, false );
						/* translators: %d: number of courses. */
						$subject = sprintf( _n( 'You have been removed from %d course', 'You have been removed from %d courses', max( 1, count( $list ) ), 'rooster-lms' ), max( 1, count( $list ) ) );
						$intro   = __( 'You no longer have access to:', 'rooster-lms' );
						break;
				}
				if ( array() === $list && ! $preview ) {
					return null;
				}
				if ( null !== $template ) {
					return \RoosterLMS\Messages\NotifierBridge::generic( $template, $user, $org_id, $lang, $payload, $subject, self::render_list( $list, NotificationKey::UNENROLLED_BULK !== $key ) );
				}
				$h .= '<p style="' . $font . 'margin:0 0 20px;font-size:15px;line-height:1.5;color:#3c434a;">' . esc_html( $intro ) . '</p>';
				$h .= self::render_list( $list, NotificationKey::UNENROLLED_BULK !== $key );
				$h .= '<p style="' . $font . 'margin:16px 0 0;font-size:14px;color:#3c434a;">' . esc_html( $site ) . '</p>';
				return array(
					'subject' => $subject,
					'html'    => Services::branded_renderer()->render( $org_id, $lang, $subject, $h, (int) $user->ID ),
				);
			}
		);
	}

	private static function announcement_list( array $ids ): array {
		$out = array();
		foreach ( \RoosterLMS\Account\AnnouncementRepository::published( array_map( 'intval', $ids ) ) as $a ) {
			$text  = trim( (string) preg_replace( '/\s+/u', ' ', wp_strip_all_tags( $a->body ) ) );
			$out[] = array(
				'course_id' => 0,
				'title'     => $a->title,
				'url'       => \RoosterLMS\Account\AccountUrls::has_page() ? \RoosterLMS\Account\AccountUrls::url( 'announcements', 'learner' ) : '',
				'items'     => '' === $text ? array() : array(
					array(
						'title' => mb_strlen( $text ) > 300 ? mb_substr( $text, 0, 299 ) . '…' : $text,
						'url'   => '',
					),
				),
			);
		}
		return $out;
	}

	private function regraded_list( int $user_id, array $attempt_ids, string $lang ): array {
		$out = array();
		foreach ( CourseRepository::ids( $attempt_ids ) as $attempt_id ) {
			$attempt = Services::attempt_repo()->get( $attempt_id );
			if ( null === $attempt || $attempt->user_id !== $user_id || $attempt->withheld() ) {
				continue;
			}
			$titles = Services::posts()->titles( \RoosterLMS\Content\ObjectType::UNIT, array( $attempt->unit_id ), $lang );
			$out[]  = array(
				'course_id' => $attempt->course_id,
				'title'     => (string) ( $titles[ $attempt->unit_id ]['title'] ?? '' ),
				'url'       => \RoosterLMS\Routing\Urls::item_url( $attempt->course_id, $attempt->item_id, $lang ),
				'items'     => array(
					array(
						/* translators: %s: a score in percent, e.g. 80%. */
						'title' => sprintf( __( 'Your score: %s', 'rooster-lms' ), Format::percent( (int) round( (float) $attempt->score_pct ) ) ),
						'url'   => '',
					),
				),
			);
		}
		return $out;
	}

	private function new_for_role( int $org_id, int $user_id, int $from ): array {
		$now    = array_keys( Services::programme()->desired( $org_id, $user_id ) );
		$before = $from > 0 ? Services::programme()->job_role_courses( $org_id, $from ) : array();
		return array_values( array_diff( $now, $before ) );
	}

	private static function render_list( array $courses, bool $links ): string {
		if ( array() === $courses ) {
			return '';
		}
		$font = 'font-family:Arial,Helvetica,sans-serif;';
		$h    = '<ol style="' . $font . 'margin:0 0 18px;padding-inline-start:22px;font-size:14px;line-height:1.5;">';
		foreach ( $courses as $course ) {
			$title = esc_html( $course['title'] );
			$h    .= '<li style="margin:4px 0;">' . ( $links && '' !== $course['url'] ? '<a href="' . esc_url( $course['url'] ) . '" style="color:#2a69b8;text-decoration:none;">' . $title . '</a>' : $title );
			if ( array() !== $course['items'] ) {
				$h .= '<ol style="margin:4px 0 2px;padding-inline-start:20px;font-size:13px;color:#50575e;">';
				foreach ( $course['items'] as $item ) {
					$h .= '<li style="margin:2px 0;">' . esc_html( $item['title'] ) . '</li>';
				}
				$h .= '</ol>';
			}
			$h .= '</li>';
		}
		return $h . '</ol>';
	}

	private function mail( string $to, string $subject, string $html, int $org_id, string $lang = '', array $attachments = array(), array $headers = array(), int $user_id = 0 ): bool {
		$extra = array();
		foreach ( $headers as $header ) {
			$header = trim( str_replace( array( "\r", "\n" ), '', (string) $header ) );
			if ( 1 === preg_match( '/^[A-Za-z][A-Za-z0-9-]*:\s*\S/', $header ) ) {
				$extra[] = $header;
			}
		}
		$org = $org_id > 0 ? Services::org_repo()->get( $org_id ) : null;
		$sender = null === $org ? '' : \RoosterLMS\Orgs\OrgBranding::of( $org, $lang, $user_id )->sender_name;
		$name   = static fn( $current ) => '' !== $sender ? $sender : $current;
		$attach = static function ( $phpmailer ) use ( $attachments ): void {
			if ( is_object( $phpmailer ) && method_exists( $phpmailer, 'addStringAttachment' ) ) {
				foreach ( $attachments as $file => $content ) {
					$phpmailer->addStringAttachment( (string) $content, sanitize_file_name( (string) $file ), 'base64', 'text/calendar; charset=utf-8; method=PUBLISH' );
				}
			}
		};
		add_filter( 'wp_mail_from_name', $name, 20 );
		if ( array() !== $attachments ) {
			add_action( 'phpmailer_init', $attach, 20 );
		}
		try {
			return (bool) MemberMailWrapper::own( static fn() => wp_mail( $to, $subject, $html, array_merge( array( 'Content-Type: text/html; charset=UTF-8' ), $extra ) ) );
		} finally {
			remove_filter( 'wp_mail_from_name', $name, 20 );
			remove_action( 'phpmailer_init', $attach, 20 );
		}
	}

	public function deliver( string $to, string $subject, string $html, int $org_id = 0, string $lang = '', array $attachments = array(), array $headers = array(), string $key = '', int $user_id = 0 ): bool {
		if ( ! is_email( $to ) || '' === trim( $subject ) ) {
			return false;
		}
		$sent = $this->mail( $to, $subject, $html, $org_id, $lang, $attachments, $headers, $user_id );
		if ( $sent && '' !== $key ) {
			do_action( 'rooster_lms_notification_sent', 0, $key, $user_id );
		}
		return $sent;
	}

	private function hold_quiet(): void {
		$at   = \RoosterLMS\Messages\QuietHours::ends_at();
		$live = array();
		foreach ( NotificationKey::cases() as $key ) {
			if ( $key->is_live() ) {
				$live[] = $key->value;
			}
		}
		Db::query(

				'UPDATE %i SET send_after = %s WHERE status = %d AND send_after <= %s AND notif_key NOT IN (' . implode( ',', array_fill( 0, count( $live ), '%s' ) ) . ')',
				array_merge( array( Db::table( 'notifications' ), gmdate( 'Y-m-d H:i:s', $at ), NotificationStatus::PENDING->value, Clock::now() ), $live )

		);
		NotifyJobs::schedule( $at );
	}

	private function finish( int $id, NotificationStatus $status, string $lang = '' ): void {
		$now = Clock::now();
		if ( NotificationStatus::SENT === $status ) {
			Db::query( 'UPDATE %i SET status = %d, sent_at = %s, lang = %s, open_slot = NULL, tries = tries + 1 WHERE id = %d', Db::table( 'notifications' ), $status->value, $now, $lang, $id );
			return;
		}
		Db::query( 'UPDATE %i SET status = %d, open_slot = NULL, tries = tries + 1 WHERE id = %d', Db::table( 'notifications' ), $status->value, $id );
	}

	private function retry( int $id, NotificationKey $key, int $recipient, int $org_id, int $minutes ): void {
		Transaction::run(
			static function () use ( $id, $key, $recipient, $org_id, $minutes ): void {
			$open  = Db::value( 'SELECT id FROM %i WHERE recipient_id = %d AND notif_key = %s AND org_id = %d AND open_slot = 1 FOR UPDATE', Db::table( 'notifications' ), $recipient, $key->value, $org_id );
				$after = gmdate( 'Y-m-d H:i:s', Clock::timestamp() + $minutes * MINUTE_IN_SECONDS );
				if ( null === $open ) {
					Db::query( 'UPDATE %i SET tries = tries + 1, send_after = %s, open_slot = 1 WHERE id = %d', Db::table( 'notifications' ), $after, $id );
				} else {
					Db::query( 'UPDATE %i SET tries = tries + 1, send_after = %s WHERE id = %d', Db::table( 'notifications' ), $after, $id );
				}
			}
		);
		NotifyJobs::schedule( Clock::timestamp() + $minutes * MINUTE_IN_SECONDS );
	}

	private static function clean( array $payload ): array {
		$out = array();
		if ( isset( $payload['course_ids'] ) ) {
			$ids = CourseRepository::ids( (array) $payload['course_ids'] );
			sort( $ids );
			$out['course_ids'] = $ids;
		}
		foreach ( array( 'from', 'to', 'run_id', 'unit_id', 'assignment_id', 'days', 'plan_status' ) as $key ) {
			if ( isset( $payload[ $key ] ) ) {
				$out[ $key ] = max( 0, (int) $payload[ $key ] );
			}
		}
		if ( isset( $payload['attempt_ids'] ) ) {
			$ids = CourseRepository::ids( (array) $payload['attempt_ids'] );
			sort( $ids );
			$out['attempt_ids'] = $ids;
		}
		if ( isset( $payload['submission_ids'] ) ) {
			$ids = CourseRepository::ids( (array) $payload['submission_ids'] );
			sort( $ids );
			$out['submission_ids'] = array_slice( $ids, 0, \RoosterLMS\Messages\GradingNotice::MAX );
		}
		if ( isset( $payload['report_ids'] ) ) {
			$ids = CourseRepository::ids( (array) $payload['report_ids'] );
			sort( $ids );
			$out['report_ids'] = array_slice( $ids, 0, \RoosterLMS\Messages\QuizReportNotice::MAX );
		}
		if ( isset( $payload['announcement_ids'] ) ) {
			$ids = CourseRepository::ids( (array) $payload['announcement_ids'] );
			sort( $ids );
			$out['announcement_ids'] = $ids;
		}
		if ( isset( $payload['learner_ids'] ) ) {
			$ids = CourseRepository::ids( (array) $payload['learner_ids'] );
			sort( $ids );
			$out['learner_ids'] = array_slice( $ids, 0, 500 );
		}
		if ( isset( $payload['live'] ) && is_array( $payload['live'] ) ) {
			$out['live'] = \RoosterLMS\Live\Notices\LiveNotices::merge_items( '', array(), $payload['live'] );
		}
		if ( isset( $payload['reason'] ) && in_array( $payload['reason'], array( 'regraded', 'reevaluated' ), true ) ) {
			$out['reason'] = (string) $payload['reason'];
		}
		return $out;
	}

	private static function merge( NotificationKey $key, array $old, array $change ): array {
		$old = self::clean( $old );
		if ( NotificationKey::WELCOME === $key ) {
			return $old;
		}
		if ( NotificationKey::JOB_ROLE_CHANGED === $key ) {
			$old['from'] = $old['from'] ?? (int) ( $change['from'] ?? 0 );
			$old['to']   = (int) ( $change['to'] ?? ( $old['to'] ?? 0 ) );
			return $old;
		}
		if ( NotificationKey::ANNOUNCEMENT === $key || $key->is_offer() ) {
			$ids = array_values( array_unique( array_merge( (array) ( $old['announcement_ids'] ?? array() ), (array) ( $change['announcement_ids'] ?? array() ) ) ) );
			sort( $ids );
			$old['announcement_ids'] = $ids;
			return $old;
		}
		if ( $key->is_live() ) {
			$old['live'] = \RoosterLMS\Live\Notices\LiveNotices::merge_items( $key->value, (array) ( $old['live'] ?? array() ), (array) ( $change['live'] ?? array() ) );
			return $old;
		}
		if ( $key->is_grading() ) {
			return \RoosterLMS\Messages\GradingNotice::merge( $old, self::clean( $change ) );
		}
		if ( $key->is_report() ) {
			return \RoosterLMS\Messages\QuizReportNotice::merge( $old, self::clean( $change ) );
		}
		if ( NotificationKey::PLAN_EXPIRING === $key || NotificationKey::PLAN_STATUS === $key ) {
			return array_merge( $old, self::clean( $change ) );
		}
		if ( NotificationKey::QUIZ_REGRADED === $key || NotificationKey::RESULTS_RELEASED === $key ) {
			$ids = array_values( array_unique( array_merge( (array) ( $old['attempt_ids'] ?? array() ), (array) ( $change['attempt_ids'] ?? array() ) ) ) );
			sort( $ids );
			$old['attempt_ids'] = $ids;
			if ( isset( $change['unit_id'] ) ) {
				$old['unit_id'] = (int) $change['unit_id'];
			}
			if ( isset( $change['reason'] ) && in_array( $change['reason'], array( 'regraded', 'reevaluated' ), true ) ) {
				$old['reason'] = (string) $change['reason'];
			}
			return $old;
		}
		$ids = array_values( array_unique( array_merge( (array) ( $old['course_ids'] ?? array() ), (array) ( $change['course_ids'] ?? array() ) ) ) );
		sort( $ids );
		$old['course_ids'] = $ids;
		if ( $key->is_staff() ) {
			$learners = array_values( array_unique( array_merge( (array) ( $old['learner_ids'] ?? array() ), array_map( 'intval', (array) ( $change['learner_ids'] ?? array() ) ) ) ) );
			sort( $learners );
			$old['learner_ids'] = array_slice( $learners, 0, 500 );
		}
		if ( isset( $change['run_id'] ) ) {
			$old['run_id'] = (int) $change['run_id'];
		}
		return $old;
	}
}