<?php
namespace AntivirusAI\V1;

final class Notifications {
	/** Explicit owner action only; queue a bounded test using existing mail consent. */
	public static function test(): void {
		$settings = Store::freshOption( 'antivirus_ai_settings', array() );
		if ( null === NotificationDelivery::recipient( $settings ) ) { throw new \RuntimeException( 'Enable email alerts and save a valid recipient in Settings first.' ); }
		$store = new Store(); $lock = $store->lock( 'notification_test', 30 );
		if ( ! $lock ) { throw new \RuntimeException( 'A test request is already being prepared.' ); }
		try {
			$last = (int) Store::freshOption( 'antivirus_ai_notification_test_at', 0 );
			if ( $last > time() - 300 ) { throw new \RuntimeException( 'Wait five minutes before requesting another test message.' ); }
			// Reserve before creating any deliverable record. A failed reservation
			// must not leave mail queued; a later queue failure safely retains it.
			Store::saveOption( 'antivirus_ai_notification_test_at', time() );
			$key = 'test_' . bin2hex( random_bytes( 12 ) );
			self::queue( $key, array( 'type' => 'test' ) );
			if ( ! $store->get( 'n_' . $key ) ) { throw new \RuntimeException( 'The test could not be queued. Review notification consent and storage limits.' ); }
		} finally { $store->unlock( 'notification_test', $lock ); }
	}
	public static function accountEvent( string $event, int $accountId ): void {
		self::queue( 'account_' . substr( hash( 'sha256', $event . '|' . $accountId . '|' . gmdate( 'YmdHi' ) ), 0, 40 ), array( 'type' => 'account', 'event' => $event, 'account_id' => $accountId ) );
	}
	public static function register(): void {
		add_action( 'antivirus_ai_finding_recorded', array( self::class, 'critical' ) );
		add_action( 'antivirus_ai_scan_completed', array( self::class, 'queueDigest' ) );
		add_action( 'antivirus_ai_notify', array( self::class, 'process' ) );
		add_action( 'antivirus_ai_worker', array( self::class, 'worker' ) );
	}
	/** Recover a lost mail wake-up only from the authenticated local worker; existing consent/retry gates still apply. */
	public static function worker(): void {
		$due = wp_next_scheduled( 'antivirus_ai_notify' );
		if ( $due && $due > time() ) { return; }
		$store = new Store();
		if ( $store->count( 'notification', 'queued' ) + $store->count( 'notification', 'retry' ) < 1 ) { return; }
		wp_clear_scheduled_hook( 'antivirus_ai_notify' );
		self::process();
	}
	public static function critical( array $finding ): void {
		$id = FindingGuide::id( $finding );
		$current = $id ? ( new Store() )->get( $id ) : null;
		// Scanner hooks can carry the pre-storage body without _status; use the saved decision.
		if ( ! $current || 'finding' !== ( $current['_kind'] ?? '' ) || 'critical' !== ( $current['severity'] ?? '' ) || ! in_array( $current['_status'] ?? '', array( 'open', 'acknowledged' ), true ) || Finding::exceptionKey( $current ) !== Finding::exceptionKey( $finding ) ) { return; }
		$finding = $current;
		$key = Finding::exceptionKey( $finding );
		self::queue(
			'critical_' . substr( $key, 0, 48 ),
			array(
				'type'       => 'critical',
				'finding_id' => $finding['id'] ?? $finding['_id'],
				'finding_key' => $key,
				'severity'   => 'critical',
			)
		);
	}
	public static function queueDigest( string $scanId ): void {
		self::queue(
			'digest_' . gmdate( 'Ymd' ),
			array(
				'type'    => 'digest',
				'scan_id' => $scanId,
			)
		);
	}
	private static function queue( string $key, array $body ): void {
		$settings = Store::freshOption( 'antivirus_ai_settings', array() );
		if ( null === NotificationDelivery::recipient( $settings ) ) {
			return; }
		$store = new Store();
		$id    = 'n_' . $key;
		if ( $store->get( $id ) ) {
			return; }
		if ( $store->count( 'notification' ) >= 2000 ) {
			$store->prune();
			if ( $store->count( 'notification' ) >= 2000 ) {
				update_option(
					'antivirus_ai_notification_warning',
					array(
						'at'      => time(),
						'message' => 'Notification storage budget reached. A new alert could not be queued; review findings and retained notification history.',
					),
					false
				);
				return; }
		}
		$store->put(
			'notification',
			$id,
			$body + array(
				'attempts'     => 0,
				'next_attempt' => time(),
				'queued_at'    => gmdate( 'c' ),
			),
			'queued'
		);
		self::schedule();
	}
	private static function schedule( int $delay = 20 ): void {
		if ( ! wp_next_scheduled( 'antivirus_ai_notify' ) ) {
			wp_schedule_single_event( time() + $delay, 'antivirus_ai_notify' ); }
	}
	public static function process(): void {
		$store    = new Store();
		$token    = $store->lock( 'notifications', 120 );
		if ( ! $token ) {
			self::schedule( 120 );
			return; }
		try {
			// Rotate bounded windows so fresh arrivals cannot starve older retries.
			$cursor  = get_option(
				'antivirus_ai_notification_cursor',
				array(
					'queued' => 0,
					'retry'  => 0,
				)
			);
			// This cursor is only a bounded fairness hint, never permission or delivery state.
			if ( ! is_array( $cursor ) ) { $cursor = array(); }
			foreach ( array( 'queued', 'retry' ) as $state ) { if ( ! is_int( $cursor[ $state ] ?? null ) || $cursor[ $state ] < 0 || $cursor[ $state ] > 2000 ) { $cursor[ $state ] = 0; } }
			$pending = array();
			foreach ( array( 'retry', 'queued' ) as $state ) {
				$offset           = max( 0, min( 2000, (int) ( $cursor[ $state ] ?? 0 ) ) );
				$window           = $store->list( 'notification', $state, 50, $offset );
				$pending          = array_merge( $pending, $window );
				$cursor[ $state ] = count( $window ) < 50 ? 0 : $offset + 50;
			}
			update_option( 'antivirus_ai_notification_cursor', $cursor, false );
			usort( $pending, static fn( $a, $b ) => ( is_int( $a['next_attempt'] ?? null ) ? $a['next_attempt'] : 0 ) <=> ( is_int( $b['next_attempt'] ?? null ) ? $b['next_attempt'] : 0 ) );
			$processed = 0;
			foreach ( $pending as $item ) {
				if ( $processed >= 10 ) {
					break; }
				// Re-read the durable job and permission before reserving one delivery attempt.
				$current = $store->get( $item['_id'] );
				if ( ! $current || ! in_array( $current['_status'] ?? '', array( 'queued', 'retry' ), true ) ) { continue; }
				$item = $current;
				$recipient = NotificationDelivery::recipient( Store::freshOption( 'antivirus_ai_settings', array() ) );
				if ( null === $recipient ) {
					$item['last_error'] = 'Notification permission or recipient is absent or invalid. No mail was attempted.';
					$store->put( 'notification', $item['_id'], $item, 'suppressed', $item['_revision'] );
					continue;
				}
				if ( ! self::metadata( $item ) ) {
					$item['last_error'] = 'Invalid saved notification metadata. No mail was attempted.';
					$store->put( 'notification', $item['_id'], $item, 'blocked', $item['_revision'] ); continue;
				}
				if ( $item['next_attempt'] > time() ) { continue; }
				++$processed;
				$subject = 'test' === $item['type'] ? __( 'Shieldlume Security: your requested notification test', 'shieldlume-security' ) : ( 'account' === $item['type'] ? __( 'Shieldlume Security: administrator access changed', 'shieldlume-security' ) : ( 'critical' === $item['type'] ? __( 'Shieldlume Security: critical finding needs review', 'shieldlume-security' ) : __( 'Shieldlume Security: scan digest', 'shieldlume-security' ) ) );
				$body = self::message( $item, $store );
				if ( ! $store->ownsLock( 'notifications', $token ) ) { throw new \RuntimeException( 'Notification worker lease expired before delivery.' ); }
				++$item['attempts'];
				$item['last_attempt'] = gmdate( 'c' );
				$item['next_attempt'] = 0;
				$item['last_error'] = 'Delivery attempt reserved. If processing stops here, its outcome is unconfirmed and it will not be repeated automatically.';
				// Persist before wp_mail: an interrupted process must never leave this job retryable.
				$claim = $store->put( 'notification', $item['_id'], $item, 'attempting', $item['_revision'] );
				$result = NotificationDelivery::send( $store, $claim, $recipient, $subject, $body, $token, static fn(): string => self::message( $claim, $store ) );
				$claim['last_error'] = $result['message'];
				$status = $result['accepted'] ? 'accepted' : ( $result['stopped'] ? 'suppressed' : 'unknown' );
				$store->put( 'notification', $claim['_id'], $claim, $status, $claim['_revision'] );
				$store->activity( 'notification_' . $status, array( 'notification_id' => $claim['_id'], 'attempts' => $claim['attempts'], 'meaning' => $result['accepted'] ? 'Accepted by wp_mail; inbox delivery is unverified.' : $claim['last_error'] ) );
			}
			if ( $store->count( 'notification', 'queued' ) + $store->count( 'notification', 'retry' ) > 0 ) {
				self::schedule( 120 ); }
		} finally {
			$store->unlock( 'notifications', $token ); }
	}
	/** Validate retained data before conversion or mail composition; legacy alerts may lack finding_key. */
	private static function metadata( array $item ): bool {
		if ( ! is_int( $item['attempts'] ?? null ) || $item['attempts'] < 0 || $item['attempts'] > 2 || ! is_int( $item['next_attempt'] ?? null ) || $item['next_attempt'] < 0 ) { return false; }
		switch ( $item['type'] ?? null ) {
			case 'test': return true;
			case 'account': return is_string( $item['event'] ?? null ) && (bool) preg_match( '/^[a-z][a-z0-9_]{0,79}$/D', $item['event'] ) && is_int( $item['account_id'] ?? null ) && $item['account_id'] > 0;
			case 'critical': return is_string( $item['finding_id'] ?? null ) && (bool) preg_match( '/^f_[a-f0-9]{60}$/D', $item['finding_id'] ) && ( ! array_key_exists( 'finding_key', $item ) || ( is_string( $item['finding_key'] ) && (bool) preg_match( '/^[a-f0-9]{64}$/D', $item['finding_key'] ) ) );
			case 'digest': return is_string( $item['scan_id'] ?? null ) && (bool) preg_match( '/^s_[a-f0-9]{32}$/D', $item['scan_id'] );
			default: return false;
		}
	}
	private static function message( array $item, Store $store ): string {
		$text = __( 'Shieldlume Security security review', 'shieldlume-security' ) . "\n\n";
		$url = Admin::url( 'activity' );
		if ( 'test' === $item['type'] ) {
			$text .= "An administrator requested this notification test from Shieldlume Security Protection. Receiving it confirms delivery of this test only; future delivery can vary.\n\nReview notification preferences and recent attempts in your local WordPress dashboard. No security finding or source content is included.\n";
			$url = Admin::url( 'settings' );
		} elseif ( 'account' === $item['type'] ) {
			$text .= sprintf( "Administrator security event: %s\nAccount ID: %d\nReview this change in your local Activity history. Legitimate administrator actions can produce this alert.\n", str_replace( '_', ' ', (string) $item['event'] ), (int) $item['account_id'] );
		} elseif ( 'critical' === $item['type'] ) {
			$id = is_string( $item['finding_id'] ?? null ) ? $item['finding_id'] : '';
			$finding = preg_match( '/^f_[a-f0-9]{60}$/D', $id ) ? $store->get( $id ) : null;
			if ( $finding && 'finding' === ( $finding['_kind'] ?? '' ) && FindingGuide::id( $finding ) === $id ) {
				$key = $item['finding_key'] ?? '';
				$changed = is_string( $key ) && '' !== $key && ! hash_equals( $key, Finding::exceptionKey( $finding ) );
				$text .= $changed ? __( 'The evidence changed after this alert was queued. The following details are the current retained observation, not the earlier alert evidence.', 'shieldlume-security' ) . "\n" : __( 'Current retained observation:', 'shieldlume-security' ) . "\n";
				$text .= sprintf( "Severity: %s\nConfidence: %s\nStatus: %s\nReason: %s\n", FindingGuide::text( $finding['severity'] ?? '', '', 100 ), FindingGuide::text( $finding['confidence'] ?? '', '', 100 ), FindingGuide::text( $finding['_status'] ?? '', '', 100 ), FindingGuide::text( $finding['reason'] ?? '' ) );
				$url = FindingGuide::url( $finding );
			} else {
				$text .= __( 'The finding is no longer available. Open retained findings to review current evidence; this alert does not recreate the missing observation.', 'shieldlume-security' ) . "\n";
				$url = Admin::url( 'findings' );
			}
		} else {
			$id = is_string( $item['scan_id'] ?? null ) ? $item['scan_id'] : '';
			$scan = preg_match( '/^s_[a-f0-9]{32}$/D', $id ) ? $store->get( $id ) : null;
			if ( $scan && 'scan' === ( $scan['_kind'] ?? '' ) && ( $scan['_id'] ?? '' ) === $id ) {
				$projection = Diagnostics::scan( $scan );
				$counts = array();
				foreach ( array( 'checked', 'skipped', 'unreadable' ) as $counter ) { $counts[] = null === $projection['counters'][ $counter ] ? __( 'Unknown', 'shieldlume-security' ) : (string) $projection['counters'][ $counter ]; }
				$text .= sprintf( "Scan state: %s\nChecked: %s\nSkipped: %s\nUnreadable: %s\n", $projection['status'], $counts[0], $counts[1], $counts[2] );
				$text .= __( 'The link opens findings last observed in this scan. Findings observed again later may no longer appear in that filtered view; it is not a complete historical snapshot.', 'shieldlume-security' ) . "\n";
				$url = Admin::url( 'findings', array( 'scan_id' => $id ) );
			} else { $text .= __( 'The scan record is no longer available. Open local activity to review retained records.', 'shieldlume-security' ) . "\n"; }
		}
		return $text . "\n" . __( 'Open the relevant local screen (WordPress sign-in and administrator access are required):', 'shieldlume-security' ) . "\n" . $url . "\n\n" . __( 'This alert does not establish that every check completed or every business workflow is intact.', 'shieldlume-security' );
	}
}