<?php
/**
 * Delivery repository (the queue and the delivery log).
 *
 * @package Hookbird
 */

namespace Hookbird;

defined( 'ABSPATH' ) || exit;

/**
 * Deliveries.
 */
class Deliveries {

	const STATUSES = array( 'pending', 'processing', 'success', 'failed', 'cancelled' );

	/**
	 * Current UTC time in MySQL format, optionally offset.
	 *
	 * @param int $offset Seconds to add.
	 * @return string
	 */
	public static function now( $offset = 0 ) {
		return gmdate( 'Y-m-d H:i:s', time() + (int) $offset );
	}

	/**
	 * Hydrate a row.
	 *
	 * @param object|null $row Row.
	 * @return array|null
	 */
	public static function hydrate( $row ) {
		if ( ! $row ) {
			return null;
		}
		$payload = json_decode( (string) $row->payload, true );
		return array(
			'id'              => (int) $row->id,
			'uuid'            => (string) $row->uuid,
			'event_id'        => (string) $row->event_id,
			'endpoint_id'     => (int) $row->endpoint_id,
			'event'           => (string) $row->event,
			'payload'         => is_array( $payload ) ? $payload : array(),
			'status'          => (string) $row->status,
			'attempts'        => (int) $row->attempts,
			'next_attempt_at' => $row->next_attempt_at ? (string) $row->next_attempt_at : null,
			'response_code'   => null === $row->response_code ? null : (int) $row->response_code,
			'response_body'   => (string) $row->response_body,
			'error'           => (string) $row->error,
			'duration_ms'     => null === $row->duration_ms ? null : (int) $row->duration_ms,
			'is_test'         => (bool) $row->is_test,
			'created_at'      => (string) $row->created_at,
			'updated_at'      => (string) $row->updated_at,
		);
	}

	/**
	 * Queue a delivery.
	 *
	 * @param int   $endpoint_id Endpoint ID.
	 * @param array $envelope    Event envelope.
	 * @param bool  $is_test     Test delivery.
	 * @return int Delivery ID, 0 on failure.
	 */
	public static function create( $endpoint_id, array $envelope, $is_test = false ) {
		global $wpdb;
		$now = self::now();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery -- Custom table.
		$ok = $wpdb->insert(
			Installer::deliveries_table(),
			array(
				'uuid'            => 'msg_' . str_replace( '-', '', wp_generate_uuid4() ),
				'event_id'        => isset( $envelope['id'] ) ? (string) $envelope['id'] : '',
				'endpoint_id'     => (int) $endpoint_id,
				'event'           => isset( $envelope['event'] ) ? (string) $envelope['event'] : '',
				'payload'         => (string) wp_json_encode( $envelope, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRESERVE_ZERO_FRACTION ),
				'status'          => 'pending',
				'attempts'        => 0,
				'next_attempt_at' => $now,
				'is_test'         => $is_test ? 1 : 0,
				'created_at'      => $now,
				'updated_at'      => $now,
			),
			array( '%s', '%s', '%d', '%s', '%s', '%s', '%d', '%s', '%d', '%s', '%s' )
		);
		return $ok ? (int) $wpdb->insert_id : 0;
	}

	/**
	 * Get one delivery.
	 *
	 * @param int $id Delivery ID.
	 * @return array|null
	 */
	public static function get( $id ) {
		global $wpdb;
		$table = Installer::deliveries_table();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Custom table.
		return self::hydrate( $wpdb->get_row( $wpdb->prepare( 'SELECT * FROM %i WHERE id = %d', $table, $id ) ) );
	}

	/**
	 * Update columns of a delivery.
	 *
	 * @param int   $id     Delivery ID.
	 * @param array $fields Columns.
	 */
	public static function update( $id, array $fields ) {
		global $wpdb;
		$fields['updated_at'] = self::now();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Custom table.
		$wpdb->update( Installer::deliveries_table(), $fields, array( 'id' => (int) $id ) );
	}

	/**
	 * Atomically claim a pending delivery so two workers never send it twice.
	 *
	 * @param int $id Delivery ID.
	 * @return bool
	 */
	public static function claim( $id ) {
		global $wpdb;
		$table = Installer::deliveries_table();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Custom table.
		$updated = $wpdb->query( $wpdb->prepare( "UPDATE %i SET status = 'processing', updated_at = %s WHERE id = %d AND status = 'pending'", $table, self::now(), $id ) );
		return 1 === (int) $updated;
	}

	/**
	 * Due deliveries for live endpoints.
	 *
	 * @param int $limit Max rows.
	 * @return array[]
	 */
	public static function due( $limit ) {
		global $wpdb;
		$deliveries = Installer::deliveries_table();
		$endpoints  = Installer::endpoints_table();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Custom tables.
		$rows = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT d.* FROM %i d INNER JOIN %i e ON e.id = d.endpoint_id
				WHERE d.status = 'pending' AND d.next_attempt_at <= %s AND e.active = 1 AND e.paused_at IS NULL
				ORDER BY d.next_attempt_at ASC, d.id ASC LIMIT %d",
				$deliveries,
				$endpoints,
				self::now(),
				$limit
			)
		);
		return array_values( array_filter( array_map( array( __CLASS__, 'hydrate' ), (array) $rows ) ) );
	}

	/**
	 * Return deliveries stuck in "processing" (for example after a PHP timeout) to the queue.
	 *
	 * @return int Rows recovered.
	 */
	public static function recover_stuck() {
		global $wpdb;
		$table = Installer::deliveries_table();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Custom table.
		return (int) $wpdb->query( $wpdb->prepare( "UPDATE %i SET status = 'pending', updated_at = %s WHERE status = 'processing' AND updated_at < %s", $table, self::now(), self::now( -10 * MINUTE_IN_SECONDS ) ) );
	}

	/**
	 * Earliest next attempt among pending deliveries for live endpoints.
	 *
	 * @return int|null Unix timestamp.
	 */
	public static function next_due_time() {
		global $wpdb;
		$deliveries = Installer::deliveries_table();
		$endpoints  = Installer::endpoints_table();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Custom tables.
		$next = $wpdb->get_var( $wpdb->prepare( "SELECT MIN(d.next_attempt_at) FROM %i d INNER JOIN %i e ON e.id = d.endpoint_id WHERE d.status = 'pending' AND e.active = 1 AND e.paused_at IS NULL", $deliveries, $endpoints ) );
		return $next ? (int) strtotime( $next . ' UTC' ) : null;
	}

	/**
	 * Cancel pending deliveries for an endpoint.
	 *
	 * @param int $endpoint_id Endpoint ID.
	 */
	public static function cancel_pending_for_endpoint( $endpoint_id ) {
		global $wpdb;
		$table = Installer::deliveries_table();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Custom table.
		$wpdb->query( $wpdb->prepare( "UPDATE %i SET status = 'cancelled', next_attempt_at = NULL, updated_at = %s WHERE endpoint_id = %d AND status IN ('pending','processing')", $table, self::now(), $endpoint_id ) );
	}

	/**
	 * Paginated list.
	 *
	 * Every filter is always part of the (fixed) SQL; an empty filter value turns its
	 * condition into a no-op, so the query text never has to be assembled at runtime.
	 *
	 * @param array $args Filters (endpoint_id, event, status, search) plus per_page and page.
	 * @return array { items: array[], total: int }
	 */
	public static function query( array $args = array() ) {
		global $wpdb;
		$table    = Installer::deliveries_table();
		$per_page = isset( $args['per_page'] ) ? min( 100, max( 1, (int) $args['per_page'] ) ) : 25;
		$page     = isset( $args['page'] ) ? max( 1, (int) $args['page'] ) : 1;
		$offset   = ( $page - 1 ) * $per_page;

		$endpoint = ! empty( $args['endpoint_id'] ) ? (int) $args['endpoint_id'] : 0;
		$event    = ! empty( $args['event'] ) ? (string) $args['event'] : '';
		$status   = ! empty( $args['status'] ) && in_array( $args['status'], self::STATUSES, true ) ? (string) $args['status'] : '';
		$search   = ! empty( $args['search'] ) ? (string) $args['search'] : '';
		$like     = '%' . $wpdb->esc_like( $search ) . '%';

		// phpcs:disable WordPress.DB.DirectDatabaseQuery -- Custom table; results are paginated log rows that change constantly.
		$total = (int) $wpdb->get_var(
			$wpdb->prepare(
				"SELECT COUNT(*) FROM %i
				WHERE ( %d = 0 OR endpoint_id = %d )
				AND ( %s = '' OR event = %s )
				AND ( %s = '' OR status = %s )
				AND ( %s = '' OR event_id = %s OR uuid = %s OR payload LIKE %s )",
				$table,
				$endpoint,
				$endpoint,
				$event,
				$event,
				$status,
				$status,
				$search,
				$search,
				$search,
				$like
			)
		);
		$rows  = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT * FROM %i
				WHERE ( %d = 0 OR endpoint_id = %d )
				AND ( %s = '' OR event = %s )
				AND ( %s = '' OR status = %s )
				AND ( %s = '' OR event_id = %s OR uuid = %s OR payload LIKE %s )
				ORDER BY id DESC LIMIT %d OFFSET %d",
				$table,
				$endpoint,
				$endpoint,
				$event,
				$event,
				$status,
				$status,
				$search,
				$search,
				$search,
				$like,
				$per_page,
				$offset
			)
		);
		// phpcs:enable

		return array(
			'items' => array_values( array_filter( array_map( array( __CLASS__, 'hydrate' ), (array) $rows ) ) ),
			'total' => $total,
		);
	}

	/**
	 * Delivery counts by status for the last N hours, per endpoint.
	 *
	 * @param int $hours Window.
	 * @return array endpoint_id => [ status => count, avg_ms => int ]
	 */
	public static function stats( $hours = 24 ) {
		global $wpdb;
		$table = Installer::deliveries_table();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Custom table.
		$rows  = $wpdb->get_results( $wpdb->prepare( 'SELECT endpoint_id, status, COUNT(*) AS total, AVG(duration_ms) AS avg_ms FROM %i WHERE created_at >= %s AND is_test = 0 GROUP BY endpoint_id, status', $table, self::now( -$hours * HOUR_IN_SECONDS ) ) );
		$stats = array();
		foreach ( (array) $rows as $row ) {
			$id = (int) $row->endpoint_id;
			if ( ! isset( $stats[ $id ] ) ) {
				$stats[ $id ] = array(
					'pending' => 0,
					'success' => 0,
					'failed'  => 0,
					'avg_ms'  => 0,
				);
			}
			$key                  = 'processing' === $row->status ? 'pending' : $row->status;
			$stats[ $id ][ $key ] = ( isset( $stats[ $id ][ $key ] ) ? $stats[ $id ][ $key ] : 0 ) + (int) $row->total;
			if ( 'success' === $row->status ) {
				$stats[ $id ]['avg_ms'] = (int) round( (float) $row->avg_ms );
			}
		}
		return $stats;
	}

	/**
	 * Count deliveries by status.
	 *
	 * @param string $status Status.
	 * @return int
	 */
	public static function count( $status ) {
		global $wpdb;
		$table = Installer::deliveries_table();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Custom table.
		return (int) $wpdb->get_var( $wpdb->prepare( 'SELECT COUNT(*) FROM %i WHERE status = %s', $table, $status ) );
	}

	/**
	 * Daily cleanup (cron callback). WordPress passes an empty string to callbacks of events
	 * without arguments, so this must not forward its argument to purge().
	 */
	public static function cleanup() {
		self::purge();
	}

	/**
	 * Delete finished deliveries older than the retention period.
	 *
	 * @param int|null $days Days to keep. Defaults to the setting.
	 * @return int Rows deleted.
	 */
	public static function purge( $days = null ) {
		global $wpdb;
		$table = Installer::deliveries_table();
		$days  = null === $days || '' === $days ? (int) Settings::get( 'retention_days' ) : max( 0, (int) $days );
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Custom table.
		return (int) $wpdb->query( $wpdb->prepare( "DELETE FROM %i WHERE status IN ('success','failed','cancelled') AND created_at <= %s", $table, self::now( -$days * DAY_IN_SECONDS ) ) );
	}
}