<?php
/**
 * Activity feed: recent publishes, edits, moves, trash and feedback.
 *
 * @package KarmaDocs
 */

namespace KarmaDocs;

use KarmaDocs\Rest\Routes;

defined( 'ABSPATH' ) || exit;

/**
 * Keeps the last 200 events in the `kdocs_activity` option (newest last).
 * Edits by the same person on the same article within an hour count once.
 */
class Activity {

	/**
	 * Option name.
	 */
	const OPTION = 'kdocs_activity';

	/**
	 * Events kept.
	 */
	const LIMIT = 200;

	/**
	 * Hooks.
	 */
	public function register() {
		add_action( 'transition_post_status', array( $this, 'status' ), 10, 3 );
		add_action( 'post_updated', array( $this, 'updated' ), 10, 3 );
		add_action( 'kdocs_feedback_submitted', array( $this, 'feedback' ), 30, 3 );
		add_action( 'kdocs_rest_routes', array( $this, 'routes' ) );
	}

	/**
	 * Adds an event.
	 *
	 * @param string $type    published|updated|moved|trashed|restored|feedback.
	 * @param int    $post_id Article.
	 * @param array  $extra   More fields.
	 */
	public static function add( $type, $post_id, array $extra = array() ) {
		$list  = get_option( self::OPTION, array() );
		$list  = is_array( $list ) ? $list : array();
		$user  = get_current_user_id();
		$now   = time();
		$last  = end( $list );
		$merge = $last && 'updated' === $type && 'updated' === $last['type'] && (int) $last['post'] === (int) $post_id && (int) $last['user'] === $user && $now - (int) $last['time'] < HOUR_IN_SECONDS;
		if ( $merge ) {
			$list[ key( $list ) ]['time'] = $now;
		} else {
			$list[] = array(
				'type' => $type,
				'post' => (int) $post_id,
				'user' => $user,
				'time' => $now,
			) + $extra;
		}
		update_option( self::OPTION, array_slice( $list, -self::LIMIT ), false );
	}

	/**
	 * Publish, trash and restore.
	 *
	 * @param string   $new  New status.
	 * @param string   $old  Old status.
	 * @param \WP_Post $post Post.
	 */
	public function status( $new, $old, $post ) {
		if ( PostTypes::ARTICLE !== $post->post_type || $new === $old ) {
			return;
		}
		if ( 'publish' === $new ) {
			self::add( 'trash' === $old ? 'restored' : 'published', $post->ID );
		} elseif ( 'trash' === $new ) {
			self::add( 'trashed', $post->ID );
		}
	}

	/**
	 * Edits of published articles, and moves (new parent).
	 *
	 * @param int      $post_id Post.
	 * @param \WP_Post $after   After.
	 * @param \WP_Post $before  Before.
	 */
	public function updated( $post_id, $after, $before ) {
		if ( PostTypes::ARTICLE !== $after->post_type || 'publish' !== $after->post_status || 'publish' !== $before->post_status ) {
			return;
		}
		if ( (int) $after->post_parent !== (int) $before->post_parent || (int) $after->menu_order !== (int) $before->menu_order ) {
			self::add( 'moved', $post_id );
		} elseif ( $after->post_content !== $before->post_content || $after->post_title !== $before->post_title ) {
			self::add( 'updated', $post_id );
		}
	}

	/**
	 * Reader feedback (votes only count when a reason or message was given).
	 *
	 * @param int    $post_id Article.
	 * @param string $vote    yes|no.
	 * @param string $message Message.
	 */
	public function feedback( $post_id, $vote, $message ) {
		if ( '' !== trim( (string) $message ) ) {
			self::add( 'feedback', $post_id, array( 'vote' => $vote ) );
		}
	}

	/**
	 * GET /activity.
	 *
	 * @param string $ns Namespace.
	 */
	public function routes( $ns ) {
		register_rest_route(
			$ns,
			'/activity',
			array(
				'methods'             => 'GET',
				'callback'            => static fn( $request ) => rest_ensure_response( self::feed( (int) ( $request['limit'] ?? 20 ) ) ),
				'args'                => array(
					'limit' => array(
						'type'    => 'integer',
						'default' => 20,
						'minimum' => 1,
						'maximum' => 100,
					),
				),
				'permission_callback' => array( Routes::class, 'can_edit' ),
			)
		);
	}

	/**
	 * Newest events with names, avatars and links.
	 *
	 * @param int $limit Events.
	 * @return array[]
	 */
	public static function feed( $limit = 20 ) {
		$list = get_option( self::OPTION, array() );
		$out  = array();
		foreach ( array_reverse( is_array( $list ) ? $list : array() ) as $event ) {
			$post = get_post( (int) $event['post'] );
			if ( ! $post || ! current_user_can( 'edit_post', $post->ID ) ) {
				continue;
			}
			$user  = $event['user'] ? get_userdata( (int) $event['user'] ) : null;
			$out[] = array(
				'type' => $event['type'],
				'time' => (int) $event['time'],
				'vote' => $event['vote'] ?? '',
				'user' => $user ? array(
					'name'   => $user->display_name,
					'avatar' => get_avatar_url( $user->ID, array( 'size' => 48 ) ),
				) : null,
				'post' => array(
					'id'       => $post->ID,
					'title'    => html_entity_decode( get_the_title( $post ), ENT_QUOTES, 'UTF-8' ),
					'editLink' => get_edit_post_link( $post->ID, 'raw' ),
				),
			);
			if ( count( $out ) >= $limit ) {
				break;
			}
		}
		return $out;
	}
}