<?php
/**
 * REST output for posts and comments.
 *
 * @package SpaceBay
 */

namespace SpaceBay\Feed;

use SpaceBay\Content\Media;
use SpaceBay\Content\Reactions;
use SpaceBay\Content\Terms;
use SpaceBay\Frontend\Portal;
use SpaceBay\Members\MemberDirectory;
use SpaceBay\Spaces\SpaceAccess;
use SpaceBay\Spaces\SpaceRepository;
use SpaceBay\Support\Time;

defined( 'ABSPATH' ) || exit;

/**
 * Formats posts and comments, loading related data in batches.
 */
final class Formatter {

	/**
	 * Formats several posts for a viewer.
	 *
	 * @param array[] $posts     Post rows.
	 * @param int     $viewer_id Viewer ID.
	 * @return array[]
	 */
	public static function posts( array $posts, $viewer_id ) {
		if ( ! $posts ) {
			return array();
		}

		$ids        = wp_list_pluck( $posts, 'id' );
		$media      = Media::for_objects( 'post', $ids );
		$terms      = Terms::for_posts( $ids );
		$liked      = Reactions::of_user( 'post', $ids, $viewer_id, 'like' );
		$bookmarked = Reactions::of_user( 'post', $ids, $viewer_id, 'bookmark' );
		$authors    = self::authors( wp_list_pluck( $posts, 'user_id' ) );
		$items      = array();

		foreach ( $posts as $post ) {
			$space = SpaceRepository::find( $post['space_id'] );

			if ( ! $space ) {
				continue;
			}

			$can_change = PostAccess::can_change( $space, $post['user_id'], $viewer_id );

			$items[] = array(
				'id'             => $post['id'],
				'title'          => $post['title'],
				'content'        => $post['message_rendered'],
				'raw'            => $can_change ? $post['message'] : null,
				'author'         => $authors[ $post['user_id'] ] ?? self::deleted_author(),
				'space'          => array(
					'id'    => $space['id'],
					'title' => $space['title'],
					'slug'  => $space['slug'],
					'icon'  => (string) ( $space['settings']['icon'] ?? '' ),
					'color' => (string) ( $space['settings']['color'] ?? '' ),
				),
				'media'          => $media[ $post['id'] ] ?? array(),
				'preview'        => $post['meta']['preview'] ?? null,
				'topics'         => $terms[ $post['id'] ]['topics'] ?? array(),
				'hashtags'       => $terms[ $post['id'] ]['hashtags'] ?? array(),
				'status'         => $post['status'],
				'is_pinned'      => $post['is_pinned'],
				'likes_count'    => $post['reactions_count'],
				'comments_count' => $post['comments_count'],
				'is_edited'      => ! empty( $post['meta']['edited_by'] ),
				'url'            => Portal::link( 'posts/' . $post['id'] ),
				'created_at'     => Time::iso( $post['created_at'] ),
				'updated_at'     => Time::iso( $post['updated_at'] ),
				'viewer'         => array(
					'liked'       => in_array( $post['id'], $liked, true ),
					'bookmarked'  => in_array( $post['id'], $bookmarked, true ),
					'can_edit'    => $can_change,
					'can_delete'  => $can_change,
					'can_pin'     => SpaceAccess::can_moderate( $space, $viewer_id ),
					'can_comment' => PostAccess::can_comment( $space, $viewer_id ),
					'can_report'  => self::can_report( $post['user_id'], $viewer_id ),
				),
			);
		}

		return $items;
	}

	/**
	 * Formats one post.
	 *
	 * @param array $post      Post row.
	 * @param int   $viewer_id Viewer ID.
	 * @return array
	 */
	public static function post( array $post, $viewer_id ) {
		$items = self::posts( array( $post ), $viewer_id );

		return $items ? $items[0] : array();
	}

	/**
	 * Formats comments of one post.
	 *
	 * @param array[] $comments  Comment rows.
	 * @param array   $space     Space of the post.
	 * @param int     $viewer_id Viewer ID.
	 * @return array[]
	 */
	public static function comments( array $comments, array $space, $viewer_id ) {
		if ( ! $comments ) {
			return array();
		}

		$liked   = Reactions::of_user( 'comment', wp_list_pluck( $comments, 'id' ), $viewer_id, 'like' );
		$authors = self::authors( wp_list_pluck( $comments, 'user_id' ) );
		$can_add = PostAccess::can_comment( $space, $viewer_id );
		$items   = array();

		$by_id = array_column( $comments, null, 'id' );

		foreach ( $comments as $comment ) {
			$can_change = PostAccess::can_change( $space, $comment['user_id'], $viewer_id );
			$depth      = 1;
			$cursor     = $comment;

			// Walk up inside the list; ask the database for a parent outside it.
			while ( $cursor['parent_id'] && $depth < 100 ) {
				if ( isset( $by_id[ $cursor['parent_id'] ] ) && $cursor['parent_id'] !== $comment['id'] ) {
					$cursor = $by_id[ $cursor['parent_id'] ];
					++$depth;
					continue;
				}

				$outside = Comments::find( $cursor['parent_id'] );
				$depth  += $outside ? Comments::depth( $outside ) : 0;
				break;
			}

			$items[] = array(
				'id'          => $comment['id'],
				'post_id'     => $comment['post_id'],
				'parent_id'   => $comment['parent_id'],
				'depth'       => $depth,
				'content'     => $comment['message_rendered'],
				'raw'         => $can_change ? $comment['message'] : null,
				'author'      => $authors[ $comment['user_id'] ] ?? self::deleted_author(),
				'status'      => $comment['status'],
				'likes_count' => $comment['reactions_count'],
				'is_edited'   => $comment['updated_at'] !== $comment['created_at'],
				'created_at'  => Time::iso( $comment['created_at'] ),
				'viewer'      => array(
					'liked'      => in_array( $comment['id'], $liked, true ),
					'can_edit'   => $can_change,
					'can_delete' => $can_change,
					'can_reply'  => $can_add,
					'can_report' => self::can_report( $comment['user_id'], $viewer_id ),
				),
			);
		}

		return $items;
	}

	/**
	 * Whether the viewer may report something the author wrote.
	 *
	 * @param int $author_id Author.
	 * @param int $viewer_id Viewer.
	 * @return bool
	 */
	public static function can_report( $author_id, $viewer_id ) {
		return $viewer_id > 0 && (int) $author_id !== (int) $viewer_id && ! SpaceAccess::is_restricted( $viewer_id );
	}

	/**
	 * Formats authors by ID.
	 *
	 * @param int[] $user_ids User IDs.
	 * @return array<int, array>
	 */
	public static function authors( array $user_ids ) {
		$user_ids = array_values( array_unique( array_map( 'intval', $user_ids ) ) );

		cache_users( $user_ids );

		$users = array();

		foreach ( $user_ids as $user_id ) {
			$user = get_userdata( $user_id );

			if ( $user ) {
				$users[] = $user;
			}
		}

		$authors = array();

		foreach ( MemberDirectory::format_many( $users ) as $member ) {
			$authors[ $member['id'] ] = $member;
		}

		return $authors;
	}

	/**
	 * Placeholder for content whose author no longer exists.
	 *
	 * @return array
	 */
	public static function deleted_author() {
		return array(
			'id'         => 0,
			'name'       => __( 'Former member', 'spacebay' ),
			'slug'       => '',
			'avatar'     => get_avatar_url( 0, array( 'size' => 128 ) ),
			'headline'   => '',
			'is_manager' => false,
			'joined_at'  => null,
			'level'      => '',
			'level_rank' => 0,
		);
	}
}