<?php
/**
 * Likes and bookmarks.
 *
 * @package SpaceBay
 */

namespace SpaceBay\Content;

use SpaceBay\Database\Tables;
use SpaceBay\Support\Time;

defined( 'ABSPATH' ) || exit;

/**
 * Stores likes on posts and comments, and bookmarks on posts.
 */
final class Reactions {

	/**
	 * Allowed reaction types.
	 *
	 * @var string[]
	 */
	const TYPES = array( 'like', 'bookmark' );

	/**
	 * Allowed object types.
	 *
	 * @var string[]
	 */
	const OBJECTS = array( 'post', 'comment' );

	/**
	 * Turns a reaction on or off.
	 *
	 * @param string $object_type "post" or "comment".
	 * @param int    $object_id   Object ID.
	 * @param int    $user_id     User ID.
	 * @param string $type        "like" or "bookmark".
	 * @param bool   $on          True to add, false to remove.
	 * @return bool Whether the reaction is now on.
	 */
	public static function set( $object_type, $object_id, $user_id, $type, $on ) {
		global $wpdb;

		if ( ! in_array( $object_type, self::OBJECTS, true ) || ! in_array( $type, self::TYPES, true ) ) {
			return false;
		}

		$table = Tables::name( 'reactions' );
		$where = array(
			'object_type' => $object_type,
			'object_id'   => absint( $object_id ),
			'user_id'     => absint( $user_id ),
			'type'        => $type,
		);
		$has   = self::has( $object_type, $object_id, $user_id, $type );

		if ( $on && ! $has ) {
			$wpdb->insert( $table, array_merge( $where, array( 'created_at' => Time::now() ) ) ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Custom table.

			/**
			 * Fires after a member likes or bookmarks something.
			 *
			 * @since 1.0.0
			 *
			 * @param string $object_type "post" or "comment".
			 * @param int    $object_id   Object ID.
			 * @param int    $user_id     User ID.
			 * @param string $type        "like" or "bookmark".
			 */
			do_action( 'spacebay_reaction_added', $object_type, absint( $object_id ), absint( $user_id ), $type );
		} elseif ( ! $on && $has ) {
			$wpdb->delete( $table, $where ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Custom table.

			/**
			 * Fires after a member takes back a like or a bookmark.
			 *
			 * @since 1.0.0
			 *
			 * @param string $object_type "post" or "comment".
			 * @param int    $object_id   Object ID.
			 * @param int    $user_id     User ID.
			 * @param string $type        "like" or "bookmark".
			 */
			do_action( 'spacebay_reaction_removed', $object_type, absint( $object_id ), absint( $user_id ), $type );
		}

		if ( 'like' === $type ) {
			self::recount( $object_type, $object_id );
		}

		return $on;
	}

	/**
	 * Whether a user reacted.
	 *
	 * @param string $object_type Object type.
	 * @param int    $object_id   Object ID.
	 * @param int    $user_id     User ID.
	 * @param string $type        Reaction type.
	 * @return bool
	 */
	public static function has( $object_type, $object_id, $user_id, $type ) {
		global $wpdb;

		return (bool) $wpdb->get_var( // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Fresh read before writing.
			$wpdb->prepare(
				'SELECT id FROM %i WHERE object_type = %s AND object_id = %d AND user_id = %d AND type = %s',
				Tables::name( 'reactions' ),
				$object_type,
				absint( $object_id ),
				absint( $user_id ),
				$type
			)
		);
	}

	/**
	 * IDs among the given objects that a user reacted to.
	 *
	 * @param string $object_type Object type.
	 * @param int[]  $object_ids  Object IDs.
	 * @param int    $user_id     User ID.
	 * @param string $type        Reaction type.
	 * @return int[]
	 */
	public static function of_user( $object_type, array $object_ids, $user_id, $type ) {
		global $wpdb;

		$object_ids = array_values( array_filter( array_map( 'absint', $object_ids ) ) );

		if ( ! $object_ids || ! $user_id ) {
			return array();
		}

		$placeholders = implode( ',', array_fill( 0, count( $object_ids ), '%d' ) );
		$ids          = $wpdb->get_col( // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Custom table, one query per feed page.
			$wpdb->prepare( // phpcs:ignore WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber -- The IN() list has one %d per ID.
				"SELECT object_id FROM %i WHERE object_type = %s AND user_id = %d AND type = %s AND object_id IN ($placeholders)", // phpcs:ignore WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare, WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Placeholders are built from %d only.
				array_merge( array( Tables::name( 'reactions' ), $object_type, absint( $user_id ), $type ), $object_ids )
			)
		);

		return array_map( 'intval', (array) $ids );
	}

	/**
	 * Removes every reaction on objects.
	 *
	 * @param string $object_type Object type.
	 * @param int[]  $object_ids  Object IDs.
	 * @return void
	 */
	public static function delete_for( $object_type, array $object_ids ) {
		global $wpdb;

		foreach ( array_map( 'absint', $object_ids ) as $object_id ) {
			$wpdb->delete( // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Custom table.
				Tables::name( 'reactions' ),
				array(
					'object_type' => $object_type,
					'object_id'   => $object_id,
				)
			);
		}
	}

	/**
	 * Stores the like count on the post or comment row.
	 *
	 * @param string $object_type Object type.
	 * @param int    $object_id   Object ID.
	 * @return void
	 */
	private static function recount( $object_type, $object_id ) {
		global $wpdb;

		$count = (int) $wpdb->get_var( // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Counter refresh after a write.
			$wpdb->prepare(
				'SELECT COUNT(id) FROM %i WHERE object_type = %s AND object_id = %d AND type = %s',
				Tables::name( 'reactions' ),
				$object_type,
				absint( $object_id ),
				'like'
			)
		);

		$wpdb->update( // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Custom table.
			Tables::name( 'post' === $object_type ? 'posts' : 'comments' ),
			array( 'reactions_count' => $count ),
			array( 'id' => absint( $object_id ) )
		);
	}
}