<?php
/**
 * Private message endpoints.
 *
 * @package SpaceBay
 */

namespace SpaceBay\Rest;

use SpaceBay\Feed\Formatter;
use SpaceBay\Members\MemberDirectory;
use SpaceBay\Messages\Conversations;
use SpaceBay\Messages\Messages;
use SpaceBay\Messages\Rules;
use SpaceBay\Notifications\Notifications;
use WP_Error;
use WP_REST_Request;
use WP_REST_Response;
use WP_REST_Server;

defined( 'ABSPATH' ) || exit;

/**
 * Conversations, messages, blocked members and the "pulse" the apps poll.
 */
final class MessagesController extends Controller {

	/**
	 * Registers the routes.
	 *
	 * @return void
	 */
	public function register_routes() {
		$id = array(
			'id' => array(
				'type'     => 'integer',
				'required' => true,
			),
		);

		register_rest_route(
			$this->namespace,
			'/me/pulse',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_pulse' ),
					'permission_callback' => array( $this, 'permission_logged_in' ),
				),
			)
		);

		register_rest_route(
			$this->namespace,
			'/conversations',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_items' ),
					'permission_callback' => array( $this, 'permission_messages' ),
					'args'                => $this->paging_args( 50 ),
				),
				array(
					'methods'             => WP_REST_Server::CREATABLE,
					'callback'            => array( $this, 'create_item' ),
					'permission_callback' => array( $this, 'permission_messages' ),
					'args'                => array(
						'user_ids' => array(
							'type'     => 'array',
							'items'    => array( 'type' => 'integer' ),
							'required' => true,
							'minItems' => 1,
							'maxItems' => 100,
						),
						'title'    => array(
							'type'      => 'string',
							'default'   => '',
							'maxLength' => 100,
						),
						'group'    => array(
							'type'    => 'boolean',
							'default' => false,
						),
					),
				),
			)
		);

		register_rest_route(
			$this->namespace,
			'/conversations/(?P<id>\d+)',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_item' ),
					'permission_callback' => array( $this, 'permission_messages' ),
				),
				array(
					'methods'             => WP_REST_Server::EDITABLE,
					'callback'            => array( $this, 'update_item' ),
					'permission_callback' => array( $this, 'permission_messages' ),
					'args'                => array(
						'title' => array(
							'type'      => 'string',
							'maxLength' => 100,
						),
						'muted' => array( 'type' => 'boolean' ),
					),
				),
			)
		);

		register_rest_route(
			$this->namespace,
			'/conversations/(?P<id>\d+)/members',
			array(
				array(
					'methods'             => WP_REST_Server::CREATABLE,
					'callback'            => array( $this, 'add_members' ),
					'permission_callback' => array( $this, 'permission_messages' ),
					'args'                => array(
						'user_ids' => array(
							'type'     => 'array',
							'items'    => array( 'type' => 'integer' ),
							'required' => true,
							'minItems' => 1,
							'maxItems' => 100,
						),
					),
				),
			)
		);

		register_rest_route(
			$this->namespace,
			'/conversations/(?P<id>\d+)/members/(?P<user_id>\d+)',
			array(
				array(
					'methods'             => WP_REST_Server::DELETABLE,
					'callback'            => array( $this, 'remove_member' ),
					'permission_callback' => array( $this, 'permission_messages' ),
				),
			)
		);

		register_rest_route(
			$this->namespace,
			'/conversations/(?P<id>\d+)/messages',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_messages' ),
					'permission_callback' => array( $this, 'permission_messages' ),
					'args'                => array(
						'before' => array(
							'type'    => 'integer',
							'default' => 0,
						),
						'after'  => array(
							'type'    => 'integer',
							'default' => 0,
						),
						'limit'  => array(
							'type'    => 'integer',
							'default' => 30,
							'minimum' => 1,
							'maximum' => 100,
						),
					),
				),
				array(
					'methods'             => WP_REST_Server::CREATABLE,
					'callback'            => array( $this, 'create_message' ),
					'permission_callback' => array( $this, 'permission_messages' ),
					'args'                => array(
						'message'   => array(
							'type'    => 'string',
							'default' => '',
						),
						'media_ids' => array(
							'type'     => 'array',
							'items'    => array( 'type' => 'integer' ),
							'default'  => array(),
							'maxItems' => 10,
						),
					),
				),
			)
		);

		register_rest_route(
			$this->namespace,
			'/conversations/(?P<id>\d+)/read',
			array(
				array(
					'methods'             => WP_REST_Server::CREATABLE,
					'callback'            => array( $this, 'mark_read' ),
					'permission_callback' => array( $this, 'permission_messages' ),
					'args'                => array(
						'message_id' => array(
							'type'     => 'integer',
							'required' => true,
						),
					),
				),
			)
		);

		register_rest_route(
			$this->namespace,
			'/messages/(?P<id>\d+)',
			array(
				array(
					'methods'             => WP_REST_Server::DELETABLE,
					'callback'            => array( $this, 'delete_message' ),
					'permission_callback' => array( $this, 'permission_messages' ),
					'args'                => $id,
				),
			)
		);

		register_rest_route(
			$this->namespace,
			'/messages/recipients',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_recipients' ),
					'permission_callback' => array( $this, 'permission_messages' ),
					'args'                => array(
						'search' => array(
							'type'              => 'string',
							'default'           => '',
							'sanitize_callback' => 'sanitize_text_field',
						),
					),
				),
			)
		);

		register_rest_route(
			$this->namespace,
			'/me/blocks',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_blocks' ),
					'permission_callback' => array( $this, 'permission_logged_in' ),
				),
				array(
					'methods'             => WP_REST_Server::CREATABLE,
					'callback'            => array( $this, 'set_block' ),
					'permission_callback' => array( $this, 'permission_logged_in' ),
					'args'                => array(
						'user_id' => array(
							'type'     => 'integer',
							'required' => true,
							'minimum'  => 1,
						),
						'blocked' => array(
							'type'     => 'boolean',
							'required' => true,
						),
					),
				),
			)
		);
	}

	/**
	 * Requires a member who may use messages.
	 *
	 * @return true|WP_Error
	 */
	public function permission_messages() {
		$logged_in = $this->permission_logged_in();

		if ( is_wp_error( $logged_in ) ) {
			return $logged_in;
		}

		if ( ! Rules::enabled() ) {
			return new WP_Error( 'spacebay_messages_off', __( 'Private messages are turned off in this community.', 'spacebay' ), array( 'status' => 403 ) );
		}

		return true;
	}

	/**
	 * Unread counts, polled by the apps. Add-ons add their own data (ringing calls).
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response
	 */
	public function get_pulse( $request ) {
		unset( $request );

		$user_id = get_current_user_id();
		$data    = array(
			'messages'      => Rules::enabled() ? Conversations::unread_total( $user_id ) : 0,
			'notifications' => Notifications::unread_count( $user_id ),
		);

		/**
		 * Filters the data of the pulse endpoint that the apps poll.
		 *
		 * @since 1.0.0
		 *
		 * @param array $data    Unread counts.
		 * @param int   $user_id Member.
		 */
		$response = rest_ensure_response( apply_filters( 'spacebay_pulse', $data, $user_id ) );
		$response->header( 'Cache-Control', 'no-store' );

		return $response;
	}

	/**
	 * Lists the member's conversations.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response
	 */
	public function get_items( $request ) {
		$user_id = get_current_user_id();
		$result  = Conversations::for_user( $user_id, $request['page'], $request['per_page'], $request['search'] );

		return $this->paged_response( $this->format_conversations( $result['items'], $user_id ), $result['total'], $request['per_page'] );
	}

	/**
	 * Opens a one-to-one chat or starts a group chat.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function create_item( $request ) {
		$user_id = get_current_user_id();
		$others  = array_values( array_diff( array_unique( array_map( 'absint', (array) $request['user_ids'] ) ), array( $user_id, 0 ) ) );

		if ( ! Rules::can_use( $user_id ) ) {
			return $this->forbidden();
		}

		if ( ! $others ) {
			return new WP_Error( 'spacebay_no_recipients', __( 'Choose who you want to message.', 'spacebay' ), array( 'status' => 400 ) );
		}

		$conversation = 1 === count( $others ) && ! $request['group']
			? Conversations::direct( $user_id, $others[0] )
			: Conversations::create_group( $user_id, $others, (string) $request['title'] );

		if ( is_wp_error( $conversation ) ) {
			return $conversation;
		}

		return rest_ensure_response( $this->format_conversations( array( $this->with_membership( $conversation, $user_id ) ), $user_id )[0] );
	}

	/**
	 * One conversation.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function get_item( $request ) {
		$conversation = $this->own_conversation( $request['id'] );

		if ( is_wp_error( $conversation ) ) {
			return $conversation;
		}

		return rest_ensure_response( $this->format_conversations( array( $conversation ), get_current_user_id() )[0] );
	}

	/**
	 * Renames a group or mutes a conversation.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function update_item( $request ) {
		$user_id      = get_current_user_id();
		$conversation = $this->own_conversation( $request['id'] );

		if ( is_wp_error( $conversation ) ) {
			return $conversation;
		}

		if ( isset( $request['title'] ) && 'group' === $conversation['type'] ) {
			Conversations::rename( $conversation, $user_id, $request['title'] );
		}

		if ( isset( $request['muted'] ) ) {
			Conversations::set_muted( $conversation['id'], $user_id, (bool) $request['muted'] );
		}

		return $this->get_item( $request );
	}

	/**
	 * Adds people to a group.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function add_members( $request ) {
		$conversation = $this->own_conversation( $request['id'] );

		if ( is_wp_error( $conversation ) ) {
			return $conversation;
		}

		$result = Conversations::add_members( $conversation, get_current_user_id(), (array) $request['user_ids'] );

		return is_wp_error( $result ) ? $result : $this->get_item( $request );
	}

	/**
	 * Removes someone from a group, or leaves a conversation.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function remove_member( $request ) {
		$conversation = $this->own_conversation( $request['id'] );

		if ( is_wp_error( $conversation ) ) {
			return $conversation;
		}

		$result = Conversations::remove_member( $conversation, get_current_user_id(), absint( $request['user_id'] ) );

		if ( is_wp_error( $result ) ) {
			return $result;
		}

		return rest_ensure_response( array( 'removed' => true ) );
	}

	/**
	 * Messages of a conversation. Marks nothing as read.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function get_messages( $request ) {
		$user_id      = get_current_user_id();
		$conversation = $this->own_conversation( $request['id'] );

		if ( is_wp_error( $conversation ) ) {
			return $conversation;
		}

		$result  = Messages::for_conversation( $conversation['id'], $request['before'], $request['after'], $request['limit'], Messages::since( $conversation, $user_id ) );
		$members = Conversations::members( $conversation['id'] );
		$read    = array();

		// Read receipts: the last message each other member has seen.
		foreach ( $members as $member ) {
			if ( $member['user_id'] !== $user_id ) {
				$read[] = array(
					'user_id'      => $member['user_id'],
					'last_read_id' => $member['last_read_id'],
				);
			}
		}

		$data = array(
			'items'    => Messages::format_many( $result['items'], $user_id ),
			'has_more' => $result['has_more'],
			'read'     => $read,
		);

		/**
		 * Filters a page of a conversation's messages.
		 *
		 * @since 1.0.0
		 *
		 * @param array $data         Messages, has_more and read receipts.
		 * @param array $conversation Conversation row.
		 * @param int   $user_id      Viewer.
		 */
		$response = rest_ensure_response( apply_filters( 'spacebay_conversation_messages', $data, $conversation, $user_id ) );
		$response->header( 'Cache-Control', 'no-store' );

		return $response;
	}

	/**
	 * Sends a message.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function create_message( $request ) {
		$user_id      = get_current_user_id();
		$conversation = $this->own_conversation( $request['id'] );

		if ( is_wp_error( $conversation ) ) {
			return $conversation;
		}

		$message = Messages::create(
			$conversation,
			$user_id,
			array(
				'message'   => (string) $request['message'],
				'media_ids' => (array) $request['media_ids'],
			)
		);

		if ( is_wp_error( $message ) ) {
			return $message;
		}

		return rest_ensure_response( Messages::format_many( array( $message ), $user_id )[0] );
	}

	/**
	 * Marks messages as read.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function mark_read( $request ) {
		$user_id      = get_current_user_id();
		$conversation = $this->own_conversation( $request['id'] );

		if ( is_wp_error( $conversation ) ) {
			return $conversation;
		}

		Conversations::mark_read( $conversation['id'], $user_id, min( absint( $request['message_id'] ), $conversation['last_message_id'] ) );

		return rest_ensure_response( array( 'unread' => Conversations::unread_total( $user_id ) ) );
	}

	/**
	 * Deletes one of the member's own messages. Moderators may delete any.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function delete_message( $request ) {
		$user_id = get_current_user_id();
		$message = Messages::find( $request['id'] );

		if ( ! $message || 'text' !== $message['type'] || ! Messages::visible_to( $message, $user_id ) ) {
			return new WP_Error( 'spacebay_message_not_found', __( 'Message not found.', 'spacebay' ), array( 'status' => 404 ) );
		}

		if ( $message['user_id'] !== $user_id && ! Rules::is_staff( $user_id ) ) {
			return $this->forbidden();
		}

		return rest_ensure_response( Messages::format_many( array( Messages::delete( $message ) ), $user_id )[0] );
	}

	/**
	 * Members the current member may message.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response
	 */
	public function get_recipients( $request ) {
		$user_id = get_current_user_id();
		$items   = array();

		// Look through a few pages of the directory and keep the people the rules allow.
		for ( $page = 1; $page <= 4; $page++ ) {
			$found = MemberDirectory::query(
				array(
					'search'   => $request['search'],
					'per_page' => 50,
					'page'     => $page,
					'orderby'  => 'name',
				)
			);

			foreach ( $found['items'] as $member ) {
				if ( Rules::can_message( $user_id, $member['id'] ) ) {
					$items[] = $member;
				}
			}

			if ( count( $items ) >= 12 || $page * 50 >= $found['total'] ) {
				break;
			}
		}

		$items = array_slice( $items, 0, 12 );

		return rest_ensure_response( $items );
	}

	/**
	 * Members the current member has blocked.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response
	 */
	public function get_blocks( $request ) {
		unset( $request );

		return rest_ensure_response( array_values( Formatter::authors( Rules::blocked_ids( get_current_user_id() ) ) ) );
	}

	/**
	 * Blocks or unblocks a member.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function set_block( $request ) {
		$user_id = get_current_user_id();
		$other   = absint( $request['user_id'] );

		if ( $other === $user_id || ! get_userdata( $other ) ) {
			return new WP_Error( 'spacebay_member_not_found', __( 'Member not found.', 'spacebay' ), array( 'status' => 404 ) );
		}

		if ( $request['blocked'] && Rules::is_staff( $other ) ) {
			return new WP_Error( 'spacebay_cannot_block_staff', __( 'Community managers and moderators cannot be blocked.', 'spacebay' ), array( 'status' => 400 ) );
		}

		Rules::set_blocked( $user_id, $other, (bool) $request['blocked'] );

		return rest_ensure_response(
			array(
				'blocked'     => Rules::has_blocked( $user_id, $other ),
				'can_message' => Rules::can_message( $user_id, $other ),
			)
		);
	}

	/**
	 * A conversation the current member takes part in, or a 404 error.
	 *
	 * @param int $id Conversation ID.
	 * @return array|WP_Error Conversation with the member's own state.
	 */
	private function own_conversation( $id ) {
		$user_id      = get_current_user_id();
		$conversation = Conversations::find( $id );

		if ( ! $conversation || ! Conversations::is_member( $conversation['id'], $user_id ) ) {
			return new WP_Error( 'spacebay_conversation_not_found', __( 'Conversation not found.', 'spacebay' ), array( 'status' => 404 ) );
		}

		return $this->with_membership( $conversation, $user_id );
	}

	/**
	 * Adds the member's read position, mute and role to a conversation.
	 *
	 * @param array $conversation Conversation row.
	 * @param int   $user_id      Member.
	 * @return array
	 */
	private function with_membership( array $conversation, $user_id ) {
		$membership = Conversations::membership( $conversation['id'], $user_id );

		$conversation['last_read_id'] = $membership ? $membership['last_read_id'] : 0;
		$conversation['is_muted']     = $membership ? $membership['is_muted'] : 0;
		$conversation['role']         = $membership ? $membership['role'] : 'member';
		$conversation['joined_at']    = $membership ? $membership['joined_at'] : '';

		return $conversation;
	}

	/**
	 * Formats conversations for the apps.
	 *
	 * @param array[] $rows    Conversation rows with membership fields.
	 * @param int     $user_id Viewer.
	 * @return array[]
	 */
	private function format_conversations( array $rows, $user_id ) {
		if ( ! $rows ) {
			return array();
		}

		$ids     = wp_list_pluck( $rows, 'id' );
		$unread  = Conversations::unread( $user_id, $ids );
		$members = array();
		$people  = array();
		$last    = array();

		// One query for the members of every chat on the page and one for the last messages.
		$active   = Conversations::member_ids_many( $ids );
		$messages = Messages::find_many( wp_list_pluck( $rows, 'last_message_id' ) );

		foreach ( $rows as $row ) {
			$members[ $row['id'] ] = $active[ $row['id'] ] ?? array();

			if ( 'direct' === $row['type'] ) {
				$members[ $row['id'] ] = array_values( array_unique( array_merge( $members[ $row['id'] ], array( Messages::direct_other( $row, $user_id ) ) ) ) );
			}

			$people = array_merge( $people, $members[ $row['id'] ] );

			// People added to a group later do not see the message from before they joined.
			$hidden = 'group' === $row['type'] && isset( $messages[ $row['last_message_id'] ] ) && ! empty( $row['joined_at'] ) && $messages[ $row['last_message_id'] ]['created_at'] < $row['joined_at'];

			if ( $row['last_message_id'] && isset( $messages[ $row['last_message_id'] ] ) && ! $hidden ) {
				$last[ $row['id'] ] = $messages[ $row['last_message_id'] ];
			}
		}

		$authors   = Formatter::authors( array_merge( $people, wp_list_pluck( $last, 'user_id' ) ) );
		$previews  = array();
		$formatted = $last ? Messages::format_many( array_values( $last ), $user_id ) : array();

		foreach ( $formatted as $message ) {
			$previews[ $message['conversation_id'] ] = $message;
		}

		$items = array();

		foreach ( $rows as $row ) {
			$others = array();

			foreach ( $members[ $row['id'] ] as $member_id ) {
				if ( (int) $member_id !== (int) $user_id && isset( $authors[ $member_id ] ) ) {
					$others[] = $authors[ $member_id ];
				}
			}

			$is_direct = 'direct' === $row['type'];
			$other_id  = $is_direct ? Messages::direct_other( $row, $user_id ) : 0;
			$preview   = $previews[ $row['id'] ] ?? null;
			$size      = count( $active[ $row['id'] ] ?? array() );

			$items[] = array(
				'id'           => $row['id'],
				'type'         => $row['type'],
				'title'        => $is_direct ? ( $others[0]['name'] ?? __( 'Deleted member', 'spacebay' ) ) : ( '' !== $row['title'] ? $row['title'] : implode( ', ', wp_list_pluck( array_slice( $others, 0, 3 ), 'name' ) ) ),
				'has_title'    => ! $is_direct && '' !== $row['title'],
				'others'       => $others,
				'size'         => $size,
				'role'         => $row['role'] ?? 'member',
				'muted'        => ! empty( $row['is_muted'] ),
				'unread'       => $unread[ $row['id'] ] ?? 0,
				'last_read_id' => (int) ( $row['last_read_id'] ?? 0 ),
				'last_message' => $preview ? array(
					'id'         => $preview['id'],
					'text'       => $this->preview_text( $preview ),
					'is_mine'    => $preview['is_mine'],
					'is_event'   => 'system' === $preview['type'],
					'author'     => $preview['author']['name'],
					'created_at' => $preview['created_at'],
				) : null,
				'can_send'     => $is_direct ? Rules::can_message( $user_id, $other_id ) : $size > 1,
				'blocked'      => $is_direct && Rules::has_blocked( $user_id, $other_id ),
				'updated_at'   => \SpaceBay\Support\Time::iso( $row['last_message_at'] ),
			);
		}

		/**
		 * Filters the formatted conversations of a list.
		 *
		 * @since 1.0.0
		 *
		 * @param array[] $items   Conversations.
		 * @param int     $user_id Viewer.
		 */
		$items = apply_filters( 'spacebay_conversation_items', $items, $user_id );

		return $items;
	}

	/**
	 * One-line preview of a message.
	 *
	 * @param array $message Formatted message.
	 * @return string
	 */
	private function preview_text( array $message ) {
		if ( $message['deleted'] ) {
			return __( 'Message deleted', 'spacebay' );
		}

		if ( isset( $message['text'] ) ) {
			return $message['text'];
		}

		$text = trim( preg_replace( '/\s+/', ' ', wp_strip_all_tags( $message['content'] ) ) );

		if ( '' === $text && $message['media'] ) {
			return __( 'Sent a photo', 'spacebay' );
		}

		return mb_substr( $text, 0, 120 );
	}
}