/*
Copyright 2020 Bruno Windels <bruno@windels.cloud>
Copyright 2020 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import {LeftPanelViewModel} from "./leftpanel/LeftPanelViewModel.js";
import {RoomViewModel} from "./room/RoomViewModel.js";
import {SessionStatusViewModel} from "./SessionStatusViewModel.js";
import {RoomGridViewModel} from "./RoomGridViewModel.js";
import {ViewModel} from "../ViewModel.js";

export class SessionViewModel extends ViewModel {
    constructor(options) {
        super(options);
        const {sessionContainer} = options;
        this._sessionContainer = this.track(sessionContainer);
        this._sessionStatusViewModel = this.track(new SessionStatusViewModel(this.childOptions({
            sync: sessionContainer.sync,
            reconnector: sessionContainer.reconnector,
            session: sessionContainer.session,
        })));
        this._leftPanelViewModel = new LeftPanelViewModel(this.childOptions({
            rooms: this._sessionContainer.session.rooms
        }));
        this._currentRoomViewModel = null;
        this._gridViewModel = null;
        this._setupNavigation();
    }

    _setupNavigation() {
        const gridRooms = this.navigation.observe("rooms");
        // this gives us a set of room ids in the grid
        this.track(gridRooms.subscribe(roomIds => {
            this._updateGrid(roomIds);
        }));
        if (gridRooms.get()) {
            this._updateGrid(gridRooms.get());
        }

        const currentRoomId = this.navigation.observe("room");
        // this gives us the active room
        this.track(currentRoomId.subscribe(roomId => {
            if (!this._gridViewModel) {
                this._openRoom(roomId);
            }
        }));
        if (currentRoomId.get() && !this._gridViewModel) {
            this._openRoom(currentRoomId.get());
        }
    }

    start() {
        this._sessionStatusViewModel.start();
    }

    get activeSection() {
        if (this._currentRoomViewModel) {
            return this._currentRoomViewModel.id;
        } else if (this._gridViewModel) {
            return "roomgrid";
        }
        return "placeholder";
    }

    get roomGridViewModel() {
        return this._gridViewModel;
    }

    get leftPanelViewModel() {
        return this._leftPanelViewModel;
    }

    get sessionStatusViewModel() {
        return this._sessionStatusViewModel;
    }

    get roomList() {
        return this._roomList;
    }

    get currentRoomViewModel() {
        return this._currentRoomViewModel;
    }

    _updateGrid(roomIds) {
        const changed = !(this._gridViewModel && roomIds);
        const currentRoomId = this.navigation.path.get("room");
        if (roomIds) {
            if (!this._gridViewModel) {
                this._gridViewModel = this.track(new RoomGridViewModel(this.childOptions({
                    width: 3,
                    height: 2,
                    createRoomViewModel: roomId => this._createRoomViewModel(roomId),
                })));
                if (this._gridViewModel.initializeRoomIdsAndTransferVM(roomIds, this._currentRoomViewModel)) {
                    this._currentRoomViewModel = this.untrack(this._currentRoomViewModel);
                } else if (this._currentRoomViewModel) {
                    this._currentRoomViewModel = this.disposeTracked(this._currentRoomViewModel);
                }
            } else {
                this._gridViewModel.setRoomIds(roomIds);
            }
        } else if (this._gridViewModel && !roomIds) {
            if (currentRoomId) {
                const vm = this._gridViewModel.releaseRoomViewModel(currentRoomId.value);
                this._currentRoomViewModel = this.track(vm);
            }
            this._gridViewModel = this.disposeTracked(this._gridViewModel);
        }
        if (changed) {
            this.emitChange("middlePanelViewType");
        }
    }

    _createRoomViewModel(roomId) {
        const room = this._sessionContainer.session.rooms.get(roomId);
        if (!room) {
            return null;
        }
        const roomVM = new RoomViewModel(this.childOptions({
            room,
            ownUserId: this._sessionContainer.session.user.id,
        }));
        roomVM.load();
        return roomVM;
    }

    _openRoom(roomId) {
        // already open?
        if (this._currentRoomViewModel?.id === roomId) {
            return;
        }
        this._currentRoomViewModel = this.disposeTracked(this._currentRoomViewModel);
        const roomVM = this._createRoomViewModel(roomId);
        if (roomVM) {
            this._currentRoomViewModel = this.track(roomVM);
            this.emitChange("currentRoom");
        }
    }
}