/*
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 {Link} from "./Link.js";
import {ViewModel} from "./utils/ViewModel.js";
import {OpenLinkViewModel} from "./open/OpenLinkViewModel.js";
import {createClients} from "./open/clients/index.js";
import {CreateLinkViewModel} from "./create/CreateLinkViewModel.js";
import {LoadServerPolicyViewModel} from "./policy/LoadServerPolicyViewModel.js";
import {InvalidUrlViewModel} from "./InvalidUrlViewModel.js";
import {Platform} from "./Platform.js";

export class RootViewModel extends ViewModel {
    constructor(options) {
        super(options);
        this.link = null;
        this.openLinkViewModel = null;
        this.createLinkViewModel = null;
        this.loadServerPolicyViewModel = null;
        this.invalidUrlViewModel = null;
        this.showDisclaimer = false;
        this.preferences.on("canClear", () => {
            this.emitChange();
        });
    }

    _updateChildVMs(newLink, oldLink) {
        this.link = newLink;
        if (!newLink) {
            this.openLinkViewModel = null;
        } else if (!oldLink || !oldLink.equals(newLink)) {
            this.openLinkViewModel = new OpenLinkViewModel(this.childOptions({
                link: newLink,
                clients: createClients(),
            }));
        }
    }

    _hideLinks() {
        this.link = null;
        this.openLinkViewModel = null;
        this.createLinkViewModel = null;
    }

    updateHash(hash) {
        // All view models except openLink are re-created anyway. Might as well
        // clear them to avoid having to manually reset (n-1)/n view models in every case.
        // That just doesn't scale well when we add new views.
        const oldLink = this.link;
        this.invalidUrlViewModel = null;
        this.showDisclaimer = false;
        this.loadServerPolicyViewModel = null;
        this.createLinkViewModel = null;
        let newLink;
        if (hash.startsWith("#/policy/")) {
            const server = hash.substr(9);
            this._updateChildVMs(null, oldLink);
            this.loadServerPolicyViewModel = new LoadServerPolicyViewModel(this.childOptions({server}));
            this.loadServerPolicyViewModel.load();
        } else if (hash.startsWith("#/disclaimer/")) {
            this._updateChildVMs(null, oldLink);
            this.showDisclaimer = true;
        }  else if (hash === "" || hash === "#" || hash === "#/") {
            this._updateChildVMs(null, oldLink);
            this.createLinkViewModel = new CreateLinkViewModel(this.childOptions());
        } else if (newLink = Link.parseFragment(hash)) {
            this._updateChildVMs(newLink, oldLink);
        } else {
            this._updateChildVMs(null, oldLink);
            this.invalidUrlViewModel = new InvalidUrlViewModel(this.childOptions({
                fragment: hash
            }));
        }
        this.emitChange();
    }

    clearPreferences() {
        this.preferences.clear();
        this._updateChildVMs();
    }

    get hasPreferences() {
        return this.preferences.canClear;
    }
}