/*
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 { MatrixClient } from "matrix-js-sdk/src/client";
import { AsyncStore } from "./AsyncStore";
import { ActionPayload } from "../dispatcher/payloads";
import { Dispatcher } from "flux";
import { MatrixClientPeg } from "../MatrixClientPeg";

export abstract class AsyncStoreWithClient<T extends Object> extends AsyncStore<T> {
    protected matrixClient: MatrixClient;

    protected abstract async onAction(payload: ActionPayload);

    protected constructor(dispatcher: Dispatcher<ActionPayload>, initialState: T = <T>{}) {
        super(dispatcher, initialState);

        if (MatrixClientPeg.get()) {
            this.matrixClient = MatrixClientPeg.get();

            // noinspection JSIgnoredPromiseFromCall
            this.onReady();
        }
    }

    protected async onReady() {
        // Default implementation is to do nothing.
    }

    protected async onNotReady() {
        // Default implementation is to do nothing.
    }

    protected async onDispatch(payload: ActionPayload) {
        await this.onAction(payload);

        if (payload.action === 'MatrixActions.sync') {
            // Only set the client on the transition into the PREPARED state.
            // Everything after this is unnecessary (we only need to know once we have a client)
            // and we intentionally don't set the client before this point to avoid stores
            // updating for every event emitted during the cached sync.
            if (!(payload.prevState === 'PREPARED' && payload.state !== 'PREPARED')) {
                return;
            }

            if (this.matrixClient !== payload.matrixClient) {
                if (this.matrixClient) {
                    await this.onNotReady();
                }
                this.matrixClient = payload.matrixClient;
                await this.onReady();
            }
        } else if (payload.action === 'on_client_not_viable' || payload.action === 'on_logged_out') {
            if (this.matrixClient) {
                await this.onNotReady();
                this.matrixClient = null;
            }
        }
    }
}