/**
 * Copyright 2025 Angus.Fenying <fenying@litert.org>
 *
 * 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
 *
 *   https://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 * as LwDFX from '@litert/lwdfx';
import type * as dT from '../Transporter.decl';
import { EventEmitter } from 'node:events';
import { LwDFXTransporter } from './LwDFX.Transporter';
import type * as dL from './LwDFX.decl';

export type ILwDfxTcpGatewayOptions = LwDFX.Tcp.ITcpGatewayOptions;

class LwDfxTcpGateway extends EventEmitter implements dT.IGateway {

    private _gateway: LwDFX.Tcp.ITcpGateway | null = null;

    private readonly _lwdfxServer: LwDFX.IServer;

    public constructor(
        serverOpts: dL.ILwDfxServerOptions,
        private readonly _gatewayOpts: ILwDfxTcpGatewayOptions,
        private readonly _server: dT.IServer,
    ) {

        super();

        this._lwdfxServer = LwDFX.createServer({
            ...serverOpts,
            alpWhitelist: ['televoke2']
        });

        this._lwdfxServer.on('connection', (conn) => {

            this._server.registerChannel(new LwDFXTransporter('lwdfx/tcp', conn));
        });
    }

    public get running(): boolean {

        return !!this._gateway;
    }

    public async start(): Promise<void> {

        if (this._gateway) {

            return;
        }

        this._gateway = LwDFX.Tcp.createGateway(this._lwdfxServer, this._gatewayOpts);

        try {

            await this._gateway.start();
        }
        catch (e) {

            this._gateway = null;
            throw e;
        }
    }

    public async stop(): Promise<void> {

        if (!this._gateway) {

            return;
        }

        await this._gateway.stop();
        this._gateway = null;
    }
}

export function createTcpGateway(
    server: dT.IServer,
    gatewayOpts: ILwDfxTcpGatewayOptions = {},
    serverOpts: dL.ILwDfxServerOptions = {},
): dT.IGateway {

    return new LwDfxTcpGateway(serverOpts, gatewayOpts, server);
}