import { createClient, RedisClientType } from "redis";
import uuid4 from "uuid4";

import { IncomingResponse, OutgoingRequest } from "./types";

class MessageBusClient {
  client: RedisClientType;
  constructor(port = 6379) {
    this.client = createClient({
      socket: {
        port: port,
      },
    });
    this.connect();
  }

  async connect() {
    this.client.connect();
  }

  async disconnect() {
    this.client.disconnect();
  }

  async send(
    requestCommand: string,
    requestData: string,
    destinationTwinId: number,
    expirationMinutes: number,
  ): Promise<string> {
    const uuid = uuid4();
    const outgoingRequest: OutgoingRequest = {
      ver: 1,
      ref: uuid,
      cmd: requestCommand,
      exp: expirationMinutes * 60,
      dat: Buffer.from(requestData).toString("base64"),
      tag: "",
      dst: [destinationTwinId],
      ret: uuid,
      shm: "application/json",
      now: Math.floor(new Date().getTime() / 1000),
    };

    const request = JSON.stringify(outgoingRequest);
    await this.client.lPush("msgbus.system.local", request);
    return outgoingRequest.ref;
  }

  async read(requestId: string, timeoutMinutes = 1): Promise<unknown> {
    const res = await this.client.blPop(requestId, timeoutMinutes * 60);

    if (res) {
      const incomingResponse: IncomingResponse = JSON.parse(res.element);
      if (incomingResponse.err) {
        throw Error(`Failed to read response due to: ${incomingResponse.err.message}`);
      }
      const data = Buffer.from(incomingResponse.dat, "base64").toString("ascii");
      return JSON.parse(data);
    }
    throw Error(`Couldn't get the response in ${timeoutMinutes} minutes`);
  }
}

export { MessageBusClient };