const crypto = require("crypto");
const phin = require("phin");

const conf = require("./config");

async function ussdClient(phone, sessionId, input = "") {
  const requestOptions = {
    url: conf.ussd.endpoint,
    method: "POST",
    parse: "string",
    timeout: conf.ussd.timeout,
    form: {
      sessionId: sessionId,
      // Get from a conf file, then pass as a param
      phoneNumber: phone,
      serviceCode: conf.ussd.serviceCode,
      text: input,
    },
  };

  try {
    const { body } = await phin(requestOptions);

    if (body.length > 1) {
      return {
        code: body.slice(0, 3),
        text: body.slice(4),
      };
    }

    throw new Error("EMPTY_BODY");
  } catch (error) {
    console.log(error);
  }
}

function newSession() {
  return crypto.randomBytes(16).toString("hex");
}

const wait = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

module.exports = { ussdClient, newSession, wait };