const EventEmitter = require("events");
const _ = require("underscore");

class MockDriver {
  constructor() {
    this.started = false;
    this.events = new EventEmitter();
    this.seconds = 0;
    this.level = 1;
    this.workoutState = {
      minutes: 0,
      seconds: 0,
      speed: 0,
      rpm: 0,
      distance: 0,
      calories: 0,
      pulse: 0,
      watt: 0,
      level: 1,
    };

    this.interval = null;
  }

  connect() {
    return Promise.resolve();
  }

  start() {
    if (this.started) {
      return;
    }

    this.started = true;
    this.interval = setInterval(() => {
      this.seconds++;
      
      this.workoutState.minutes = Math.floor(this.seconds / 60);
      this.workoutState.seconds = this.seconds % 60;
      this.workoutState.speed = Math.floor(300 + Math.random() * 200) / 10;
      this.workoutState.rpm = Math.floor(57 + Math.random() * 5);
      this.workoutState.distance += (this.seconds % 5 == 0) ? 0.1 : 0;
      this.workoutState.calories += (this.seconds % 2 == 0) ? 1 : 0;
      this.workoutState.pulse = null;
      this.workoutState.watt = Math.floor(100 + Math.random() * 20);
      this.workoutState.level = this.level;

      this.events.emit("workoutState", {...this.workoutState});
    }, 1000);

    this.workoutState.level = 1;
    this.workoutState.speed = 0;
    this.workoutState.rpm = 0;
    this.workoutState.watt = 0;

    if (this.seconds === 0) {
      this.events.emit("workoutState", {...this.workoutState});
    }

    return Promise.resolve();
  }

  setLevel(n) {
    if (n < 0 || n > 32) {
      return Promise.reject(new Error("Level is out of range (0..=32)"))
    }

    this.level = n;
  }

  pause() {
    clearInterval(this.interval);
    this.started = false;
    
    return Promise.resolve();
  }

  stop() {
    this.pause();
    this.workoutState = {
      minutes: 0,
      seconds: 0,
      speed: 0,
      rpm: 0,
      distance: 0,
      calories: 0,
      pulse: 0,
      watt: 0,
      level: 1,
    };
    this.seconds = 0;

    return Promise.resolve();
  }

  destroy() {
    this.stop();
    this.events.emit("destroy");
    this.events.removeAllListeners();
  }
}

module.exports = MockDriver;