strikeentco/feels

'use strict';

/* eslint-disable no-mixed-operators */

const isCorrect = data => !(data == null) && Number.isFinite(data);

module.exports.isCorrect = (...args) => args.every(arg => isCorrect(arg));

const tempFormat = (temp) => {
  if (temp === 'f' || temp === 'fahrenheit') {
    return 'f';
  } else if (temp === 'k' || temp === 'kelvin') {
    return 'k';
  }
  return 'c';
};

const speedFormat = (speed) => {
  if (speed === 'mph' || speed === 'mi/h') {
    return 'mph';
  } else if (['kmh', 'kph', 'kmph', 'km/h'].includes(speed)) {
    return 'kph';
  }
  return 'mps';
};

module.exports.unitsFormat = (units) => {
  if (!units) {
    return {
      temp: 'c',
      speed: 'mps'
    };
  }

  const temp = (units.temp) ? units.temp.toLowerCase() : 'c';
  const speed = (units.speed) ? units.speed.toLowerCase() : 'mps';

  return { temp: tempFormat(temp), speed: speedFormat(speed) };
};

module.exports.tempConvert = (temp, from, to) => {
  if (!isCorrect(temp)) {
    throw new TypeError('Temp must be specified and must be a number');
  }
  if (from === to) {
    return temp;
  }
  if (!(['c', 'f', 'k'].includes(from) && ['c', 'f', 'k'].includes(to))) {
    throw new RangeError('Units must be c, f or k');
  }
  if (from === 'c') {
    return (to === 'f') ?
      (temp * 1000 * (9 / 5) + 32 * 1000) / 1000 :
      (temp * 1000 + 273.15 * 1000) / 1000;
  }
  if (from === 'f') {
    return (to === 'c') ?
      ((temp - 32) * 1000 * (5 / 9)) / 1000 :
      ((temp + 459.67) * 1000 * (5 / 9)) / 1000;
  }
  return (to === 'c') ? // k
    (temp * 1000 - 273.15 * 1000) / 1000 :
    (temp * 1000 * (9 / 5) - 459.67 * 1000) / 1000;
};

module.exports.speedConvert = (speed, from, to) => {
  if (!isCorrect(speed)) {
    throw new TypeError('Speed must be specified and must be a number');
  }
  if (from === to) {
    return speed;
  }
  if (!(['mps', 'mph', 'kph'].includes(from) && ['mps', 'mph', 'kph'].includes(to))) {
    throw new RangeError('Units must be mps, mph or kph');
  }
  if (from === 'mps') {
    return (to === 'mph') ? speed / 0.44704 : speed * 3.6;
  }
  if (from === 'mph') {
    return (to === 'mps') ? speed * 0.44704 : speed * 1.609344;
  }
  return (to === 'mps') ? speed / 3.6 : speed / 1.609344; // kph
};