const cartesianToPolar = ({x, y}) => ({r: Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2)), t: Math.atan2(y, x)})
const polarToCartesian = ({r, t}) => ({x: r * Math.cos(t), y: r * Math.sin(t)})

const findMemory = (mem) => {
  let originalSnap = Object.assign({}, Array.from(mem))
  let snap = Object.assign({}, Array.from(mem))
  let criteria = () => true
  let finalCriteria = () => true

  const check = () => {
    for (let key of Object.keys(snap)) {
      if (!criteria(mem[key], snap[key])) delete snap[key]
      else snap[key] = mem[key]
    }
    return o
  }

  const result = () => {
    console.log(
      Object.keys(snap)
      .filter(x => finalCriteria(snap[x], originalSnap[x]))
      .map(x => `0x${x.toString(16).padStart(4, '0')}`)
    )
  }

  const setCriteria = (c, f) => {
    criteria = c
    finalCriteria = f
    return o
  }
  const o = {
    with: c => setCriteria(c),
    increasing: () => setCriteria((a, b) => a >= b, (a, b) => a > b),
    decreasing: () => setCriteria((a, b) => a <= b, (a, b) => a > b),
    static: () => setCriteria((a, b) => a === b, () => true),
    check,
    result
  }

  return o
}

module.exports = {
  cartesianToPolar,
  polarToCartesian,
  findMemory
}