'use strict'

const MAX_TIMEOUT = 1000

function wait (state, index, expected, timeout, done) {
  const max = Date.now() + timeout
  let current = Atomics.load(state, index)
  if (current === expected) {
    done(null, 'ok')
    return
  }
  let prior = current
  const check = (backoff) => {
    if (Date.now() > max) {
      done(null, 'timed-out')
    } else {
      setTimeout(() => {
        prior = current
        current = Atomics.load(state, index)
        if (current === prior) {
          check(backoff >= MAX_TIMEOUT ? MAX_TIMEOUT : backoff * 2)
        } else {
          if (current === expected) done(null, 'ok')
          else done(null, 'not-equal')
        }
      }, backoff)
    }
  }
  check(1)
}

// let waitDiffCount = 0
function waitDiff (state, index, expected, timeout, done) {
  // const id = waitDiffCount++
  // process._rawDebug(`>>> waitDiff ${id}`)
  const max = Date.now() + timeout
  let current = Atomics.load(state, index)
  if (current !== expected) {
    done(null, 'ok')
    return
  }
  const check = (backoff) => {
    // process._rawDebug(`${id} ${index} current ${current} expected ${expected}`)
    // process._rawDebug('' + backoff)
    if (Date.now() > max) {
      done(null, 'timed-out')
    } else {
      setTimeout(() => {
        current = Atomics.load(state, index)
        if (current !== expected) {
          done(null, 'ok')
        } else {
          check(backoff >= MAX_TIMEOUT ? MAX_TIMEOUT : backoff * 2)
        }
      }, backoff)
    }
  }
  check(1)
}

module.exports = { wait, waitDiff }