// @flow
/* eslint-env mocha */

import assert from 'assert'
import eachHourOfInterval from '.'

describe('eachHourOfInterval', () => {
  it('returns an array with starts of hours from the hour of the start date to the hour of the end date', () => {
    const result = eachHourOfInterval({
      start: new Date(2014, 9 /* Oct */, 6, 12),
      end: new Date(2014, 9 /* Oct */, 6, 15)
    })
    assert.deepEqual(result, [
      new Date(2014, 9 /* Oct */, 6, 12),
      new Date(2014, 9 /* Oct */, 6, 13),
      new Date(2014, 9 /* Oct */, 6, 14),
      new Date(2014, 9 /* Oct */, 6, 15)
    ])
  })

  it('accepts timestamps', () => {
    const result = eachHourOfInterval({
      start: new Date(2014, 9 /* Oct */, 6, 12).getTime(),
      end: new Date(2014, 9 /* Oct */, 6, 15).getTime()
    })
    assert.deepEqual(result, [
      new Date(2014, 9 /* Oct */, 6, 12),
      new Date(2014, 9 /* Oct */, 6, 13),
      new Date(2014, 9 /* Oct */, 6, 14),
      new Date(2014, 9 /* Oct */, 6, 15)
    ])
  })

  it('handles the hours that are not starts of hours', () => {
    const result = eachHourOfInterval({
      start: new Date(2014, 9 /* Oct */, 6, 12, 59, 59, 999),
      end: new Date(2014, 9 /* Oct */, 6, 15, 59, 59, 999)
    })
    assert.deepEqual(result, [
      new Date(2014, 9 /* Oct */, 6, 12),
      new Date(2014, 9 /* Oct */, 6, 13),
      new Date(2014, 9 /* Oct */, 6, 14),
      new Date(2014, 9 /* Oct */, 6, 15)
    ])
  })

  it('returns one hour if the both arguments are on the same hour', () => {
    const result = eachHourOfInterval({
      start: new Date(2014, 9 /* Oct */, 6, 12, 35),
      end: new Date(2014, 9 /* Oct */, 6, 12, 47)
    })
    assert.deepEqual(result, [new Date(2014, 9 /* Oct */, 6, 12)])
  })

  it('returns one hour if the both arguments are the same', () => {
    const result = eachHourOfInterval({
      start: new Date(2014, 9 /* Oct */, 6, 12, 35),
      end: new Date(2014, 9 /* Oct */, 6, 12, 35)
    })
    assert.deepEqual(result, [new Date(2014, 9 /* Oct */, 6, 12)])
  })

  it('throws an exception if the start date is after the end date', () => {
    const block = eachHourOfInterval.bind(null, {
      start: new Date(2014, 9 /* Oct */, 12, 35, 0, 0, 1),
      end: new Date(2014, 9 /* Oct */, 12, 35, 0, 0, 0)
    })
    assert.throws(block, RangeError)
  })

  it('throws an exception if the start date is `Invalid Date`', () => {
    const block = eachHourOfInterval.bind(null, {
      start: new Date(NaN),
      end: new Date(2014, 9 /* Oct */, 6, 12)
    })
    assert.throws(block, RangeError)
  })

  it('throws an exception if the end date is `Invalid Date`', () => {
    const block = eachHourOfInterval.bind(null, {
      start: new Date(2014, 9 /* Oct */, 12, 12),
      end: new Date(NaN)
    })
    assert.throws(block, RangeError)
  })

  it('throws an exception if the interval is undefined', () => {
    const block = eachHourOfInterval.bind(
      null,
      // $ExpectedMistake
      undefined
    )
    assert.throws(block, RangeError)
  })

  it('throws TypeError exception if passed less than 1 argument', () => {
    assert.throws(eachHourOfInterval.bind(null), TypeError)
  })

  describe('options.step', () => {
    const interval = {
      start: new Date(2014, 9 /* Oct */, 6, 12),
      end: new Date(2014, 9 /* Oct */, 6, 18)
    }

    const stepError = /^RangeError: `options.step` must be a number greater than 1$/

    it('returns an array with starts of hours from the hour of the start date to the hour of the end date with the given step', () => {
      const result = eachHourOfInterval(interval, { step: 3 })
      assert.deepEqual(result, [
        new Date(2014, 9 /* Oct */, 6, 12),
        new Date(2014, 9 /* Oct */, 6, 15),
        new Date(2014, 9 /* Oct */, 6, 18)
      ])
    })

    it('throws TypeError error if `options.step` is less than 1', () => {
      assert.throws(() => eachHourOfInterval(interval, { step: 0 }), stepError)
      assert.throws(() => eachHourOfInterval(interval, { step: -3 }), stepError)
    })

    it('throws TypeError error if `options.step` is NaN', () => {
      // $ExpectedMistake
      assert.throws(
        () => eachHourOfInterval(interval, { step: 'w' }),
        stepError
      )
      assert.throws(
        () => eachHourOfInterval(interval, { step: NaN }),
        stepError
      )
    })
  })
})