import { expect } from 'chai'
import fu from '@/fileUtils.js'
import sinon from 'sinon'

describe('fileUtils.js', () => {
  afterEach(() => {
    document.createElement.restore()
  })

  it('exportToFile (octet/stream by default)', () => {
    const spyAnchor = document.createElement('a')
    sinon.spy(spyAnchor, 'click')
    sinon.spy(spyAnchor, 'remove')
    sinon.stub(document, 'createElement').returns(spyAnchor)
    sinon.spy(URL, 'createObjectURL')
    sinon.spy(URL, 'revokeObjectURL')
    sinon.spy(window, 'Blob')

    fu.exportToFile('foo', 'foo.txt')

    expect(document.createElement.calledOnceWith('a')).to.equal(true)

    expect(window.Blob.calledOnceWith(['foo'], { type: 'octet/stream' })).to.equal(true)
    const blob = window.Blob.returnValues[0]
    expect(URL.createObjectURL.calledOnceWith(blob)).to.equal(true)

    const url = URL.createObjectURL.returnValues[0]
    expect(spyAnchor.href).to.equal(url)

    expect(spyAnchor.download).to.equal('foo.txt')

    expect(spyAnchor.click.calledOnce).to.equal(true)

    expect(spyAnchor.remove.calledOnce).to.equal(true)
    expect(URL.revokeObjectURL.calledOnceWith(url)).to.equal(true)

    URL.revokeObjectURL.restore()
    URL.createObjectURL.restore()
    window.Blob.restore()
  })

  it('exportToFile', () => {
    const spyAnchor = document.createElement('a')
    sinon.spy(spyAnchor, 'click')
    sinon.spy(spyAnchor, 'remove')
    sinon.stub(document, 'createElement').returns(spyAnchor)
    sinon.spy(URL, 'createObjectURL')
    sinon.spy(URL, 'revokeObjectURL')
    sinon.spy(window, 'Blob')

    fu.exportToFile('foo', 'foo.html', 'text/html')

    expect(document.createElement.calledOnceWith('a')).to.equal(true)

    expect(window.Blob.calledOnceWith(['foo'], { type: 'text/html' })).to.equal(true)
    const blob = window.Blob.returnValues[0]
    expect(URL.createObjectURL.calledOnceWith(blob)).to.equal(true)

    const url = URL.createObjectURL.returnValues[0]
    expect(spyAnchor.href).to.equal(url)

    expect(spyAnchor.download).to.equal('foo.html')

    expect(spyAnchor.click.calledOnce).to.equal(true)

    expect(spyAnchor.remove.calledOnce).to.equal(true)
    expect(URL.revokeObjectURL.calledOnceWith(url)).to.equal(true)

    URL.revokeObjectURL.restore()
    URL.createObjectURL.restore()
    window.Blob.restore()
  })

  it('importFile', () => {
    const spyInput = document.createElement('input')
    sinon.spy(spyInput, 'click')
    sinon.spy(spyInput, 'remove')
    
    const blob = new Blob(['foo'])
    Object.defineProperty(spyInput, 'files', {
      value: [blob],
      writable: false,
    })

    sinon.stub(document, 'createElement').returns(spyInput)

    setTimeout(() => { spyInput.dispatchEvent(new Event('change')) })

    return fu.importFile()
      .then((data) => {
        expect(data).to.equal('foo')
        expect(document.createElement.calledOnceWith('input')).to.equal(true)
        expect(spyInput.type).to.equal('file')
        expect(spyInput.accept).to.equal('.json')
        expect(spyInput.click.calledOnce).to.equal(true)
        expect(spyInput.remove.calledOnce).to.equal(true)
      })
  })
})