// Licensed to the Software Freedom Conservancy (SFC) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The SFC licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

'use strict'

const assert = require('assert')
const sinon = require('sinon')

class StubError extends Error {
  constructor(opt_msg) {
    super(opt_msg)
    this.name = this.constructor.name
  }
}
exports.StubError = StubError

exports.throwStubError = function () {
  throw new StubError()
}

exports.assertIsStubError = function (value) {
  assert.ok(value instanceof StubError, value + ' is not a ' + StubError.name)
}

exports.assertIsInstance = function (ctor, value) {
  assert.ok(value instanceof ctor, 'Not a ' + ctor.name + ': ' + value)
}

function callbackPair(cb, eb) {
  if (cb && eb) {
    throw new TypeError('can only specify one of callback or errback')
  }

  let callback = cb ? sinon.spy(cb) : sinon.spy()
  let errback = eb ? sinon.spy(eb) : sinon.spy()

  function assertCallback() {
    assert.ok(callback.called, 'callback not called')
    assert.ok(!errback.called, 'errback called')
    if (callback.threw()) {
      throw callback.exceptions[0]
    }
  }

  function assertErrback() {
    assert.ok(!callback.called, 'callback called')
    assert.ok(errback.called, 'errback not called')
    if (errback.threw()) {
      throw errback.exceptions[0]
    }
  }

  function assertNeither() {
    assert.ok(!callback.called, 'callback called')
    assert.ok(!errback.called, 'errback called')
  }

  return {
    callback,
    errback,
    assertCallback,
    assertErrback,
    assertNeither,
  }
}
exports.callbackPair = callbackPair

exports.callbackHelper = function (cb) {
  let pair = callbackPair(cb)
  let wrapped = pair.callback.bind(null)
  wrapped.assertCalled = () => pair.assertCallback()
  wrapped.assertNotCalled = () => pair.assertNeither()
  return wrapped
}