/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import {bazelDefineCompileValue} from './bazel_define_compile_value';

/**
 * A function to conditionally include a test or a block of tests only when tests run against Ivy.
 *
 * The modification of the behavior must be well justified, not affect common usage patterns, and
 * documented as a breaking change.
 *
 * ```
 * ivyEnabled && describe(...);
 * ```
 *
 * or
 *
 * ```
 * ivyEnabled && it(...);
 * ```
 */
export const ivyEnabled = 'aot' === (bazelDefineCompileValue as string);

/**
 * A function to conditionally skip the execution of tests that are not relevant when
 * running against Ivy.
 *
 * Any tests disabled using this switch should not be user-facing breaking changes.
 *
 * ```
 * obsoleteInIvy('some reason').describe(...);
 * ```
 *
 * or
 *
 * ```
 * obsoleteInIvy('some reason').it(...);
 * ```
 */
export function obsoleteInIvy(reason: string): JasmineMethods {
  return ivyEnabled ? IGNORE : PASSTHROUGH;
}

/**
 * A function to conditionally skip the execution of tests that are not relevant when
 * not running against Ivy.
 *
 * ```
 * onlyInIvy('some reason').describe(...);
 * ```
 *
 * or
 *
 * ```
 * onlyInIvy('some reason').it(...);
 * ```
 */
export function onlyInIvy(reason: string): JasmineMethods {
  return ivyEnabled ? PASSTHROUGH : IGNORE;
}

/**
 * A function to conditionally skip the execution of tests that have intentionally
 * been broken when running against Ivy.
 *
 * The modification of the behavior must be well justified, not affect common usage patterns, and
 * documented as a breaking change.
 *
 * ```
 * modifiedInIvy('some reason').describe(...);
 * ```
 *
 * or
 *
 * ```
 * modifiedInIvy('some reason').it(...);
 * ```
 */
export function modifiedInIvy(reason: string): JasmineMethods {
  return ivyEnabled ? IGNORE : PASSTHROUGH;
}

export interface JasmineMethods {
  it: typeof it;
  fit: typeof fit;
  describe: typeof describe;
  fdescribe: typeof fdescribe;

  /**
   * Runs jasmine expectations against the provided keys for `ngDevMode`.
   *
   * Will not perform expectations for keys that are not provided.
   *
   * ```ts
   * // Expect that `ngDevMode.styleMap` is `1`, and `ngDevMode.tNode` is `3`, but we don't care
   * // about the other values.
   * onlyInIvy('perf counters').expectPerfCounters({
   *   stylingMap: 1,
   *   tNode: 3,
   * })
   * ```
   */
  expectPerfCounters: (expectedCounters: Partial<NgDevModePerfCounters>) => void;
  isEnabled: boolean;
}

const PASSTHROUGH: JasmineMethods = {
  it,
  fit,
  describe,
  fdescribe,
  expectPerfCounters,
  isEnabled: true,
};

function noop() {}

function expectPerfCounters(expectedCounters: Partial<NgDevModePerfCounters>) {
  Object.keys(expectedCounters).forEach(key => {
    const expected = (expectedCounters as any)[key];
    const actual = (ngDevMode as any)[key];
    expect(actual).toBe(expected, `ngDevMode.${key}`);
  });
}

const IGNORE: JasmineMethods = {
  it: noop,
  fit: noop,
  describe: noop,
  fdescribe: noop,
  expectPerfCounters: noop,
  isEnabled: false,
};