/**
 * @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
 */
(function(_global: any) {
  class AsyncTestZoneSpec implements ZoneSpec {
    static symbolParentUnresolved = Zone.__symbol__('parentUnresolved');

    _pendingMicroTasks: boolean = false;
    _pendingMacroTasks: boolean = false;
    _alreadyErrored: boolean = false;
    _isSync: boolean = false;
    runZone = Zone.current;
    unresolvedChainedPromiseCount = 0;

    supportWaitUnresolvedChainedPromise = false;

    constructor(
        private finishCallback: Function, private failCallback: Function, namePrefix: string) {
      this.name = 'asyncTestZone for ' + namePrefix;
      this.properties = {'AsyncTestZoneSpec': this};
      this.supportWaitUnresolvedChainedPromise =
          _global[Zone.__symbol__('supportWaitUnResolvedChainedPromise')] === true;
    }

    isUnresolvedChainedPromisePending() { return this.unresolvedChainedPromiseCount > 0; }

    _finishCallbackIfDone() {
      if (!(this._pendingMicroTasks || this._pendingMacroTasks ||
            (this.supportWaitUnresolvedChainedPromise &&
             this.isUnresolvedChainedPromisePending()))) {
        // We do this because we would like to catch unhandled rejected promises.
        this.runZone.run(() => {
          setTimeout(() => {
            if (!this._alreadyErrored && !(this._pendingMicroTasks || this._pendingMacroTasks)) {
              this.finishCallback();
            }
          }, 0);
        });
      }
    }

    patchPromiseForTest() {
      if (!this.supportWaitUnresolvedChainedPromise) {
        return;
      }
      const patchPromiseForTest = (Promise as any)[Zone.__symbol__('patchPromiseForTest')];
      if (patchPromiseForTest) {
        patchPromiseForTest();
      }
    }

    unPatchPromiseForTest() {
      if (!this.supportWaitUnresolvedChainedPromise) {
        return;
      }
      const unPatchPromiseForTest = (Promise as any)[Zone.__symbol__('unPatchPromiseForTest')];
      if (unPatchPromiseForTest) {
        unPatchPromiseForTest();
      }
    }

    // ZoneSpec implementation below.

    name: string;

    properties: {[key: string]: any};

    onScheduleTask(delegate: ZoneDelegate, current: Zone, target: Zone, task: Task): Task {
      if (task.type !== 'eventTask') {
        this._isSync = false;
      }
      if (task.type === 'microTask' && task.data && task.data instanceof Promise) {
        // check whether the promise is a chained promise
        if ((task.data as any)[AsyncTestZoneSpec.symbolParentUnresolved] === true) {
          // chained promise is being scheduled
          this.unresolvedChainedPromiseCount--;
        }
      }
      return delegate.scheduleTask(target, task);
    }

    onInvokeTask(
        delegate: ZoneDelegate, current: Zone, target: Zone, task: Task, applyThis: any,
        applyArgs: any) {
      if (task.type !== 'eventTask') {
        this._isSync = false;
      }
      return delegate.invokeTask(target, task, applyThis, applyArgs);
    }

    onCancelTask(delegate: ZoneDelegate, current: Zone, target: Zone, task: Task) {
      if (task.type !== 'eventTask') {
        this._isSync = false;
      }
      return delegate.cancelTask(target, task);
    }

    // Note - we need to use onInvoke at the moment to call finish when a test is
    // fully synchronous. TODO(juliemr): remove this when the logic for
    // onHasTask changes and it calls whenever the task queues are dirty.
    // updated by(JiaLiPassion), only call finish callback when no task
    // was scheduled/invoked/canceled.
    onInvoke(
        parentZoneDelegate: ZoneDelegate, currentZone: Zone, targetZone: Zone, delegate: Function,
        applyThis: any, applyArgs?: any[], source?: string): any {
      let previousTaskCounts: any = null;
      try {
        this._isSync = true;
        return parentZoneDelegate.invoke(targetZone, delegate, applyThis, applyArgs, source);
      } finally {
        const afterTaskCounts: any = (parentZoneDelegate as any)._taskCounts;
        if (this._isSync) {
          this._finishCallbackIfDone();
        }
      }
    }

    onHandleError(
        parentZoneDelegate: ZoneDelegate, currentZone: Zone, targetZone: Zone,
        error: any): boolean {
      // Let the parent try to handle the error.
      const result = parentZoneDelegate.handleError(targetZone, error);
      if (result) {
        this.failCallback(error);
        this._alreadyErrored = true;
      }
      return false;
    }

    onHasTask(delegate: ZoneDelegate, current: Zone, target: Zone, hasTaskState: HasTaskState) {
      delegate.hasTask(target, hasTaskState);
      if (hasTaskState.change == 'microTask') {
        this._pendingMicroTasks = hasTaskState.microTask;
        this._finishCallbackIfDone();
      } else if (hasTaskState.change == 'macroTask') {
        this._pendingMacroTasks = hasTaskState.macroTask;
        this._finishCallbackIfDone();
      }
    }
  }

  // Export the class so that new instances can be created with proper
  // constructor params.
  (Zone as any)['AsyncTestZoneSpec'] = AsyncTestZoneSpec;
})(typeof window !== 'undefined' && window || typeof self !== 'undefined' && self || global);