import {XHR} from 'angular2/src/core/render/xhr';

import {ListWrapper, Map, MapWrapper} from 'angular2/src/core/facade/collection';

import {isBlank, isPresent, normalizeBlank, BaseException} from 'angular2/src/core/facade/lang';

import {PromiseCompleter, PromiseWrapper, Promise} from 'angular2/src/core/facade/async';

export class MockXHR extends XHR {

private _expectations: _Expectation[];

private _definitions: Map<string, string>;

private _requests: _PendingRequest[];

constructor() {

super();

this._expectations = [];

this._definitions = new Map();

this._requests = [];

}

get(url: string): Promise<string> {

var request = new _PendingRequest(url);

this._requests.push(request);

return request.getPromise();

}

expect(url: string, response: string) {

var expectation = new _Expectation(url, response);

this._expectations.push(expectation);

}

when(url: string, response: string) { this._definitions.set(url, response); }

flush() {

if (this._requests.length === 0) {

throw new BaseException('No pending requests to flush');

}

do {

var request = ListWrapper.removeAt(this._requests, 0);

this._processRequest(request);

} while (this._requests.length > 0);

this.verifyNoOustandingExpectations();

}

verifyNoOustandingExpectations() {

if (this._expectations.length === 0) return;

var urls = [];

for (var i = 0; i < this._expectations.length; i++) {

var expectation = this._expectations[i];

urls.push(expectation.url);

}

throw new BaseException(`Unsatisfied requests: ${ListWrapper.join(urls, ', ')}`);

}

private _processRequest(request: _PendingRequest) {

var url = request.url;

if (this._expectations.length > 0) {

var expectation = this._expectations[0];

if (expectation.url == url) {

ListWrapper.remove(this._expectations, expectation);

request.complete(expectation.response);

return;

}

}

if (this._definitions.has(url)) {

var response = this._definitions.get(url);

request.complete(normalizeBlank(response));

return;

}

throw new BaseException(`Unexpected request ${url}`);

}

}

class _PendingRequest {

url: string;

completer: PromiseCompleter<string>;

constructor(url) {

this.url = url;

this.completer = PromiseWrapper.completer();

}

complete(response: string) {

if (isBlank(response)) {

this.completer.reject(`Failed to load ${this.url}`, null);

} else {

this.completer.resolve(response);

}

}

getPromise(): Promise<string> { return this.completer.promise; }

}

class _Expectation {

url: string;

response: string;

constructor(url: string, response: string) {

this.url = url;

this.response = response;

}

}