import { Http, BaseRequestOptions, Response, ResponseOptions, RequestMethod } from '@angular/http';
import { MockBackend, MockConnection } from '@angular/http/testing';

export function mockBackEndFactory(backend: MockBackend, options: BaseRequestOptions) {
  // configure fake backend
  backend.connections.subscribe((connection: MockConnection) => {
    let testUser = {
      id: "123",
      username: "john.doe@gmail.com",
      password: "johnpasswd",
      name: "John DOE",
      givenName: "John",
      familyName: "DOE",
      email: "john.doe@gmail.com"
    };

    // wrap in timeout to simulate server api call
    setTimeout(() => {

      // fake authenticate api end point
      if (connection.request.url.endsWith('/api/authenticate') && connection.request.method === RequestMethod.Post) {
        // get parameters from post request
        let params = JSON.parse(connection.request.getBody());

        // check user credentials and return fake jwt token if valid
        if (params.username === testUser.username && params.password === testUser.password) {
          connection.mockRespond(new Response(
            new ResponseOptions({status: 200, body: {token: 'fake-jwt-token'}})
          ));
        } else {
          connection.mockRespond(new Response(
            new ResponseOptions({status: 200})
          ));
        }
      }

      // fake users api end point
      if (connection.request.url.endsWith('/api/users') && connection.request.method === RequestMethod.Get) {
        // check for fake auth token in header and return test users if valid, this security is implemented server side
        // in a real application
        if (connection.request.headers.get('Authorization') === 'Bearer fake-jwt-token') {
          connection.mockRespond(new Response(
            new ResponseOptions({status: 200, body: [testUser]})
          ));
        } else {
          // return 401 not authorised if token is null or invalid
          connection.mockRespond(new Response(
            new ResponseOptions({status: 401})
          ));
        }
      }

    }, 500);

  });

  return new Http(backend, options);
}

export let fakeBackendProvider = {
  // use fake backend in place of Http service for backend-less development
  provide: Http,
  deps: [MockBackend, BaseRequestOptions],
  useFactory: mockBackEndFactory
};