2 files changed, 128 insertions, 0 deletions
diff --git a/Timeline/ClientApp/src/app/user/user-service/user.service.spec.ts b/Timeline/ClientApp/src/app/user/user-service/user.service.spec.ts
new file mode 100644
index 00000000..b9221b90
--- /dev/null
+++ b/Timeline/ClientApp/src/app/user/user-service/user.service.spec.ts
@@ -0,0 +1,12 @@
+import { TestBed } from '@angular/core/testing';
+
+import { UserService } from './user.service';
+
+xdescribe('UserService', () => {
+  beforeEach(() => TestBed.configureTestingModule({}));
+
+  it('should be created', () => {
+    const service: UserService = TestBed.get(UserService);
+    expect(service).toBeTruthy();
+  });
+});
diff --git a/Timeline/ClientApp/src/app/user/user-service/user.service.ts b/Timeline/ClientApp/src/app/user/user-service/user.service.ts
new file mode 100644
index 00000000..009e5292
--- /dev/null
+++ b/Timeline/ClientApp/src/app/user/user-service/user.service.ts
@@ -0,0 +1,116 @@
+import { Injectable } from '@angular/core';
+import { HttpClient, HttpErrorResponse } from '@angular/common/http';
+import { Observable, of, throwError } from 'rxjs';
+import { map, catchError, retry } from 'rxjs/operators';
+
+import { UserInfo } from '../user-info';
+
+export interface UserCredentials {
+  username: string;
+  password: string;
+}
+
+export interface CreateTokenResult {
+  token: string;
+  userInfo: UserInfo;
+}
+
+export interface TokenValidationRequest {
+  token: string;
+}
+
+export interface TokenValidationResult {
+  isValid: boolean;
+  userInfo?: UserInfo;
+}
+
+export interface UserLoginState {
+  state: 'nologin' | 'invalidlogin' | 'success';
+  userInfo?: UserInfo;
+}
+
+export class BadNetworkException extends Error {
+  constructor() {
+    super('Network is bad.');
+  }
+}
+
+export class AlreadyLoginException extends Error {
+  constructor() {
+    super('There is already a token saved. Please call validateUserLoginState first.');
+  }
+}
+
+export class BadCredentialsException extends Error {
+  constructor() {
+    super(`Username or password is wrong.`);
+  }
+}
+
+@Injectable({
+  providedIn: 'root'
+})
+export class UserService {
+
+  private token: string;
+  private userInfo: UserInfo;
+
+  constructor(private httpClient: HttpClient) { }
+
+  validateUserLoginState(): Observable<UserLoginState> {
+    if (this.token === undefined || this.token === null) {
+      return of(<UserLoginState>{ state: 'nologin' });
+    }
+
+    return this.httpClient.post<TokenValidationResult>('/api/User/ValidateToken', <TokenValidationRequest>{ token: this.token }).pipe(
+      retry(3),
+      catchError(error => {
+        console.error('Failed to validate token.');
+        return throwError(error);
+      }),
+      map(result => {
+        if (result.isValid) {
+          this.userInfo = result.userInfo;
+          return <UserLoginState>{
+            state: 'success',
+            userInfo: result.userInfo
+          };
+        } else {
+          this.token = null;
+          this.userInfo = null;
+          return <UserLoginState>{
+            state: 'invalidlogin'
+          };
+        }
+      })
+    );
+  }
+
+  tryLogin(username: string, password: string): Observable<UserInfo> {
+    if (this.token) {
+      return throwError(new AlreadyLoginException());
+    }
+
+    return this.httpClient.post<CreateTokenResult>('/api/User/CreateToken', <UserCredentials>{
+      username, password
+    }).pipe(
+      catchError((error: HttpErrorResponse) => {
+        if (error.error instanceof ErrorEvent) {
+          console.error('An error occurred when login: ' + error.error.message);
+          return throwError(new BadNetworkException());
+        } else if (error.status === 400) {
+          console.error('An error occurred when login: wrong credentials.');
+          return throwError(new BadCredentialsException());
+        } else {
+          console.error('An unknown error occurred when login: ' + error);
+          return throwError(error);
+        }
+      }),
+      map(result => {
+        this.token = result.token;
+        this.userInfo = result.userInfo;
+        return result.userInfo;
+      })
+    );
+  }
+}