Implement sessions management

src/app.module.ts

@@ -7,6 +7,9 @@ import { StripeService } from './service/stripe.service';
 import { TypeOrmModule } from '@nestjs/typeorm';
 import { User } from './dto/user';
 import { Purchase } from './dto/purchase';
+import { SessionService } from './service/session.service';
+import { SessionController } from './controller/session.controller';
+import { Session } from './dto/session';
 
 @Module({
   imports: [
@@ -18,12 +21,12 @@ import { Purchase } from './dto/purchase';
       username: process.env.DB_USER || 'postgres',
       password: process.env.DB_PASSWORD || 'postgres',
       database: process.env.DB_NAME || 'appdb',
-      entities: [User, Purchase],
+      entities: [User, Purchase, Session],
       synchronize: true,
     }),
-    TypeOrmModule.forFeature([User, Purchase]),
+    TypeOrmModule.forFeature([User, Purchase, Session]),
   ],
-  controllers: [AccessController, BuyController],
+  controllers: [AccessController, BuyController, SessionController],
-  providers: [UserService, PurchaseService, StripeService],
+  providers: [UserService, PurchaseService, StripeService, SessionService],
 })
 export class AppModule {}

src/controller/session.controller.ts

@@ -0,0 +1,50 @@
+import { Body, Controller, Get, Post, Query } from '@nestjs/common';
+import { SessionService } from 'src/service/session.service';
+import { UserService } from 'src/service/user.service';
+
+@Controller('/session')
+export class SessionController {
+  constructor(
+    private readonly userService: UserService,
+    private readonly sessionService: SessionService,
+  ) {}
+
+  @Post('/create')
+  public createSession() {
+    this.sessionService.createSession(
+      new Date(Date.now() + 24 * 3600 * 1000),
+      10,
+    );
+  }
+
+  @Get()
+  public async getAllSessions(@Query('userId') userId: string) {
+    const sessions = await this.sessionService.getAllSessions();
+    const user = await this.userService.getUserById(userId);
+    return sessions.map((session) => ({
+      id: session.id,
+      size: session.size,
+      userCount: session.users.length,
+      includesRequester: session.users.includes(user),
+      date: session.date,
+    }));
+  }
+
+  @Post('/join')
+  public async joinSession(
+    @Body('userId') userId: string,
+    @Body('sessionId') sessionId: string,
+  ) {
+    const user = await this.userService.getUserById(userId);
+    this.sessionService.joinSession(user, sessionId);
+  }
+
+  @Post('/leave')
+  public async leaveSession(
+    @Body('userId') userId: string,
+    @Body('sessionId') sessionId: string,
+  ) {
+    const user = await this.userService.getUserById(userId);
+    this.sessionService.leaveSession(user, sessionId);
+  }
+}

src/dto/session.ts

@@ -0,0 +1,17 @@
+import { Column, Entity, ManyToMany, PrimaryGeneratedColumn } from 'typeorm';
+import { User } from './user';
+
+@Entity('SESSIONS')
+export class Session {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @ManyToMany(() => User, (user) => user.joinedSessions)
+  users: User[];
+
+  @Column()
+  size: number;
+
+  @Column()
+  date: Date;
+}

src/dto/user.ts

@@ -1,5 +1,13 @@
-import { Column, Entity, OneToMany, PrimaryGeneratedColumn } from 'typeorm';
+import {
+  Column,
+  Entity,
+  JoinTable,
+  ManyToMany,
+  OneToMany,
+  PrimaryGeneratedColumn,
+} from 'typeorm';
 import { Purchase } from './purchase';
+import { Session } from './session';
 
 @Entity('USERS')
 export class User {
@@ -14,4 +22,8 @@ export class User {
 
   @OneToMany(() => Purchase, (purchase) => purchase.purchasedBy)
   purchases: Purchase[];
+
+  @ManyToMany(() => Session, (session) => session.users)
+  @JoinTable()
+  joinedSessions: Session[];
 }

src/service/session.service.ts

@@ -0,0 +1,59 @@
+import { Injectable, Logger, NotFoundException } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Session } from 'src/dto/session';
+import { User } from 'src/dto/user';
+import { Repository } from 'typeorm';
+
+@Injectable()
+export class SessionService {
+  private readonly logger = new Logger(SessionService.name);
+
+  constructor(
+    @InjectRepository(Session) private sessionRepo: Repository<Session>,
+  ) {}
+
+  public createSession(date: Date, size: number) {
+    const session = this.sessionRepo.create({
+      users: [],
+      date,
+      size,
+    });
+    this.sessionRepo.save(session);
+  }
+
+  public getAllSessions() {
+    return this.sessionRepo.find({ relations: { users: true } });
+  }
+
+  public async joinSession(user: User, sessionId: string) {
+    const session = await this.sessionRepo.findOneOrFail({
+      where: {
+        id: sessionId,
+      },
+    });
+    if (!session) {
+      throw new NotFoundException();
+    }
+    if (
+      session.users.find((u) => u === user) ||
+      session.users.length >= session.size
+    ) {
+      return;
+    }
+    session.users.push(user);
+    await this.sessionRepo.save(session);
+  }
+
+  public async leaveSession(user: User, sessionId: string) {
+    const session = await this.sessionRepo.findOneOrFail({
+      where: {
+        id: sessionId,
+      },
+    });
+    if (!session) {
+      throw new NotFoundException();
+    }
+    session.users = session.users.filter((u) => u !== user);
+    await this.sessionRepo.save(session);
+  }
+}

src/service/user.service.ts

@@ -40,6 +40,7 @@ export class UserService {
       name,
       password,
       purchases: [],
+      joinedSessions: [],
     });
     return this.userRepo.save(user);
   }