import { Module } from '@nestjs/common';
import { UsersController } from './users.controller';
import { UsersService } from './users.service';

@Module({
  controllers: [UsersController],
  providers: [UsersService],
})
export class UsersModule {}

@Module({
  providers: [UsersService, UserRepository],
})
export class UsersModule {}

@Module({
  controllers: [UsersController],
  providers: [UsersService],
})
export class UsersModule {}

@Module({
  imports: [DatabaseModule, AuthModule],
  controllers: [UsersController],
  providers: [UsersService],
})
export class UsersModule {}

@Module({
  providers: [UsersService],
  exports: [UsersService], // Cho phép modules khác import UsersService
})
export class UsersModule {}

import { Module } from '@nestjs/common';
import { ProductsController } from './products.controller';
import { ProductsService } from './products.service';
import { ProductRepository } from './products.repository';

@Module({
  controllers: [ProductsController],
  providers: [ProductsService, ProductRepository],
})
export class ProductsModule {}

import { Module } from '@nestjs/common';
import { DatabaseModule } from '../database/database.module';
import { OrdersController } from './orders.controller';
import { OrdersService } from './orders.service';

@Module({
  imports: [DatabaseModule],
  controllers: [OrdersController],
  providers: [OrdersService],
  exports: [OrdersService],
})
export class OrdersModule {}

import { Module } from '@nestjs/common';
import { UsersModule } from './users/users.module';
import { ProductsModule } from './products/products.module';
import { OrdersModule } from './orders/orders.module';
import { DatabaseModule } from './database/database.module';

@Module({
  imports: [
    DatabaseModule,
    UsersModule,
    ProductsModule,
    OrdersModule,
  ],
})
export class AppModule {}

// auth.module.ts
@Module({
  providers: [AuthService, JwtService],
  exports: [AuthService], // Chỉ export AuthService
})
export class AuthModule {}

// users.module.ts
@Module({
  imports: [AuthModule], // Import AuthModule
  providers: [UsersService],
})
export class UsersModule {
  constructor(private authService: AuthService) {} // Có thể sử dụng AuthService
}

import { Module, Global } from '@nestjs/common';
import { ConfigService } from './config.service';

@Global()
@Module({
  providers: [ConfigService],
  exports: [ConfigService],
})
export class ConfigModule {}

@Module({
  controllers: [AppController],
  providers: [ConfigService], // Không cần import ConfigModule
})
export class AppModule {}

// database.module.ts
@Module({})
export class DatabaseModule {
  static forRoot(options: DatabaseOptions): DynamicModule {
    return {
      module: DatabaseModule,
      providers: [
        {
          provide: 'DATABASE_OPTIONS',
          useValue: options,
        },
        DatabaseService,
      ],
      exports: [DatabaseService],
    };
  }
}

// app.module.ts
@Module({
  imports: [
    DatabaseModule.forRoot({
      host: 'localhost',
      port: 5432,
    }),
  ],
})
export class AppModule {}

src/
├── users/
│   ├── users.controller.ts
│   ├── users.service.ts
│   ├── users.module.ts
│   └── users.repository.ts
├── products/
│   ├── products.controller.ts
│   ├── products.service.ts
│   └── products.module.ts
└── app.module.ts

@Module({
  providers: [
    UsersService,
    UserRepository,
    UserValidator, // Internal, không export
  ],
  exports: [UsersService], // Chỉ export service
})
export class UsersModule {}

// ❌ Sai - Circular dependency
// users.module.ts imports orders.module
// orders.module.ts imports users.module

// ✅ Đúng - Tạo shared module
@Module({
  providers: [SharedService],
  exports: [SharedService],
})
export class SharedModule {}

@Module({
  imports: [SharedModule],
  providers: [UsersService],
})
export class UsersModule {}

@Module({
  imports: [SharedModule],
  providers: [OrdersService],
})
export class OrdersModule {}

// main.ts
import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  await app.listen(3000);
}
bootstrap();

Module Initialization
       ↓
  OnModuleInit()
       ↓
 Application Bootstrap
       ↓
OnApplicationBootstrap()
       ↓
Application Running
       ↓
 (Graceful Shutdown)
       ↓
 OnModuleDestroy()
       ↓
OnApplicationShutdown()

@Module({
  providers: [DatabaseService],
})
export class DatabaseModule implements OnModuleInit {
  constructor(private dbService: DatabaseService) {}

  onModuleInit() {
    this.dbService.connect();
  }
}

// config.module.ts
import { Module, Global } from '@nestjs/common';
import { ConfigService } from './config.service';

@Global()
@Module({
  providers: [ConfigService],
  exports: [ConfigService],
})
export class ConfigModule {}

// database.module.ts
import { Module } from '@nestjs/common';
import { DatabaseService } from './database.service';

@Module({
  providers: [DatabaseService],
  exports: [DatabaseService],
})
export class DatabaseModule {}

// users.module.ts
import { Module } from '@nestjs/common';
import { DatabaseModule } from '../database/database.module';
import { UsersController } from './users.controller';
import { UsersService } from './users.service';

@Module({
  imports: [DatabaseModule],
  controllers: [UsersController],
  providers: [UsersService],
  exports: [UsersService],
})
export class UsersModule {}

// app.module.ts
import { Module } from '@nestjs/common';
import { ConfigModule } from './config/config.module';
import { DatabaseModule } from './database/database.module';
import { UsersModule } from './users/users.module';
import { AppController } from './app.controller';

@Module({
  imports: [
    ConfigModule,
    DatabaseModule,
    UsersModule,
  ],
  controllers: [AppController],
})
export class AppModule {}