plugins {
    kotlin("jvm") version "1.9.22"
    kotlin("plugin.spring") version "1.9.22"
    id("org.springframework.boot") version "3.3.5"
    id("io.spring.dependency-management") version "1.1.6"
}

dependencies {
    implementation("org.springframework.boot:spring-boot-starter-web")
    implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
    implementation("org.jetbrains.kotlin:kotlin-reflect")
    implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
    testImplementation("org.springframework.boot:spring-boot-starter-test")
}

tasks.withType<KotlinCompile> {
    kotlinOptions {
        freeCompilerArgs = listOf(
            "-Xjsr305=strict",           // 啟用 JSR-305 注解的嚴(yán)格空檢查
            "-Xjvm-default=all"          // 支持接口中的默認(rèn)方法（適用于 Spring 接口代理）
        )
        jvmTarget = "17"                 // 或更高版本（根據(jù)項目需求）
    }
}

@SpringBootApplication
class DemoApplication
fun main(args: Array<String>) {
    SpringApplication.run(DemoApplication::class.java, *args)
}

@Entity
@Table(name = "users")
data class User(
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    val id: Long? = null,
    @Column(nullable = false)
    val name: String,
    @Email
    @Column(unique = true, nullable = false)
    val email: String
)

// 在根 build.gradle.kts 中配置 all-open 插件
allOpen {
    annotation("jakarta.persistence.Entity")
    annotation("jakarta.persistence.MappedSuperclass")
    annotation("jakarta.persistence.Embeddable")
}

@Service
class UserService(
    private val userRepository: UserRepository,
    private val emailService: EmailService
) {
    fun createUser(name: String, email: String): User {
        val user = User(name = name, email = email)
        return userRepository.save(user).also { emailService.sendWelcome(it) }
    }
}

@RestController
class UserController {
    @Autowired
    private lateinit var userService: UserService
}

@RestController
@RequestMapping("/api/users")
class UserController(
    private val userService: UserService
) {
    private val logger = LoggerFactory.getLogger(javaClass)
    @GetMapping
    fun getAllUsers(): ResponseEntity<List<User>> =
        ResponseEntity.ok(userService.findAll())
    @PostMapping
    fun createUser(@RequestBody @Valid userDto: CreateUserDto): ResponseEntity<User> =
        ResponseEntity.created(URI.create("/api/users/${user.id}"))
            .body(userService.createUser(userDto.name, userDto.email))
    @ExceptionHandler(ConstraintViolationException::class)
    fun handleValidationException(e: ConstraintViolationException): ResponseEntity<String> {
        logger.warn("Validation failed: ${e.message}")
        return ResponseEntity.badRequest().body("Invalid input: ${e.message}")
    }
}

myapp/
├── build.gradle.kts         ← 根構(gòu)建腳本
├── settings.gradle.kts      ← 模塊注冊
├── app/                     ← 主啟動模塊（bootJar）
│   └── src/main/kotlin/...
├── service/                 ← 業(yè)務(wù)邏輯模塊（jar）
│   └── src/main/kotlin/...
├── domain/                  ← 領(lǐng)域模型與接口定義
│   └── src/main/kotlin/...
└── infrastructure/          ← 數(shù)據(jù)訪問、外部集成
    └── src/main/kotlin/...

rootProject.name = "myapp"
include("app", "service", "domain", "infrastructure")

subprojects {
    apply(plugin = "org.springframework.boot")
    apply(plugin = "io.spring.dependency-management")
    apply(plugin = "org.jetbrains.kotlin.jvm")
    apply(plugin = "org.jetbrains.kotlin.plugin.spring")
    group = "com.example"
    version = "0.0.1-SNAPSHOT"
    repositories {
        mavenCentral()
    }
    dependencies {
        implementation("org.jetbrains.kotlin:kotlin-stdlib")
        implementation("org.jetbrains.kotlin:kotlin-reflect")
        implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
    }
    tasks.withType<KotlinCompile> {
        kotlinOptions {
            freeCompilerArgs += "-Xjsr305=strict"
            jvmTarget = "17"
        }
    }
}

dependencies {
    implementation(project(":service"))
    implementation(project(":infrastructure"))
    implementation(project(":domain"))
}

// service/build.gradle.kts
tasks.named<BootJar>("bootJar") {
    enabled = false
}
tasks.named<Jar>("jar") {
    enabled = true
}

tasks.jar {
    archiveFileName.set("${project.name}.jar")
    manifest {
        attributes["Main-Class"] = "com.example.app.DemoApplication"
    }
}

@GetMapping("/search")
fun searchUsers(
    @RequestParam name: String,           // 必填 → 非空 String
    @RequestParam email: String? = null   // 可選 → String?
): List<User> {
    return if (email != null) {
        userService.findByNameAndEmail(name, email)
    } else {
        userService.findByName(name)
    }
}

@SpringBootApplication(scanBasePackages = ["com.example"])
class DemoApplication

private val expensiveService: ExpensiveService by lazy {
    initializeExpensiveService()
}