#Kotlin 学习资源

// Kotlin Koans - 官方交互式练习
// 访问: https://play.kotlinlang.org/koans/

fun main() {
    println("开始 Kotlin 学习之旅!")
}

data class DevelopmentTool(
    val name: String,
    val type: String,
    val platform: String,
    val features: List<String>
)

val recommendedIDEs = listOf(
    DevelopmentTool(
        name = "IntelliJ IDEA",
        type = "IDE",
        platform = "跨平台",
        features = listOf("智能代码补全", "调试器", "版本控制", "插件生态")
    ),
    DevelopmentTool(
        name = "Android Studio",
        type = "IDE",
        platform = "跨平台",
        features = listOf("Android 开发", "模拟器", "布局编辑器", "性能分析")
    ),
    DevelopmentTool(
        name = "Visual Studio Code",
        type = "编辑器",
        platform = "跨平台",
        features = listOf("轻量级", "扩展丰富", "Git 集成", "调试支持")
    )
)

class KotlinCommunity {
    val platforms = mapOf(
        "Reddit" to "r/Kotlin",
        "Stack Overflow" to "kotlin tag",
        "GitHub" to "JetBrains/kotlin",
        "Twitter" to "@kotlin",
        "Discord" to "Kotlin Discord Server"
    )
    
    fun joinCommunity(platform: String) {
        println("加入 Kotlin $platform 社区，与其他开发者交流!")
    }
}

// 1. 控制台计算器
class Calculator {
    fun add(a: Double, b: Double) = a + b
    fun subtract(a: Double, b: Double) = a - b
    fun multiply(a: Double, b: Double) = a * b
    fun divide(a: Double, b: Double) = if (b != 0.0) a / b else throw IllegalArgumentException("除数不能为零")
}

// 2. 待办事项管理器
data class TodoItem(
    val id: Int,
    val title: String,
    val completed: Boolean = false,
    val createdAt: Long = System.currentTimeMillis()
)

class TodoManager {
    private val todos = mutableListOf<TodoItem>()
    
    fun addTodo(title: String) {
        val id = todos.size + 1
        todos.add(TodoItem(id, title))
    }
    
    fun completeTodo(id: Int) {
        todos.find { it.id == id }?.let { todo ->
            val index = todos.indexOf(todo)
            todos[index] = todo.copy(completed = true)
        }
    }
    
    fun getAllTodos() = todos.toList()
}

// 3. HTTP 客户端
import kotlinx.coroutines.*
import kotlinx.serialization.json.*

class HttpClient {
    suspend fun get(url: String): String = withContext(Dispatchers.IO) {
        // 使用 Ktor 或 OkHttp 实现
        "HTTP 响应数据"
    }
}

// 4. 数据库操作
data class User(val id: Int, val name: String, val email: String)

interface UserRepository {
    suspend fun findById(id: Int): User?
    suspend fun save(user: User): User
    suspend fun findAll(): List<User>
}

// 5. Android 记事本应用
class NoteViewModel : ViewModel() {
    private val _notes = MutableLiveData<List<Note>>()
    val notes: LiveData<List<Note>> = _notes
    
    fun addNote(title: String, content: String) {
        viewModelScope.launch {
            val note = Note(title = title, content = content)
            repository.insert(note)
            loadNotes()
        }
    }
}

// 6. Android 天气应用
class WeatherRepository {
    suspend fun getCurrentWeather(city: String): Weather {
        return weatherApi.getCurrentWeather(city)
    }
}

val beginnerPath = listOf(
    "第1周" to listOf("Kotlin 基础语法", "变量和函数", "控制流"),
    "第2周" to listOf("面向对象编程", "类和对象", "继承"),
    "第3周" to listOf("集合和泛型", "异常处理", "文件操作"),
    "第4周" to listOf("协程基础", "标准库", "实践项目"),
    "第5-6周" to listOf("Android 基础", "综合项目")
)

val javaDevPath = listOf(
    "第1周" to listOf("Kotlin vs Java", "空安全", "扩展函数", "协程"),
    "第2周" to listOf("函数式编程", "DSL", "元编程"),
    "第3周" to listOf("Kotlin Multiplatform", "高级特性", "最佳实践")
)

val recommendedPlugins = listOf(
    "Kotlin" to "官方 Kotlin 支持",
    "Rainbow Brackets" to "彩色括号",
    "String Manipulation" to "字符串操作",
    "Key Promoter X" to "快捷键提示",
    "GitToolBox" to "Git 增强",
    "SonarLint" to "代码质量检查",
    "Kotlin Fill Class" to "自动生成构造函数",
    "Detekt" to "Kotlin 静态代码分析",
    "Android ButterKnife Zelezny" to "Android 视图注入",
    "Kotlin Multiplatform Mobile" to "KMM 支持"
)

// IntelliJ IDEA 快捷键推荐
val kotlinShortcuts = mapOf(
    "Ctrl + Shift + K" to "删除当前行",
    "Ctrl + D" to "复制当前行",
    "Alt + Enter" to "显示意图操作",
    "Ctrl + Alt + L" to "格式化代码",
    "Ctrl + Shift + F10" to "运行当前文件",
    "Ctrl + Shift + T" to "创建测试",
    "F2" to "下一个错误",
    "Shift + F6" to "重命名"
)

// build.gradle.kts
plugins {
    kotlin("jvm") version "1.9.20"
    kotlin("plugin.serialization") version "1.9.20"
}

dependencies {
    implementation("org.jetbrains.kotlin:kotlin-stdlib")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.3")
    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.6.0")
    
    testImplementation("org.jetbrains.kotlin:kotlin-test")
    testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.7.3")
}

// Android 官方资源
val androidResources = mapOf(
    "官方文档" to "https://developer.android.com/kotlin",
    "Kotlin First" to "https://developer.android.com/kotlin/first",
    "Jetpack Compose" to "https://developer.android.com/jetpack/compose",
    "Android KTX" to "https://developer.android.com/kotlin/ktx"
)

// 推荐的 Android 库
val androidLibraries = listOf(
    "Retrofit" to "网络请求",
    "Room" to "数据库",
    "Jetpack Compose" to "UI 框架",
    "Hilt" to "依赖注入",
    "Coroutines" to "异步编程"
)

// KMP 资源
val kmpResources = listOf(
    "官方文档" to "https://kotlinlang.org/docs/multiplatform.html",
    "KMP 示例" to "https://github.com/JetBrains/kotlin-multiplatform-dev-docs",
    "Compose Multiplatform" to "https://www.jetbrains.com/lp/compose-multiplatform/"
)

data class PracticePlatform(
    val name: String,
    val url: String,
    val difficulty: String,
    val features: List<String>
)

val practicePlatforms = listOf(
    PracticePlatform(
        name = "LeetCode",
        url = "https://leetcode.com/",
        difficulty = "中等-困难",
        features = listOf("算法题", "面试准备", "竞赛")
    ),
    PracticePlatform(
        name = "HackerRank",
        url = "https://www.hackerrank.com/",
        difficulty = "简单-中等",
        features = listOf("编程练习", "技能认证", "招聘平台")
    ),
    PracticePlatform(
        name = "Codewars",
        url = "https://www.codewars.com/",
        difficulty = "简单-困难",
        features = listOf("Kata 挑战", "社区评分", "多语言支持")
    )
)

// 30 天 Kotlin 挑战
val kotlinChallenge = mapOf(
    "第1-7天" to "基础语法掌握",
    "第8-14天" to "面向对象编程",
    "第15-21天" to "函数式编程和协程",
    "第22-28天" to "实际项目开发",
    "第29-30天" to "代码优化和最佳实践"
)

class TechNewsTracker {
    val sources = listOf(
        "Kotlin Weekly" to "https://kotlinweekly.net/",
        "Android Weekly" to "https://androidweekly.net/",
        "JetBrains Blog" to "https://blog.jetbrains.com/",
        "Kotlin Reddit" to "https://reddit.com/r/Kotlin"
    )
    
    fun subscribeToAll() {
        sources.forEach { (name, url) ->
            println("订阅 $name: $url")
        }
    }
}

// 推荐的开源项目
val openSourceProjects = listOf(
    "kotlinx.coroutines" to "协程库",
    "kotlinx.serialization" to "序列化库", 
    "Ktor" to "Web 框架",
    "Exposed" to "数据库框架",
    "Compose" to "UI 框架"
)

val certificationCourses = listOf(
    "Coursera Kotlin 专项课程",
    "Udacity Android Kotlin 纳米学位",
    "Pluralsight Kotlin 学习路径",
    "LinkedIn Learning Kotlin 课程"
)

data class LearningTip(
    val title: String,
    val description: String,
    val practiceIdea: String
)

val learningTips = listOf(
    LearningTip(
        title = "边学边练",
        description = "理论学习后立即动手实践",
        practiceIdea = "每学一个概念就写一个小程序验证"
    ),
    LearningTip(
        title = "阅读源码",
        description = "阅读优秀的开源项目源码",
        practiceIdea = "分析 Kotlin 标准库和知名项目的实现"
    ),
    LearningTip(
        title = "参与社区",
        description = "积极参与技术社区讨论",
        practiceIdea = "在 Stack Overflow 回答问题，发布技术博客"
    ),
    LearningTip(
        title = "构建项目",
        description = "从零开始构建完整的应用项目",
        practiceIdea = "开发一个个人感兴趣的应用并发布"
    ),
    LearningTip(
        title = "代码复查",
        description = "定期复查和优化自己的代码",
        practiceIdea = "每周选择一个项目进行代码重构"
    ),
    LearningTip(
        title = "学习源码",
        description = "研究知名库的设计模式和架构",
        practiceIdea = "分析 Retrofit、OkHttp、Coroutines 等库的实现"
    )
)

// Kotlin 编程最佳实践
val kotlinBestPractices = listOf(
    "优先使用不可变集合" to "listOf(), setOf(), mapOf()",
    "使用数据类" to "简化 POJO 类的定义",
    "合理使用空安全" to "避免不必要的 null 检查",
    "优先使用表达式" to "when 表达式代替 if-else",
    "使用扩展函数" to "增强现有类的功能",
    "合理使用协程" to "处理异步操作和 I/O 密集型任务"
)

val commonMistakes = listOf(
    "只学语法不做项目" to "应该理论结合实践",
    "忽略 Java 互操作性" to "Kotlin 和 Java 的关系很重要",
    "不使用协程" to "协程是 Kotlin 的杀手级特性",
    "不关注性能" to "要了解 Kotlin 的性能特征",
    "不阅读官方文档" to "官方文档是最权威的学习资源"
)

data class LearningWeek(
    val week: Int,
    val topics: List<String>,
    val projects: List<String>,
    val goals: String
)

val threeMonthPlan = listOf(
    // 第一月：基础
    LearningWeek(1, listOf("Kotlin 语法", "变量和函数"), listOf("Hello World", "计算器"), "掌握基础语法"),
    LearningWeek(2, listOf("面向对象", "类和继承"), listOf("学生管理系统"), "理解 OOP 概念"),
    LearningWeek(3, listOf("集合操作", "泛型"), listOf("图书管理系统"), "熟练使用集合"),
    LearningWeek(4, listOf("异常处理", "文件操作"), listOf("文本编辑器"), "掌握错误处理"),
    
    // 第二月：进阶
    LearningWeek(5, listOf("协程基础", "异步编程"), listOf("网络爬虫"), "理解异步编程"),
    LearningWeek(6, listOf("函数式编程", "高阶函数"), listOf("数据处理工具"), "掌握函数式编程"),
    LearningWeek(7, listOf("DSL 构建", "元编程"), listOf("配置文件解析器"), "学会构建 DSL"),
    LearningWeek(8, listOf("测试编写", "调试技巧"), listOf("单元测试框架"), "提高代码质量"),
    
    // 第三月：实战
    LearningWeek(9, listOf("Android 基础", "Activity 生命周期"), listOf("简单 Android 应用"), "入门移动开发"),
    LearningWeek(10, listOf("UI 开发", "Jetpack Compose"), listOf("待办事项应用"), "掌握 UI 开发"),
    LearningWeek(11, listOf("网络请求", "数据存储"), listOf("天气应用"), "集成第三方服务"),
    LearningWeek(12, listOf("项目优化", "发布准备"), listOf("完整应用项目"), "完成项目开发")
)

when (problemType) {
    "语法问题" -> "查阅官方文档或 Stack Overflow"
    "概念理解" -> "阅读相关书籍或观看视频教程"
    "项目实战" -> "查看 GitHub 示例项目或咨询社区"
    "职业发展" -> "参加技术会议或加入专业社群"
    else -> "综合使用多种资源进行学习"
}

fun main() {
    println("🚀 开始您的 Kotlin 学习之旅！")
    println("📚 记住：持续学习，不断实践，积极分享！")
    println("🎯 目标：成为优秀的 Kotlin 开发者！")
}

// 性能优化技巧
class PerformanceTips {
    // 1. 使用内联函数减少函数调用开销
    inline fun <T> measureTime(block: () -> T): Pair<T, Long> {
        val start = System.currentTimeMillis()
        val result = block()
        val time = System.currentTimeMillis() - start
        return result to time
    }
    
    // 2. 使用序列处理大数据集
    fun processLargeDataset(data: List<String>): List<String> {
        return data.asSequence()
            .filter { it.isNotEmpty() }
            .map { it.uppercase() }
            .take(1000)
            .toList()
    }
    
    // 3. 使用原生数组减少装箱开销
    fun sumArray(numbers: IntArray): Long {
        var sum = 0L
        for (number in numbers) {
            sum += number
        }
        return sum
    }
}

// 调试工具函数
fun <T> T.debug(tag: String = "DEBUG"): T {
    println("[$tag] $this")
    return this
}

// 使用示例
fun calculateSum(numbers: List<Int>): Int {
    return numbers
        .debug("INPUT")
        .filter { it > 0 }
        .debug("FILTERED")
        .sum()
        .debug("RESULT")
}

// 条件断点
fun processUser(user: User) {
    require(user.age >= 18) { "User must be at least 18 years old" }
    check(user.email.contains("@")) { "Invalid email format" }
    
    // 业务逻辑
}

// 使用 MockK 进行测试
class UserServiceTest {
    
    @Test
    fun `should create user when valid data provided`() = runTest {
        // Given
        val userRepository = mockk<UserRepository>()
        val userService = UserService(userRepository)
        val userData = CreateUserRequest("John", "john@example.com")
        
        every { userRepository.save(any()) } returns User(1, "John", "john@example.com")
        
        // When
        val result = userService.createUser(userData)
        
        // Then
        assertEquals("John", result.name)
        assertEquals("john@example.com", result.email)
        verify { userRepository.save(any()) }
    }
    
    @Test
    fun `should throw exception when email is invalid`() {
        // Given
        val userRepository = mockk<UserRepository>()
        val userService = UserService(userRepository)
        val userData = CreateUserRequest("John", "invalid-email")
        
        // When & Then
        assertThrows<IllegalArgumentException> {
            userService.createUser(userData)
        }
    }
}

// HTML DSL 示例
class HtmlBuilder {
    private val content = StringBuilder()
    
    fun html(block: HtmlBuilder.() -> Unit): String {
        this.block()
        return content.toString()
    }
    
    fun head(block: HeadBuilder.() -> Unit) {
        content.append("<head>")
        HeadBuilder(content).block()
        content.append("</head>")
    }
    
    fun body(block: BodyBuilder.() -> Unit) {
        content.append("<body>")
        BodyBuilder(content).block()
        content.append("</body>")
    }
}

// 使用示例
val htmlContent = HtmlBuilder().html {
    head {
        title("My Page")
    }
    body {
        h1("Welcome to Kotlin!")
        p("This is a DSL example.")
    }
}

// build.gradle.kts 最佳实践
object Versions {
    const val kotlin = "1.9.20"
    const val coroutines = "1.7.3"
    const val ktor = "2.3.5"
    const val serialization = "1.6.0"
    const val junit = "5.10.0"
}

dependencies {
    // Kotlin 标准库
    implementation("org.jetbrains.kotlin:kotlin-stdlib:${Versions.kotlin}")
    
    // 协程
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:${Versions.coroutines}")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:${Versions.coroutines}")
    
    // 序列化
    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:${Versions.serialization}")
    
    // 网络库
    implementation("io.ktor:ktor-client-core:${Versions.ktor}")
    implementation("io.ktor:ktor-client-cio:${Versions.ktor}")
    
    // 测试
    testImplementation("org.junit.jupiter:junit-jupiter:${Versions.junit}")
    testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:${Versions.coroutines}")
}

// Kotlin 学习路线地图
val kotlinLearningRoadmap = mapOf(
    "初学者" to listOf(
        "Kotlin 基础语法" to "变量、函数、类",
        "集合操作" to "List, Set, Map 的使用",
        "异常处理" to "try-catch, 自定义异常",
        "文件 I/O" to "文件读写操作"
    ),
    "进阶开发者" to listOf(
        "协程编程" to "async/await, 协程作用域",
        "函数式编程" to "高阶函数、Lambda",
        "泛型编程" to "泛型类、泛型函数",
        "DSL 设计" to "内部 DSL 构建"
    ),
    "专家级" to listOf(
        "元编程" to "反射、注解处理",
        "编译器插件" to "Kotlin 编译器扩展",
        "性能优化" to "内存管理、性能调优",
        "Multiplatform" to "跨平台开发"
    )
)