# Rust 工具链
rustc --version   # >= 1.70
cargo --version
cargo install cargo-ndk

# 添加目标平台
rustup target add aarch64-linux-android    # Android ARM64
rustup target add aarch64-apple-ios        # iOS ARM64
rustup target add x86_64-apple-darwin      # macOS Desktop（用于生成绑定）

# Kotlin / Gradle
java --version    # >= 17
gradle --version  # >= 8.0

# Android NDK（通过 Android Studio SDK Manager 安装）
# 或设置环境变量
export ANDROID_NDK_HOME=$HOME/Android/Sdk/ndk/26.0.10792818

mkdir rust-core && cd rust-core
cargo init --lib

[package]
name = "rust_core"
version = "0.1.0"
edition = "2021"

[lib]
crate-type = ["cdylib", "staticlib"]
name = "rust_core"

[dependencies]
uniffi = { version = "0.31", features = ["tokio", "cli"] }
thiserror = "1.0"

[[bin]]
name = "uniffi-bindgen"
path = "src/bin/uniffi-bindgen.rs"

#[uniffi::export]
pub fn greet(name: String) -> String {
    format!("Hello, {}! Welcome to Rust.", name)
}

#[uniffi::export]
pub fn add(a: i64, b: i64) -> i64 {
    a + b
}

// 导出自定义类型
#[derive(uniffi::Record)]
pub struct Person {
    pub name: String,
    pub age: u32,
}

#[uniffi::export]
pub fn create_person(name: String, age: u32) -> Person {
    Person { name, age }
}

// 导出枚举
#[derive(uniffi::Enum)]
pub enum Status {
    Idle,
    Running { progress: f64 },
    Completed { result: String },
}

// 导出带方法的对象
#[derive(uniffi::Object)]
pub struct Counter {
    count: std::sync::atomic::AtomicI64,
}

#[uniffi::export]
impl Counter {
    #[uniffi::constructor]
    pub fn new() -> Self {
        Self {
            count: std::sync::atomic::AtomicI64::new(0),
        }
    }

    pub fn increment(&self) -> i64 {
        self.count.fetch_add(1, std::sync::atomic::Ordering::SeqCst) + 1
    }

    pub fn get(&self) -> i64 {
        self.count.load(std::sync::atomic::Ordering::SeqCst)
    }
}

// 异步函数支持（需要指定 async_runtime）
#[uniffi::export(async_runtime = "tokio")]
pub async fn fetch_data(url: String) -> Result<String, RustError> {
    // 实际项目中使用 reqwest 等 HTTP 客户端
    Ok(format!("Fetched from: {}", url))
}

// 错误类型
#[derive(Debug, thiserror::Error, uniffi::Error)]
pub enum RustError {
    #[error("Network error: {message}")]
    Network { message: String },
    #[error("Invalid input: {message}")]
    InvalidInput { message: String },
}

uniffi::setup_scaffolding!();

[bindings.kotlin]
package_name = "org.forge.kmp.uniffi.rust"
cdylib_name = "rust_core"

# 生成 Kotlin 绑定
cargo run --bin uniffi-bindgen -- generate \
    --library target/debug/librust_core.dylib \
    --language kotlin \
    --out-dir ./bindings

# 生成 Swift 绑定
cargo run --bin uniffi-bindgen -- generate \
    --library target/debug/librust_core.dylib \
    --language swift \
    --out-dir ./bindings

import org.gradle.internal.os.OperatingSystem
import java.util.Properties

plugins {
    id("org.jetbrains.kotlin.multiplatform")
    id("com.android.kotlin.multiplatform.library") // gradle 9.0 KMP 专用架构
}

/* ==========================================================================
 * 1. 路径与环境变量初始化
 * ========================================================================== */
val rustProjectDir: File = rootProject.file("rust-core")
val rustTargetDir: File = rustProjectDir.resolve("target")

// 【混合路由策略】
val buildDir = layout.buildDirectory.get().asFile
// 1. Kotlin 接口代码和 JVM 本地资源放入 build 目录（保持 src 纯净）
val generatedKotlinDir = File(buildDir, "generated/rust/uniffi/kotlin")
val generatedJvmResourcesDir = File(buildDir, "generated/rust/resources")

// 2. Android 的 JNI 库放回 src 目录，顺应 gradle 9.0 默认嗅探机制
// ⚠️ 极其重要：必须在 .gitignore 中忽略此目录！(src/androidMain/jniLibs/)
val jniLibsDir = projectDir.resolve("src/androidMain/jniLibs")

val localPropertiesFile: File = rootProject.file("local.properties")
val localProperties = Properties()
if (localPropertiesFile.exists()) {
    localPropertiesFile.inputStream().use { stream ->
        localProperties.load(stream)
    }
}

val cargoPath: String = localProperties.getProperty("cargo.path")
    ?: error("cargo.path not set (use local.properties or -Pcargo.path=...)")
val ndkHome: String = localProperties.getProperty("ndk.dir")
    ?: error("ndk.dir not set (use local.properties or -Pndk.dir=...)")

/* ==========================================================================
 * 2. KMP 与 Android 基础配置
 * ========================================================================== */
kotlin {
    // Android 平台 (gradle 9.0 极简配置，不写 sourceSets 避免 DSL 报错)
    androidLibrary {
        namespace = "org.forge.kmp.uniffi.rust"
        compileSdk = 36
        minSdk = 34
    }

    jvm()
    iosX64()
    iosArm64()

    sourceSets {
        val commonMain by getting

        val androidMain by getting {
            // 【降维打击】把生成的代码直接挂载给 Android 叶子节点
            kotlin.srcDir(generatedKotlinDir)
            dependencies {
                implementation(libs.jna.get().toString()) {
                    artifact {
                        type = "aar"
                    }
                }
            }
        }

        val jvmMain by getting {
            // 【降维打击】把生成的代码也直接挂载给 Desktop 叶子节点
            kotlin.srcDir(generatedKotlinDir)
            resources.srcDir(generatedJvmResourcesDir)
            dependencies {
                implementation(libs.jna)
            }
        }

        val nativeMain by creating {
            dependsOn(commonMain)
        }
        iosArm64Main.get().dependsOn(nativeMain)
        iosX64Main.get().dependsOn(nativeMain)
    }
}

/* ==========================================================================
 * 3. 宿主机 (Mac/Linux/Win) 目标环境判断
 * ========================================================================== */
fun hostTarget(): String = when {
    OperatingSystem.current().isMacOsX -> {
        val arch = System.getProperty("os.arch").lowercase()
        if (arch.contains("aarch64") || arch.contains("arm64")) {
            "aarch64-apple-darwin"
        } else {
            "x86_64-apple-darwin"
        }
    }
    OperatingSystem.current().isLinux -> "x86_64-unknown-linux-gnu"
    OperatingSystem.current().isWindows -> "x86_64-pc-windows-msvc"
    else -> error("Unsupported OS")
}

fun hostLibName(): String = when {
    OperatingSystem.current().isMacOsX -> "librust_core.dylib"
    OperatingSystem.current().isLinux -> "librust_core.so"
    OperatingSystem.current().isWindows -> "rust_core.dll"
    else -> error("Unsupported OS")
}

// 极简 ABI 定义，配合 cargo-ndk 使用
data class RustAndroidTarget(val androidAbi: String)
val androidTargets = listOf(
    RustAndroidTarget("arm64-v8a")
    // 未来按需解开：RustAndroidTarget("armeabi-v7a"), RustAndroidTarget("x86_64")
)

/* ==========================================================================
 * 4. 自定义 Gradle 任务 (Cargo, cargo-ndk, UniFFI Bindgen)
 * ========================================================================== */

// 4.1 编译宿主机架构 (用于桌面端运行和提取 Bindgen 接口)
tasks.register<Exec>("buildRustHost") {
    group = "rust"
    description = "Build Rust host library for bindgen & desktop"

    inputs.dir(rustProjectDir.resolve("src"))
    inputs.file(rustProjectDir.resolve("Cargo.toml"))
    outputs.dir(rustTargetDir)

    workingDir = rustProjectDir
    executable = cargoPath
    args("build", "--release", "--target", hostTarget())
}

// 4.2 复制宿主机动态库到桌面端资源目录
tasks.register<Copy>("copyRustHostResources") {
    group = "rust"
    dependsOn("buildRustHost")

    from(rustTargetDir.resolve("${hostTarget()}/release/${hostLibName()}"))
    into(generatedJvmResourcesDir)
}

// 4.3 生成 Kotlin 接口代码
tasks.register<Exec>("generateKotlinBindings") {
    group = "rust"
    dependsOn("buildRustHost")

    inputs.file(rustProjectDir.resolve("uniffi.toml"))
    inputs.file(rustTargetDir.resolve("${hostTarget()}/release/${hostLibName()}"))
    outputs.dir(generatedKotlinDir)

    workingDir = rustProjectDir
    executable = cargoPath
    args(
        "run", "--bin", "uniffi-bindgen", "--",
        "generate",
        "--library", "${rustTargetDir.absolutePath}/${hostTarget()}/release/${hostLibName()}",
        "--language", "kotlin",
        "--config", "uniffi.toml",
        "--out-dir", generatedKotlinDir.absolutePath
    )
}

// 4.4 极简无忧的 Android NDK 编译流程 (基于 cargo-ndk)
androidTargets.forEach { target ->
    val buildTaskName = "buildRustAndroid_${target.androidAbi}"

    tasks.register<Exec>(buildTaskName) {
        group = "rust"
        description = "Build Rust for ${target.androidAbi} using cargo-ndk"

        inputs.dir(rustProjectDir.resolve("src"))
        inputs.file(rustProjectDir.resolve("Cargo.toml"))
        outputs.dir(jniLibsDir.resolve(target.androidAbi))

        workingDir = rustProjectDir
        executable = cargoPath

        // 借助 cargo-ndk，省去所有路径拼接和 Copy 任务
        args(
            "ndk",
            "-t", target.androidAbi,
            "-o", jniLibsDir.absolutePath,
            "build",
            "--release"
        )
        environment("ANDROID_NDK_HOME", ndkHome)
    }
}

// 4.5 聚合任务
tasks.register("buildRustAndroid") {
    group = "rust"
    description = "Build all Android ABIs via cargo-ndk"
    dependsOn(androidTargets.map { "buildRustAndroid_${it.androidAbi}" })
}

/* ==========================================================================
 * 5. 生命周期自动化挂载与 Clean 强迫症清理
 * ========================================================================== */

// 不管是点 AS 的绿三角、Make Project 还是命令行编译
// 直接拦截所有带 compile 或 preBuild 字眼的早期核心任务
tasks.configureEach {
    val tName = name
    // 如果任务是编译、打包、资源处理、预构建的任何一种
    if (tName.startsWith("compile") ||
        tName.startsWith("preBuild") ||
        tName.startsWith("merge") ||
        tName.startsWith("package") ||
        tName.startsWith("process")
    ) {
        // Kotlin 必须先有代码才能编
        dependsOn("generateKotlinBindings")
        // 如果是跟 Android 或者 JNI 相关的任务流，必定先生出 .so 文件
        if (tName.contains("Android") || tName.contains("JniLib") || tName.contains("Debug") || tName.contains("Release")) {
            dependsOn("buildRustAndroid")
        }

        // 如果是 Desktop
        if (tName.contains("Jvm") || tName.contains("Desktop")) {
            dependsOn("copyRustHostResources")
        }
    }
}

// 【强迫症清理】执行 ./gradlew clean 时，把放在 src 下的生成的 jniLibs 一起删干净
tasks.named<Delete>("clean") {
    delete(jniLibsDir)
}

package com.example.shared

// UniFFI 生成的代码在 androidMain 中
// 通过 expect/actual 机制暴露给 commonMain

expect object RustBridge {
    fun greet(name: String): String
    fun add(left: ULong, right: ULong): ULong
}

package com.example.shared

import com.example.rust.* // UniFFI 生成的包

actual object RustCore {
    actual fun greet(name: String): String = greet(name)
    actual fun add(a: Long, b: Long): Long = add(a, b)

    // 使用自定义类型
    fun createPerson(name: String, age: Long): Person {
        return createPerson(name, age.toUInt())
    }

    // 使用 Counter 对象
    fun createCounter(): Counter = Counter()
}

// 包声明（由 uniffi.toml 配置）
package com.example.rust

// FFI 函数声明（JNA）
import com.sun.jna.Library
import com.sun.jna.Native

internal interface RustCoreLib : Library {
    companion object {
        val INSTANCE: RustCoreLib = Native.load("rust_core", RustCoreLib::class.java)
    }

    // FFI 函数
    fun uniffi_greet(name: RustBuffer.ByValue): RustBuffer.ByValue
    fun uniffi_add(a: Long, b: Long): Long
}

// 对外暴露的包装函数
fun greet(name: String): String {
    val rustName = FfiConverterString.lower(name)
    val rustResult = RustCoreLib.INSTANCE.uniffi_greet(rustName)
    return FfiConverterString.lift(rustResult)
}

// 数据类（对应 #[derive(uniffi::Record)]）
data class Person(
    val name: String,
    val age: UInt
)

// 枚举（对应 #[derive(uniffi::Enum)]）
sealed class Status {
    object Idle : Status()
    data class Running(val progress: Double) : Status()
    data class Completed(val result: String) : Status()
}

// 对象（对应 #[derive(uniffi::Object)]）
class Counter internal constructor(handle: Long) {
    internal val handle: Long = handle

    companion object {
        internal val DESTROYER = RustCallStatusHandler()
    }

    fun increment(): Long {
        return RustCoreLib.INSTANCE.uniffi_counter_increment(handle)
    }

    fun get(): Long {
        return RustCoreLib.INSTANCE.uniffi_counter_get(handle)
    }
}

// 工厂函数（对应 #[uniffi::constructor]）
fun Counter(): Counter {
    val handle = RustCoreLib.INSTANCE.uniffi_counter_new()
    return Counter(handle)
}

# 确保所有 uniffi 依赖版本一致
[dependencies]
uniffi = { version = "0.31", features = ["tokio"] }

[build-dependencies]
uniffi = { version = "0.31", features = ["build"] }

[dev-dependencies]
uniffi = { version = "0.31", features = ["bindgen-tests"] }

# macOS / Linux
export ANDROID_NDK_HOME=$HOME/Android/Sdk/ndk/26.0.10792818

# 或在 Gradle 中硬编码（不推荐）
val ndkHome = "/path/to/ndk"

rustup target add aarch64-apple-ios-sim

// Kotlin 调用异步函数
scope.launch {
    val result = withContext(Dispatchers.IO) {
        fetchData("https://example.com")
    }
    println(result)
}

tasks.register("buildRustAndroid") {
    inputs.dir("${rustProjectDir}/src")  // 输入
    inputs.file("${rustProjectDir}/Cargo.toml")
    outputs.dir(jniLibsDir)  // 输出

    doLast { /* ... */ }
}