amberjs 1.17.0

// 延迟初始化 Web系统
// 实现 API 的延迟加载、按需初始化等启动优化功能

use std::collections::{HashMap, HashSet};
use std::sync::{Arc, Mutex, RwLock};
use std::time::{Duration, Instant};

// use crate::web_api::WebApiRegistry;
/// Web API 延迟加载器
pub struct LazyWebAPI {
    /// 已初始化的 API 集合
    initialized_apis: Arc<RwLock<HashSet<String>>>,
    /// 初始化队列
    initialization_queue: Arc<Mutex<Vec<ApiInitTask>>>,
    /// 初始化信号量（限制并发数）
    init_semaphore: Arc<Semaphore>,
    /// Web API 注册表
    // web_api_registry: Arc<WebApiRegistry>,
    /// 统计信息
    stats: Arc<Mutex<LazyInitStats>>,
}
/// API 初始化任务
#[derive(Debug, Clone)]
struct ApiInitTask {
    name: String,
    priority: u8,
    created_at: Instant,
}
impl ApiInitTask {
    fn new(name: String) -> Self {
        Self {
            name,
            priority: 5, // 默认优先级
            created_at: Instant::now(),
        }
    }
    fn with_priority(name: String, priority: u8) -> Self {
        Self {
            name,
            priority,
            created_at: Instant::now(),
        }
    }
}
/// 延迟初始化统计
#[derive(Debug, Clone, Default)]
pub struct LazyInitStats {
    pub total_initializations: u64,
    pub successful_initializations: u64,
    pub failed_initializations: u64,
    pub total_init_time_ms: u64,
    pub cache_hits: u64,
    pub cache_misses: u64,
}
impl LazyWebAPI {
    /// 创建新的延迟 Web API 加载器
    pub fn new() -> Self {
        Self {
            initialized_apis: Arc::new(Mutex::new(HashSet::new())),
            initialization_queue: Arc::new(Mutex::new(Vec::new())),
            init_semaphore: Arc::new(Mutex::new(Semaphore::new(10))), // 最多 10 个并发初始化
            // web_api_registry: Arc::new(Mutex::new(WebApiRegistry::new()))
            stats: Arc::new(Mutex::new(LazyInitStats::default())),
        }
    }
    /// 检查 API 是否已初始化
    pub async fn is_initialized(&self, api_name: &str) -> bool {
        let initialized: _ = self.initialized_apis.read().await;
        initialized.contains(api_name)
    }
    /// 按需初始化 Web API
    pub async fn init_on_demand(&self, api_name: &str) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
        // 先检查是否已经初始化
        if self.is_initialized(api_name).await {
            let mut stats = self.stats.lock().unwrap();
            stats.cache_hits += 1;
            return Ok(());
        }
        let mut stats = self.stats.lock().unwrap();
        stats.total_initializations += 1;
        stats.cache_misses += 1;
        drop(stats);
        // 获取信号量许可
        let _permit: _ = self.init_semaphore.acquire().await.map_err(|_| "Failed to acquire semaphore")?;
        // 双重检查模式
        if self.is_initialized(api_name).await {
            return Ok(());
        }
        let start: _ = Instant::now();
        // 执行实际初始化
        self.perform_initialization(api_name).await?;
        let elapsed: _ = start.elapsed();
        // 更新统计
        let mut stats = self.stats.lock().unwrap();
        stats.successful_initializations += 1;
        stats.total_init_time_ms += elapsed.as_millis() as u64;
        Ok(())
    }
    /// 执行实际的 API 初始化
    async fn perform_initialization(&self, api_name: &str) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
        // 模拟 API 初始化过程
        // 实际实现中会调用 WebApiRegistry
        // 小延迟模拟初始化开销
        tokio::time::sleep(Duration::from_micros(100)).await;
        // 标记为已初始化
        let mut initialized = self.initialized_apis.write().await;
        initialized.insert(api_name.to_string());
        Ok(())
    }
    /// 批量初始化多个 API
    pub async fn init_multiple(&self, apis: &[&str]) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
        let mut tasks: Vec<String> = Vec::new();
        for &api in apis {
            if !self.is_initialized(api).await {
                let api: _ = api.to_string();
                let init_result: _ = self.init_on_demand(&api).await;
                if let Err(e) = init_result {
                    return Err(e);
                }
            }
        }
        Ok(())
    }
    /// 获取统计信息
    pub fn get_stats(&self) -> LazyInitStats {
        self.stats.lock().unwrap().clone()
    }
    /// 重置统计信息
    pub fn reset_stats(&self) {
        let mut stats = self.stats.lock().unwrap();
        *stats = LazyInitStats::default();
    }
}
impl Default for LazyWebAPI {
    fn default() -> Self {
        Self::new()
    }
}
/// 通用延迟初始化器
pub struct LazyInitializer<T> {
    /// 初始化函数
    init_fn: Arc<dyn Fn() -> Result<T, Box<dyn std::error::Error + Send + Sync>> + Send + Sync>,
    /// 缓存的值
    value: Arc<Mutex<Option<T>>>,
    /// 是否已初始化
    initialized: Arc<Mutex<bool>>,
    /// 统计信息
    stats: Arc<Mutex<InitStats>>,
}
/// 初始化统计
#[derive(Debug, Clone)]
pub struct InitStats {
    pub initialization_count: u64,
    pub total_init_time: Duration,
    pub last_init_time: Option<Duration>,
}
impl InitStats {
    pub fn new() -> Self {
        Self {
            initialization_count: 0,
            total_init_time: Duration::from_nanos(0),
            last_init_time: None,
        }
    }
}
impl Default for InitStats {
    fn default() -> Self {
        Self::new()
    }
}
impl<T> LazyInitializer<T> {
    /// 创建新的延迟初始化器
    pub fn new<F>(init_fn: F) -> Self
    where
        F: Fn() -> Result<T, Box<dyn std::error::Error + Send + Sync>> + Send + Sync + 'static,
    {
        Self {
            init_fn: Arc::new(Mutex::new(init_fn)),
            value: Arc::new(Mutex::new(None)),
            initialized: Arc::new(Mutex::new(false)),
            stats: Arc::new(Mutex::new(InitStats::new())),
        }
    }
    /// 获取或初始化值
    pub async fn get(&self) -> Result<T, Box<dyn std::error::Error + Send + Sync>>
    where
        T: Clone,
    {
        // 检查是否已初始化
        {
            let initialized: _ = self.initialized.lock().unwrap();
            if *initialized {
                let value: _ = self.value.lock().unwrap();
                if let Some(ref val) = *value {
                    return Ok(val.clone());
                }
            }
        }
        // 执行初始化
        let start: _ = Instant::now();
        let init_fn: _ = self.init_fn.clone();
        let result: _ = init_fn()?;
        let elapsed: _ = start.elapsed();
        // 缓存结果
        {
            let mut value = self.value.lock().unwrap();
            *value = Some(result.clone());
        }
        {
            let mut initialized = self.initialized.lock().unwrap();
            *initialized = true;
        }
        {
            let mut stats = self.stats.lock().unwrap();
            stats.initialization_count += 1;
            stats.total_init_time += elapsed;
            stats.last_init_time = Some(elapsed);
        }
        Ok(result)
    }
    /// 强制重新初始化
    pub async fn reinit(&self) -> Result<T, Box<dyn std::error::Error + Send + Sync>>
    where
        T: Clone,
    {
        {
            let mut initialized = self.initialized.lock().unwrap();
            *initialized = false;
        }
        {
            let mut value = self.value.lock().unwrap();
            *value = None;
        }
        self.get().await
    }
    /// 获取统计信息
    pub fn get_stats(&self) -> InitStats {
        self.stats.lock().unwrap().clone()
    }
    /// 检查是否已初始化
    pub fn is_initialized(&self) -> bool {
        *self.initialized.lock().unwrap()
    }
}
/// 按需模块加载器
pub struct OnDemandLoader {
    /// 已加载的模块
    loaded_modules: Arc<RwLock<HashMap<String, LoadedModule>>>,
    /// 模块工厂
    module_factory: Arc<dyn ModuleFactory + Send + Sync>,
    /// 统计信息
    stats: Arc<Mutex<LoaderStats>>,
}
/// 已加载的模块
#[derive(Debug, Clone)]
struct LoadedModule {
    data: Vec<u8>,
    load_time: Instant,
    access_count: u64,
}
/// 模块工厂 trait
pub trait ModuleFactory {
    fn create_module(&self, name: &str) -> Result<Vec<u8>, Box<dyn std::error::Error + Send + Sync>>;
}
/// 简单模块工厂实现
pub struct SimpleModuleFactory;
impl ModuleFactory for SimpleModuleFactory {
    fn create_module(&self, name: &str) -> Result<Vec<u8>, Box<dyn std::error::Error + Send + Sync>> {
        // 模拟模块加载
        let module_data: _ = format!("// Module: {}\nconsole.log('{} loaded');", name, name);
        Ok(module_data.into_bytes())
    }
}
/// 加载器统计
#[derive(Debug, Clone, Default)]
pub struct LoaderStats {
    pub total_loads: u64,
    pub successful_loads: u64,
    pub failed_loads: u64,
    pub total_load_time_ms: u64,
    pub cache_hits: u64,
    pub cache_misses: u64,
}
impl OnDemandLoader {
    /// 创建新的按需加载器
    pub fn new() -> Self {
        Self::with_factory(Box::new(SimpleModuleFactory))
    }
    /// 使用指定工厂创建加载器
    pub fn with_factory(factory: Box<dyn ModuleFactory + Send + Sync>) -> Self {
        Self {
            loaded_modules: Arc::new(Mutex::new(HashMap::new())),
            module_factory: Arc::from(factory),
            stats: Arc::new(Mutex::new(LoaderStats::default())),
        }
    }
    /// 按需加载模块
    pub async fn load_module(&self, name: &str) -> Result<Option<Vec<u8>, Box<dyn std::error::Error + Send + Sync>>> {
        // 先检查缓存
        let module_data: _ = {
            let modules: _ = self.loaded_modules.read().await;
            modules.get(name).map(|module| module.data.clone())
        };
        if let Some(data) = module_data {
            let mut stats = self.stats.lock().unwrap();
            stats.cache_hits += 1;
            // 更新访问计数
            let mut modules = self.loaded_modules.write().await;
            if let Some(module) = modules.get_mut(name) {
                module.access_count += 1;
            }
            return Ok(Some(data));
        }
        let mut stats = self.stats.lock().unwrap();
        stats.total_loads += 1;
        stats.cache_misses += 1;
        drop(stats);
        // 加载模块
        let start: _ = Instant::now();
        let data: _ = self.module_factory.create_module(name)?;
        let elapsed: _ = start.elapsed();
        // 缓存模块
        {
            let mut modules = self.loaded_modules.write().await;
            modules.insert(
                name.to_string(),
                LoadedModule {
                    data: data.clone(),
                    load_time: Instant::now(),
                    access_count: 1,
                },
            );
        }
        // 更新统计
        let mut stats = self.stats.lock().unwrap();
        stats.successful_loads += 1;
        stats.total_load_time_ms += elapsed.as_millis() as u64;
        Ok(Some(data))
    }
    /// 获取模块统计信息
    pub fn get_stats(&self) -> LoaderStats {
        self.stats.lock().unwrap().clone()
    }
    /// 清理未使用的模块
    pub async fn cleanup_unused(&self, max_age: Duration) -> usize {
        let mut modules = self.loaded_modules.write().await;
        let now: _ = Instant::now();
        let mut removed = 0;
        modules.retain(|_, module| {
            if now.duration_since(module.load_time) > max_age && module.access_count == 0 {
                removed += 1;
                false
            } else {
                true
            }
        });
        removed
    }
}
impl Default for OnDemandLoader {
    fn default() -> Self {
        Self::new()
    }
}
/// 启动时间优化器
pub struct StartupOptimizer {
    /// 延迟 Web API
    lazy_web_api: Arc<LazyWebAPI>,
    /// 按需加载器
    on_demand_loader: Arc<OnDemandLoader>,
    /// 启动时间记录
    startup_time: Arc<Mutex<Option<Instant>>>,
    /// 优化策略
    optimization_level: OptimizationLevel,
}
/// 优化级别
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum OptimizationLevel {
    /// 无优化
    None,
    /// 基础优化
    Basic,
    /// 激进优化
    Aggressive,
    /// 最大优化
    Maximum,
}
impl StartupOptimizer {
    /// 创建新的启动优化器
    pub fn new(level: OptimizationLevel) -> Self {
        Self {
            lazy_web_api: Arc::new(Mutex::new(LazyWebAPI::new())),
            on_demand_loader: Arc::new(Mutex::new(OnDemandLoader::new())),
            startup_time: Arc::new(Mutex::new(None)),
            optimization_level: level,
        }
    }
    /// 开始优化
    pub fn start_optimization(&self) {
        let mut startup_time = self.startup_time.lock().unwrap();
        *startup_time = Some(Instant::now());
    }
    /// 获取启动时间
    pub fn get_startup_time(&self) -> Option<Duration> {
        let startup_time: _ = self.startup_time.lock().unwrap();
        startup_time.map(|start| start.elapsed())
    }
    /// 获取优化器
    pub fn get_lazy_web_api(&self) -> Arc<LazyWebAPI> {
        self.lazy_web_api.clone()
    }
    /// 获取按需加载器
    pub fn get_on_demand_loader(&self) -> Arc<OnDemandLoader> {
        self.on_demand_loader.clone()
    }
    /// 根据优化级别执行预优化
    pub async fn perform_pre_optimization(&self) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
        match self.optimization_level {
            OptimizationLevel::None => {}
            OptimizationLevel::Basic => {
                // 预初始化核心 API
                self.lazy_web_api.init_multiple(&["console", "process"]).await?;
            }
            OptimizationLevel::Aggressive => {
                // 预初始化更多 API
                let apis: _ = &["console", "process", "path", "util", "buffer"];
                self.lazy_web_api.init_multiple(apis).await?;
            }
            OptimizationLevel::Maximum => {
                // 预初始化所有常用 API 并预加载模块
                let apis: _ = &["console", "process", "path", "util", "buffer", "fs", "os", "url"];
                self.lazy_web_api.init_multiple(apis).await?;
                // 预加载常用模块
                let modules: _ = &["util", "buffer", "events", "stream"];
                for &module in modules {
                    let _: _ = self.on_demand_loader.load_module(module).await;
                }
            }
        }
        Ok(())
    }
}
impl Default for StartupOptimizer {
    fn default() -> Self {
        Self::new(OptimizationLevel::Aggressive)
    }
}