use std::any::Any;
use std::sync::Arc;

use uuid::Uuid;

use crate::error::AppResult;
use crate::events::EventBus;

/// 模块注册接口
/// 所有业务模块（Auth, Workflow, Message, Config, 行业模块）都实现此 trait
#[async_trait::async_trait]
pub trait ErpModule: Send + Sync {
    /// 模块名称（唯一标识）
    fn name(&self) -> &str;

    /// 模块版本
    fn version(&self) -> &str {
        env!("CARGO_PKG_VERSION")
    }

    /// 依赖的其他模块名称
    fn dependencies(&self) -> Vec<&str> {
        vec![]
    }

    /// 注册事件处理器
    fn register_event_handlers(&self, _bus: &EventBus) {}

    /// 租户创建时的初始化钩子
    async fn on_tenant_created(&self, _tenant_id: Uuid) -> AppResult<()> {
        Ok(())
    }

    /// 租户删除时的清理钩子
    async fn on_tenant_deleted(&self, _tenant_id: Uuid) -> AppResult<()> {
        Ok(())
    }

    /// Downcast support: return `self` as `&dyn Any` for concrete type access.
    ///
    /// This allows the server crate to retrieve module-specific methods
    /// (e.g. `AuthModule::public_routes()`) that are not part of the trait.
    fn as_any(&self) -> &dyn Any;
}

/// 模块注册器 — 用 Arc 包装使其可 Clone（用于 Axum State）
#[derive(Clone, Default)]
pub struct ModuleRegistry {
    modules: Arc<Vec<Arc<dyn ErpModule>>>,
}

impl ModuleRegistry {
    pub fn new() -> Self {
        Self {
            modules: Arc::new(vec![]),
        }
    }

    pub fn register(mut self, module: impl ErpModule + 'static) -> Self {
        tracing::info!(module = module.name(), version = module.version(), "Module registered");
        let mut modules = (*self.modules).clone();
        modules.push(Arc::new(module));
        self.modules = Arc::new(modules);
        self
    }

    pub fn register_handlers(&self, bus: &EventBus) {
        for module in self.modules.iter() {
            module.register_event_handlers(bus);
        }
    }

    pub fn modules(&self) -> &[Arc<dyn ErpModule>] {
        &self.modules
    }
}