package events

import (
	"awesomeProject/internal/config"
	"log"
	"sync"
)

// ConfigEventManager 配置事件管理器
type ConfigEventManager struct {
	handlers map[string][]config.ConfigEventHandler // key: config_key, value: handlers
	mutex    sync.RWMutex
}

var (
	configEventManager *ConfigEventManager
	once               sync.Once
)

// GetConfigEventManager 获取配置事件管理器单例
func GetConfigEventManager() *ConfigEventManager {
	once.Do(func() {
		configEventManager = &ConfigEventManager{
			handlers: make(map[string][]config.ConfigEventHandler),
		}
	})
	return configEventManager
}

// RegisterHandler 注册配置事件处理器
func (cem *ConfigEventManager) RegisterHandler(handler config.ConfigEventHandler) {
	cem.mutex.Lock()
	defer cem.mutex.Unlock()

	configKeys := handler.GetConfigKeys()
	for _, key := range configKeys {
		if cem.handlers[key] == nil {
			cem.handlers[key] = []config.ConfigEventHandler{}
		}
		cem.handlers[key] = append(cem.handlers[key], handler)
	}

	log.Printf("注册配置事件处理器，监听配置: %v", configKeys)
}

// TriggerEvent 触发配置变更事件
func (cem *ConfigEventManager) TriggerEvent(event config.ConfigEvent) {
	cem.mutex.RLock()
	handlers := cem.handlers[event.ConfigKey]
	cem.mutex.RUnlock()

	if len(handlers) == 0 {
		log.Printf("配置 %s 无对应的事件处理器", event.ConfigKey)
		return
	}

	log.Printf("触发配置变更事件: %s, 旧值: %v, 新值: %v", event.ConfigKey, event.OldValue, event.NewValue)

	// 并发处理事件，避免阻塞
	for _, handler := range handlers {
		go func(h config.ConfigEventHandler) {
			if err := h.Handle(event); err != nil {
				log.Printf("处理配置事件失败: %s, 错误: %v", event.ConfigKey, err)
			}
		}(handler)
	}
}

// ListRegisteredHandlers 列出已注册的处理器（用于调试）
func (cem *ConfigEventManager) ListRegisteredHandlers() map[string]int {
	cem.mutex.RLock()
	defer cem.mutex.RUnlock()

	result := make(map[string]int)
	for key, handlers := range cem.handlers {
		result[key] = len(handlers)
	}
	return result
}