package ecs

import (
	"fmt"
	"reflect"
	"sync"

	"github.com/yohamta/donburi"
	"github.com/yohamta/donburi/features/events"
)

// 注意事件相关操作的最终执行者均为world协程

// 事件相关定义
type (
	// 事件类型定义
	EventType[T any] struct {
		et                *events.EventType[T]
		subscriberMap     map[string]events.Subscriber[T]
		subscriberMapLock sync.Mutex //
	}
	// 事件订阅者定义
	Subscriber[T any] func(w World, event T)
	// 事件管理回调定义
	ManageEventFunc func()
)

// 开启底层事件处理调试
func EventsDebugEnable() {
	events.Debug = true
}

// 创建事件类型的实例
func NewEventType[T any]() *EventType[T] {
	return &EventType[T]{
		et:                events.NewEventType[T](),
		subscriberMap:     make(map[string]events.Subscriber[T]),
		subscriberMapLock: sync.Mutex{},
	}
}

// 迭代处理所有事件
// 在world协程中执行
func processAllEvents(w World) {
	events.ProcessAllEvents(w.(*world).world)
}

// 订阅该类型的事件
func (me *EventType[T]) Subscribe(wd World, subscriber Subscriber[T]) {
	if wd.GoroutineId() == currentGoId() {
		me.subscribe(wd, subscriber)
	} else {
		wd.(*world).chanManageEvent <- func() {
			me.subscribe(wd, subscriber)
		}
	}
}

// 取消订阅该类型的事件
func (me *EventType[T]) Unsubscribe(wd World, subscriber Subscriber[T]) {
	if wd.GoroutineId() == currentGoId() {
		me.unsubscribe(wd, subscriber)
	} else {
		wd.(*world).chanManageEvent <- func() {
			me.unsubscribe(wd, subscriber)
		}
	}
}

// 发布该类型的事件
func (me *EventType[T]) Publish(wd World, event *T) {
	if wd.GoroutineId() == currentGoId() {
		me.publish(wd, event)
	} else {
		wd.(*world).chanManageEvent <- func() {
			me.publish(wd, event)
		}
	}
}

///////////////////////////////////////////////////////////////////////////////////

// 订阅该类型的事件
func (me *EventType[T]) subscribe(wd World, subscriber Subscriber[T]) {
	me.subscriberMapLock.Lock()
	defer me.subscriberMapLock.Unlock()
	//
	subscriberKey := subscriberKey[T](wd, subscriber)
	if _, exist := me.subscriberMap[subscriberKey]; !exist {
		me.subscriberMap[subscriberKey] = func(w donburi.World, event T) {
			subscriber(wd, event)
		}
		me.et.Subscribe(wd.(*world).world, me.subscriberMap[subscriberKey])
	} else {
		panic("重复注册事件订阅者")
	}
}

// 取消订阅该类型的事件
func (me *EventType[T]) unsubscribe(wd World, subscriber Subscriber[T]) {
	me.subscriberMapLock.Lock()
	defer me.subscriberMapLock.Unlock()
	//
	subscriberKey := subscriberKey[T](wd, subscriber)
	if sub, ok := me.subscriberMap[subscriberKey]; ok {
		me.et.Unsubscribe(wd.(*world).world, sub)
		delete(me.subscriberMap, subscriberKey)
	}
}

// 发布该类型的事件
func (me *EventType[T]) publish(wd World, event *T) {
	me.et.Publish(wd.(*world).world, *event)
}

func subscriberKey[T any](wd World, subscriber Subscriber[T]) string {
	wdSubscriberPointer := reflect.ValueOf(subscriber).Pointer()
	subscriberKey := fmt.Sprintf("%d-%d", wd.Id(), wdSubscriberPointer)
	return subscriberKey
}