package system

import (
	"sync"
	"time"

	"joylink.club/ecs"
)

// 外界与world交互请求定义
type FaceRequest func(w ecs.World) any
type faceOutcome struct {
	outcome any
	ok      bool
}

// 外界与world的交互
type FaceSystem struct {
	req   chan FaceRequest
	rsp   chan *faceOutcome
	world ecs.World
	//保证与world的交互串行
	locker *sync.Mutex
}

func NewFaceSystem(w ecs.World) *FaceSystem {
	return &FaceSystem{req: make(chan FaceRequest), rsp: make(chan *faceOutcome), locker: &sync.Mutex{}, world: w}
}

// world 执行
func (me *FaceSystem) Update(world ecs.World) {
	select {
	case reqFunc := <-me.req:
		{
			response := reqFunc(world)
			if nil != response {
				me.rsp <- &faceOutcome{outcome: response, ok: true}
			} else {
				me.rsp <- &faceOutcome{outcome: nil, ok: false}
			}
		}
	default:
	}
}

// 外界调用此方法与world交互
func (me *FaceSystem) Call(request FaceRequest) (any, bool) {
	if !me.world.Running() {
		return nil, false
	}
	//
	me.locker.Lock()
	defer me.locker.Unlock()
	//
	me.req <- request
	//
	result := <-me.rsp
	return result.outcome, result.ok
}

// 获取world当前时间
func (me *FaceSystem) WorldTime() *time.Time {
	now, ok := me.Call(func(w ecs.World) any {
		return GetWorldNow(w)
	})
	if ok {
		return now.(*time.Time)
	} else {
		return nil
	}
}