package mqtt_binding

import (
	"git.sxidc.com/go-tools/api_binding/mqtt_binding/mqtt_client"
	"git.sxidc.com/go-tools/api_binding/mqtt_binding/mqtt_client/router"
	"git.sxidc.com/go-tools/api_binding/mqtt_binding/request"
	"git.sxidc.com/go-tools/api_binding/mqtt_binding/response"
	"git.sxidc.com/go-tools/api_binding/utils"
	"reflect"
)

type BusinessFunc[I any, O any] func(c *mqtt_client.MqttClient, inputModel I) (O, error)
type BindingFunc[O any] func(c *mqtt_client.MqttClient, item *router.Item, request any, sendFunc response.SendFunc[O]) bool

type Binding struct {
	router *router.Router
}

// NewBinding 创建版本对应的binding
func NewBinding(apiVersion string, handlers ...router.Handler) *Binding {
	var group string

	if utils.IsStringNotEmpty(apiVersion) && apiVersion != "root" {
		group = apiVersion
	}

	r := mqttClientInstance.GetRouter(group, handlers)

	return &Binding{router: r}
}

func Bind[I any, O any](b *Binding, item *BindItem[I, O], handlers ...router.Handler) {
	item.bind(b.router, handlers...)
}

// BindItem 路由条目结构
type BindItem[I any, O any] struct {
	Topic               string               // 请求路径
	Qos                 byte                 // QOS
	Retained            bool                 // 是否保留响应
	ResponseFunc        response.SendFunc[O] // 响应泛型函数
	BusinessFunc        BusinessFunc[I, O]   // 业务泛型函数
	OptionalBindingFunc BindingFunc[O]       // 可选的绑定函数
}

func (item *BindItem[I, O]) bind(r *router.Router, handlers ...router.Handler) {
	if utils.IsStringEmpty(item.Topic) {
		panic("需要指定主题")
	}

	if item.ResponseFunc == nil {
		panic("需要指定响应函数")
	}

	var inputCheckModel I
	inputType := reflect.TypeOf(inputCheckModel)
	if inputType != nil {
		if inputType.Kind() == reflect.Pointer {
			panic("输入对象不能使用指针类型")
		}

		if inputType.Kind() != reflect.Struct {
			panic("输入对象必须是结构")
		}
	}

	// 给单个路由增加中间件
	handlers = append(handlers, func(routerItem *router.Item, data []byte) {
		var inputModel I

		// 请求的结构类型不为any
		if inputType != nil {
			// 将请求数据解析到inputModel中
			if item.OptionalBindingFunc != nil {
				ok := item.OptionalBindingFunc(mqttClientInstance, routerItem, &inputModel, item.ResponseFunc)
				if !ok {
					return
				}
			} else {
				ok := request.BindingJson(mqttClientInstance, routerItem, &inputModel, item.ResponseFunc)
				if !ok {
					return
				}
			}
		}

		// 执行业务函数
		if item.BusinessFunc != nil {
			outputModel, err := item.BusinessFunc(mqttClientInstance, inputModel)
			item.ResponseFunc(mqttClientInstance, routerItem, outputModel, err)
			return
		}
	})

	// 所有的函数加入到执行链中
	routerItem, err := router.NewItem(r.Group+item.Topic, item.Qos, handlers)
	if err != nil {
		panic("创建路由条目失败: " + err.Error())
		return
	}

	err = r.AddItem(routerItem)
	if err != nil {
		panic("添加路由条目失败: " + err.Error())
		return
	}
}