package mqtt_binding

import (
	"errors"
	"git.sxidc.com/go-tools/api_binding/mqtt_binding/middleware"
	"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/utils/strutils"
	"git.sxidc.com/service-supports/fslog"
	"reflect"
	"strings"
)

var ErrIgnoreBusinessResult = errors.New("忽略业务结果")

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 {
	responseIdentifier response.Identifier
	router             *router.Router
}

// NewBinding 创建版本对应的binding
func NewBinding(apiVersion string, responseIdentifier response.Identifier, handlers ...router.Handler) *Binding {
	group := topicPrefix
	if strutils.IsStringNotEmpty(apiVersion) && apiVersion != "root" {
		group += "/" + apiVersion
	}

	handlers = append([]router.Handler{
		middleware.Logger([]string{group + "/version"}),
		middleware.Recovery(),
	}, handlers...)

	r := mqttClientInstance.GetRouter(group, handlers)

	return &Binding{
		responseIdentifier: responseIdentifier,
		router:             r,
	}
}

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

func (binding *Binding) AddHandler(topic string, handlers ...router.Handler) error {
	if strutils.IsStringEmpty(topic) {
		return errors.New("没有传递主题")
	}

	if handlers == nil || len(handlers) == 0 {
		return errors.New("没有传递处理函数")
	}

	err := binding.router.RangeItem(func(existItem *router.Item) error {
		if existItem.Topic == binding.router.Group+topic {
			return errors.New("主题已存在: " + existItem.Topic)
		}

		return nil
	})
	if err != nil {
		if strings.Contains(err.Error(), "主题已存在: ") {
			fslog.Error(err)
			return nil
		}

		return err
	}

	return binding.router.AddTopic(binding.router.Group+topic, handlers...)
}

// BindItem 路由条目结构
type BindItem[I any, O any] struct {
	Topic               string               // 请求路径
	ResponseIdentifier  response.Identifier  // 响应标识符提供接口，会在响应主题添加该标识符
	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, bindingResponseIdentifier response.Identifier, handlers ...router.Handler) {
	if strutils.IsStringEmpty(item.Topic) {
		panic("需要指定主题")
	}

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

	err := r.RangeItem(func(existItem *router.Item) error {
		if existItem.Topic == r.Group+item.Topic {
			return errors.New("主题已存在: " + existItem.Topic)
		}

		return nil
	})
	if err != nil {
		panic(err)
	}

	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")
		}
	}

	var responseIdentifier response.Identifier
	if item.ResponseIdentifier != nil {
		responseIdentifier = item.ResponseIdentifier.Copy()
	} else if bindingResponseIdentifier != nil {
		responseIdentifier = bindingResponseIdentifier.Copy()
	}

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

		var req any
		if inputType != nil {
			req = &inputModel
		}

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

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

			item.ResponseFunc(mqttClientInstance, routerItem, responseIdentifier, outputModel, err)
			return
		}
	})

	// 所有的函数加入到执行链中
	routerItem, err := router.NewItem(r.Group+item.Topic, 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
	}
}