package main

import (
	"context"
	"fmt"
	"github.com/asim/go-micro/plugins/client/grpc/v4"
	"github.com/asim/go-micro/plugins/registry/consul/v4"
	"github.com/gin-gonic/gin"
	"github.com/panjf2000/ants/v2"
	"github.com/spf13/cobra"
	"go-micro.dev/v4"
	"go-micro.dev/v4/client"
	"go-micro.dev/v4/registry"
	"go-micro.dev/v4/selector"
	"net/http"
	"os"
	"sync"
	"time"
)

var (
	port          string            // http监听端口
	consulAddr    []string          // consul注册中心地址
	microRegistry registry.Registry // 注册中心实例
	microClient   client.Client     // 客户端实例
	pool          *ants.Pool        // 协程池, 并发查询GetService用
)

// http响应对象
type response struct {
	Message string      `json:"message"`
	Result  interface{} `json:"result"`
}

// 超时控制
type timeoutWrapper struct {
	client.Client
}

func NewTimeoutWrapper(c client.Client) client.Client {
	return &timeoutWrapper{c}
}

func (t *timeoutWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
	// 2秒超时
	timeoutCtx, cancel := context.WithTimeout(ctx, time.Second*2)
	defer cancel()
	return t.Client.Call(timeoutCtx, req, rsp, opts...)
}

func main() {
	pool, _ = ants.NewPool(16) // 协程池, 并发查询GetService用
	defer pool.Release()

	cmd := &cobra.Command{
		Use:   "go run gateway.go或go build -o .",
		Short: "go-micro开发调试网关 转发http->grpc, 例如: post请求 /service.demo/Demo.GetDemo",
		Run: func(cmd *cobra.Command, args []string) {
			start()
		},
	}
	// 解析命令行参数
	cmd.Flags().StringVarP(&port, "port", "p", "8100", "监听端口")
	cmd.Flags().StringSliceVarP(&consulAddr, "consul", "c", []string{}, "consul注册中心地址,多个则逗号隔开")
	cmd.MarkFlagRequired("consul")

	err := cmd.Execute()
	if err != nil {
		os.Exit(0)
	}
}

func start() {
	microRegistry = consul.NewRegistry(registry.Addrs(consulAddr...))
	// 轮询访问
	newSelector := selector.NewSelector(
		selector.Registry(microRegistry),
		selector.SetStrategy(selector.RoundRobin),
	)

	service := micro.NewService(
		micro.Client(grpc.NewClient()),
		micro.Selector(newSelector),
		micro.WrapClient(NewTimeoutWrapper),
	)
	microClient = service.Client()

	// gin http服务
	r := gin.Default()
	r.GET("/list", listService)
	r.POST("/:service/:endpoint", callService)
	r.Run(fmt.Sprintf(":%s", port))
}

// 列出注册的服务
func listService(ctx *gin.Context) {
	srvs, err := microRegistry.ListServices()
	if err != nil {
		ctx.JSON(http.StatusOK, &response{Message: err.Error()})
		return
	}

	// 组装响应信息
	type serviceInfo struct {
		Name      string           `json:"name"`
		Endpoints []string         `json:"endpoints"`
		Nodes     []*registry.Node `json:"nodes"`
	}

	resultChan := make(chan *serviceInfo, 100)
	wg := &sync.WaitGroup{}

	var services = make(map[string][]*serviceInfo)
	for _, srv := range srvs {
		wg.Add(1)
		tempName := srv.Name
		pool.Submit(func() {
			defer wg.Done()
			srvDetail, _ := microRegistry.GetService(tempName)
			for _, v := range srvDetail {
				s := &serviceInfo{
					Name:  tempName,
					Nodes: v.Nodes,
				}
				e := make([]string, 0)
				for _, ee := range v.Endpoints {
					e = append(e, ee.Name)
				}
				s.Endpoints = e
				resultChan <- s
			}
		})
	}

	go func() {
		wg.Wait()
		close(resultChan)
	}()

	for v := range resultChan {
		services[v.Name] = append(services[v.Name], v)
	}

	ctx.JSON(http.StatusOK, &response{Message: "ok", Result: services})
}

// 调用服务
func callService(ctx *gin.Context) {
	var requestData map[string]interface{}
	err := ctx.ShouldBindJSON(&requestData)
	if err != nil {
		ctx.JSON(http.StatusOK, &response{Message: fmt.Sprintf("获取body参数失败: %s", err)})
		return
	}

	//req := cli.NewRequest("service.demo", "Demo.GetDemo", requestData, mClient.WithContentType("application/json"))
	req := microClient.NewRequest(ctx.Param("service"), ctx.Param("endpoint"), requestData, client.WithContentType("application/json"))
	var res map[string]interface{}
	err = microClient.Call(context.Background(), req, &res)
	if err != nil {
		ctx.JSON(http.StatusOK, &response{
			Message: "grpc响应异常",
			Result:  err,
		})
		return
	}

	ctx.JSON(http.StatusOK, &response{
		Message: "ok",
		Result:  res,
	})
}