package rpc

import (
	"context"
	"sync"

	"github.com/gogf/gf/v2/frame/g"
	consulClient "github.com/rpcxio/rpcx-consul/client"
	"github.com/smallnest/rpcx/client"
)

var (
	xclientMap = make(map[string]client.XClient)
	xclientMu  sync.RWMutex
)

// CallWithConsul 基于Consul服务发现调用RPC
func CallWithConsul(ctx context.Context, serviceName string, args, reply interface{}) error {
	xclient, err := getOrCreatXClient(serviceName)
	if err != nil {
		return err
	}

	err = xclient.Call(ctx, "Mul", args, reply)
	if err != nil {
		// 调用失败，清理失效客户端
		removeXClient(serviceName)
	}
	return err
}

func removeXClient(serviceName string) {
	xclientMu.Lock()
	defer xclientMu.Unlock()
	if c, ok := xclientMap[serviceName]; ok {
		c.Close()
		delete(xclientMap, serviceName)
	}
}

func getOrCreatXClient(serviceName string) (client.XClient, error) {
	// 第一次：读锁，快速判断是否存在
	xclientMu.RLock()
	if c, ok := xclientMap[serviceName]; ok {
		xclientMu.RUnlock()
		return c, nil
	}
	xclientMu.RUnlock()

	// 没找到，加写锁准备创建
	xclientMu.Lock()
	defer xclientMu.Unlock()

	// 第二次：双重检查，防止刚被别人创建完
	if c, ok := xclientMap[serviceName]; ok {
		return c, nil
	}

	consulAddr := g.Cfg().MustGet(nil, "consul.address").String()

	d, err := consulClient.NewConsulDiscovery("rpcx", serviceName, []string{consulAddr}, nil)
	if err != nil {
		return nil, err
	}

	c := client.NewXClient(serviceName, client.Failtry, client.RandomSelect, d, client.DefaultOption)
	xclientMap[serviceName] = c
	return c, nil
}