package svc

import (
	"fmt"
	"net"
	"strconv"
	"sync"
	"time"

	"lone-services/pkg/discovery"
	"lone-services/pkg/utils"

	"github.com/zeromicro/go-zero/core/logx"
	"github.com/zeromicro/go-zero/zrpc"
)

type rpcClientCacheEntry struct {
	cli      zrpc.Client
	target   string
	expireAt time.Time
}

const rpcClientCacheTTL = 30 * time.Second

var (
	rpcCacheLock sync.Mutex
	rpcCache     = make(map[string]*rpcClientCacheEntry)
)

func GetRpcClient(serviceName string) (zrpc.Client, error) {
	if serviceName == utils.StringEmpty {
		err := fmt.Errorf("rpc serviceName is empty")
		logx.Error(err)
		return nil, err
	}

	rpcCacheLock.Lock()
	entry, ok := rpcCache[serviceName]
	if ok && time.Now().Before(entry.expireAt) {
		rpcCacheLock.Unlock()
		return entry.cli, nil
	}
	delete(rpcCache, serviceName)
	rpcCacheLock.Unlock()

	inst, err := discovery.Pick(serviceName)
	if err != nil {
		err = fmt.Errorf("discovery pick %s failed: %w", serviceName, err)
		logx.Error(err)
		return nil, err
	}

	target := net.JoinHostPort(inst.IP, strconv.FormatUint(inst.Port, utils.NumberTen))
	cli := zrpc.MustNewClient(zrpc.RpcClientConf{
		Target:  target,
		Timeout: utils.RpcTimeOut,
	})

	rpcCacheLock.Lock()
	rpcCache[serviceName] = &rpcClientCacheEntry{
		cli:      cli,
		target:   target,
		expireAt: time.Now().Add(rpcClientCacheTTL),
	}
	rpcCacheLock.Unlock()

	return cli, nil
}