package consul

import (
	"context"
	"errors"
	"fmt"
	"net"
	"net/http"
	"sync"
	"time"

	"github.com/gogf/gf/contrib/registry/consul/v2"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/net/gsel"
	"github.com/gogf/gf/v2/net/gsvc"
	"github.com/gogf/gf/v2/util/grand"
)

var (
	registry       gsvc.Registry
	consulAddr     string
	reconnectMutex sync.RWMutex
	reconnectDone  chan struct{}
	connected      bool
	httpClient     *http.Client
)

// connectConsul 连接 Consul
func connectConsul(ctx context.Context) error {
	reconnectMutex.Lock()
	defer reconnectMutex.Unlock()

	// 如果已经连接，不再重复连接
	if connected && registry != nil {
		return nil
	}

	var err error
	registry, err = consul.New(consul.WithAddress(consulAddr))
	if err != nil {
		g.Log().Errorf(ctx, "❌ Consul 连接失败: %v", err)
		return err
	}

	gsvc.SetRegistry(registry)
	gsel.SetBuilder(gsel.NewBuilderRoundRobin())
	connected = true
	g.Log().Infof(ctx, "✅ Consul 初始化成功: %s", consulAddr)

	return nil
}

// startHealthCheckAndReconnect 启动健康检查和自动重连
func startHealthCheckAndReconnect() {
	if reconnectDone != nil {
		close(reconnectDone)
	}

	reconnectDone = make(chan struct{})
	ticker := time.NewTicker(30 * time.Second)
	defer ticker.Stop()

	ctx := context.Background()

	// 初始化HTTP客户端用于健康检查
	httpClient = &http.Client{
		Timeout: 5 * time.Second,
	}

	for {
		select {
		case <-ticker.C:
			// 检查服务发现是否正常工作
			if checkConsulHealth(ctx) {
				continue
			}

			g.Log().Warning(ctx, "⚠️  Consul 连接异常,尝试重新连接...")

			// 重置连接状态并重连
			reconnectMutex.Lock()
			connected = false
			registry = nil
			reconnectMutex.Unlock()

			if err := connectConsul(ctx); err != nil {
				g.Log().Errorf(ctx, "❌ Consul 重连失败: %v,30秒后重试...", err)
			}

		case <-reconnectDone:
			g.Log().Info(ctx, "🛑 Consul 健康检查已停止")
			return
		}
	}
}

// checkConsulHealth 检查 Consul 健康状态
func checkConsulHealth(ctx context.Context) bool {
	reconnectMutex.RLock()
	defer reconnectMutex.RUnlock()

	if registry == nil || !connected {
		return false
	}

	// 使用consul原生API进行健康检查
	// 调用 /v1/agent/self 接口检测连接状态
	url := fmt.Sprintf("http://%s/v1/agent/self", consulAddr)
	resp, err := httpClient.Get(url)
	if err != nil {
		g.Log().Debugf(ctx, "Consul 健康检查失败: %v", err)
		return false
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		g.Log().Debugf(ctx, "Consul 健康检查失败,状态码: %d", resp.StatusCode)
		return false
	}

	//g.Log().Debugf(ctx, "✅ Consul 健康检查通过")
	return true
}

func init() {
	consulAddr = g.Cfg().MustGet(context.Background(), "consul.address").String()
	if consulAddr == "" {
		g.Log().Warning(context.Background(), "⚠️  Consul 配置未找到,跳过初始化")
		return
	}

	if err := connectConsul(context.Background()); err != nil {
		g.Log().Errorf(context.Background(), "❌ Consul 初始化失败: %v", err)
	} else {
		// 连接成功后启动健康检查和自动重连
		go startHealthCheckAndReconnect()
	}
}
func getLocalIP() (string, error) {
	// 获取本机所有网络接口
	addrs, err := net.InterfaceAddrs()
	if err != nil {
		return "", err
	}

	for _, addr := range addrs {
		// 检查是否是IP地址
		if ipNet, ok := addr.(*net.IPNet); ok && !ipNet.IP.IsLoopback() {
			if ipNet.IP.To4() != nil {
				// 返回第一个非回环的IPv4地址
				return ipNet.IP.String(), nil
			}
		}
	}

	return "", fmt.Errorf("无法找到本地IP地址")
}
func getInstanceAddrByIp(ctx context.Context, ip string, services []gsvc.Service) (addr string) {
	for _, s := range services {
		if s.GetEndpoints()[0].Host() == ip {
			addr = s.GetEndpoints()[0].String()
			return
		}
	}
	return
}
func GetInstanceAddr(ctx context.Context, name string) (addr string, err error) {
	watch, err := gsvc.GetRegistry().Watch(ctx, name)
	if err != nil {
		err = errors.New("获取服务监听器失败")
		return
	}

	service, err := watch.Proceed()
	if err != nil || service == nil {
		err = errors.New("获取服务实例失败")
		return
	}
	//优先使用客户端IP获取实例(前后端在同一台机器调试)
	addr = getInstanceAddrByIp(ctx, g.RequestFromCtx(ctx).GetClientIp(), service)
	if !g.IsEmpty(addr) {
		return
	}
	//优先使用gateway同IP的服务实例(前后端不同机器调试)
	addr, err = getLocalIP()
	if err != nil {
		return
	}
	addr = getInstanceAddrByIp(ctx, addr, service)
	if !g.IsEmpty(addr) {
		return
	}
	//随机获取一个服务实例
	maxService := grand.N(0, len(service)-1)
	addr = service[maxService].GetEndpoints()[0].String()
	return
}