package grpcsr

import (
	"context"
	"fmt"
	"git.makemake.in/kzkzzzz/mycommon"
	"git.makemake.in/kzkzzzz/mycommon/graceful"
	"git.makemake.in/kzkzzzz/mycommon/myconf"
	"git.makemake.in/kzkzzzz/mycommon/mygrpc"
	"git.makemake.in/kzkzzzz/mycommon/mylog"
	"git.makemake.in/kzkzzzz/mycommon/myregistry"
	"github.com/spf13/pflag"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/health"
	"google.golang.org/grpc/health/grpc_health_v1"
	"google.golang.org/grpc/keepalive"
	"google.golang.org/grpc/reflection"
	"google.golang.org/grpc/status"
	"log"
	"net"

	"runtime/debug"
	"time"
)

//const DefaultInstanceName = "grpc"

var _ graceful.IRunner = (*Server)(nil)

type Conf struct {
	Addr string
	Port int
	Ip   string
	Log  bool
}

type Opt func(server *Server)

type Server struct {
	gs             *grpc.Server
	serviceId      string
	serviceName    string
	serverConf     *Conf
	reg            myregistry.IRegister
	grpcOpts       []grpc.ServerOption
	logger         mylog.ILogger
	registerGrpcFn func(*grpc.Server) // 注册grpc服务, 使用函数延迟调用, 便于先初始化中间件等操作

	unaryMiddlewares []grpc.UnaryServerInterceptor // grpc一元服务端中间件

	useDefaultBufferCfg bool
	delayStopMs         int

	serviceRegInfo *myregistry.ServiceInfo
}

func UseDefaultBufferCfg(v bool) Opt {
	return func(server *Server) {
		server.useDefaultBufferCfg = v
	}
}

func WithRegistry(serviceName string, reg myregistry.IRegister) Opt {
	return func(server *Server) {
		server.serviceName = mygrpc.ServicePrefix + serviceName
		server.reg = reg
	}
}

func WithGrpcOpts(v ...grpc.ServerOption) Opt {
	return func(server *Server) {
		server.grpcOpts = v
	}
}

func WithDelayStopMs(v int) Opt {
	return func(server *Server) {
		server.delayStopMs = v
	}
}

func SetFlag() {
	pflag.Int("grpc.port", 0, "listen port, 0 is random port")
	pflag.String("grpc.log", "true", "enable request log")
}

func New(cfg *myconf.Config, opts ...Opt) *Server {
	cf := &Conf{}
	err := cfg.UnmarshalKey("grpc", cf)
	if err != nil {
		panic(err)
	}

	// 命令行的参数覆盖一次, Unmarshal解析的时候, 不会用命令行的参数覆盖 https://github.com/spf13/viper/issues/190
	cf.Port = cfg.GetInt(fmt.Sprintf("grpc.port"))
	cf.Log = cfg.GetBool(fmt.Sprintf("grpc.log"))

	return NewByConf(cf, opts...)
}

func NewByConf(conf *Conf, opts ...Opt) *Server {
	s := &Server{
		serverConf:          conf,
		useDefaultBufferCfg: true,
	}
	for _, opt := range opts {
		opt(s)
	}

	if s.logger == nil {
		s.logger = mylog.GetLoggerSkip(-1)
	}

	if s.reg != nil && s.serviceName == "" {
		panic("service name is empty")
	}

	s.unaryMiddlewares = []grpc.UnaryServerInterceptor{
		s.grpcRecover(), // 默认启用recover中间件
	}

	if s.serverConf.Log {
		s.unaryMiddlewares = append(s.unaryMiddlewares, s.requestLog())
	}

	return s
}

func (s *Server) Use(middlewares ...grpc.UnaryServerInterceptor) {
	s.unaryMiddlewares = append(s.unaryMiddlewares, middlewares...)
}

func (s *Server) RegisterGrpc(fn func(*grpc.Server)) {
	s.registerGrpcFn = fn
}

func (s *Server) initServer() {
	grpcOpts := []grpc.ServerOption{
		grpc.KeepaliveEnforcementPolicy(keepalive.EnforcementPolicy{
			MinTime:             time.Second * 5, // 如果客户端两次 ping 的间隔小于 N，则关闭连接
			PermitWithoutStream: true,            // 即使没有 active stream, 也允许 ping
		}),
		grpc.KeepaliveParams(keepalive.ServerParameters{
			MaxConnectionIdle:     time.Minute * 15, // 空闲连接时间
			MaxConnectionAgeGrace: time.Second * 30, // 在强制关闭连接之间, 允许有 N 的时间完成 pending 的 rpc 请求
			Time:                  time.Second * 20, // 如果一个连接空闲超过 N, 则发送一个 ping 请求
			Timeout:               time.Second * 5,  // 如果 ping 请求 N 内未收到回复, 则认为该连接已断开
		}),
	}

	if s.useDefaultBufferCfg {
		grpcOpts = append(grpcOpts,
			grpc.InitialWindowSize(mygrpc.DefaultWindowSize),
			grpc.InitialConnWindowSize(mygrpc.DefaultWindowSize),

			grpc.ReadBufferSize(mygrpc.DefaultReadBufferSize),
			grpc.WriteBufferSize(mygrpc.DefaultWriteBufferSize),
		)
	}

	if len(s.unaryMiddlewares) > 0 {
		grpcOpts = append(grpcOpts, grpc.ChainUnaryInterceptor(s.unaryMiddlewares...))
	}

	if len(s.grpcOpts) > 0 {
		grpcOpts = append(grpcOpts, s.grpcOpts...)
	}

	s.gs = grpc.NewServer(grpcOpts...)

	// 注册grpc服务
	s.registerGrpcFn(s.gs)
}

func (s *Server) Run(ctx context.Context) error {
	s.initServer()

	// 端口如果=0, 监听随机端口
	addr0 := fmt.Sprintf("%s:%d", s.serverConf.Addr, s.serverConf.Port)
	lis, err := net.Listen("tcp", addr0)
	if err != nil {
		return err
	}

	// 获取监听的端口
	port := lis.Addr().(*net.TCPAddr).Port

	// 健康服务
	healthServer := health.NewServer()
	grpc_health_v1.RegisterHealthServer(s.gs, healthServer)

	// 服务反射, 方便调试
	reflection.Register(s.gs)

	var svcIp = s.serverConf.Ip
	if svcIp == "" {
		svcIp = mycommon.GetOutboundIP()
	}

	// 注册服务
	if s.reg != nil {
		s.serviceRegInfo = &myregistry.ServiceInfo{
			ServiceName: s.serviceName,
			Ip:          svcIp,
			Port:        port,
		}

		err = s.reg.Register(s.serviceRegInfo)
		if err != nil {
			return err
		}

		log.Printf("[%s] register service: %s - %s:%d",
			s.reg.Name(),
			s.serviceRegInfo.ServiceName,
			s.serviceRegInfo.Ip, s.serviceRegInfo.Port,
		)
	}

	addr := fmt.Sprintf("%s:%d", s.serverConf.Addr, port)
	log.Printf("grpc server listen on %s", addr)

	err = s.gs.Serve(lis)
	if err != nil {
		log.Printf("start grpc server err: %s", err)
		return err
	}

	return nil
}

func (s *Server) Stop() {
	if s.reg != nil {
		err := s.reg.Deregister(s.serviceRegInfo)
		if err != nil {
			s.logger.Errorf("grpc server deregister err: %s", err)
		}

		log.Printf("[%s] deregister service: %s - %s:%d",
			s.reg.Name(),
			s.serviceRegInfo.ServiceName,
			s.serviceRegInfo.Ip, s.serviceRegInfo.Port,
		)

	}

	// 如果使用k8s service, 关闭pod和往service注销ip是同时进行的, 如果退出服务比注销ip先完成, 可能有流量继续进来, 导致请求失败
	// 延迟一段时间, 确保服务已经注销ip, 再关闭服务

	// 如何使用注册中心, 先从中心退出ip, 也延迟一段时间, 等上游网关更新ip完成(正常不会太久), 不会有流量进来旧服务, 再退出服务
	if s.delayStopMs > 0 {
		delayTime := time.Millisecond * time.Duration(s.delayStopMs)
		log.Printf("grpc server delay stop: %s", delayTime)
		time.Sleep(delayTime)
	}

	s.gs.GracefulStop()

	log.Printf("grpc server stop")
}

type handleResp struct {
	resp interface{}
	err  error
}

func (s *Server) requestLog() grpc.UnaryServerInterceptor {
	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
		start := time.Now()

		resp, err := handler(ctx, req)

		var (
			code    codes.Code
			codeMsg = "OK"
		)
		if err != nil {
			fromError, ok := status.FromError(err)
			if ok {
				code = fromError.Code()
			} else {
				code = status.New(codes.Unknown, err.Error()).Code()
			}

			codeMsg = fmt.Sprintf("%s(%d)", code.String(), uint32(code))
		}

		s.logger.Infof(
			"%s - %s - %s - %s",
			codeMsg, time.Since(start), mygrpc.ClientIP(ctx), info.FullMethod,
		)

		return resp, err
	}
}

func (s *Server) grpcRecover() grpc.UnaryServerInterceptor {
	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp interface{}, err error) {
		defer func() {
			if err0 := recover(); err0 != nil {
				log.Printf("%s - panic: %v\n%s", info.FullMethod, err0, debug.Stack())
				err = fmt.Errorf("server err %s - %s", info.FullMethod, err0)
			}
		}()

		return handler(ctx, req)
	}
}

// Timeout 控制服务端超时
func Timeout(timeout time.Duration) grpc.UnaryServerInterceptor {
	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp interface{}, err error) {
		tCtx, cancel := context.WithTimeout(ctx, timeout)
		defer cancel()

		ch := make(chan *handleResp, 1)

		go func() {
			defer func() {
				if err0 := recover(); err0 != nil {
					log.Printf("%s - panic: %v\n%s", info.FullMethod, err0, debug.Stack())
					ch <- &handleResp{nil, fmt.Errorf("server err: %s - system err: %s", info.FullMethod, err0)}
				}
			}()
			//start := time.Now()
			r := &handleResp{}
			r.resp, r.err = handler(tCtx, req)
			//log.Printf("rta server time: %s", time.Since(start))
			ch <- r
		}()

		select {
		case <-tCtx.Done():
			return nil, mygrpc.GrpcServerTimeout("server err: grpc handle timeout %s %s", timeout, info.FullMethod)
			//return nil, status.Errorf(codes.DeadlineExceeded, "grpc handle timeout %s %s", timeout, info.FullMethod)

		case res := <-ch:
			return res.resp, res.err
		}

		//return nil, fmt.Errorf("handle err %s.%s", info.Server, info.FullMethod)
	}
}