package grpcclient

import (
	"context"
	"fmt"
	"sync"
	"time"

	grpcmiddleware "github.com/grpc-ecosystem/go-grpc-middleware"
	grpcretry "github.com/grpc-ecosystem/go-grpc-middleware/retry"
	grpcopentracing "github.com/grpc-ecosystem/go-grpc-middleware/tracing/opentracing"

	"go.uber.org/zap"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/keepalive"

	"github.com/milvus-io/milvus/internal/log"
	"github.com/milvus-io/milvus/internal/util/funcutil"
	"github.com/milvus-io/milvus/internal/util/retry"
	"github.com/milvus-io/milvus/internal/util/trace"
)

// GrpcClient abstracts client of grpc
type GrpcClient interface {
	SetRole(string)
	GetRole() string
	SetGetAddrFunc(func() (string, error))
	SetNewGrpcClientFunc(func(cc *grpc.ClientConn) interface{})
	GetGrpcClient(ctx context.Context) (interface{}, error)
	ReCall(ctx context.Context, caller func(client interface{}) (interface{}, error)) (interface{}, error)
	Call(ctx context.Context, caller func(client interface{}) (interface{}, error)) (interface{}, error)
	Close() error
}

// ClientBase is a base of grpc client
type ClientBase struct {
	getAddrFunc   func() (string, error)
	newGrpcClient func(cc *grpc.ClientConn) interface{}

	grpcClient        interface{}
	conn              *grpc.ClientConn
	grpcClientMtx     sync.RWMutex
	role              string
	ClientMaxSendSize int
	ClientMaxRecvSize int
}

// SetRole sets role of client
func (c *ClientBase) SetRole(role string) {
	c.role = role
}

// GetRole returns role of client
func (c *ClientBase) GetRole() string {
	return c.role
}

// SetGetAddrFunc sets getAddrFunc of client
func (c *ClientBase) SetGetAddrFunc(f func() (string, error)) {
	c.getAddrFunc = f
}

// SetNewGrpcClientFunc sets newGrpcClient of client
func (c *ClientBase) SetNewGrpcClientFunc(f func(cc *grpc.ClientConn) interface{}) {
	c.newGrpcClient = f
}

// GetGrpcClient returns grpc client
func (c *ClientBase) GetGrpcClient(ctx context.Context) (interface{}, error) {
	c.grpcClientMtx.RLock()

	if c.grpcClient != nil {
		defer c.grpcClientMtx.RUnlock()
		return c.grpcClient, nil
	}
	c.grpcClientMtx.RUnlock()

	c.grpcClientMtx.Lock()
	defer c.grpcClientMtx.Unlock()

	if c.grpcClient != nil {
		return c.grpcClient, nil
	}

	err := c.connect(ctx, retry.Attempts(5))
	if err != nil {
		return nil, err
	}

	return c.grpcClient, nil
}

func (c *ClientBase) resetConnection(client interface{}) {
	c.grpcClientMtx.Lock()
	defer c.grpcClientMtx.Unlock()
	if c.grpcClient == nil {
		return
	}

	if client != c.grpcClient {
		return
	}
	if c.conn != nil {
		_ = c.conn.Close()
	}
	c.conn = nil
	c.grpcClient = nil
}

func (c *ClientBase) connect(ctx context.Context, retryOptions ...retry.Option) error {
	var kacp = keepalive.ClientParameters{
		Time:                60 * time.Second, // send pings every 60 seconds if there is no activity
		Timeout:             6 * time.Second,  // wait 6 second for ping ack before considering the connection dead
		PermitWithoutStream: true,             // send pings even without active streams
	}

	var err error
	var addr string
	connectServiceFunc := func() error {
		addr, err = c.getAddrFunc()
		if err != nil {
			log.Debug(c.GetRole()+" client getAddr failed", zap.Error(err))
			return err
		}
		opts := trace.GetInterceptorOpts()
		ctx1, cancel := context.WithTimeout(ctx, 15*time.Second)
		defer cancel()
		conn, err2 := grpc.DialContext(ctx1, addr,
			grpc.WithKeepaliveParams(kacp),
			grpc.WithInsecure(), grpc.WithBlock(),
			grpc.WithDefaultCallOptions(
				grpc.MaxCallRecvMsgSize(c.ClientMaxRecvSize),
				grpc.MaxCallSendMsgSize(c.ClientMaxSendSize)),
			grpc.WithUnaryInterceptor(
				grpcmiddleware.ChainUnaryClient(
					grpcretry.UnaryClientInterceptor(
						grpcretry.WithMax(3),
						grpcretry.WithCodes(codes.Aborted, codes.Unavailable),
					),
					grpcopentracing.UnaryClientInterceptor(opts...),
				)),
			grpc.WithStreamInterceptor(
				grpcmiddleware.ChainStreamClient(
					grpcretry.StreamClientInterceptor(grpcretry.WithMax(3),
						grpcretry.WithCodes(codes.Aborted, codes.Unavailable),
					),
					grpcopentracing.StreamClientInterceptor(opts...),
				)),
		)
		if err2 != nil {
			return err2
		}
		if c.conn != nil {
			_ = c.conn.Close()
		}
		c.conn = conn
		return nil
	}

	err = retry.Do(ctx, connectServiceFunc, retryOptions...)
	if err != nil {
		log.Debug(c.GetRole()+" client try reconnect failed", zap.Error(err))
		return err
	}
	c.grpcClient = c.newGrpcClient(c.conn)
	return nil
}

func (c *ClientBase) callOnce(ctx context.Context, caller func(client interface{}) (interface{}, error)) (interface{}, error) {
	client, err := c.GetGrpcClient(ctx)
	if err != nil {
		return nil, err
	}

	ret, err2 := caller(client)
	if err2 == nil {
		return ret, nil
	}
	if err2 == context.Canceled || err2 == context.DeadlineExceeded {
		return nil, err2
	}

	log.Debug(c.GetRole()+" ClientBase grpc error, start to reset connection", zap.Error(err2))

	c.resetConnection(client)
	return ret, err2
}

// Call does a grpc call
func (c *ClientBase) Call(ctx context.Context, caller func(client interface{}) (interface{}, error)) (interface{}, error) {
	if !funcutil.CheckCtxValid(ctx) {
		return nil, ctx.Err()
	}

	ret, err := c.callOnce(ctx, caller)
	if err != nil {
		traceErr := fmt.Errorf("err: %s\n, %s", err.Error(), trace.StackTrace())
		log.Error(c.GetRole()+" ClientBase Call grpc first call get error ", zap.Error(traceErr))
		return nil, traceErr
	}
	return ret, err
}

func (c *ClientBase) ReCall(ctx context.Context, caller func(client interface{}) (interface{}, error)) (interface{}, error) {
	if !funcutil.CheckCtxValid(ctx) {
		return nil, ctx.Err()
	}

	ret, err := c.callOnce(ctx, caller)
	if err == nil {
		return ret, nil
	}

	traceErr := fmt.Errorf("err: %s\n, %s", err.Error(), trace.StackTrace())
	log.Warn(c.GetRole()+" ClientBase ReCall grpc first call get error ", zap.Error(traceErr))

	if !funcutil.CheckCtxValid(ctx) {
		return nil, ctx.Err()
	}

	ret, err = c.callOnce(ctx, caller)
	if err != nil {
		traceErr = fmt.Errorf("err: %s\n, %s", err.Error(), trace.StackTrace())
		log.Error(c.GetRole()+" ClientBase ReCall grpc second call get error ", zap.Error(traceErr))
		return nil, traceErr
	}
	return ret, err
}

// Close close the client connection
func (c *ClientBase) Close() error {
	c.grpcClientMtx.Lock()
	defer c.grpcClientMtx.Unlock()
	if c.conn != nil {
		return c.conn.Close()
	}
	return nil
}