// Package drpc provides a drpc client
package drpc

import (
	"bytes"
	"context"
	"fmt"
	"net"
	"os"
	"strings"
	"sync"
	"time"

	"github.com/unistack-org/micro/v3/broker"
	"github.com/unistack-org/micro/v3/client"
	"github.com/unistack-org/micro/v3/codec"
	"github.com/unistack-org/micro/v3/errors"
	"github.com/unistack-org/micro/v3/metadata"
	"storj.io/drpc/drpcconn"
	dmetadata "storj.io/drpc/drpcmetadata"
)

var DefaultContentType = "application/drpc+proto"

type drpcClient struct {
	opts client.Options
	// pool *pool
	init bool
	sync.RWMutex
}

func (d *drpcClient) call(ctx context.Context, addr string, req client.Request, rsp interface{}, opts client.CallOptions) error {
	var header map[string]string

	if md, ok := metadata.FromOutgoingContext(ctx); ok {
		header = make(map[string]string, len(md))
		for k, v := range md {
			header[strings.ToLower(k)] = v
		}
	} else {
		header = make(map[string]string, 2)
	}

	// set timeout in nanoseconds
	header[metadata.HeaderTimeout] = fmt.Sprintf("%d", opts.RequestTimeout)
	// set the content type for the request
	// header["x-content-type"] = req.ContentType()

	ctx = dmetadata.AddPairs(ctx, header)
	cf, err := d.newCodec(req.ContentType())
	if err != nil {
		return errors.InternalServerError("go.micro.client", err.Error())
	}

	// maxRecvMsgSize := d.maxRecvMsgSizeValue()
	// maxSendMsgSize := d.maxSendMsgSizeValue()

	var grr error

	var dialCtx context.Context
	var cancel context.CancelFunc
	if opts.DialTimeout >= 0 {
		dialCtx, cancel = context.WithTimeout(ctx, opts.DialTimeout)
	} else {
		dialCtx, cancel = context.WithCancel(ctx)
	}
	defer cancel()

	// TODO: handle g.secure
	/*
		grpcDialOptions := []grpc.DialOption{
			g.secure(addr),
			grpc.WithDefaultCallOptions(
				grpc.MaxCallRecvMsgSize(maxRecvMsgSize),
				grpc.MaxCallSendMsgSize(maxSendMsgSize),
			),
		}

		if opts := g.getGrpcDialOptions(); opts != nil {
			grpcDialOptions = append(grpcDialOptions, opts...)
		}

		cc, err := g.pool.getConn(dialCtx, addr, grpcDialOptions...)
		if err != nil {
			return errors.InternalServerError("go.micro.client", fmt.Sprintf("Error sending request: %v", err))
		}
		defer func() {
			// defer execution of release
			g.pool.release(cc, grr)
		}()
	*/
	ch := make(chan error, 1)
	_ = dialCtx
	// rc, err := net.DialContext(ctx, "tcp", addr)
	rc, err := net.Dial("tcp", addr)
	if err != nil {
		return err
	}
	defer rc.Close()

	cc := drpcconn.New(rc)
	defer cc.Close()
	go func() {
		err := cc.Invoke(ctx, methodToDRPC(req.Service(), req.Endpoint()), &wrapMicroCodec{cf}, req.Body(), rsp)
		ch <- microError(err)
	}()

	select {
	case err := <-ch:
		grr = err
	case <-ctx.Done():
		grr = errors.Timeout("go.micro.client", "%v", ctx.Err())
	}

	return grr
}

/*
func (g *drpcClient) stream(ctx context.Context, addr string, req client.Request, rsp interface{}, opts client.CallOptions) error {
	var header map[string]string

	if md, ok := metadata.FromOutgoingContext(ctx); ok {
		header = make(map[string]string, len(md))
		for k, v := range md {
			header[k] = v
		}
	} else {
		header = make(map[string]string)
	}

	// set timeout in nanoseconds
	if opts.StreamTimeout > time.Duration(0) {
		header["timeout"] = fmt.Sprintf("%d", opts.StreamTimeout)
	}
	// set the content type for the request
	header["x-content-type"] = req.ContentType()

	md := gmetadata.New(header)
	ctx = gmetadata.NewOutgoingContext(ctx, md)

	cf, err := g.newCodec(req.ContentType())
	if err != nil {
		return errors.InternalServerError("go.micro.client", err.Error())
	}

	var dialCtx context.Context
	var cancel context.CancelFunc
	if opts.DialTimeout >= 0 {
		dialCtx, cancel = context.WithTimeout(ctx, opts.DialTimeout)
	} else {
		dialCtx, cancel = context.WithCancel(ctx)
	}
	defer cancel()

	grpcDialOptions := []grpc.DialOption{
		//	g.secure(addr),
	}

	if opts := g.getGrpcDialOptions(); opts != nil {
		grpcDialOptions = append(grpcDialOptions, opts...)
	}

	cc, err := g.pool.getConn(dialCtx, addr, grpcDialOptions...)
	if err != nil {
		return errors.InternalServerError("go.micro.client", fmt.Sprintf("Error sending request: %v", err))
	}

	desc := &grpc.StreamDesc{
		StreamName:    req.Service() + req.Endpoint(),
		ClientStreams: true,
		ServerStreams: true,
	}

	grpcCallOptions := []grpc.CallOption{
		grpc.ForceCodec(cf),
		grpc.CallContentSubtype(cf.String()),
	}
	if opts := g.getGrpcCallOptions(); opts != nil {
		grpcCallOptions = append(grpcCallOptions, opts...)
	}

	// create a new cancelling context
	newCtx, cancel := context.WithCancel(ctx)

	st, err := cc.NewStream(newCtx, desc, methodToGRPC(req.Service(), req.Endpoint()), grpcCallOptions...)
	if err != nil {
		// we need to cleanup as we dialled and created a context
		// cancel the context
		cancel()
		// release the connection
		g.pool.release(cc, err)
		// now return the error
		return errors.InternalServerError("go.micro.client", fmt.Sprintf("Error creating stream: %v", err))
	}

	// set request codec
	if r, ok := req.(*grpcRequest); ok {
		r.codec = cf
	}

	// setup the stream response
	stream := &grpcStream{
		ClientStream: st,
		context:      ctx,
		request:      req,
		response: &response{
			conn:   cc,
			stream: st,
			codec:  cf,
		},
		conn: cc,
		close: func(err error) {
			// cancel the context if an error occurred
			if err != nil {
				cancel()
			}

			// defer execution of release
			g.pool.release(cc, err)
		},
	}

	// set the stream as the response
	val := reflect.ValueOf(rsp).Elem()
	val.Set(reflect.ValueOf(stream).Elem())
	return nil
}

func (g *drpcClient) poolMaxStreams() int {
	if g.opts.Context == nil {
		return DefaultPoolMaxStreams
	}
	v := g.opts.Context.Value(poolMaxStreams{})
	if v == nil {
		return DefaultPoolMaxStreams
	}
	return v.(int)
}

func (g *drpcClient) poolMaxIdle() int {
	if g.opts.Context == nil {
		return DefaultPoolMaxIdle
	}
	v := g.opts.Context.Value(poolMaxIdle{})
	if v == nil {
		return DefaultPoolMaxIdle
	}
	return v.(int)
}

func (g *drpcClient) maxRecvMsgSizeValue() int {
	if g.opts.Context == nil {
		return DefaultMaxRecvMsgSize
	}
	v := g.opts.Context.Value(maxRecvMsgSizeKey{})
	if v == nil {
		return DefaultMaxRecvMsgSize
	}
	return v.(int)
}

func (g *drpcClient) maxSendMsgSizeValue() int {
	if g.opts.Context == nil {
		return DefaultMaxSendMsgSize
	}
	v := g.opts.Context.Value(maxSendMsgSizeKey{})
	if v == nil {
		return DefaultMaxSendMsgSize
	}
	return v.(int)
}
*/

func (d *drpcClient) newCodec(ct string) (codec.Codec, error) {
	d.RLock()
	defer d.RUnlock()

	if idx := strings.IndexRune(ct, ';'); idx >= 0 {
		ct = ct[:idx]
	}

	if c, ok := d.opts.Codecs[ct]; ok {
		return c, nil
	}
	return nil, codec.ErrUnknownContentType
}

func (d *drpcClient) Init(opts ...client.Option) error {
	if len(opts) == 0 && d.init {
		return nil
	}
	//	size := d.opts.PoolSize
	//	ttl := d.opts.PoolTTL

	for _, o := range opts {
		o(&d.opts)
	}

	/*
		// update pool configuration if the options changed
		if size != d.opts.PoolSize || ttl != d.opts.PoolTTL {
			d.pool.Lock()
			d.pool.size = d.opts.PoolSize
			d.pool.ttl = int64(d.opts.PoolTTL.Seconds())
			d.pool.Unlock()
		}
	*/

	if err := d.opts.Broker.Init(); err != nil {
		return err
	}
	if err := d.opts.Tracer.Init(); err != nil {
		return err
	}
	if err := d.opts.Router.Init(); err != nil {
		return err
	}
	if err := d.opts.Logger.Init(); err != nil {
		return err
	}
	if err := d.opts.Meter.Init(); err != nil {
		return err
	}
	if err := d.opts.Transport.Init(); err != nil {
		return err
	}

	d.init = true

	return nil
}

func (d *drpcClient) Options() client.Options {
	return d.opts
}

func (d *drpcClient) NewMessage(topic string, msg interface{}, opts ...client.MessageOption) client.Message {
	return newDRPCEvent(topic, msg, d.opts.ContentType, opts...)
}

func (d *drpcClient) NewRequest(service, method string, req interface{}, reqOpts ...client.RequestOption) client.Request {
	return newDRPCRequest(service, method, req, d.opts.ContentType, reqOpts...)
}

func (d *drpcClient) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
	if req == nil {
		return errors.InternalServerError("go.micro.client", "req is nil")
	} else if rsp == nil {
		return errors.InternalServerError("go.micro.client", "rsp is nil")
	}
	// make a copy of call opts
	callOpts := d.opts.CallOptions
	for _, opt := range opts {
		opt(&callOpts)
	}

	// check if we already have a deadline
	td, ok := ctx.Deadline()
	if !ok {
		// no deadline so we create a new one
		var cancel context.CancelFunc
		ctx, cancel = context.WithTimeout(ctx, callOpts.RequestTimeout)
		defer cancel()
	} else {
		// got a deadline so no need to setup context
		// but we need to set the timeout we pass along
		opt := client.WithRequestTimeout(time.Until(td))
		opt(&callOpts)
	}

	// should we noop right here?
	select {
	case <-ctx.Done():
		return errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
	default:
	}

	// make copy of call method
	dcall := d.call

	// wrap the call in reverse
	for i := len(callOpts.CallWrappers); i > 0; i-- {
		dcall = callOpts.CallWrappers[i-1](dcall)
	}

	// use the router passed as a call option, or fallback to the rpc clients router
	if callOpts.Router == nil {
		callOpts.Router = d.opts.Router
	}

	if callOpts.Selector == nil {
		callOpts.Selector = d.opts.Selector
	}

	// inject proxy address
	// TODO: don't even bother using Lookup/Select in this case
	if len(d.opts.Proxy) > 0 {
		callOpts.Address = []string{d.opts.Proxy}
	}

	// lookup the route to send the reques to
	// TODO apply any filtering here
	routes, err := d.opts.Lookup(ctx, req, callOpts)
	if err != nil {
		return errors.InternalServerError("go.micro.client", err.Error())
	}

	// balance the list of nodes
	next, err := callOpts.Selector.Select(routes)
	if err != nil {
		return err
	}

	// return errors.New("go.micro.client", "request timeout", 408)
	call := func(i int) error {
		// call backoff first. Someone may want an initial start delay
		t, err := callOpts.Backoff(ctx, req, i)
		if err != nil {
			return errors.InternalServerError("go.micro.client", err.Error())
		}

		// only sleep if greater than 0
		if t.Seconds() > 0 {
			time.Sleep(t)
		}

		// get the next node
		node := next()

		// make the call
		err = dcall(ctx, node, req, rsp, callOpts)

		// record the result of the call to inform future routing decisions
		if verr := d.opts.Selector.Record(node, err); verr != nil {
			return verr
		}

		// try and transform the error to a go-micro error
		if verr, ok := err.(*errors.Error); ok {
			return verr
		}

		return err
	}

	ch := make(chan error, callOpts.Retries+1)
	var derr error

	for i := 0; i <= callOpts.Retries; i++ {
		go func(i int) {
			ch <- call(i)
		}(i)

		select {
		case <-ctx.Done():
			return errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
		case err := <-ch:
			// if the call succeeded lets bail early
			if err == nil {
				return nil
			}

			retry, rerr := callOpts.Retry(ctx, req, i, err)
			if rerr != nil {
				return rerr
			}

			if !retry {
				return err
			}

			derr = err
		}
	}

	return derr
}

func (g *drpcClient) Stream(ctx context.Context, req client.Request, opts ...client.CallOption) (client.Stream, error) {
	return nil, nil
	/*
		// make a copy of call opts
		callOpts := g.opts.CallOptions
		for _, opt := range opts {
			opt(&callOpts)
		}

		// #200 - streams shouldn't have a request timeout set on the context

		// should we noop right here?
		select {
		case <-ctx.Done():
			return nil, errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
		default:
		}

		// make a copy of stream
		gstream := g.stream

		// wrap the call in reverse
		for i := len(callOpts.CallWrappers); i > 0; i-- {
			gstream = callOpts.CallWrappers[i-1](gstream)
		}

		// use the router passed as a call option, or fallback to the rpc clients router
		if callOpts.Router == nil {
			callOpts.Router = g.opts.Router
		}

		if callOpts.Selector == nil {
			callOpts.Selector = g.opts.Selector
		}

		// inject proxy address
		// TODO: don't even bother using Lookup/Select in this case
		if len(g.opts.Proxy) > 0 {
			callOpts.Address = []string{g.opts.Proxy}
		}

		// lookup the route to send the reques to
		// TODO: move to internal lookup func
		routes, err := g.opts.Lookup(ctx, req, callOpts)
		if err != nil {
			return nil, errors.InternalServerError("go.micro.client", err.Error())
		}

		// balance the list of nodes
		next, err := callOpts.Selector.Select(routes)
		if err != nil {
			return nil, err
		}

		call := func(i int) (client.Stream, error) {
			// call backoff first. Someone may want an initial start delay
			t, err := callOpts.Backoff(ctx, req, i)
			if err != nil {
				return nil, errors.InternalServerError("go.micro.client", err.Error())
			}

			// only sleep if greater than 0
			if t.Seconds() > 0 {
				time.Sleep(t)
			}

			// get the next node
			node := next()

			// make the call
			stream := &grpcStream{}
			err = gstream(ctx, node, req, stream, callOpts)

			// record the result of the call to inform future routing decisions
			if verr := g.opts.Selector.Record(node, err); verr != nil {
				return nil, verr
			}

			// try and transform the error to a go-micro error
			if verr, ok := err.(*errors.Error); ok {
				return nil, verr
			}

			if rerr := g.opts.Selector.Record(node, err); rerr != nil {
				return nil, rerr
			}

			return stream, err
		}

		type response struct {
			stream client.Stream
			err    error
		}

		ch := make(chan response, callOpts.Retries+1)
		var grr error

		for i := 0; i <= callOpts.Retries; i++ {
			go func(i int) {
				s, err := call(i)
				ch <- response{s, err}
			}(i)

			select {
			case <-ctx.Done():
				return nil, errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
			case rsp := <-ch:
				// if the call succeeded lets bail early
				if rsp.err == nil {
					return rsp.stream, nil
				}

				retry, rerr := callOpts.Retry(ctx, req, i, grr)
				if rerr != nil {
					return nil, rerr
				}

				if !retry {
					return nil, rsp.err
				}

				grr = rsp.err
			}
		}

		return nil, grr
	*/
}

func (c *drpcClient) BatchPublish(ctx context.Context, msgs []client.Message, opts ...client.PublishOption) error {
	return c.publish(ctx, msgs, opts...)
}

func (c *drpcClient) Publish(ctx context.Context, msg client.Message, opts ...client.PublishOption) error {
	return c.publish(ctx, []client.Message{msg}, opts...)
}

func (c *drpcClient) publish(ctx context.Context, ps []client.Message, opts ...client.PublishOption) error {
	options := client.NewPublishOptions(opts...)

	// get proxy
	exchange := ""
	if v, ok := os.LookupEnv("MICRO_PROXY"); ok {
		exchange = v
	}

	omd, ok := metadata.FromOutgoingContext(ctx)
	if !ok {
		omd = metadata.New(2)
	}

	msgs := make([]*broker.Message, 0, len(ps))

	for _, p := range ps {
		md := metadata.Copy(omd)
		md[metadata.HeaderContentType] = p.ContentType()
		md[metadata.HeaderTopic] = p.Topic()

		cf, err := c.newCodec(p.ContentType())
		if err != nil {
			return errors.InternalServerError("go.micro.client", err.Error())
		}

		var body []byte

		// passed in raw data
		if d, ok := p.Payload().(*codec.Frame); ok {
			body = d.Data
		} else {
			b := bytes.NewBuffer(nil)
			if err := cf.Write(b, &codec.Message{Type: codec.Event}, p.Payload()); err != nil {
				return errors.InternalServerError("go.micro.client", err.Error())
			}
			body = b.Bytes()
		}

		topic := p.Topic()
		if len(exchange) > 0 {
			topic = exchange
		}

		md.Set(metadata.HeaderTopic, topic)
		msgs = append(msgs, &broker.Message{Header: md, Body: body})
	}

	return c.opts.Broker.BatchPublish(ctx, msgs,
		broker.PublishContext(ctx),
		broker.PublishBodyOnly(options.BodyOnly),
	)
}

func (d *drpcClient) String() string {
	return "drpc"
}

func (d *drpcClient) Name() string {
	return d.opts.Name
}

/*
func (g *drpcClient) getGrpcDialOptions() []grpc.DialOption {
	if g.opts.CallOptions.Context == nil {
		return nil
	}

	v := g.opts.CallOptions.Context.Value(grpcDialOptions{})

	if v == nil {
		return nil
	}

	opts, ok := v.([]grpc.DialOption)

	if !ok {
		return nil
	}

	return opts
}

func (g *drpcClient) getGrpcCallOptions() []grpc.CallOption {
	if g.opts.CallOptions.Context == nil {
		return nil
	}

	v := g.opts.CallOptions.Context.Value(grpcCallOptions{})

	if v == nil {
		return nil
	}

	opts, ok := v.([]grpc.CallOption)

	if !ok {
		return nil
	}

	return opts
}

*/

func NewClient(opts ...client.Option) client.Client {
	options := client.NewOptions(opts...)
	// default content type for grpc
	options.ContentType = DefaultContentType

	rc := &drpcClient{
		opts: options,
	}

	c := client.Client(rc)

	// wrap in reverse
	for i := len(options.Wrappers); i > 0; i-- {
		c = options.Wrappers[i-1](c)
	}

	return c
}