/*
Copyright IBM Corp. 2017 All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

                 http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package mocks

import (
	"fmt"
	"net"
	"sync/atomic"
	"testing"

	"github.com/golang/protobuf/proto"
	"github.com/hyperledger/fabric/protos/common"
	"github.com/hyperledger/fabric/protos/orderer"
	"github.com/stretchr/testify/assert"
	"google.golang.org/grpc"
)

type Orderer struct {
	net.Listener
	*grpc.Server
	nextExpectedSeek uint64
	t                *testing.T
	blockChannel     chan uint64
	stopChan         chan struct{}
	failFlag         int32
	connCount        uint32
}

func NewOrderer(port int, t *testing.T) *Orderer {
	srv := grpc.NewServer()
	lsnr, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", port))
	if err != nil {
		panic(err)
	}
	go srv.Serve(lsnr)
	o := &Orderer{Server: srv,
		Listener:         lsnr,
		t:                t,
		nextExpectedSeek: uint64(1),
		blockChannel:     make(chan uint64, 1),
		stopChan:         make(chan struct{}, 1),
	}
	orderer.RegisterAtomicBroadcastServer(srv, o)
	return o
}

func (o *Orderer) Shutdown() {
	o.stopChan <- struct{}{}
	o.Server.Stop()
	o.Listener.Close()
}

func (o *Orderer) Fail() {
	atomic.StoreInt32(&o.failFlag, int32(1))
	o.blockChannel <- 0
}

func (o *Orderer) ConnCount() int {
	return int(atomic.LoadUint32(&o.connCount))
}

func (o *Orderer) hasFailed() bool {
	return atomic.LoadInt32(&o.failFlag) == int32(1)
}

func (*Orderer) Broadcast(orderer.AtomicBroadcast_BroadcastServer) error {
	panic("Should not have ben called")
}

func (o *Orderer) SetNextExpectedSeek(seq uint64) {
	atomic.StoreUint64(&o.nextExpectedSeek, uint64(seq))
}

func (o *Orderer) SendBlock(seq uint64) {
	o.blockChannel <- seq
}

func (o *Orderer) Deliver(stream orderer.AtomicBroadcast_DeliverServer) error {
	atomic.AddUint32(&o.connCount, 1)
	envlp, err := stream.Recv()
	if err != nil {
		return nil
	}
	if o.hasFailed() {
		return stream.Send(statusUnavailable())
	}
	payload := &common.Payload{}
	proto.Unmarshal(envlp.Payload, payload)
	seekInfo := &orderer.SeekInfo{}
	proto.Unmarshal(payload.Data, seekInfo)
	assert.True(o.t, seekInfo.Behavior == orderer.SeekInfo_BLOCK_UNTIL_READY)
	assert.Equal(o.t, atomic.LoadUint64(&o.nextExpectedSeek), seekInfo.Start.GetSpecified().Number)

	for {
		select {
		case <-o.stopChan:
			return nil
		case seq := <-o.blockChannel:
			if o.hasFailed() {
				return stream.Send(statusUnavailable())
			}
			o.sendBlock(stream, seq)
		}
	}
}

func statusUnavailable() *orderer.DeliverResponse {
	return &orderer.DeliverResponse{
		Type: &orderer.DeliverResponse_Status{
			Status: common.Status_SERVICE_UNAVAILABLE,
		},
	}
}

func (o *Orderer) sendBlock(stream orderer.AtomicBroadcast_DeliverServer, seq uint64) {
	block := &common.Block{
		Header: &common.BlockHeader{
			Number: seq,
		},
	}
	stream.Send(&orderer.DeliverResponse{
		Type: &orderer.DeliverResponse_Block{Block: block},
	})
}