/*
Copyright IBM Corp. 2016 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 node

import (
	"errors"
	"fmt"
	"net"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"strconv"
	"sync"
	"syscall"
	"time"

	"github.com/hyperledger/fabric/consensus/helper"
	"github.com/hyperledger/fabric/core"
	"github.com/hyperledger/fabric/core/chaincode"
	"github.com/hyperledger/fabric/core/comm"
	"github.com/hyperledger/fabric/core/crypto"
	"github.com/hyperledger/fabric/core/db"
	"github.com/hyperledger/fabric/core/ledger/genesis"
	"github.com/hyperledger/fabric/core/peer"
	"github.com/hyperledger/fabric/core/rest"
	"github.com/hyperledger/fabric/core/system_chaincode"
	"github.com/hyperledger/fabric/events/producer"
	pb "github.com/hyperledger/fabric/protos"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"
	"google.golang.org/grpc/grpclog"
)

var chaincodeDevMode bool

func startCmd() *cobra.Command {
	// Set the flags on the node start command.
	flags := nodeStartCmd.Flags()
	flags.BoolVarP(&chaincodeDevMode, "peer-chaincodedev", "", false,
		"Whether peer in chaincode development mode")

	return nodeStartCmd
}

var nodeStartCmd = &cobra.Command{
	Use:   "start",
	Short: "Starts the node.",
	Long:  `Starts a node that interacts with the network.`,
	RunE: func(cmd *cobra.Command, args []string) error {
		return serve(args)
	},
}

func serve(args []string) error {
	// Parameter overrides must be processed before any paramaters are
	// cached. Failures to cache cause the server to terminate immediately.
	if chaincodeDevMode {
		logger.Info("Running in chaincode development mode")
		logger.Info("Set consensus to NOOPS and user starts chaincode")
		logger.Info("Disable loading validity system chaincode")

		viper.Set("peer.validator.enabled", "true")
		viper.Set("peer.validator.consensus", "noops")
		viper.Set("chaincode.mode", chaincode.DevModeUserRunsChaincode)

	}

	if err := peer.CacheConfiguration(); err != nil {
		return err
	}

	peerEndpoint, err := peer.GetPeerEndpoint()
	if err != nil {
		err = fmt.Errorf("Failed to get Peer Endpoint: %s", err)
		return err
	}

	listenAddr := viper.GetString("peer.listenAddress")

	if "" == listenAddr {
		logger.Debug("Listen address not specified, using peer endpoint address")
		listenAddr = peerEndpoint.Address
	}

	lis, err := net.Listen("tcp", listenAddr)
	if err != nil {
		grpclog.Fatalf("Failed to listen: %v", err)
	}

	ehubLis, ehubGrpcServer, err := createEventHubServer()
	if err != nil {
		grpclog.Fatalf("Failed to create ehub server: %v", err)
	}

	logger.Infof("Security enabled status: %t", core.SecurityEnabled())
	if viper.GetBool("security.privacy") {
		if core.SecurityEnabled() {
			logger.Infof("Privacy enabled status: true")
		} else {
			panic(errors.New("Privacy cannot be enabled as requested because security is disabled"))
		}
	} else {
		logger.Infof("Privacy enabled status: false")
	}

	db.Start()

	var opts []grpc.ServerOption
	if comm.TLSEnabled() {
		creds, err := credentials.NewServerTLSFromFile(viper.GetString("peer.tls.cert.file"),
			viper.GetString("peer.tls.key.file"))

		if err != nil {
			grpclog.Fatalf("Failed to generate credentials %v", err)
		}
		opts = []grpc.ServerOption{grpc.Creds(creds)}
	}

	grpcServer := grpc.NewServer(opts...)

	secHelper, err := getSecHelper()
	if err != nil {
		return err
	}

	secHelperFunc := func() crypto.Peer {
		return secHelper
	}

	registerChaincodeSupport(chaincode.DefaultChain, grpcServer, secHelper)

	var peerServer *peer.Impl

	// Create the peerServer
	if peer.ValidatorEnabled() {
		logger.Debug("Running as validating peer - making genesis block if needed")
		makeGenesisError := genesis.MakeGenesis()
		if makeGenesisError != nil {
			return makeGenesisError
		}
		logger.Debugf("Running as validating peer - installing consensus %s",
			viper.GetString("peer.validator.consensus"))

		peerServer, err = peer.NewPeerWithEngine(secHelperFunc, helper.GetEngine)
	} else {
		logger.Debug("Running as non-validating peer")
		peerServer, err = peer.NewPeerWithHandler(secHelperFunc, peer.NewPeerHandler)
	}

	if err != nil {
		logger.Fatalf("Failed creating new peer with handler %v", err)

		return err
	}

	// Register the Peer server
	pb.RegisterPeerServer(grpcServer, peerServer)

	// Register the Admin server
	pb.RegisterAdminServer(grpcServer, core.NewAdminServer())

	// Register Devops server
	serverDevops := core.NewDevopsServer(peerServer)
	pb.RegisterDevopsServer(grpcServer, serverDevops)

	// Register the ServerOpenchain server
	serverOpenchain, err := rest.NewOpenchainServerWithPeerInfo(peerServer)
	if err != nil {
		err = fmt.Errorf("Error creating OpenchainServer: %s", err)
		return err
	}

	pb.RegisterOpenchainServer(grpcServer, serverOpenchain)

	// Create and register the REST service if configured
	if viper.GetBool("rest.enabled") {
		go rest.StartOpenchainRESTServer(serverOpenchain, serverDevops)
	}

	logger.Infof("Starting peer with ID=%s, network ID=%s, address=%s, rootnodes=%v, validator=%v",
		peerEndpoint.ID, viper.GetString("peer.networkId"), peerEndpoint.Address,
		viper.GetString("peer.discovery.rootnode"), peer.ValidatorEnabled())

	// Start the grpc server. Done in a goroutine so we can deploy the
	// genesis block if needed.
	serve := make(chan error)

	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
	go func() {
		sig := <-sigs
		fmt.Println()
		fmt.Println(sig)
		serve <- nil
	}()

	go func() {
		var grpcErr error
		if grpcErr = grpcServer.Serve(lis); grpcErr != nil {
			grpcErr = fmt.Errorf("grpc server exited with error: %s", grpcErr)
		} else {
			logger.Info("grpc server exited")
		}
		serve <- grpcErr
	}()

	if err := writePid(viper.GetString("peer.fileSystemPath")+"/peer.pid", os.Getpid()); err != nil {
		return err
	}

	// Start the event hub server
	if ehubGrpcServer != nil && ehubLis != nil {
		go ehubGrpcServer.Serve(ehubLis)
	}

	if viper.GetBool("peer.profile.enabled") {
		go func() {
			profileListenAddress := viper.GetString("peer.profile.listenAddress")
			logger.Infof("Starting profiling server with listenAddress = %s", profileListenAddress)
			if profileErr := http.ListenAndServe(profileListenAddress, nil); profileErr != nil {
				logger.Errorf("Error starting profiler: %s", profileErr)
			}
		}()
	}

	// Block until grpc server exits
	return <-serve
}

func registerChaincodeSupport(chainname chaincode.ChainName, grpcServer *grpc.Server,
	secHelper crypto.Peer) {

	//get user mode
	userRunsCC := false
	if viper.GetString("chaincode.mode") == chaincode.DevModeUserRunsChaincode {
		userRunsCC = true
	}

	//get chaincode startup timeout
	tOut, err := strconv.Atoi(viper.GetString("chaincode.startuptimeout"))
	if err != nil { //what went wrong ?
		fmt.Printf("could not retrive timeout var...setting to 5secs\n")
		tOut = 5000
	}
	ccStartupTimeout := time.Duration(tOut) * time.Millisecond

	ccSrv := chaincode.NewChaincodeSupport(chainname, peer.GetPeerEndpoint, userRunsCC,
		ccStartupTimeout, secHelper)

	//Now that chaincode is initialized, register all system chaincodes.
	system_chaincode.RegisterSysCCs()

	pb.RegisterChaincodeSupportServer(grpcServer, ccSrv)
}

func createEventHubServer() (net.Listener, *grpc.Server, error) {
	var lis net.Listener
	var grpcServer *grpc.Server
	var err error
	if peer.ValidatorEnabled() {
		lis, err = net.Listen("tcp", viper.GetString("peer.validator.events.address"))
		if err != nil {
			return nil, nil, fmt.Errorf("failed to listen: %v", err)
		}

		//TODO - do we need different SSL material for events ?
		var opts []grpc.ServerOption
		if comm.TLSEnabled() {
			creds, err := credentials.NewServerTLSFromFile(
				viper.GetString("peer.tls.cert.file"),
				viper.GetString("peer.tls.key.file"))

			if err != nil {
				return nil, nil, fmt.Errorf("Failed to generate credentials %v", err)
			}
			opts = []grpc.ServerOption{grpc.Creds(creds)}
		}

		grpcServer = grpc.NewServer(opts...)
		ehServer := producer.NewEventsServer(
			uint(viper.GetInt("peer.validator.events.buffersize")),
			viper.GetInt("peer.validator.events.timeout"))

		pb.RegisterEventsServer(grpcServer, ehServer)
	}
	return lis, grpcServer, err
}

func writePid(fileName string, pid int) error {
	err := os.MkdirAll(filepath.Dir(fileName), 0755)
	if err != nil {
		return err
	}

	fd, err := os.OpenFile(fileName, os.O_RDWR|os.O_CREATE, 0644)
	if err != nil {
		return err
	}
	defer fd.Close()
	if err := syscall.Flock(int(fd.Fd()), syscall.LOCK_EX|syscall.LOCK_NB); err != nil {
		return fmt.Errorf("can't lock '%s', lock is held", fd.Name())
	}

	if _, err := fd.Seek(0, 0); err != nil {
		return err
	}

	if err := fd.Truncate(0); err != nil {
		return err
	}

	if _, err := fmt.Fprintf(fd, "%d", pid); err != nil {
		return err
	}

	if err := fd.Sync(); err != nil {
		return err
	}

	if err := syscall.Flock(int(fd.Fd()), syscall.LOCK_UN); err != nil {
		return fmt.Errorf("can't release lock '%s', lock is held", fd.Name())
	}
	return nil
}

var once sync.Once

//this should be called exactly once and the result cached
//NOTE- this crypto func might rightly belong in a crypto package
//and universally accessed
func getSecHelper() (crypto.Peer, error) {
	var secHelper crypto.Peer
	var err error
	once.Do(func() {
		if core.SecurityEnabled() {
			enrollID := viper.GetString("security.enrollID")
			enrollSecret := viper.GetString("security.enrollSecret")
			if peer.ValidatorEnabled() {
				logger.Debugf("Registering validator with enroll ID: %s", enrollID)
				if err = crypto.RegisterValidator(enrollID, nil, enrollID, enrollSecret); nil != err {
					return
				}
				logger.Debugf("Initializing validator with enroll ID: %s", enrollID)
				secHelper, err = crypto.InitValidator(enrollID, nil)
				if nil != err {
					return
				}
			} else {
				logger.Debugf("Registering non-validator with enroll ID: %s", enrollID)
				if err = crypto.RegisterPeer(enrollID, nil, enrollID, enrollSecret); nil != err {
					return
				}
				logger.Debugf("Initializing non-validator with enroll ID: %s", enrollID)
				secHelper, err = crypto.InitPeer(enrollID, nil)
				if nil != err {
					return
				}
			}
		}
	})
	return secHelper, err
}