package eth

import (
	"fmt"
	"net"
	"sync"

	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/ethdb"
	"github.com/ethereum/go-ethereum/ethutil"
	"github.com/ethereum/go-ethereum/event"
	ethlogger "github.com/ethereum/go-ethereum/logger"
	"github.com/ethereum/go-ethereum/p2p"
	"github.com/ethereum/go-ethereum/pow/ezp"
	"github.com/ethereum/go-ethereum/rpc"
	"github.com/ethereum/go-ethereum/whisper"
)

const (
	seedNodeAddress = "poc-8.ethdev.com:30303"
)

type Config struct {
	Name       string
	Version    string
	Identifier string
	KeyStore   string
	DataDir    string
	LogFile    string
	LogLevel   int
	LogFormat  string
	KeyRing    string

	MaxPeers   int
	Port       string
	NATType    string
	PMPGateway string

	Shh  bool
	Dial bool

	KeyManager *crypto.KeyManager
}

var logger = ethlogger.NewLogger("SERV")

type Ethereum struct {
	// Channel for shutting down the ethereum
	shutdownChan chan bool
	quit         chan bool

	// DB interface
	db        ethutil.Database
	blacklist p2p.Blacklist

	//*** SERVICES ***
	// State manager for processing new blocks and managing the over all states
	blockProcessor *core.BlockProcessor
	txPool         *core.TxPool
	chainManager   *core.ChainManager
	blockPool      *BlockPool
	whisper        *whisper.Whisper

	net      *p2p.Server
	eventMux *event.TypeMux
	txSub    event.Subscription
	blockSub event.Subscription

	RpcServer  *rpc.JsonRpcServer
	keyManager *crypto.KeyManager

	clientIdentity p2p.ClientIdentity
	logger         ethlogger.LogSystem

	synclock  sync.Mutex
	syncGroup sync.WaitGroup

	Mining bool
}

func New(config *Config) (*Ethereum, error) {
	// Boostrap database
	logger := ethlogger.New(config.DataDir, config.LogFile, config.LogLevel, config.LogFormat)
	db, err := ethdb.NewLDBDatabase("blockchain")
	if err != nil {
		return nil, err
	}

	// Perform database sanity checks
	d, _ := db.Get([]byte("ProtocolVersion"))
	protov := ethutil.NewValue(d).Uint()
	if protov != ProtocolVersion && protov != 0 {
		return nil, fmt.Errorf("Database version mismatch. Protocol(%d / %d). `rm -rf %s`", protov, ProtocolVersion, ethutil.Config.ExecPath+"/database")
	}

	// Create new keymanager
	var keyManager *crypto.KeyManager
	switch config.KeyStore {
	case "db":
		keyManager = crypto.NewDBKeyManager(db)
	case "file":
		keyManager = crypto.NewFileKeyManager(config.DataDir)
	default:
		return nil, fmt.Errorf("unknown keystore type: %s", config.KeyStore)
	}
	// Initialise the keyring
	keyManager.Init(config.KeyRing, 0, false)

	// Create a new client id for this instance. This will help identifying the node on the network
	clientId := p2p.NewSimpleClientIdentity(config.Name, config.Version, config.Identifier, keyManager.PublicKey())

	saveProtocolVersion(db)
	//ethutil.Config.Db = db

	eth := &Ethereum{
		shutdownChan:   make(chan bool),
		quit:           make(chan bool),
		db:             db,
		keyManager:     keyManager,
		clientIdentity: clientId,
		blacklist:      p2p.NewBlacklist(),
		eventMux:       &event.TypeMux{},
		logger:         logger,
	}

	eth.chainManager = core.NewChainManager(db, eth.EventMux())
	eth.txPool = core.NewTxPool(eth.EventMux())
	eth.blockProcessor = core.NewBlockProcessor(db, eth.txPool, eth.chainManager, eth.EventMux())
	eth.chainManager.SetProcessor(eth.blockProcessor)
	eth.whisper = whisper.New()

	hasBlock := eth.chainManager.HasBlock
	insertChain := eth.chainManager.InsertChain
	eth.blockPool = NewBlockPool(hasBlock, insertChain, ezp.Verify)

	ethProto := EthProtocol(eth.txPool, eth.chainManager, eth.blockPool)
	protocols := []p2p.Protocol{ethProto, eth.whisper.Protocol()}

	nat, err := p2p.ParseNAT(config.NATType, config.PMPGateway)
	if err != nil {
		return nil, err
	}
	fmt.Println(nat)

	eth.net = &p2p.Server{
		Identity:  clientId,
		MaxPeers:  config.MaxPeers,
		Protocols: protocols,
		Blacklist: eth.blacklist,
		NAT:       p2p.UPNP(),
		NoDial:    !config.Dial,
	}

	if len(config.Port) > 0 {
		eth.net.ListenAddr = ":" + config.Port
	}

	return eth, nil
}

func (s *Ethereum) KeyManager() *crypto.KeyManager {
	return s.keyManager
}

func (s *Ethereum) Logger() ethlogger.LogSystem {
	return s.logger
}

func (s *Ethereum) ClientIdentity() p2p.ClientIdentity {
	return s.clientIdentity
}

func (s *Ethereum) ChainManager() *core.ChainManager {
	return s.chainManager
}

func (s *Ethereum) BlockProcessor() *core.BlockProcessor {
	return s.blockProcessor
}

func (s *Ethereum) TxPool() *core.TxPool {
	return s.txPool
}

func (s *Ethereum) BlockPool() *BlockPool {
	return s.blockPool
}

func (s *Ethereum) Whisper() *whisper.Whisper {
	return s.whisper
}

func (s *Ethereum) EventMux() *event.TypeMux {
	return s.eventMux
}
func (self *Ethereum) Db() ethutil.Database {
	return self.db
}

func (s *Ethereum) IsMining() bool {
	return s.Mining
}

func (s *Ethereum) IsListening() bool {
	// XXX TODO
	return false
}

func (s *Ethereum) PeerCount() int {
	return s.net.PeerCount()
}

func (s *Ethereum) Peers() []*p2p.Peer {
	return s.net.Peers()
}

func (s *Ethereum) MaxPeers() int {
	return s.net.MaxPeers
}

// Start the ethereum
func (s *Ethereum) Start(seed bool) error {
	err := s.net.Start()
	if err != nil {
		return err
	}

	// Start services
	s.txPool.Start()
	s.blockPool.Start()

	if s.whisper != nil {
		s.whisper.Start()
	}

	// broadcast transactions
	s.txSub = s.eventMux.Subscribe(core.TxPreEvent{})
	go s.txBroadcastLoop()

	// broadcast mined blocks
	s.blockSub = s.eventMux.Subscribe(core.NewMinedBlockEvent{})
	go s.blockBroadcastLoop()

	// TODO: read peers here
	if seed {
		logger.Infof("Connect to seed node %v", seedNodeAddress)
		if err := s.SuggestPeer(seedNodeAddress); err != nil {
			logger.Infoln(err)
		}
	}

	logger.Infoln("Server started")
	return nil
}

func (self *Ethereum) SuggestPeer(addr string) error {
	netaddr, err := net.ResolveTCPAddr("tcp", addr)
	if err != nil {
		logger.Errorf("couldn't resolve %s:", addr, err)
		return err
	}

	self.net.SuggestPeer(netaddr.IP, netaddr.Port, nil)
	return nil
}

func (s *Ethereum) Stop() {
	// Close the database
	defer s.db.Close()

	close(s.quit)

	s.txSub.Unsubscribe()    // quits txBroadcastLoop
	s.blockSub.Unsubscribe() // quits blockBroadcastLoop

	if s.RpcServer != nil {
		s.RpcServer.Stop()
	}
	s.txPool.Stop()
	s.eventMux.Stop()
	s.blockPool.Stop()
	if s.whisper != nil {
		s.whisper.Stop()
	}

	logger.Infoln("Server stopped")
	close(s.shutdownChan)
}

// This function will wait for a shutdown and resumes main thread execution
func (s *Ethereum) WaitForShutdown() {
	<-s.shutdownChan
}

// now tx broadcasting is taken out of txPool
// handled here via subscription, efficiency?
func (self *Ethereum) txBroadcastLoop() {
	// automatically stops if unsubscribe
	for obj := range self.txSub.Chan() {
		event := obj.(core.TxPreEvent)
		self.net.Broadcast("eth", TxMsg, event.Tx.RlpData())
	}
}

func (self *Ethereum) blockBroadcastLoop() {
	// automatically stops if unsubscribe
	for obj := range self.blockSub.Chan() {
		switch ev := obj.(type) {
		case core.NewMinedBlockEvent:
			self.net.Broadcast("eth", NewBlockMsg, ev.Block.RlpData(), ev.Block.Td)
		}
	}
}

func saveProtocolVersion(db ethutil.Database) {
	d, _ := db.Get([]byte("ProtocolVersion"))
	protocolVersion := ethutil.NewValue(d).Uint()

	if protocolVersion == 0 {
		db.Put([]byte("ProtocolVersion"), ethutil.NewValue(ProtocolVersion).Bytes())
	}
}