package consensus

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"os"
	"path"
	"sort"
	"sync"
	"testing"
	"time"

	"github.com/spf13/viper"

	abcicli "github.com/tendermint/abci/client"
	abci "github.com/tendermint/abci/types"
	bc "github.com/tendermint/tendermint/blockchain"
	"github.com/tendermint/tendermint/config/tendermint_test"
	mempl "github.com/tendermint/tendermint/mempool"
	"github.com/tendermint/tendermint/p2p"
	sm "github.com/tendermint/tendermint/state"
	"github.com/tendermint/tendermint/types"
	. "github.com/tendermint/tmlibs/common"
	dbm "github.com/tendermint/tmlibs/db"

	"github.com/tendermint/abci/example/counter"
	"github.com/tendermint/abci/example/dummy"
)

var config *viper.Viper // NOTE: must be reset for each _test.go file
var ensureTimeout = time.Duration(2)

func ensureDir(dir string, mode os.FileMode) {
	if err := EnsureDir(dir, mode); err != nil {
		panic(err)
	}
}

//-------------------------------------------------------------------------------
// validator stub (a dummy consensus peer we control)

type validatorStub struct {
	Index  int // Validator index. NOTE: we don't assume validator set changes.
	Height int
	Round  int
	*types.PrivValidator
}

var testMinPower = 10

func NewValidatorStub(privValidator *types.PrivValidator, valIndex int) *validatorStub {
	return &validatorStub{
		Index:         valIndex,
		PrivValidator: privValidator,
	}
}

func (vs *validatorStub) signVote(voteType byte, hash []byte, header types.PartSetHeader) (*types.Vote, error) {
	vote := &types.Vote{
		ValidatorIndex:   vs.Index,
		ValidatorAddress: vs.PrivValidator.Address,
		Height:           vs.Height,
		Round:            vs.Round,
		Type:             voteType,
		BlockID:          types.BlockID{hash, header},
	}
	err := vs.PrivValidator.SignVote(config.GetString("chain_id"), vote)
	return vote, err
}

// Sign vote for type/hash/header
func signVote(vs *validatorStub, voteType byte, hash []byte, header types.PartSetHeader) *types.Vote {
	v, err := vs.signVote(voteType, hash, header)
	if err != nil {
		panic(fmt.Errorf("failed to sign vote: %v", err))
	}
	return v
}

func signVotes(voteType byte, hash []byte, header types.PartSetHeader, vss ...*validatorStub) []*types.Vote {
	votes := make([]*types.Vote, len(vss))
	for i, vs := range vss {
		votes[i] = signVote(vs, voteType, hash, header)
	}
	return votes
}

func incrementHeight(vss ...*validatorStub) {
	for _, vs := range vss {
		vs.Height += 1
	}
}

func incrementRound(vss ...*validatorStub) {
	for _, vs := range vss {
		vs.Round += 1
	}
}

//-------------------------------------------------------------------------------
// Functions for transitioning the consensus state

func startTestRound(cs *ConsensusState, height, round int) {
	cs.enterNewRound(height, round)
	cs.startRoutines(0)
}

// Create proposal block from cs1 but sign it with vs
func decideProposal(cs1 *ConsensusState, vs *validatorStub, height, round int) (proposal *types.Proposal, block *types.Block) {
	block, blockParts := cs1.createProposalBlock()
	if block == nil { // on error
		panic("error creating proposal block")
	}

	// Make proposal
	polRound, polBlockID := cs1.Votes.POLInfo()
	proposal = types.NewProposal(height, round, blockParts.Header(), polRound, polBlockID)
	if err := vs.SignProposal(config.GetString("chain_id"), proposal); err != nil {
		panic(err)
	}
	return
}

func addVotes(to *ConsensusState, votes ...*types.Vote) {
	for _, vote := range votes {
		to.peerMsgQueue <- msgInfo{Msg: &VoteMessage{vote}}
	}
}

func signAddVotes(to *ConsensusState, voteType byte, hash []byte, header types.PartSetHeader, vss ...*validatorStub) {
	votes := signVotes(voteType, hash, header, vss...)
	addVotes(to, votes...)
}

func validatePrevote(t *testing.T, cs *ConsensusState, round int, privVal *validatorStub, blockHash []byte) {
	prevotes := cs.Votes.Prevotes(round)
	var vote *types.Vote
	if vote = prevotes.GetByAddress(privVal.Address); vote == nil {
		panic("Failed to find prevote from validator")
	}
	if blockHash == nil {
		if vote.BlockID.Hash != nil {
			panic(fmt.Sprintf("Expected prevote to be for nil, got %X", vote.BlockID.Hash))
		}
	} else {
		if !bytes.Equal(vote.BlockID.Hash, blockHash) {
			panic(fmt.Sprintf("Expected prevote to be for %X, got %X", blockHash, vote.BlockID.Hash))
		}
	}
}

func validateLastPrecommit(t *testing.T, cs *ConsensusState, privVal *validatorStub, blockHash []byte) {
	votes := cs.LastCommit
	var vote *types.Vote
	if vote = votes.GetByAddress(privVal.Address); vote == nil {
		panic("Failed to find precommit from validator")
	}
	if !bytes.Equal(vote.BlockID.Hash, blockHash) {
		panic(fmt.Sprintf("Expected precommit to be for %X, got %X", blockHash, vote.BlockID.Hash))
	}
}

func validatePrecommit(t *testing.T, cs *ConsensusState, thisRound, lockRound int, privVal *validatorStub, votedBlockHash, lockedBlockHash []byte) {
	precommits := cs.Votes.Precommits(thisRound)
	var vote *types.Vote
	if vote = precommits.GetByAddress(privVal.Address); vote == nil {
		panic("Failed to find precommit from validator")
	}

	if votedBlockHash == nil {
		if vote.BlockID.Hash != nil {
			panic("Expected precommit to be for nil")
		}
	} else {
		if !bytes.Equal(vote.BlockID.Hash, votedBlockHash) {
			panic("Expected precommit to be for proposal block")
		}
	}

	if lockedBlockHash == nil {
		if cs.LockedRound != lockRound || cs.LockedBlock != nil {
			panic(fmt.Sprintf("Expected to be locked on nil at round %d. Got locked at round %d with block %v", lockRound, cs.LockedRound, cs.LockedBlock))
		}
	} else {
		if cs.LockedRound != lockRound || !bytes.Equal(cs.LockedBlock.Hash(), lockedBlockHash) {
			panic(fmt.Sprintf("Expected block to be locked on round %d, got %d. Got locked block %X, expected %X", lockRound, cs.LockedRound, cs.LockedBlock.Hash(), lockedBlockHash))
		}
	}

}

func validatePrevoteAndPrecommit(t *testing.T, cs *ConsensusState, thisRound, lockRound int, privVal *validatorStub, votedBlockHash, lockedBlockHash []byte) {
	// verify the prevote
	validatePrevote(t, cs, thisRound, privVal, votedBlockHash)
	// verify precommit
	cs.mtx.Lock()
	validatePrecommit(t, cs, thisRound, lockRound, privVal, votedBlockHash, lockedBlockHash)
	cs.mtx.Unlock()
}

// genesis
func subscribeToVoter(cs *ConsensusState, addr []byte) chan interface{} {
	voteCh0 := subscribeToEvent(cs.evsw, "tester", types.EventStringVote(), 1)
	voteCh := make(chan interface{})
	go func() {
		for {
			v := <-voteCh0
			vote := v.(types.TMEventData).Unwrap().(types.EventDataVote)
			// we only fire for our own votes
			if bytes.Equal(addr, vote.Vote.ValidatorAddress) {
				voteCh <- v
			}
		}
	}()
	return voteCh
}

func readVotes(ch chan interface{}, reads int) chan struct{} {
	wg := make(chan struct{})
	go func() {
		for i := 0; i < reads; i++ {
			<-ch // read the precommit event
		}
		close(wg)
	}()
	return wg
}

//-------------------------------------------------------------------------------
// consensus states

func newConsensusState(state *sm.State, pv *types.PrivValidator, app abci.Application) *ConsensusState {
	return newConsensusStateWithConfig(config, state, pv, app)
}

func newConsensusStateWithConfig(thisConfig *viper.Viper, state *sm.State, pv *types.PrivValidator, app abci.Application) *ConsensusState {
	// Get BlockStore
	blockDB := dbm.NewMemDB()
	blockStore := bc.NewBlockStore(blockDB)

	// one for mempool, one for consensus
	mtx := new(sync.Mutex)
	proxyAppConnMem := abcicli.NewLocalClient(mtx, app)
	proxyAppConnCon := abcicli.NewLocalClient(mtx, app)

	// Make Mempool
	mempool := mempl.NewMempool(thisConfig, proxyAppConnMem)

	// Make ConsensusReactor
	cs := NewConsensusState(thisConfig, state, proxyAppConnCon, blockStore, mempool)
	cs.SetPrivValidator(pv)

	evsw := types.NewEventSwitch()
	cs.SetEventSwitch(evsw)
	evsw.Start()
	return cs
}

func loadPrivValidator(conf *viper.Viper) *types.PrivValidator {
	privValidatorFile := conf.GetString("priv_validator_file")
	ensureDir(path.Dir(privValidatorFile), 0700)
	privValidator := types.LoadOrGenPrivValidator(privValidatorFile)
	privValidator.Reset()
	return privValidator
}

func fixedConsensusState() *ConsensusState {
	stateDB := dbm.NewMemDB()
	state := sm.MakeGenesisStateFromFile(stateDB, config.GetString("genesis_file"))
	privValidator := loadPrivValidator(config)
	cs := newConsensusState(state, privValidator, counter.NewCounterApplication(true))
	return cs
}

func fixedConsensusStateDummy() *ConsensusState {
	stateDB := dbm.NewMemDB()
	state := sm.MakeGenesisStateFromFile(stateDB, config.GetString("genesis_file"))
	privValidator := loadPrivValidator(config)
	cs := newConsensusState(state, privValidator, dummy.NewDummyApplication())
	return cs
}

func randConsensusState(nValidators int) (*ConsensusState, []*validatorStub) {
	// Get State
	state, privVals := randGenesisState(nValidators, false, 10)

	vss := make([]*validatorStub, nValidators)

	cs := newConsensusState(state, privVals[0], counter.NewCounterApplication(true))

	for i := 0; i < nValidators; i++ {
		vss[i] = NewValidatorStub(privVals[i], i)
	}
	// since cs1 starts at 1
	incrementHeight(vss[1:]...)

	return cs, vss
}

//-------------------------------------------------------------------------------

func ensureNoNewStep(stepCh chan interface{}) {
	timeout := time.NewTicker(ensureTimeout * time.Second)
	select {
	case <-timeout.C:
		break
	case <-stepCh:
		panic("We should be stuck waiting for more votes, not moving to the next step")
	}
}

//-------------------------------------------------------------------------------
// consensus nets

func randConsensusNet(nValidators int, testName string, tickerFunc func() TimeoutTicker, appFunc func() abci.Application) []*ConsensusState {
	genDoc, privVals := randGenesisDoc(nValidators, false, 10)
	css := make([]*ConsensusState, nValidators)
	for i := 0; i < nValidators; i++ {
		db := dbm.NewMemDB() // each state needs its own db
		state := sm.MakeGenesisState(db, genDoc)
		state.Save()
		thisConfig := tendermint_test.ResetConfig(Fmt("%s_%d", testName, i))
		ensureDir(path.Dir(thisConfig.GetString("cs_wal_file")), 0700) // dir for wal
		css[i] = newConsensusStateWithConfig(thisConfig, state, privVals[i], appFunc())
		css[i].SetTimeoutTicker(tickerFunc())
	}
	return css
}

// nPeers = nValidators + nNotValidator
func randConsensusNetWithPeers(nValidators, nPeers int, testName string, tickerFunc func() TimeoutTicker, appFunc func() abci.Application) []*ConsensusState {
	genDoc, privVals := randGenesisDoc(nValidators, false, int64(testMinPower))
	css := make([]*ConsensusState, nPeers)
	for i := 0; i < nPeers; i++ {
		db := dbm.NewMemDB() // each state needs its own db
		state := sm.MakeGenesisState(db, genDoc)
		state.Save()
		thisConfig := tendermint_test.ResetConfig(Fmt("%s_%d", testName, i))
		ensureDir(path.Dir(thisConfig.GetString("cs_wal_file")), 0700) // dir for wal
		var privVal *types.PrivValidator
		if i < nValidators {
			privVal = privVals[i]
		} else {
			privVal = types.GenPrivValidator()
			_, tempFilePath := Tempfile("priv_validator_")
			privVal.SetFile(tempFilePath)
		}

		css[i] = newConsensusStateWithConfig(thisConfig, state, privVal, appFunc())
		css[i].SetTimeoutTicker(tickerFunc())
	}
	return css
}

func getSwitchIndex(switches []*p2p.Switch, peer *p2p.Peer) int {
	for i, s := range switches {
		if bytes.Equal(peer.NodeInfo.PubKey.Address(), s.NodeInfo().PubKey.Address()) {
			return i
		}
	}
	panic("didnt find peer in switches")
	return -1
}

//-------------------------------------------------------------------------------
// genesis

func randGenesisDoc(numValidators int, randPower bool, minPower int64) (*types.GenesisDoc, []*types.PrivValidator) {
	validators := make([]types.GenesisValidator, numValidators)
	privValidators := make([]*types.PrivValidator, numValidators)
	for i := 0; i < numValidators; i++ {
		val, privVal := types.RandValidator(randPower, minPower)
		validators[i] = types.GenesisValidator{
			PubKey: val.PubKey,
			Amount: val.VotingPower,
		}
		privValidators[i] = privVal
	}
	sort.Sort(types.PrivValidatorsByAddress(privValidators))
	return &types.GenesisDoc{
		GenesisTime: time.Now(),
		ChainID:     config.GetString("chain_id"),
		Validators:  validators,
	}, privValidators
}

func randGenesisState(numValidators int, randPower bool, minPower int64) (*sm.State, []*types.PrivValidator) {
	genDoc, privValidators := randGenesisDoc(numValidators, randPower, minPower)
	db := dbm.NewMemDB()
	s0 := sm.MakeGenesisState(db, genDoc)
	s0.Save()
	return s0, privValidators
}

//------------------------------------
// mock ticker

func newMockTickerFunc(onlyOnce bool) func() TimeoutTicker {
	return func() TimeoutTicker {
		return &mockTicker{
			c:        make(chan timeoutInfo, 10),
			onlyOnce: onlyOnce,
		}
	}
}

// mock ticker only fires on RoundStepNewHeight
// and only once if onlyOnce=true
type mockTicker struct {
	c chan timeoutInfo

	mtx      sync.Mutex
	onlyOnce bool
	fired    bool
}

func (m *mockTicker) Start() (bool, error) {
	return true, nil
}

func (m *mockTicker) Stop() bool {
	return true
}

func (m *mockTicker) ScheduleTimeout(ti timeoutInfo) {
	m.mtx.Lock()
	defer m.mtx.Unlock()
	if m.onlyOnce && m.fired {
		return
	}
	if ti.Step == RoundStepNewHeight {
		m.c <- ti
		m.fired = true
	}
}

func (m *mockTicker) Chan() <-chan timeoutInfo {
	return m.c
}

//------------------------------------

func newCounter() abci.Application {
	return counter.NewCounterApplication(true)
}

func newPersistentDummy() abci.Application {
	dir, _ := ioutil.TempDir("/tmp", "persistent-dummy")
	return dummy.NewPersistentDummyApplication(dir)
}