package consensus

import (
	"context"
	"fmt"
	"os"
	"runtime/pprof"
	"sync"
	"testing"
	"time"

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

	cfg "github.com/tendermint/tendermint/config"
	"github.com/tendermint/tendermint/p2p"
	"github.com/tendermint/tendermint/types"

	"github.com/stretchr/testify/require"
)

func init() {
	config = ResetConfig("consensus_reactor_test")
}

//----------------------------------------------
// in-process testnets

func startConsensusNet(t *testing.T, css []*ConsensusState, N int) ([]*ConsensusReactor, []chan interface{}, []*types.EventBus) {
	reactors := make([]*ConsensusReactor, N)
	eventChans := make([]chan interface{}, N)
	eventBuses := make([]*types.EventBus, N)
	logger := consensusLogger()
	for i := 0; i < N; i++ {
		/*thisLogger, err := tmflags.ParseLogLevel("consensus:info,*:error", logger, "info")
		if err != nil {	t.Fatal(err)}*/
		thisLogger := logger

		reactors[i] = NewConsensusReactor(css[i], true) // so we dont start the consensus states
		reactors[i].conS.SetLogger(thisLogger.With("validator", i))
		reactors[i].SetLogger(thisLogger.With("validator", i))

		eventBuses[i] = types.NewEventBus()
		eventBuses[i].SetLogger(thisLogger.With("module", "events", "validator", i))
		_, err := eventBuses[i].Start()
		require.NoError(t, err)

		reactors[i].SetEventBus(eventBuses[i])

		eventChans[i] = make(chan interface{}, 1)
		err = eventBuses[i].Subscribe(context.Background(), testSubscriber, types.EventQueryNewBlock, eventChans[i])
		require.NoError(t, err)
	}
	// make connected switches and start all reactors
	p2p.MakeConnectedSwitches(config.P2P, N, func(i int, s *p2p.Switch) *p2p.Switch {
		s.AddReactor("CONSENSUS", reactors[i])
		return s
	}, p2p.Connect2Switches)

	// now that everyone is connected,  start the state machines
	// If we started the state machines before everyone was connected,
	// we'd block when the cs fires NewBlockEvent and the peers are trying to start their reactors
	// TODO: is this still true with new pubsub?
	for i := 0; i < N; i++ {
		s := reactors[i].conS.GetState()
		reactors[i].SwitchToConsensus(s, 0)
	}
	return reactors, eventChans, eventBuses
}

func stopConsensusNet(reactors []*ConsensusReactor, eventBuses []*types.EventBus) {
	for _, r := range reactors {
		r.Switch.Stop()
	}
	for _, b := range eventBuses {
		b.Stop()
	}
}

// Ensure a testnet makes blocks
func TestReactor(t *testing.T) {
	N := 4
	css := randConsensusNet(N, "consensus_reactor_test", newMockTickerFunc(true), newCounter)
	reactors, eventChans, eventBuses := startConsensusNet(t, css, N)
	defer stopConsensusNet(reactors, eventBuses)
	// wait till everyone makes the first new block
	timeoutWaitGroup(t, N, func(wg *sync.WaitGroup, j int) {
		<-eventChans[j]
		wg.Done()
	}, css)
}

// Ensure a testnet sends proposal heartbeats and makes blocks when there are txs
func TestReactorProposalHeartbeats(t *testing.T) {
	N := 4
	css := randConsensusNet(N, "consensus_reactor_test", newMockTickerFunc(true), newCounter,
		func(c *cfg.Config) {
			c.Consensus.CreateEmptyBlocks = false
		})
	reactors, eventChans, eventBuses := startConsensusNet(t, css, N)
	defer stopConsensusNet(reactors, eventBuses)
	heartbeatChans := make([]chan interface{}, N)
	var err error
	for i := 0; i < N; i++ {
		heartbeatChans[i] = make(chan interface{}, 1)
		err = eventBuses[i].Subscribe(context.Background(), testSubscriber, types.EventQueryProposalHeartbeat, heartbeatChans[i])
		require.NoError(t, err)
	}
	// wait till everyone sends a proposal heartbeat
	timeoutWaitGroup(t, N, func(wg *sync.WaitGroup, j int) {
		<-heartbeatChans[j]
		wg.Done()
	}, css)

	// send a tx
	if err := css[3].mempool.CheckTx([]byte{1, 2, 3}, nil); err != nil {
		//t.Fatal(err)
	}

	// wait till everyone makes the first new block
	timeoutWaitGroup(t, N, func(wg *sync.WaitGroup, j int) {
		<-eventChans[j]
		wg.Done()
	}, css)
}

//-------------------------------------------------------------
// ensure we can make blocks despite cycling a validator set

func TestVotingPowerChange(t *testing.T) {
	nVals := 4
	css := randConsensusNet(nVals, "consensus_voting_power_changes_test", newMockTickerFunc(true), newPersistentDummy)
	reactors, eventChans, eventBuses := startConsensusNet(t, css, nVals)
	defer stopConsensusNet(reactors, eventBuses)

	// map of active validators
	activeVals := make(map[string]struct{})
	for i := 0; i < nVals; i++ {
		activeVals[string(css[i].privValidator.GetAddress())] = struct{}{}
	}

	// wait till everyone makes block 1
	timeoutWaitGroup(t, nVals, func(wg *sync.WaitGroup, j int) {
		<-eventChans[j]
		wg.Done()
	}, css)

	//---------------------------------------------------------------------------
	t.Log("---------------------------- Testing changing the voting power of one validator a few times")

	val1PubKey := css[0].privValidator.GetPubKey()
	updateValidatorTx := dummy.MakeValSetChangeTx(val1PubKey.Bytes(), 25)
	previousTotalVotingPower := css[0].GetRoundState().LastValidators.TotalVotingPower()

	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css, updateValidatorTx)
	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)

	if css[0].GetRoundState().LastValidators.TotalVotingPower() == previousTotalVotingPower {
		t.Fatalf("expected voting power to change (before: %d, after: %d)", previousTotalVotingPower, css[0].GetRoundState().LastValidators.TotalVotingPower())
	}

	updateValidatorTx = dummy.MakeValSetChangeTx(val1PubKey.Bytes(), 2)
	previousTotalVotingPower = css[0].GetRoundState().LastValidators.TotalVotingPower()

	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css, updateValidatorTx)
	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)

	if css[0].GetRoundState().LastValidators.TotalVotingPower() == previousTotalVotingPower {
		t.Fatalf("expected voting power to change (before: %d, after: %d)", previousTotalVotingPower, css[0].GetRoundState().LastValidators.TotalVotingPower())
	}

	updateValidatorTx = dummy.MakeValSetChangeTx(val1PubKey.Bytes(), 100)
	previousTotalVotingPower = css[0].GetRoundState().LastValidators.TotalVotingPower()

	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css, updateValidatorTx)
	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)

	if css[0].GetRoundState().LastValidators.TotalVotingPower() == previousTotalVotingPower {
		t.Fatalf("expected voting power to change (before: %d, after: %d)", previousTotalVotingPower, css[0].GetRoundState().LastValidators.TotalVotingPower())
	}
}

func TestValidatorSetChanges(t *testing.T) {
	nPeers := 7
	nVals := 4
	css := randConsensusNetWithPeers(nVals, nPeers, "consensus_val_set_changes_test", newMockTickerFunc(true), newPersistentDummy)

	reactors, eventChans, eventBuses := startConsensusNet(t, css, nPeers)
	defer stopConsensusNet(reactors, eventBuses)

	// map of active validators
	activeVals := make(map[string]struct{})
	for i := 0; i < nVals; i++ {
		activeVals[string(css[i].privValidator.GetAddress())] = struct{}{}
	}

	// wait till everyone makes block 1
	timeoutWaitGroup(t, nPeers, func(wg *sync.WaitGroup, j int) {
		<-eventChans[j]
		wg.Done()
	}, css)

	//---------------------------------------------------------------------------
	t.Log("---------------------------- Testing adding one validator")

	newValidatorPubKey1 := css[nVals].privValidator.GetPubKey()
	newValidatorTx1 := dummy.MakeValSetChangeTx(newValidatorPubKey1.Bytes(), uint64(testMinPower))

	// wait till everyone makes block 2
	// ensure the commit includes all validators
	// send newValTx to change vals in block 3
	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css, newValidatorTx1)

	// wait till everyone makes block 3.
	// it includes the commit for block 2, which is by the original validator set
	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)

	// wait till everyone makes block 4.
	// it includes the commit for block 3, which is by the original validator set
	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)

	// the commits for block 4 should be with the updated validator set
	activeVals[string(newValidatorPubKey1.Address())] = struct{}{}

	// wait till everyone makes block 5
	// it includes the commit for block 4, which should have the updated validator set
	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventChans, css)

	//---------------------------------------------------------------------------
	t.Log("---------------------------- Testing changing the voting power of one validator")

	updateValidatorPubKey1 := css[nVals].privValidator.GetPubKey()
	updateValidatorTx1 := dummy.MakeValSetChangeTx(updateValidatorPubKey1.Bytes(), 25)
	previousTotalVotingPower := css[nVals].GetRoundState().LastValidators.TotalVotingPower()

	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css, updateValidatorTx1)
	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)
	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)
	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventChans, css)

	if css[nVals].GetRoundState().LastValidators.TotalVotingPower() == previousTotalVotingPower {
		t.Errorf("expected voting power to change (before: %d, after: %d)", previousTotalVotingPower, css[nVals].GetRoundState().LastValidators.TotalVotingPower())
	}

	//---------------------------------------------------------------------------
	t.Log("---------------------------- Testing adding two validators at once")

	newValidatorPubKey2 := css[nVals+1].privValidator.GetPubKey()
	newValidatorTx2 := dummy.MakeValSetChangeTx(newValidatorPubKey2.Bytes(), uint64(testMinPower))

	newValidatorPubKey3 := css[nVals+2].privValidator.GetPubKey()
	newValidatorTx3 := dummy.MakeValSetChangeTx(newValidatorPubKey3.Bytes(), uint64(testMinPower))

	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css, newValidatorTx2, newValidatorTx3)
	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)
	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)
	activeVals[string(newValidatorPubKey2.Address())] = struct{}{}
	activeVals[string(newValidatorPubKey3.Address())] = struct{}{}
	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventChans, css)

	//---------------------------------------------------------------------------
	t.Log("---------------------------- Testing removing two validators at once")

	removeValidatorTx2 := dummy.MakeValSetChangeTx(newValidatorPubKey2.Bytes(), 0)
	removeValidatorTx3 := dummy.MakeValSetChangeTx(newValidatorPubKey3.Bytes(), 0)

	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css, removeValidatorTx2, removeValidatorTx3)
	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)
	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)
	delete(activeVals, string(newValidatorPubKey2.Address()))
	delete(activeVals, string(newValidatorPubKey3.Address()))
	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventChans, css)
}

// Check we can make blocks with skip_timeout_commit=false
func TestReactorWithTimeoutCommit(t *testing.T) {
	N := 4
	css := randConsensusNet(N, "consensus_reactor_with_timeout_commit_test", newMockTickerFunc(false), newCounter)
	// override default SkipTimeoutCommit == true for tests
	for i := 0; i < N; i++ {
		css[i].config.SkipTimeoutCommit = false
	}

	reactors, eventChans, eventBuses := startConsensusNet(t, css, N-1)
	defer stopConsensusNet(reactors, eventBuses)

	// wait till everyone makes the first new block
	timeoutWaitGroup(t, N-1, func(wg *sync.WaitGroup, j int) {
		<-eventChans[j]
		wg.Done()
	}, css)
}

func waitForAndValidateBlock(t *testing.T, n int, activeVals map[string]struct{}, eventChans []chan interface{}, css []*ConsensusState, txs ...[]byte) {
	timeoutWaitGroup(t, n, func(wg *sync.WaitGroup, j int) {
		defer wg.Done()

		newBlockI, ok := <-eventChans[j]
		if !ok {
			return
		}
		newBlock := newBlockI.(types.TMEventData).Unwrap().(types.EventDataNewBlock).Block
		t.Logf("Got block height=%v validator=%v", newBlock.Height, j)
		err := validateBlock(newBlock, activeVals)
		if err != nil {
			t.Fatal(err)
		}
		for _, tx := range txs {
			if err = css[j].mempool.CheckTx(tx, nil); err != nil {
				t.Fatal(err)
			}
		}
	}, css)
}

func waitForBlockWithUpdatedValsAndValidateIt(t *testing.T, n int, updatedVals map[string]struct{}, eventChans []chan interface{}, css []*ConsensusState) {
	timeoutWaitGroup(t, n, func(wg *sync.WaitGroup, j int) {
		defer wg.Done()

		var newBlock *types.Block
	LOOP:
		for {
			newBlockI, ok := <-eventChans[j]
			if !ok {
				return
			}
			newBlock = newBlockI.(types.TMEventData).Unwrap().(types.EventDataNewBlock).Block
			if newBlock.LastCommit.Size() == len(updatedVals) {
				t.Logf("Block with new validators height=%v validator=%v", newBlock.Height, j)
				break LOOP
			} else {
				t.Logf("Block with no new validators height=%v validator=%v. Skipping...", newBlock.Height, j)
			}
		}

		err := validateBlock(newBlock, updatedVals)
		if err != nil {
			t.Fatal(err)
		}
	}, css)
}

// expects high synchrony!
func validateBlock(block *types.Block, activeVals map[string]struct{}) error {
	if block.LastCommit.Size() != len(activeVals) {
		return fmt.Errorf("Commit size doesn't match number of active validators. Got %d, expected %d", block.LastCommit.Size(), len(activeVals))
	}

	for _, vote := range block.LastCommit.Precommits {
		if _, ok := activeVals[string(vote.ValidatorAddress)]; !ok {
			return fmt.Errorf("Found vote for unactive validator %X", vote.ValidatorAddress)
		}
	}
	return nil
}

func timeoutWaitGroup(t *testing.T, n int, f func(*sync.WaitGroup, int), css []*ConsensusState) {
	wg := new(sync.WaitGroup)
	wg.Add(n)
	for i := 0; i < n; i++ {
		go f(wg, i)
	}

	done := make(chan struct{})
	go func() {
		wg.Wait()
		close(done)
	}()

	// we're running many nodes in-process, possibly in in a virtual machine,
	// and spewing debug messages - making a block could take a while,
	timeout := time.Second * 60

	select {
	case <-done:
	case <-time.After(timeout):
		for i, cs := range css {
			t.Log("#################")
			t.Log("Validator", i)
			t.Log(cs.GetRoundState())
			t.Log("")
		}
		pprof.Lookup("goroutine").WriteTo(os.Stdout, 1)
		panic("Timed out waiting for all validators to commit a block")
	}
}

// XXX: WARNING: this function can halt the consensus as firing events is synchronous.
// Make sure to read off the channels, and in the case of subscribeToEventRespond, to write back on it

// NOTE: this blocks on receiving a response after the event is consumed
func subscribeToEventRespond(evsw types.EventSwitch, receiver, eventID string) chan interface{} {
	// listen for event
	ch := make(chan interface{})
	types.AddListenerForEvent(evsw, receiver, eventID, func(data types.TMEventData) {
		ch <- data
		<-ch
	})
	return ch
}