package state_test

import (
	"bytes"
	"fmt"
	"math"
	"math/big"
	"os"
	"testing"

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

	dbm "github.com/cometbft/cometbft-db"

	abci "github.com/cometbft/cometbft/abci/types"
	"github.com/cometbft/cometbft/crypto/ed25519"
	cryptoenc "github.com/cometbft/cometbft/crypto/encoding"
	"github.com/cometbft/cometbft/internal/test"
	cmtrand "github.com/cometbft/cometbft/libs/rand"
	sm "github.com/cometbft/cometbft/state"
	"github.com/cometbft/cometbft/types"
)

// setupTestCase does setup common to all test cases.
func setupTestCase(t *testing.T) (func(t *testing.T), dbm.DB, sm.State) {
	t.Helper()
	tearDown, stateDB, state, _ := setupTestCaseWithStore(t)
	return tearDown, stateDB, state
}

// setupTestCase does setup common to all test cases.
func setupTestCaseWithStore(t *testing.T) (func(t *testing.T), dbm.DB, sm.State, sm.Store) {
	t.Helper()
	config := test.ResetTestRoot("state_")
	dbType := dbm.BackendType(config.DBBackend)
	stateDB, err := dbm.NewDB("state", dbType, config.DBDir())
	stateStore := sm.NewStore(stateDB, sm.StoreOptions{
		DiscardABCIResponses: false,
	})
	require.NoError(t, err)
	state, err := stateStore.LoadFromDBOrGenesisFile(config.GenesisFile())
	require.NoError(t, err, "expected no error on LoadStateFromDBOrGenesisFile")
	err = stateStore.Save(state)
	require.NoError(t, err)

	tearDown := func(t *testing.T) {
		t.Helper()
		os.RemoveAll(config.RootDir)
	}

	return tearDown, stateDB, state, stateStore
}

// TestStateCopy tests the correct copying behavior of State.
func TestStateCopy(t *testing.T) {
	tearDown, _, state := setupTestCase(t)
	defer tearDown(t)
	assert := assert.New(t)

	stateCopy := state.Copy()

	assert.True(state.Equals(stateCopy),
		fmt.Sprintf("expected state and its copy to be identical.\ngot: %v\nexpected: %v\n",
			stateCopy, state))

	stateCopy.LastBlockHeight++
	stateCopy.LastValidators = state.Validators
	assert.False(state.Equals(stateCopy), fmt.Sprintf(`expected states to be different. got same
        %v`, state))
}

// TestMakeGenesisStateNilValidators tests state's consistency when genesis file's validators field is nil.
func TestMakeGenesisStateNilValidators(t *testing.T) {
	doc := types.GenesisDoc{
		ChainID:    "dummy",
		Validators: nil,
	}
	require.Nil(t, doc.ValidateAndComplete())
	state, err := sm.MakeGenesisState(&doc)
	require.Nil(t, err)
	require.Equal(t, 0, len(state.Validators.Validators))
	require.Equal(t, 0, len(state.NextValidators.Validators))
}

// TestStateSaveLoad tests saving and loading State from a db.
func TestStateSaveLoad(t *testing.T) {
	tearDown, stateDB, state := setupTestCase(t)
	defer tearDown(t)
	stateStore := sm.NewStore(stateDB, sm.StoreOptions{
		DiscardABCIResponses: false,
	})
	assert := assert.New(t)

	state.LastBlockHeight++
	state.LastValidators = state.Validators
	err := stateStore.Save(state)
	require.NoError(t, err)

	loadedState, err := stateStore.Load()
	require.NoError(t, err)
	assert.True(state.Equals(loadedState),
		fmt.Sprintf("expected state and its copy to be identical.\ngot: %v\nexpected: %v\n",
			loadedState, state))
}

// TestFinalizeBlockResponsesSaveLoad1 tests saving and loading ABCIResponses.
func TestFinalizeBlockResponsesSaveLoad1(t *testing.T) {
	tearDown, stateDB, state := setupTestCase(t)
	defer tearDown(t)
	stateStore := sm.NewStore(stateDB, sm.StoreOptions{
		DiscardABCIResponses: false,
	})
	assert := assert.New(t)

	state.LastBlockHeight++

	// Build mock responses.
	block := makeBlock(state, 2, new(types.Commit))

	abciResponses := new(abci.ResponseFinalizeBlock)
	dtxs := make([]*abci.ExecTxResult, 2)
	abciResponses.TxResults = dtxs

	abciResponses.TxResults[0] = &abci.ExecTxResult{Data: []byte("foo"), Events: nil}
	abciResponses.TxResults[1] = &abci.ExecTxResult{Data: []byte("bar"), Log: "ok", Events: nil}
	abciResponses.ValidatorUpdates = []abci.ValidatorUpdate{
		types.TM2PB.NewValidatorUpdate(ed25519.GenPrivKey().PubKey(), 10),
	}

	abciResponses.AppHash = make([]byte, 1)

	err := stateStore.SaveFinalizeBlockResponse(block.Height, abciResponses)
	require.NoError(t, err)
	loadedABCIResponses, err := stateStore.LoadFinalizeBlockResponse(block.Height)
	assert.NoError(err)
	assert.Equal(abciResponses, loadedABCIResponses)
}

// TestResultsSaveLoad tests saving and loading FinalizeBlock results.
func TestFinalizeBlockResponsesSaveLoad2(t *testing.T) {
	tearDown, stateDB, _ := setupTestCase(t)
	defer tearDown(t)
	assert := assert.New(t)

	stateStore := sm.NewStore(stateDB, sm.StoreOptions{
		DiscardABCIResponses: false,
	})

	cases := [...]struct {
		// Height is implied to equal index+2,
		// as block 1 is created from genesis.
		added    []*abci.ExecTxResult
		expected []*abci.ExecTxResult
	}{
		0: {
			nil,
			nil,
		},
		1: {
			[]*abci.ExecTxResult{
				{Code: 32, Data: []byte("Hello"), Log: "Huh?"},
			},
			[]*abci.ExecTxResult{
				{Code: 32, Data: []byte("Hello")},
			},
		},
		2: {
			[]*abci.ExecTxResult{
				{Code: 383},
				{
					Data: []byte("Gotcha!"),
					Events: []abci.Event{
						{Type: "type1", Attributes: []abci.EventAttribute{{Key: "a", Value: "1"}}},
						{Type: "type2", Attributes: []abci.EventAttribute{{Key: "build", Value: "stuff"}}},
					},
				},
			},
			[]*abci.ExecTxResult{
				{Code: 383, Data: nil},
				{Code: 0, Data: []byte("Gotcha!"), Events: []abci.Event{
					{Type: "type1", Attributes: []abci.EventAttribute{{Key: "a", Value: "1"}}},
					{Type: "type2", Attributes: []abci.EventAttribute{{Key: "build", Value: "stuff"}}},
				}},
			},
		},
		3: {
			nil,
			nil,
		},
		4: {
			[]*abci.ExecTxResult{nil},
			nil,
		},
	}

	// Query all before, this should return error.
	for i := range cases {
		h := int64(i + 1)
		res, err := stateStore.LoadFinalizeBlockResponse(h)
		assert.Error(err, "%d: %#v", i, res)
	}

	// Add all cases.
	for i, tc := range cases {
		h := int64(i + 1) // last block height, one below what we save
		responses := &abci.ResponseFinalizeBlock{
			TxResults: tc.added,
			AppHash:   []byte(fmt.Sprintf("%d", h)),
		}
		err := stateStore.SaveFinalizeBlockResponse(h, responses)
		require.NoError(t, err)
	}

	// Query all before, should return expected value.
	for i, tc := range cases {
		h := int64(i + 1)
		res, err := stateStore.LoadFinalizeBlockResponse(h)
		if assert.NoError(err, "%d", i) {
			t.Log(res)
			responses := &abci.ResponseFinalizeBlock{
				TxResults: tc.expected,
				AppHash:   []byte(fmt.Sprintf("%d", h)),
			}
			assert.Equal(sm.TxResultsHash(responses.TxResults), sm.TxResultsHash(res.TxResults), "%d", i)
		}
	}
}

// TestValidatorSimpleSaveLoad tests saving and loading validators.
func TestValidatorSimpleSaveLoad(t *testing.T) {
	tearDown, stateDB, state := setupTestCase(t)
	defer tearDown(t)
	assert := assert.New(t)

	statestore := sm.NewStore(stateDB, sm.StoreOptions{
		DiscardABCIResponses: false,
	})

	// Can't load anything for height 0.
	_, err := statestore.LoadValidators(0)
	assert.IsType(sm.ErrNoValSetForHeight{}, err, "expected err at height 0")

	// Should be able to load for height 1.
	v, err := statestore.LoadValidators(1)
	assert.Nil(err, "expected no err at height 1")
	assert.Equal(v.Hash(), state.Validators.Hash(), "expected validator hashes to match")

	// Should be able to load for height 2.
	v, err = statestore.LoadValidators(2)
	assert.Nil(err, "expected no err at height 2")
	assert.Equal(v.Hash(), state.NextValidators.Hash(), "expected validator hashes to match")

	// Increment height, save; should be able to load for next & next next height.
	state.LastBlockHeight++
	nextHeight := state.LastBlockHeight + 1
	err = statestore.Save(state)
	require.NoError(t, err)
	vp0, err := statestore.LoadValidators(nextHeight + 0)
	assert.Nil(err, "expected no err")
	vp1, err := statestore.LoadValidators(nextHeight + 1)
	assert.Nil(err, "expected no err")
	assert.Equal(vp0.Hash(), state.Validators.Hash(), "expected validator hashes to match")
	assert.Equal(vp1.Hash(), state.NextValidators.Hash(), "expected next validator hashes to match")
}

// TestValidatorChangesSaveLoad tests saving and loading a validator set with changes.
func TestOneValidatorChangesSaveLoad(t *testing.T) {
	tearDown, stateDB, state := setupTestCase(t)
	defer tearDown(t)
	stateStore := sm.NewStore(stateDB, sm.StoreOptions{
		DiscardABCIResponses: false,
	})

	// Change vals at these heights.
	changeHeights := []int64{1, 2, 4, 5, 10, 15, 16, 17, 20}
	N := len(changeHeights)

	// Build the validator history by running updateState
	// with the right validator set for each height.
	highestHeight := changeHeights[N-1] + 5
	changeIndex := 0
	_, val := state.Validators.GetByIndex(0)
	power := val.VotingPower
	var err error
	var validatorUpdates []*types.Validator
	for i := int64(1); i < highestHeight; i++ {
		// When we get to a change height, use the next pubkey.
		if changeIndex < len(changeHeights) && i == changeHeights[changeIndex] {
			changeIndex++
			power++
		}
		header, blockID, responses := makeHeaderPartsResponsesValPowerChange(state, power)
		validatorUpdates, err = types.PB2TM.ValidatorUpdates(responses.ValidatorUpdates)
		require.NoError(t, err)
		state, err = sm.UpdateState(state, blockID, &header, responses, validatorUpdates)
		require.NoError(t, err)
		err = stateStore.Save(state)
		require.NoError(t, err)
	}

	// On each height change, increment the power by one.
	testCases := make([]int64, highestHeight)
	changeIndex = 0
	power = val.VotingPower
	for i := int64(1); i < highestHeight+1; i++ {
		// We get to the height after a change height use the next pubkey (note
		// our counter starts at 0 this time).
		if changeIndex < len(changeHeights) && i == changeHeights[changeIndex]+1 {
			changeIndex++
			power++
		}
		testCases[i-1] = power
	}

	for i, power := range testCases {
		v, err := stateStore.LoadValidators(int64(i + 1 + 1)) // +1 because vset changes delayed by 1 block.
		assert.Nil(t, err, fmt.Sprintf("expected no err at height %d", i))
		assert.Equal(t, v.Size(), 1, "validator set size is greater than 1: %d", v.Size())
		_, val := v.GetByIndex(0)

		assert.Equal(t, val.VotingPower, power, fmt.Sprintf(`unexpected powerat
                height %d`, i))
	}
}

func TestProposerFrequency(t *testing.T) {
	// some explicit test cases
	testCases := []struct {
		powers []int64
	}{
		// 2 vals
		{[]int64{1, 1}},
		{[]int64{1, 2}},
		{[]int64{1, 100}},
		{[]int64{5, 5}},
		{[]int64{5, 100}},
		{[]int64{50, 50}},
		{[]int64{50, 100}},
		{[]int64{1, 1000}},

		// 3 vals
		{[]int64{1, 1, 1}},
		{[]int64{1, 2, 3}},
		{[]int64{1, 2, 3}},
		{[]int64{1, 1, 10}},
		{[]int64{1, 1, 100}},
		{[]int64{1, 10, 100}},
		{[]int64{1, 1, 1000}},
		{[]int64{1, 10, 1000}},
		{[]int64{1, 100, 1000}},

		// 4 vals
		{[]int64{1, 1, 1, 1}},
		{[]int64{1, 2, 3, 4}},
		{[]int64{1, 1, 1, 10}},
		{[]int64{1, 1, 1, 100}},
		{[]int64{1, 1, 1, 1000}},
		{[]int64{1, 1, 10, 100}},
		{[]int64{1, 1, 10, 1000}},
		{[]int64{1, 1, 100, 1000}},
		{[]int64{1, 10, 100, 1000}},
	}

	for caseNum, testCase := range testCases {
		// run each case 5 times to sample different
		// initial priorities
		for i := 0; i < 5; i++ {
			valSet := genValSetWithPowers(testCase.powers)
			testProposerFreq(t, caseNum, valSet)
		}
	}

	// some random test cases with up to 100 validators
	maxVals := 100
	maxPower := 1000
	nTestCases := 5
	for i := 0; i < nTestCases; i++ {
		N := cmtrand.Int()%maxVals + 1
		vals := make([]*types.Validator, N)
		totalVotePower := int64(0)
		for j := 0; j < N; j++ {
			// make sure votePower > 0
			votePower := int64(cmtrand.Int()%maxPower) + 1
			totalVotePower += votePower
			privVal := types.NewMockPV()
			pubKey, err := privVal.GetPubKey()
			require.NoError(t, err)
			val := types.NewValidator(pubKey, votePower)
			val.ProposerPriority = cmtrand.Int64()
			vals[j] = val
		}
		valSet := types.NewValidatorSet(vals)
		valSet.RescalePriorities(totalVotePower)
		testProposerFreq(t, i, valSet)
	}
}

// new val set with given powers and random initial priorities
func genValSetWithPowers(powers []int64) *types.ValidatorSet {
	size := len(powers)
	vals := make([]*types.Validator, size)
	totalVotePower := int64(0)
	for i := 0; i < size; i++ {
		totalVotePower += powers[i]
		val := types.NewValidator(ed25519.GenPrivKey().PubKey(), powers[i])
		val.ProposerPriority = cmtrand.Int64()
		vals[i] = val
	}
	valSet := types.NewValidatorSet(vals)
	valSet.RescalePriorities(totalVotePower)
	return valSet
}

// test a proposer appears as frequently as expected
func testProposerFreq(t *testing.T, caseNum int, valSet *types.ValidatorSet) {
	N := valSet.Size()
	totalPower := valSet.TotalVotingPower()

	// run the proposer selection and track frequencies
	runMult := 1
	runs := int(totalPower) * runMult
	freqs := make([]int, N)
	for i := 0; i < runs; i++ {
		prop := valSet.GetProposer()
		idx, _ := valSet.GetByAddress(prop.Address)
		freqs[idx]++
		valSet.IncrementProposerPriority(1)
	}

	// assert frequencies match expected (max off by 1)
	for i, freq := range freqs {
		_, val := valSet.GetByIndex(int32(i))
		expectFreq := int(val.VotingPower) * runMult
		gotFreq := freq
		abs := int(math.Abs(float64(expectFreq - gotFreq)))

		// max bound on expected vs seen freq was proven
		// to be 1 for the 2 validator case in
		// https://github.com/cwgoes/tm-proposer-idris
		// and inferred to generalize to N-1
		bound := N - 1
		require.True(
			t,
			abs <= bound,
			fmt.Sprintf("Case %d val %d (%d): got %d, expected %d", caseNum, i, N, gotFreq, expectFreq),
		)
	}
}

// TestProposerPriorityDoesNotGetResetToZero assert that we preserve accum when calling updateState
// see https://github.com/tendermint/tendermint/issues/2718
func TestProposerPriorityDoesNotGetResetToZero(t *testing.T) {
	tearDown, _, state := setupTestCase(t)
	defer tearDown(t)
	val1VotingPower := int64(10)
	val1PubKey := ed25519.GenPrivKey().PubKey()
	val1 := &types.Validator{Address: val1PubKey.Address(), PubKey: val1PubKey, VotingPower: val1VotingPower}

	state.Validators = types.NewValidatorSet([]*types.Validator{val1})
	state.NextValidators = state.Validators

	// NewValidatorSet calls IncrementProposerPriority but uses on a copy of val1
	assert.EqualValues(t, 0, val1.ProposerPriority)

	block := makeBlock(state, state.LastBlockHeight+1, new(types.Commit))
	bps, err := block.MakePartSet(testPartSize)
	require.NoError(t, err)
	blockID := types.BlockID{Hash: block.Hash(), PartSetHeader: bps.Header()}
	abciResponses := &abci.ResponseFinalizeBlock{}
	validatorUpdates, err := types.PB2TM.ValidatorUpdates(abciResponses.ValidatorUpdates)
	require.NoError(t, err)
	updatedState, err := sm.UpdateState(state, blockID, &block.Header, abciResponses, validatorUpdates)
	assert.NoError(t, err)
	curTotal := val1VotingPower
	// one increment step and one validator: 0 + power - total_power == 0
	assert.Equal(t, 0+val1VotingPower-curTotal, updatedState.NextValidators.Validators[0].ProposerPriority)

	// add a validator
	val2PubKey := ed25519.GenPrivKey().PubKey()
	val2VotingPower := int64(100)
	fvp, err := cryptoenc.PubKeyToProto(val2PubKey)
	require.NoError(t, err)

	updateAddVal := abci.ValidatorUpdate{PubKey: fvp, Power: val2VotingPower}
	validatorUpdates, err = types.PB2TM.ValidatorUpdates([]abci.ValidatorUpdate{updateAddVal})
	assert.NoError(t, err)
	updatedState2, err := sm.UpdateState(updatedState, blockID, &block.Header, abciResponses, validatorUpdates)
	assert.NoError(t, err)

	require.Equal(t, len(updatedState2.NextValidators.Validators), 2)
	_, updatedVal1 := updatedState2.NextValidators.GetByAddress(val1PubKey.Address())
	_, addedVal2 := updatedState2.NextValidators.GetByAddress(val2PubKey.Address())

	// adding a validator should not lead to a ProposerPriority equal to zero (unless the combination of averaging and
	// incrementing would cause so; which is not the case here)
	// Steps from adding new validator:
	// 0 - val1 prio is 0, TVP after add:
	wantVal1Prio := int64(0)
	totalPowerAfter := val1VotingPower + val2VotingPower
	// 1. Add - Val2 should be initially added with (-123) =>
	wantVal2Prio := -(totalPowerAfter + (totalPowerAfter >> 3))
	// 2. Scale - noop
	// 3. Center - with avg, resulting val2:-61, val1:62
	avg := big.NewInt(0).Add(big.NewInt(wantVal1Prio), big.NewInt(wantVal2Prio))
	avg.Div(avg, big.NewInt(2))
	wantVal2Prio -= avg.Int64() // -61
	wantVal1Prio -= avg.Int64() // 62

	// 4. Steps from IncrementProposerPriority
	wantVal1Prio += val1VotingPower // 72
	wantVal2Prio += val2VotingPower // 39
	wantVal1Prio -= totalPowerAfter // -38 as val1 is proposer

	assert.Equal(t, wantVal1Prio, updatedVal1.ProposerPriority)
	assert.Equal(t, wantVal2Prio, addedVal2.ProposerPriority)

	// Updating a validator does not reset the ProposerPriority to zero:
	// 1. Add - Val2 VotingPower change to 1 =>
	updatedVotingPowVal2 := int64(1)
	updateVal := abci.ValidatorUpdate{PubKey: fvp, Power: updatedVotingPowVal2}
	validatorUpdates, err = types.PB2TM.ValidatorUpdates([]abci.ValidatorUpdate{updateVal})
	assert.NoError(t, err)

	// this will cause the diff of priorities (77)
	// to be larger than threshold == 2*totalVotingPower (22):
	updatedState3, err := sm.UpdateState(updatedState2, blockID, &block.Header, abciResponses, validatorUpdates)
	assert.NoError(t, err)

	require.Equal(t, len(updatedState3.NextValidators.Validators), 2)
	_, prevVal1 := updatedState3.Validators.GetByAddress(val1PubKey.Address())
	_, prevVal2 := updatedState3.Validators.GetByAddress(val2PubKey.Address())
	_, updatedVal1 = updatedState3.NextValidators.GetByAddress(val1PubKey.Address())
	_, updatedVal2 := updatedState3.NextValidators.GetByAddress(val2PubKey.Address())

	// 2. Scale
	// old prios: v1(10):-38, v2(1):39
	wantVal1Prio = prevVal1.ProposerPriority
	wantVal2Prio = prevVal2.ProposerPriority
	// scale to diffMax = 22 = 2 * tvp, diff=39-(-38)=77
	// new totalPower
	totalPower := updatedVal1.VotingPower + updatedVal2.VotingPower
	dist := wantVal2Prio - wantVal1Prio
	// ratio := (dist + 2*totalPower - 1) / 2*totalPower = 98/22 = 4
	ratio := (dist + 2*totalPower - 1) / (2 * totalPower)
	// v1(10):-38/4, v2(1):39/4
	wantVal1Prio /= ratio // -9
	wantVal2Prio /= ratio // 9

	// 3. Center - noop
	// 4. IncrementProposerPriority() ->
	// v1(10):-9+10, v2(1):9+1 -> v2 proposer so subsract tvp(11)
	// v1(10):1, v2(1):-1
	wantVal2Prio += updatedVal2.VotingPower // 10 -> prop
	wantVal1Prio += updatedVal1.VotingPower // 1
	wantVal2Prio -= totalPower              // -1

	assert.Equal(t, wantVal2Prio, updatedVal2.ProposerPriority)
	assert.Equal(t, wantVal1Prio, updatedVal1.ProposerPriority)
}

func TestProposerPriorityProposerAlternates(t *testing.T) {
	// Regression test that would fail if the inner workings of
	// IncrementProposerPriority change.
	// Additionally, make sure that same power validators alternate if both
	// have the same voting power (and the 2nd was added later).
	tearDown, _, state := setupTestCase(t)
	defer tearDown(t)
	val1VotingPower := int64(10)
	val1PubKey := ed25519.GenPrivKey().PubKey()
	val1 := &types.Validator{Address: val1PubKey.Address(), PubKey: val1PubKey, VotingPower: val1VotingPower}

	// reset state validators to above validator
	state.Validators = types.NewValidatorSet([]*types.Validator{val1})
	state.NextValidators = state.Validators
	// we only have one validator:
	assert.Equal(t, val1PubKey.Address(), state.Validators.Proposer.Address)

	block := makeBlock(state, state.LastBlockHeight+1, new(types.Commit))
	bps, err := block.MakePartSet(testPartSize)
	require.NoError(t, err)
	blockID := types.BlockID{Hash: block.Hash(), PartSetHeader: bps.Header()}
	// no updates:
	abciResponses := &abci.ResponseFinalizeBlock{}
	validatorUpdates, err := types.PB2TM.ValidatorUpdates(abciResponses.ValidatorUpdates)
	require.NoError(t, err)

	updatedState, err := sm.UpdateState(state, blockID, &block.Header, abciResponses, validatorUpdates)
	assert.NoError(t, err)

	// 0 + 10 (initial prio) - 10 (avg) - 10 (mostest - total) = -10
	totalPower := val1VotingPower
	wantVal1Prio := 0 + val1VotingPower - totalPower
	assert.Equal(t, wantVal1Prio, updatedState.NextValidators.Validators[0].ProposerPriority)
	assert.Equal(t, val1PubKey.Address(), updatedState.NextValidators.Proposer.Address)

	// add a validator with the same voting power as the first
	val2PubKey := ed25519.GenPrivKey().PubKey()
	fvp, err := cryptoenc.PubKeyToProto(val2PubKey)
	require.NoError(t, err)
	updateAddVal := abci.ValidatorUpdate{PubKey: fvp, Power: val1VotingPower}
	validatorUpdates, err = types.PB2TM.ValidatorUpdates([]abci.ValidatorUpdate{updateAddVal})
	assert.NoError(t, err)

	updatedState2, err := sm.UpdateState(updatedState, blockID, &block.Header, abciResponses, validatorUpdates)
	assert.NoError(t, err)

	require.Equal(t, len(updatedState2.NextValidators.Validators), 2)
	assert.Equal(t, updatedState2.Validators, updatedState.NextValidators)

	// val1 will still be proposer as val2 just got added:
	assert.Equal(t, val1PubKey.Address(), updatedState.NextValidators.Proposer.Address)
	assert.Equal(t, updatedState2.Validators.Proposer.Address, updatedState2.NextValidators.Proposer.Address)
	assert.Equal(t, updatedState2.Validators.Proposer.Address, val1PubKey.Address())
	assert.Equal(t, updatedState2.NextValidators.Proposer.Address, val1PubKey.Address())

	_, updatedVal1 := updatedState2.NextValidators.GetByAddress(val1PubKey.Address())
	_, oldVal1 := updatedState2.Validators.GetByAddress(val1PubKey.Address())
	_, updatedVal2 := updatedState2.NextValidators.GetByAddress(val2PubKey.Address())

	// 1. Add
	val2VotingPower := val1VotingPower
	totalPower = val1VotingPower + val2VotingPower           // 20
	v2PrioWhenAddedVal2 := -(totalPower + (totalPower >> 3)) // -22
	// 2. Scale - noop
	// 3. Center
	avgSum := big.NewInt(0).Add(big.NewInt(v2PrioWhenAddedVal2), big.NewInt(oldVal1.ProposerPriority))
	avg := avgSum.Div(avgSum, big.NewInt(2))                   // -11
	expectedVal2Prio := v2PrioWhenAddedVal2 - avg.Int64()      // -11
	expectedVal1Prio := oldVal1.ProposerPriority - avg.Int64() // 11
	// 4. Increment
	expectedVal2Prio += val2VotingPower // -11 + 10 = -1
	expectedVal1Prio += val1VotingPower // 11 + 10 == 21
	expectedVal1Prio -= totalPower      // 1, val1 proposer

	assert.EqualValues(t, expectedVal1Prio, updatedVal1.ProposerPriority)
	assert.EqualValues(
		t,
		expectedVal2Prio,
		updatedVal2.ProposerPriority,
		"unexpected proposer priority for validator: %v",
		updatedVal2,
	)

	validatorUpdates, err = types.PB2TM.ValidatorUpdates(abciResponses.ValidatorUpdates)
	require.NoError(t, err)

	updatedState3, err := sm.UpdateState(updatedState2, blockID, &block.Header, abciResponses, validatorUpdates)
	assert.NoError(t, err)

	assert.Equal(t, updatedState3.Validators.Proposer.Address, updatedState3.NextValidators.Proposer.Address)

	assert.Equal(t, updatedState3.Validators, updatedState2.NextValidators)
	_, updatedVal1 = updatedState3.NextValidators.GetByAddress(val1PubKey.Address())
	_, updatedVal2 = updatedState3.NextValidators.GetByAddress(val2PubKey.Address())

	// val1 will still be proposer:
	assert.Equal(t, val1PubKey.Address(), updatedState3.NextValidators.Proposer.Address)

	// check if expected proposer prio is matched:
	// Increment
	expectedVal2Prio2 := expectedVal2Prio + val2VotingPower // -1 + 10 = 9
	expectedVal1Prio2 := expectedVal1Prio + val1VotingPower // 1 + 10 == 11
	expectedVal1Prio2 -= totalPower                         // -9, val1 proposer

	assert.EqualValues(
		t,
		expectedVal1Prio2,
		updatedVal1.ProposerPriority,
		"unexpected proposer priority for validator: %v",
		updatedVal2,
	)
	assert.EqualValues(
		t,
		expectedVal2Prio2,
		updatedVal2.ProposerPriority,
		"unexpected proposer priority for validator: %v",
		updatedVal2,
	)

	// no changes in voting power and both validators have same voting power
	// -> proposers should alternate:
	oldState := updatedState3
	abciResponses = &abci.ResponseFinalizeBlock{}
	validatorUpdates, err = types.PB2TM.ValidatorUpdates(abciResponses.ValidatorUpdates)
	require.NoError(t, err)

	oldState, err = sm.UpdateState(oldState, blockID, &block.Header, abciResponses, validatorUpdates)
	assert.NoError(t, err)
	expectedVal1Prio2 = 1
	expectedVal2Prio2 = -1
	expectedVal1Prio = -9
	expectedVal2Prio = 9

	for i := 0; i < 1000; i++ {
		// no validator updates:
		abciResponses := &abci.ResponseFinalizeBlock{}
		validatorUpdates, err = types.PB2TM.ValidatorUpdates(abciResponses.ValidatorUpdates)
		require.NoError(t, err)

		updatedState, err := sm.UpdateState(oldState, blockID, &block.Header, abciResponses, validatorUpdates)
		assert.NoError(t, err)
		// alternate (and cyclic priorities):
		assert.NotEqual(
			t,
			updatedState.Validators.Proposer.Address,
			updatedState.NextValidators.Proposer.Address,
			"iter: %v",
			i,
		)
		assert.Equal(t, oldState.Validators.Proposer.Address, updatedState.NextValidators.Proposer.Address, "iter: %v", i)

		_, updatedVal1 = updatedState.NextValidators.GetByAddress(val1PubKey.Address())
		_, updatedVal2 = updatedState.NextValidators.GetByAddress(val2PubKey.Address())

		if i%2 == 0 {
			assert.Equal(t, updatedState.Validators.Proposer.Address, val2PubKey.Address())
			assert.Equal(t, expectedVal1Prio, updatedVal1.ProposerPriority) // -19
			assert.Equal(t, expectedVal2Prio, updatedVal2.ProposerPriority) // 0
		} else {
			assert.Equal(t, updatedState.Validators.Proposer.Address, val1PubKey.Address())
			assert.Equal(t, expectedVal1Prio2, updatedVal1.ProposerPriority) // -9
			assert.Equal(t, expectedVal2Prio2, updatedVal2.ProposerPriority) // -10
		}
		// update for next iteration:
		oldState = updatedState
	}
}

func TestLargeGenesisValidator(t *testing.T) {
	tearDown, _, state := setupTestCase(t)
	defer tearDown(t)

	genesisVotingPower := types.MaxTotalVotingPower / 1000
	genesisPubKey := ed25519.GenPrivKey().PubKey()
	// fmt.Println("genesis addr: ", genesisPubKey.Address())
	genesisVal := &types.Validator{
		Address:     genesisPubKey.Address(),
		PubKey:      genesisPubKey,
		VotingPower: genesisVotingPower,
	}
	// reset state validators to above validator
	state.Validators = types.NewValidatorSet([]*types.Validator{genesisVal})
	state.NextValidators = state.Validators
	require.True(t, len(state.Validators.Validators) == 1)

	// update state a few times with no validator updates
	// asserts that the single validator's ProposerPrio stays the same
	oldState := state
	for i := 0; i < 10; i++ {
		// no updates:
		abciResponses := &abci.ResponseFinalizeBlock{}
		validatorUpdates, err := types.PB2TM.ValidatorUpdates(abciResponses.ValidatorUpdates)
		require.NoError(t, err)

		block := makeBlock(oldState, oldState.LastBlockHeight+1, new(types.Commit))
		bps, err := block.MakePartSet(testPartSize)
		require.NoError(t, err)
		blockID := types.BlockID{Hash: block.Hash(), PartSetHeader: bps.Header()}

		updatedState, err := sm.UpdateState(oldState, blockID, &block.Header, abciResponses, validatorUpdates)
		require.NoError(t, err)
		// no changes in voting power (ProposerPrio += VotingPower == Voting in 1st round; than shiftByAvg == 0,
		// than -Total == -Voting)
		// -> no change in ProposerPrio (stays zero):
		assert.EqualValues(t, oldState.NextValidators, updatedState.NextValidators)
		assert.EqualValues(t, 0, updatedState.NextValidators.Proposer.ProposerPriority)

		oldState = updatedState
	}
	// add another validator, do a few iterations (create blocks),
	// add more validators with same voting power as the 2nd
	// let the genesis validator "unbond",
	// see how long it takes until the effect wears off and both begin to alternate
	// see: https://github.com/tendermint/tendermint/issues/2960
	firstAddedValPubKey := ed25519.GenPrivKey().PubKey()
	firstAddedValVotingPower := int64(10)
	fvp, err := cryptoenc.PubKeyToProto(firstAddedValPubKey)
	require.NoError(t, err)
	firstAddedVal := abci.ValidatorUpdate{PubKey: fvp, Power: firstAddedValVotingPower}
	validatorUpdates, err := types.PB2TM.ValidatorUpdates([]abci.ValidatorUpdate{firstAddedVal})
	assert.NoError(t, err)
	abciResponses := &abci.ResponseFinalizeBlock{
		ValidatorUpdates: []abci.ValidatorUpdate{firstAddedVal},
	}
	block := makeBlock(oldState, oldState.LastBlockHeight+1, new(types.Commit))

	bps, err := block.MakePartSet(testPartSize)
	require.NoError(t, err)

	blockID := types.BlockID{Hash: block.Hash(), PartSetHeader: bps.Header()}
	updatedState, err := sm.UpdateState(oldState, blockID, &block.Header, abciResponses, validatorUpdates)
	require.NoError(t, err)

	lastState := updatedState
	for i := 0; i < 200; i++ {
		// no updates:
		abciResponses := &abci.ResponseFinalizeBlock{}
		validatorUpdates, err := types.PB2TM.ValidatorUpdates(abciResponses.ValidatorUpdates)
		require.NoError(t, err)

		block := makeBlock(lastState, lastState.LastBlockHeight+1, new(types.Commit))

		bps, err = block.MakePartSet(testPartSize)
		require.NoError(t, err)

		blockID := types.BlockID{Hash: block.Hash(), PartSetHeader: bps.Header()}

		updatedStateInner, err := sm.UpdateState(lastState, blockID, &block.Header, abciResponses, validatorUpdates)
		require.NoError(t, err)
		lastState = updatedStateInner
	}
	// set state to last state of above iteration
	state = lastState

	// set oldState to state before above iteration
	oldState = updatedState
	_, oldGenesisVal := oldState.NextValidators.GetByAddress(genesisVal.Address)
	_, newGenesisVal := state.NextValidators.GetByAddress(genesisVal.Address)
	_, addedOldVal := oldState.NextValidators.GetByAddress(firstAddedValPubKey.Address())
	_, addedNewVal := state.NextValidators.GetByAddress(firstAddedValPubKey.Address())
	// expect large negative proposer priority for both (genesis validator decreased, 2nd validator increased):
	assert.True(t, oldGenesisVal.ProposerPriority > newGenesisVal.ProposerPriority)
	assert.True(t, addedOldVal.ProposerPriority < addedNewVal.ProposerPriority)

	// add 10 validators with the same voting power as the one added directly after genesis:
	for i := 0; i < 10; i++ {
		addedPubKey := ed25519.GenPrivKey().PubKey()
		ap, err := cryptoenc.PubKeyToProto(addedPubKey)
		require.NoError(t, err)
		addedVal := abci.ValidatorUpdate{PubKey: ap, Power: firstAddedValVotingPower}
		validatorUpdates, err := types.PB2TM.ValidatorUpdates([]abci.ValidatorUpdate{addedVal})
		assert.NoError(t, err)

		abciResponses := &abci.ResponseFinalizeBlock{
			ValidatorUpdates: []abci.ValidatorUpdate{addedVal},
		}
		block := makeBlock(oldState, oldState.LastBlockHeight+1, new(types.Commit))
		bps, err := block.MakePartSet(testPartSize)
		require.NoError(t, err)

		blockID := types.BlockID{Hash: block.Hash(), PartSetHeader: bps.Header()}
		state, err = sm.UpdateState(state, blockID, &block.Header, abciResponses, validatorUpdates)
		require.NoError(t, err)
	}
	require.Equal(t, 10+2, len(state.NextValidators.Validators))

	// remove genesis validator:
	gp, err := cryptoenc.PubKeyToProto(genesisPubKey)
	require.NoError(t, err)
	removeGenesisVal := abci.ValidatorUpdate{PubKey: gp, Power: 0}
	abciResponses = &abci.ResponseFinalizeBlock{
		ValidatorUpdates: []abci.ValidatorUpdate{removeGenesisVal},
	}

	block = makeBlock(oldState, oldState.LastBlockHeight+1, new(types.Commit))
	require.NoError(t, err)

	bps, err = block.MakePartSet(testPartSize)
	require.NoError(t, err)

	blockID = types.BlockID{Hash: block.Hash(), PartSetHeader: bps.Header()}
	validatorUpdates, err = types.PB2TM.ValidatorUpdates(abciResponses.ValidatorUpdates)
	require.NoError(t, err)
	updatedState, err = sm.UpdateState(state, blockID, &block.Header, abciResponses, validatorUpdates)
	require.NoError(t, err)
	// only the first added val (not the genesis val) should be left
	assert.Equal(t, 11, len(updatedState.NextValidators.Validators))

	// call update state until the effect for the 3rd added validator
	// being proposer for a long time after the genesis validator left wears off:
	curState := updatedState
	count := 0
	isProposerUnchanged := true
	for isProposerUnchanged {
		abciResponses := &abci.ResponseFinalizeBlock{}
		validatorUpdates, err = types.PB2TM.ValidatorUpdates(abciResponses.ValidatorUpdates)
		require.NoError(t, err)
		block = makeBlock(curState, curState.LastBlockHeight+1, new(types.Commit))

		bps, err := block.MakePartSet(testPartSize)
		require.NoError(t, err)

		blockID = types.BlockID{Hash: block.Hash(), PartSetHeader: bps.Header()}
		curState, err = sm.UpdateState(curState, blockID, &block.Header, abciResponses, validatorUpdates)
		require.NoError(t, err)
		if !bytes.Equal(curState.Validators.Proposer.Address, curState.NextValidators.Proposer.Address) {
			isProposerUnchanged = false
		}
		count++
	}
	updatedState = curState
	// the proposer changes after this number of blocks
	firstProposerChangeExpectedAfter := 1
	assert.Equal(t, firstProposerChangeExpectedAfter, count)
	// store proposers here to see if we see them again in the same order:
	numVals := len(updatedState.Validators.Validators)
	proposers := make([]*types.Validator, numVals)
	for i := 0; i < 100; i++ {
		// no updates:
		abciResponses := &abci.ResponseFinalizeBlock{}
		validatorUpdates, err := types.PB2TM.ValidatorUpdates(abciResponses.ValidatorUpdates)
		require.NoError(t, err)

		block := makeBlock(updatedState, updatedState.LastBlockHeight+1, new(types.Commit))

		bps, err := block.MakePartSet(testPartSize)
		require.NoError(t, err)

		blockID := types.BlockID{Hash: block.Hash(), PartSetHeader: bps.Header()}

		updatedState, err = sm.UpdateState(updatedState, blockID, &block.Header, abciResponses, validatorUpdates)
		require.NoError(t, err)
		if i > numVals { // expect proposers to cycle through after the first iteration (of numVals blocks):
			if proposers[i%numVals] == nil {
				proposers[i%numVals] = updatedState.NextValidators.Proposer
			} else {
				assert.Equal(t, proposers[i%numVals], updatedState.NextValidators.Proposer)
			}
		}
	}
}

func TestStoreLoadValidatorsIncrementsProposerPriority(t *testing.T) {
	const valSetSize = 2
	tearDown, stateDB, state := setupTestCase(t)
	t.Cleanup(func() { tearDown(t) })
	stateStore := sm.NewStore(stateDB, sm.StoreOptions{
		DiscardABCIResponses: false,
	})
	state.Validators = genValSet(valSetSize)
	state.NextValidators = state.Validators.CopyIncrementProposerPriority(1)
	err := stateStore.Save(state)
	require.NoError(t, err)

	nextHeight := state.LastBlockHeight + 1

	v0, err := stateStore.LoadValidators(nextHeight)
	assert.Nil(t, err)
	acc0 := v0.Validators[0].ProposerPriority

	v1, err := stateStore.LoadValidators(nextHeight + 1)
	assert.Nil(t, err)
	acc1 := v1.Validators[0].ProposerPriority

	assert.NotEqual(t, acc1, acc0, "expected ProposerPriority value to change between heights")
}

// TestValidatorChangesSaveLoad tests saving and loading a validator set with
// changes.
func TestManyValidatorChangesSaveLoad(t *testing.T) {
	const valSetSize = 7
	tearDown, stateDB, state := setupTestCase(t)
	defer tearDown(t)
	stateStore := sm.NewStore(stateDB, sm.StoreOptions{
		DiscardABCIResponses: false,
	})
	require.Equal(t, int64(0), state.LastBlockHeight)
	state.Validators = genValSet(valSetSize)
	state.NextValidators = state.Validators.CopyIncrementProposerPriority(1)
	err := stateStore.Save(state)
	require.NoError(t, err)

	_, valOld := state.Validators.GetByIndex(0)
	pubkeyOld := valOld.PubKey
	pubkey := ed25519.GenPrivKey().PubKey()

	// Swap the first validator with a new one (validator set size stays the same).
	header, blockID, responses := makeHeaderPartsResponsesValPubKeyChange(state, pubkey)

	// Save state etc.
	var validatorUpdates []*types.Validator
	validatorUpdates, err = types.PB2TM.ValidatorUpdates(responses.ValidatorUpdates)
	require.NoError(t, err)
	state, err = sm.UpdateState(state, blockID, &header, responses, validatorUpdates)
	require.Nil(t, err)
	nextHeight := state.LastBlockHeight + 1
	err = stateStore.Save(state)
	require.NoError(t, err)

	// Load nextheight, it should be the oldpubkey.
	v0, err := stateStore.LoadValidators(nextHeight)
	assert.Nil(t, err)
	assert.Equal(t, valSetSize, v0.Size())
	index, val := v0.GetByAddress(pubkeyOld.Address())
	assert.NotNil(t, val)
	if index < 0 {
		t.Fatal("expected to find old validator")
	}

	// Load nextheight+1, it should be the new pubkey.
	v1, err := stateStore.LoadValidators(nextHeight + 1)
	assert.Nil(t, err)
	assert.Equal(t, valSetSize, v1.Size())
	index, val = v1.GetByAddress(pubkey.Address())
	assert.NotNil(t, val)
	if index < 0 {
		t.Fatal("expected to find newly added validator")
	}
}

func TestStateMakeBlock(t *testing.T) {
	tearDown, _, state := setupTestCase(t)
	defer tearDown(t)

	proposerAddress := state.Validators.GetProposer().Address
	stateVersion := state.Version.Consensus
	block := makeBlock(state, 2, new(types.Commit))

	// test we set some fields
	assert.Equal(t, stateVersion, block.Version)
	assert.Equal(t, proposerAddress, block.ProposerAddress)
}

// TestConsensusParamsChangesSaveLoad tests saving and loading consensus params
// with changes.
func TestConsensusParamsChangesSaveLoad(t *testing.T) {
	tearDown, stateDB, state := setupTestCase(t)
	defer tearDown(t)

	stateStore := sm.NewStore(stateDB, sm.StoreOptions{
		DiscardABCIResponses: false,
	})

	// Change vals at these heights.
	changeHeights := []int64{1, 2, 4, 5, 10, 15, 16, 17, 20}
	N := len(changeHeights)

	// Each valset is just one validator.
	// create list of them.
	params := make([]types.ConsensusParams, N+1)
	params[0] = state.ConsensusParams
	for i := 1; i < N+1; i++ {
		params[i] = *types.DefaultConsensusParams()
		params[i].Block.MaxBytes += int64(i)

	}

	// Build the params history by running updateState
	// with the right params set for each height.
	highestHeight := changeHeights[N-1] + 5
	changeIndex := 0
	cp := params[changeIndex]
	var err error
	var validatorUpdates []*types.Validator
	for i := int64(1); i < highestHeight; i++ {
		// When we get to a change height, use the next params.
		if changeIndex < len(changeHeights) && i == changeHeights[changeIndex] {
			changeIndex++
			cp = params[changeIndex]
		}
		header, blockID, responses := makeHeaderPartsResponsesParams(state, cp.ToProto())
		validatorUpdates, err = types.PB2TM.ValidatorUpdates(responses.ValidatorUpdates)
		require.NoError(t, err)
		state, err = sm.UpdateState(state, blockID, &header, responses, validatorUpdates)

		require.NoError(t, err)
		err = stateStore.Save(state)
		require.NoError(t, err)
	}

	// Make all the test cases by using the same params until after the change.
	testCases := make([]paramsChangeTestCase, highestHeight)
	changeIndex = 0
	cp = params[changeIndex]
	for i := int64(1); i < highestHeight+1; i++ {
		// We get to the height after a change height use the next pubkey (note
		// our counter starts at 0 this time).
		if changeIndex < len(changeHeights) && i == changeHeights[changeIndex]+1 {
			changeIndex++
			cp = params[changeIndex]
		}
		testCases[i-1] = paramsChangeTestCase{i, cp}
	}

	for _, testCase := range testCases {
		p, err := stateStore.LoadConsensusParams(testCase.height)
		assert.Nil(t, err, fmt.Sprintf("expected no err at height %d", testCase.height))
		assert.EqualValues(t, testCase.params, p, fmt.Sprintf(`unexpected consensus params at
                height %d`, testCase.height))
	}
}

func TestStateProto(t *testing.T) {
	tearDown, _, state := setupTestCase(t)
	defer tearDown(t)

	tc := []struct {
		testName string
		state    *sm.State
		expPass1 bool
		expPass2 bool
	}{
		{"empty state", &sm.State{}, true, false},
		{"nil failure state", nil, false, false},
		{"success state", &state, true, true},
	}

	for _, tt := range tc {
		tt := tt
		pbs, err := tt.state.ToProto()
		if !tt.expPass1 {
			assert.Error(t, err)
		} else {
			assert.NoError(t, err, tt.testName)
		}

		smt, err := sm.FromProto(pbs)
		if tt.expPass2 {
			require.NoError(t, err, tt.testName)
			require.Equal(t, tt.state, smt, tt.testName)
		} else {
			require.Error(t, err, tt.testName)
		}
	}
}
