package simapp

import (
	"encoding/json"
	"fmt"
	"math/rand"
	"os"
	"runtime/debug"
	"strings"
	"testing"

	"github.com/stretchr/testify/require"
	abci "github.com/tendermint/tendermint/abci/types"
	"github.com/tendermint/tendermint/libs/log"
	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
	dbm "github.com/tendermint/tm-db"

	"github.com/cosmos/cosmos-sdk/client/flags"
	"github.com/cosmos/cosmos-sdk/server"
	storetypes "github.com/cosmos/cosmos-sdk/store/types"

	"github.com/cosmos/cosmos-sdk/baseapp"
	"github.com/cosmos/cosmos-sdk/store"
	simtestutil "github.com/cosmos/cosmos-sdk/testutil/sims"
	sdk "github.com/cosmos/cosmos-sdk/types"
	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
	authzkeeper "github.com/cosmos/cosmos-sdk/x/authz/keeper"
	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
	capabilitytypes "github.com/cosmos/cosmos-sdk/x/capability/types"
	distrtypes "github.com/cosmos/cosmos-sdk/x/distribution/types"
	evidencetypes "github.com/cosmos/cosmos-sdk/x/evidence/types"
	govtypes "github.com/cosmos/cosmos-sdk/x/gov/types"
	minttypes "github.com/cosmos/cosmos-sdk/x/mint/types"
	paramtypes "github.com/cosmos/cosmos-sdk/x/params/types"
	"github.com/cosmos/cosmos-sdk/x/simulation"
	simcli "github.com/cosmos/cosmos-sdk/x/simulation/client/cli"
	slashingtypes "github.com/cosmos/cosmos-sdk/x/slashing/types"
	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
)

// SimAppChainID hardcoded chainID for simulation
const SimAppChainID = "simulation-app"

// Get flags every time the simulator is run
func init() {
	simcli.GetSimulatorFlags()
}

type StoreKeysPrefixes struct {
	A        storetypes.StoreKey
	B        storetypes.StoreKey
	Prefixes [][]byte
}

// fauxMerkleModeOpt returns a BaseApp option to use a dbStoreAdapter instead of
// an IAVLStore for faster simulation speed.
func fauxMerkleModeOpt(bapp *baseapp.BaseApp) {
	bapp.SetFauxMerkleMode()
}

// interBlockCacheOpt returns a BaseApp option function that sets the persistent
// inter-block write-through cache.
func interBlockCacheOpt() func(*baseapp.BaseApp) {
	return baseapp.SetInterBlockCache(store.NewCommitKVStoreCacheManager())
}

func TestFullAppSimulation(t *testing.T) {
	config := simcli.NewConfigFromFlags()
	config.ChainID = SimAppChainID

	db, dir, logger, skip, err := simtestutil.SetupSimulation(config, "leveldb-app-sim", "Simulation", simcli.FlagVerboseValue, simcli.FlagEnabledValue)
	if skip {
		t.Skip("skipping application simulation")
	}
	require.NoError(t, err, "simulation setup failed")

	defer func() {
		require.NoError(t, db.Close())
		require.NoError(t, os.RemoveAll(dir))
	}()

	appOptions := make(simtestutil.AppOptionsMap, 0)
	appOptions[flags.FlagHome] = DefaultNodeHome
	appOptions[server.FlagInvCheckPeriod] = simcli.FlagPeriodValue

	app := NewSimApp(logger, db, nil, true, appOptions, fauxMerkleModeOpt)
	require.Equal(t, "SimApp", app.Name())

	// run randomized simulation
	_, simParams, simErr := simulation.SimulateFromSeed(
		t,
		os.Stdout,
		app.BaseApp,
		AppStateFn(app.AppCodec(), app.SimulationManager()),
		simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
		simtestutil.SimulationOperations(app, app.AppCodec(), config),
		ModuleAccountAddrs(),
		config,
		app.AppCodec(),
	)

	// export state and simParams before the simulation error is checked
	err = simtestutil.CheckExportSimulation(app, config, simParams)
	require.NoError(t, err)
	require.NoError(t, simErr)

	if config.Commit {
		simtestutil.PrintStats(db)
	}
}

func TestAppImportExport(t *testing.T) {
	config := simcli.NewConfigFromFlags()
	config.ChainID = SimAppChainID

	db, dir, logger, skip, err := simtestutil.SetupSimulation(config, "leveldb-app-sim", "Simulation", simcli.FlagVerboseValue, simcli.FlagEnabledValue)
	if skip {
		t.Skip("skipping application import/export simulation")
	}
	require.NoError(t, err, "simulation setup failed")

	defer func() {
		require.NoError(t, db.Close())
		require.NoError(t, os.RemoveAll(dir))
	}()

	appOptions := make(simtestutil.AppOptionsMap, 0)
	appOptions[flags.FlagHome] = DefaultNodeHome
	appOptions[server.FlagInvCheckPeriod] = simcli.FlagPeriodValue

	app := NewSimApp(logger, db, nil, true, appOptions, fauxMerkleModeOpt)
	require.Equal(t, "SimApp", app.Name())

	// Run randomized simulation
	_, simParams, simErr := simulation.SimulateFromSeed(
		t,
		os.Stdout,
		app.BaseApp,
		AppStateFn(app.AppCodec(), app.SimulationManager()),
		simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
		simtestutil.SimulationOperations(app, app.AppCodec(), config),
		ModuleAccountAddrs(),
		config,
		app.AppCodec(),
	)

	// export state and simParams before the simulation error is checked
	err = simtestutil.CheckExportSimulation(app, config, simParams)
	require.NoError(t, err)
	require.NoError(t, simErr)

	if config.Commit {
		simtestutil.PrintStats(db)
	}

	fmt.Printf("exporting genesis...\n")

	exported, err := app.ExportAppStateAndValidators(false, []string{}, []string{})
	require.NoError(t, err)

	fmt.Printf("importing genesis...\n")

	newDB, newDir, _, _, err := simtestutil.SetupSimulation(config, "leveldb-app-sim-2", "Simulation-2", simcli.FlagVerboseValue, simcli.FlagEnabledValue)
	require.NoError(t, err, "simulation setup failed")

	defer func() {
		require.NoError(t, newDB.Close())
		require.NoError(t, os.RemoveAll(newDir))
	}()

	newApp := NewSimApp(log.NewNopLogger(), newDB, nil, true, appOptions, fauxMerkleModeOpt)
	require.Equal(t, "SimApp", newApp.Name())

	var genesisState GenesisState
	err = json.Unmarshal(exported.AppState, &genesisState)
	require.NoError(t, err)

	defer func() {
		if r := recover(); r != nil {
			err := fmt.Sprintf("%v", r)
			if !strings.Contains(err, "validator set is empty after InitGenesis") {
				panic(r)
			}
			logger.Info("Skipping simulation as all validators have been unbonded")
			logger.Info("err", err, "stacktrace", string(debug.Stack()))
		}
	}()

	ctxA := app.NewContext(true, tmproto.Header{Height: app.LastBlockHeight()})
	ctxB := newApp.NewContext(true, tmproto.Header{Height: app.LastBlockHeight()})
	newApp.ModuleManager.InitGenesis(ctxB, app.AppCodec(), genesisState)
	newApp.StoreConsensusParams(ctxB, exported.ConsensusParams)

	fmt.Printf("comparing stores...\n")

	storeKeysPrefixes := []StoreKeysPrefixes{
		{app.GetKey(authtypes.StoreKey), newApp.GetKey(authtypes.StoreKey), [][]byte{}},
		{
			app.GetKey(stakingtypes.StoreKey), newApp.GetKey(stakingtypes.StoreKey),
			[][]byte{
				stakingtypes.UnbondingQueueKey, stakingtypes.RedelegationQueueKey, stakingtypes.ValidatorQueueKey,
				stakingtypes.HistoricalInfoKey, stakingtypes.UnbondingIDKey, stakingtypes.UnbondingIndexKey, stakingtypes.UnbondingTypeKey, stakingtypes.ValidatorUpdatesKey,
			},
		}, // ordering may change but it doesn't matter
		{app.GetKey(slashingtypes.StoreKey), newApp.GetKey(slashingtypes.StoreKey), [][]byte{}},
		{app.GetKey(minttypes.StoreKey), newApp.GetKey(minttypes.StoreKey), [][]byte{}},
		{app.GetKey(distrtypes.StoreKey), newApp.GetKey(distrtypes.StoreKey), [][]byte{}},
		{app.GetKey(banktypes.StoreKey), newApp.GetKey(banktypes.StoreKey), [][]byte{banktypes.BalancesPrefix}},
		{app.GetKey(paramtypes.StoreKey), newApp.GetKey(paramtypes.StoreKey), [][]byte{}},
		{app.GetKey(govtypes.StoreKey), newApp.GetKey(govtypes.StoreKey), [][]byte{}},
		{app.GetKey(evidencetypes.StoreKey), newApp.GetKey(evidencetypes.StoreKey), [][]byte{}},
		{app.GetKey(capabilitytypes.StoreKey), newApp.GetKey(capabilitytypes.StoreKey), [][]byte{}},
		{app.GetKey(authzkeeper.StoreKey), newApp.GetKey(authzkeeper.StoreKey), [][]byte{authzkeeper.GrantKey, authzkeeper.GrantQueuePrefix}},
	}

	for _, skp := range storeKeysPrefixes {
		storeA := ctxA.KVStore(skp.A)
		storeB := ctxB.KVStore(skp.B)

		failedKVAs, failedKVBs := sdk.DiffKVStores(storeA, storeB, skp.Prefixes)
		require.Equal(t, len(failedKVAs), len(failedKVBs), "unequal sets of key-values to compare")

		fmt.Printf("compared %d different key/value pairs between %s and %s\n", len(failedKVAs), skp.A, skp.B)
		require.Equal(t, 0, len(failedKVAs), simtestutil.GetSimulationLog(skp.A.Name(), app.SimulationManager().StoreDecoders, failedKVAs, failedKVBs))
	}
}

func TestAppSimulationAfterImport(t *testing.T) {
	config := simcli.NewConfigFromFlags()
	config.ChainID = SimAppChainID

	db, dir, logger, skip, err := simtestutil.SetupSimulation(config, "leveldb-app-sim", "Simulation", simcli.FlagVerboseValue, simcli.FlagEnabledValue)
	if skip {
		t.Skip("skipping application simulation after import")
	}
	require.NoError(t, err, "simulation setup failed")

	defer func() {
		require.NoError(t, db.Close())
		require.NoError(t, os.RemoveAll(dir))
	}()

	appOptions := make(simtestutil.AppOptionsMap, 0)
	appOptions[flags.FlagHome] = DefaultNodeHome
	appOptions[server.FlagInvCheckPeriod] = simcli.FlagPeriodValue

	app := NewSimApp(logger, db, nil, true, appOptions, fauxMerkleModeOpt)
	require.Equal(t, "SimApp", app.Name())

	// Run randomized simulation
	stopEarly, simParams, simErr := simulation.SimulateFromSeed(
		t,
		os.Stdout,
		app.BaseApp,
		AppStateFn(app.AppCodec(), app.SimulationManager()),
		simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
		simtestutil.SimulationOperations(app, app.AppCodec(), config),
		ModuleAccountAddrs(),
		config,
		app.AppCodec(),
	)

	// export state and simParams before the simulation error is checked
	err = simtestutil.CheckExportSimulation(app, config, simParams)
	require.NoError(t, err)
	require.NoError(t, simErr)

	if config.Commit {
		simtestutil.PrintStats(db)
	}

	if stopEarly {
		fmt.Println("can't export or import a zero-validator genesis, exiting test...")
		return
	}

	fmt.Printf("exporting genesis...\n")

	exported, err := app.ExportAppStateAndValidators(true, []string{}, []string{})
	require.NoError(t, err)

	fmt.Printf("importing genesis...\n")

	newDB, newDir, _, _, err := simtestutil.SetupSimulation(config, "leveldb-app-sim-2", "Simulation-2", simcli.FlagVerboseValue, simcli.FlagEnabledValue)
	require.NoError(t, err, "simulation setup failed")

	defer func() {
		require.NoError(t, newDB.Close())
		require.NoError(t, os.RemoveAll(newDir))
	}()

	newApp := NewSimApp(log.NewNopLogger(), newDB, nil, true, appOptions, fauxMerkleModeOpt)
	require.Equal(t, "SimApp", newApp.Name())

	newApp.InitChain(abci.RequestInitChain{
		AppStateBytes: exported.AppState,
	})

	_, _, err = simulation.SimulateFromSeed(
		t,
		os.Stdout,
		newApp.BaseApp,
		AppStateFn(app.AppCodec(), app.SimulationManager()),
		simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
		simtestutil.SimulationOperations(newApp, newApp.AppCodec(), config),
		ModuleAccountAddrs(),
		config,
		app.AppCodec(),
	)
	require.NoError(t, err)
}

// TODO: Make another test for the fuzzer itself, which just has noOp txs
// and doesn't depend on the application.
func TestAppStateDeterminism(t *testing.T) {
	if !simcli.FlagEnabledValue {
		t.Skip("skipping application simulation")
	}

	config := simcli.NewConfigFromFlags()
	config.InitialBlockHeight = 1
	config.ExportParamsPath = ""
	config.OnOperation = false
	config.AllInvariants = false
	config.ChainID = SimAppChainID

	numSeeds := 3
	numTimesToRunPerSeed := 5
	appHashList := make([]json.RawMessage, numTimesToRunPerSeed)

	appOptions := make(simtestutil.AppOptionsMap, 0)
	appOptions[flags.FlagHome] = DefaultNodeHome
	appOptions[server.FlagInvCheckPeriod] = simcli.FlagPeriodValue

	for i := 0; i < numSeeds; i++ {
		config.Seed = rand.Int63()

		for j := 0; j < numTimesToRunPerSeed; j++ {
			var logger log.Logger
			if simcli.FlagVerboseValue {
				logger = log.TestingLogger()
			} else {
				logger = log.NewNopLogger()
			}

			db := dbm.NewMemDB()
			app := NewSimApp(logger, db, nil, true, appOptions, interBlockCacheOpt())

			fmt.Printf(
				"running non-determinism simulation; seed %d: %d/%d, attempt: %d/%d\n",
				config.Seed, i+1, numSeeds, j+1, numTimesToRunPerSeed,
			)

			_, _, err := simulation.SimulateFromSeed(
				t,
				os.Stdout,
				app.BaseApp,
				AppStateFn(app.AppCodec(), app.SimulationManager()),
				simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
				simtestutil.SimulationOperations(app, app.AppCodec(), config),
				ModuleAccountAddrs(),
				config,
				app.AppCodec(),
			)
			require.NoError(t, err)

			if config.Commit {
				simtestutil.PrintStats(db)
			}

			appHash := app.LastCommitID().Hash
			appHashList[j] = appHash

			if j != 0 {
				require.Equal(
					t, string(appHashList[0]), string(appHashList[j]),
					"non-determinism in seed %d: %d/%d, attempt: %d/%d\n", config.Seed, i+1, numSeeds, j+1, numTimesToRunPerSeed,
				)
			}
		}
	}
}