package baseapp

import (
	"context"
	"errors"
	"fmt"

	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/codec/types"
	"github.com/cosmos/cosmos-sdk/snapshots"
	"github.com/cosmos/cosmos-sdk/store"
	"github.com/cosmos/cosmos-sdk/store/rootmulti"
	storetypes "github.com/cosmos/cosmos-sdk/store/types"
	sdk "github.com/cosmos/cosmos-sdk/types"
	"github.com/cosmos/cosmos-sdk/types/tx"
)

const (
	runTxModeCheck    runTxMode = iota // Check a transaction
	runTxModeReCheck                   // Recheck a (pending) transaction after a commit
	runTxModeSimulate                  // Simulate a transaction
	runTxModeDeliver                   // Deliver a transaction
)

var (
	_ abci.Application = (*BaseApp)(nil)
)

type (
	// Enum mode for app.runTx
	runTxMode uint8

	// StoreLoader defines a customizable function to control how we load the CommitMultiStore
	// from disk. This is useful for state migration, when loading a datastore written with
	// an older version of the software. In particular, if a module changed the substore key name
	// (or removed a substore) between two versions of the software.
	StoreLoader func(ms sdk.CommitMultiStore) error
)

// BaseApp reflects the ABCI application implementation.
type BaseApp struct { // nolint: maligned
	// initialized on creation
	logger            log.Logger
	name              string               // application name from abci.Info
	db                dbm.DB               // common DB backend
	cms               sdk.CommitMultiStore // Main (uncached) state
	storeLoader       StoreLoader          // function to handle store loading, may be overridden with SetStoreLoader()
	queryRouter       sdk.QueryRouter      // router for redirecting query calls
	grpcQueryRouter   *GRPCQueryRouter     // router for redirecting gRPC query calls
	interfaceRegistry types.InterfaceRegistry
	txDecoder         sdk.TxDecoder // unmarshal []byte into sdk.Tx

	txHandler      tx.Handler       // txHandler for {Deliver,Check}Tx and simulations
	initChainer    sdk.InitChainer  // initialize state with validators and state blob
	beginBlocker   sdk.BeginBlocker // logic to run before any txs
	endBlocker     sdk.EndBlocker   // logic to run after all txs, and to determine valset changes
	addrPeerFilter sdk.PeerFilter   // filter peers by address and port
	idPeerFilter   sdk.PeerFilter   // filter peers by node ID
	fauxMerkleMode bool             // if true, IAVL MountStores uses MountStoresDB for simulation speed.

	// manages snapshots, i.e. dumps of app state at certain intervals
	snapshotManager    *snapshots.Manager
	snapshotInterval   uint64 // block interval between state sync snapshots
	snapshotKeepRecent uint32 // recent state sync snapshots to keep

	// volatile states:
	//
	// checkState is set on InitChain and reset on Commit
	// deliverState is set on InitChain and BeginBlock and set to nil on Commit
	checkState   *state // for CheckTx
	deliverState *state // for DeliverTx

	// an inter-block write-through cache provided to the context during deliverState
	interBlockCache sdk.MultiStorePersistentCache

	// absent validators from begin block
	voteInfos []abci.VoteInfo

	// paramStore is used to query for ABCI consensus parameters from an
	// application parameter store.
	paramStore ParamStore

	// The minimum gas prices a validator is willing to accept for processing a
	// transaction. This is mainly used for DoS and spam prevention.
	minGasPrices sdk.DecCoins

	// initialHeight is the initial height at which we start the baseapp
	initialHeight int64

	// flag for sealing options and parameters to a BaseApp
	sealed bool

	// block height at which to halt the chain and gracefully shutdown
	haltHeight uint64

	// minimum block time (in Unix seconds) at which to halt the chain and gracefully shutdown
	haltTime uint64

	// minRetainBlocks defines the minimum block height offset from the current
	// block being committed, such that all blocks past this offset are pruned
	// from Tendermint. It is used as part of the process of determining the
	// ResponseCommit.RetainHeight value during ABCI Commit. A value of 0 indicates
	// that no blocks should be pruned.
	//
	// Note: Tendermint block pruning is dependant on this parameter in conunction
	// with the unbonding (safety threshold) period, state pruning and state sync
	// snapshot parameters to determine the correct minimum value of
	// ResponseCommit.RetainHeight.
	minRetainBlocks uint64

	// application's version string
	version string

	// application's protocol version that increments on every upgrade
	// if BaseApp is passed to the upgrade keeper's NewKeeper method.
	appVersion uint64

	// trace set will return full stack traces for errors in ABCI Log field
	trace bool

	// indexEvents defines the set of events in the form {eventType}.{attributeKey},
	// which informs Tendermint what to index. If empty, all events will be indexed.
	indexEvents map[string]struct{}

	// abciListeners for hooking into the ABCI message processing of the BaseApp
	// and exposing the requests and responses to external consumers
	abciListeners []ABCIListener
}

// NewBaseApp returns a reference to an initialized BaseApp. It accepts a
// variadic number of option functions, which act on the BaseApp to set
// configuration choices.
//
// NOTE: The db is used to store the version number for now.
func NewBaseApp(
	name string, logger log.Logger, db dbm.DB, txDecoder sdk.TxDecoder, options ...func(*BaseApp),
) *BaseApp {
	app := &BaseApp{
		logger:          logger,
		name:            name,
		db:              db,
		cms:             store.NewCommitMultiStore(db),
		storeLoader:     DefaultStoreLoader,
		queryRouter:     NewQueryRouter(),
		grpcQueryRouter: NewGRPCQueryRouter(),
		txDecoder:       txDecoder,
		fauxMerkleMode:  false,
	}

	for _, option := range options {
		option(app)
	}

	if app.interBlockCache != nil {
		app.cms.SetInterBlockCache(app.interBlockCache)
	}

	return app
}

// Name returns the name of the BaseApp.
func (app *BaseApp) Name() string {
	return app.name
}

// AppVersion returns the application's protocol version.
func (app *BaseApp) AppVersion() uint64 {
	return app.appVersion
}

// Version returns the application's version string.
func (app *BaseApp) Version() string {
	return app.version
}

// Logger returns the logger of the BaseApp.
func (app *BaseApp) Logger() log.Logger {
	return app.logger
}

// Trace returns the boolean value for logging error stack traces.
func (app *BaseApp) Trace() bool {
	return app.trace
}

// MountStores mounts all IAVL or DB stores to the provided keys in the BaseApp
// multistore.
func (app *BaseApp) MountStores(keys ...storetypes.StoreKey) {
	for _, key := range keys {
		switch key.(type) {
		case *storetypes.KVStoreKey:
			if !app.fauxMerkleMode {
				app.MountStore(key, storetypes.StoreTypeIAVL)
			} else {
				// StoreTypeDB doesn't do anything upon commit, and it doesn't
				// retain history, but it's useful for faster simulation.
				app.MountStore(key, storetypes.StoreTypeDB)
			}

		case *storetypes.TransientStoreKey:
			app.MountStore(key, storetypes.StoreTypeTransient)

		default:
			panic(fmt.Sprintf("Unrecognized store key type :%T", key))
		}
	}
}

// MountKVStores mounts all IAVL or DB stores to the provided keys in the
// BaseApp multistore.
func (app *BaseApp) MountKVStores(keys map[string]*storetypes.KVStoreKey) {
	for _, key := range keys {
		if !app.fauxMerkleMode {
			app.MountStore(key, storetypes.StoreTypeIAVL)
		} else {
			// StoreTypeDB doesn't do anything upon commit, and it doesn't
			// retain history, but it's useful for faster simulation.
			app.MountStore(key, storetypes.StoreTypeDB)
		}
	}
}

// MountTransientStores mounts all transient stores to the provided keys in
// the BaseApp multistore.
func (app *BaseApp) MountTransientStores(keys map[string]*storetypes.TransientStoreKey) {
	for _, key := range keys {
		app.MountStore(key, storetypes.StoreTypeTransient)
	}
}

// MountMemoryStores mounts all in-memory KVStores with the BaseApp's internal
// commit multi-store.
func (app *BaseApp) MountMemoryStores(keys map[string]*storetypes.MemoryStoreKey) {
	for _, memKey := range keys {
		app.MountStore(memKey, storetypes.StoreTypeMemory)
	}
}

// MountStore mounts a store to the provided key in the BaseApp multistore,
// using the default DB.
func (app *BaseApp) MountStore(key storetypes.StoreKey, typ storetypes.StoreType) {
	app.cms.MountStoreWithDB(key, typ, nil)
}

// LoadLatestVersion loads the latest application version. It will panic if
// called more than once on a running BaseApp.
func (app *BaseApp) LoadLatestVersion() error {
	err := app.storeLoader(app.cms)
	if err != nil {
		return fmt.Errorf("failed to load latest version: %w", err)
	}

	return app.init()
}

// DefaultStoreLoader will be used by default and loads the latest version
func DefaultStoreLoader(ms sdk.CommitMultiStore) error {
	return ms.LoadLatestVersion()
}

// LoadVersion loads the BaseApp application version. It will panic if called
// more than once on a running baseapp.
func (app *BaseApp) LoadVersion(version int64) error {
	err := app.cms.LoadVersion(version)
	if err != nil {
		return fmt.Errorf("failed to load version %d: %w", version, err)
	}

	return app.init()
}

// LastCommitID returns the last CommitID of the multistore.
func (app *BaseApp) LastCommitID() storetypes.CommitID {
	return app.cms.LastCommitID()
}

// LastBlockHeight returns the last committed block height.
func (app *BaseApp) LastBlockHeight() int64 {
	return app.cms.LastCommitID().Version
}

func (app *BaseApp) init() error {
	if app.sealed {
		panic("cannot call initFromMainStore: baseapp already sealed")
	}

	// needed for the export command which inits from store but never calls initchain
	app.setCheckState(tmproto.Header{})
	app.Seal()

	// make sure the snapshot interval is a multiple of the pruning KeepEvery interval
	if app.snapshotManager != nil && app.snapshotInterval > 0 {
		rms, ok := app.cms.(*rootmulti.Store)
		if !ok {
			return errors.New("state sync snapshots require a rootmulti store")
		}
		pruningOpts := rms.GetPruning()
		if pruningOpts.KeepEvery > 0 && app.snapshotInterval%pruningOpts.KeepEvery != 0 {
			return fmt.Errorf(
				"state sync snapshot interval %v must be a multiple of pruning keep every interval %v",
				app.snapshotInterval, pruningOpts.KeepEvery)
		}
	}

	return nil
}

func (app *BaseApp) setMinGasPrices(gasPrices sdk.DecCoins) {
	app.minGasPrices = gasPrices
}

func (app *BaseApp) setHaltHeight(haltHeight uint64) {
	app.haltHeight = haltHeight
}

func (app *BaseApp) setHaltTime(haltTime uint64) {
	app.haltTime = haltTime
}

func (app *BaseApp) setMinRetainBlocks(minRetainBlocks uint64) {
	app.minRetainBlocks = minRetainBlocks
}

func (app *BaseApp) setInterBlockCache(cache sdk.MultiStorePersistentCache) {
	app.interBlockCache = cache
}

func (app *BaseApp) setTrace(trace bool) {
	app.trace = trace
}

func (app *BaseApp) setIndexEvents(ie []string) {
	app.indexEvents = make(map[string]struct{})

	for _, e := range ie {
		app.indexEvents[e] = struct{}{}
	}
}

// QueryRouter returns the QueryRouter of a BaseApp.
func (app *BaseApp) QueryRouter() sdk.QueryRouter { return app.queryRouter }

// Seal seals a BaseApp. It prohibits any further modifications to a BaseApp.
func (app *BaseApp) Seal() { app.sealed = true }

// IsSealed returns true if the BaseApp is sealed and false otherwise.
func (app *BaseApp) IsSealed() bool { return app.sealed }

// setCheckState sets the BaseApp's checkState with a branched multi-store
// (i.e. a CacheMultiStore) and a new Context with the same multi-store branch,
// provided header, and minimum gas prices set. It is set on InitChain and reset
// on Commit.
func (app *BaseApp) setCheckState(header tmproto.Header) {
	ms := app.cms.CacheMultiStore()
	app.checkState = &state{
		ms:  ms,
		ctx: sdk.NewContext(ms, header, true, app.logger).WithMinGasPrices(app.minGasPrices),
	}
}

// setDeliverState sets the BaseApp's deliverState with a branched multi-store
// (i.e. a CacheMultiStore) and a new Context with the same multi-store branch,
// and provided header. It is set on InitChain and BeginBlock and set to nil on
// Commit.
func (app *BaseApp) setDeliverState(header tmproto.Header) {
	ms := app.cms.CacheMultiStore()
	app.deliverState = &state{
		ms:  ms,
		ctx: sdk.NewContext(ms, header, false, app.logger),
	}
}

// GetConsensusParams returns the current consensus parameters from the BaseApp's
// ParamStore. If the BaseApp has no ParamStore defined, nil is returned.
func (app *BaseApp) GetConsensusParams(ctx sdk.Context) *tmproto.ConsensusParams {
	if app.paramStore == nil {
		return nil
	}

	cp := new(tmproto.ConsensusParams)

	if app.paramStore.Has(ctx, ParamStoreKeyBlockParams) {
		var bp tmproto.BlockParams

		app.paramStore.Get(ctx, ParamStoreKeyBlockParams, &bp)
		cp.Block = &bp
	}

	if app.paramStore.Has(ctx, ParamStoreKeyEvidenceParams) {
		var ep tmproto.EvidenceParams

		app.paramStore.Get(ctx, ParamStoreKeyEvidenceParams, &ep)
		cp.Evidence = &ep
	}

	if app.paramStore.Has(ctx, ParamStoreKeyValidatorParams) {
		var vp tmproto.ValidatorParams

		app.paramStore.Get(ctx, ParamStoreKeyValidatorParams, &vp)
		cp.Validator = &vp
	}

	return cp
}

// StoreConsensusParams sets the consensus parameters to the baseapp's param store.
func (app *BaseApp) StoreConsensusParams(ctx sdk.Context, cp *tmproto.ConsensusParams) {
	if app.paramStore == nil {
		panic("cannot store consensus params with no params store set")
	}

	if cp == nil {
		return
	}

	app.paramStore.Set(ctx, ParamStoreKeyBlockParams, cp.Block)
	app.paramStore.Set(ctx, ParamStoreKeyEvidenceParams, cp.Evidence)
	app.paramStore.Set(ctx, ParamStoreKeyValidatorParams, cp.Validator)
	// We're explicitly not storing the Tendermint app_version in the param store. It's
	// stored instead in the x/upgrade store, with its own bump logic.
}

// getMaximumBlockGas gets the maximum gas from the consensus params. It panics
// if maximum block gas is less than negative one and returns zero if negative
// one.
func (app *BaseApp) getMaximumBlockGas(ctx sdk.Context) uint64 {
	cp := app.GetConsensusParams(ctx)
	if cp == nil || cp.Block == nil {
		return 0
	}

	maxGas := cp.Block.MaxGas

	switch {
	case maxGas < -1:
		panic(fmt.Sprintf("invalid maximum block gas: %d", maxGas))

	case maxGas == -1:
		return 0

	default:
		return uint64(maxGas)
	}
}

func (app *BaseApp) validateHeight(req abci.RequestBeginBlock) error {
	if req.Header.Height < 1 {
		return fmt.Errorf("invalid height: %d", req.Header.Height)
	}

	// expectedHeight holds the expected height to validate.
	var expectedHeight int64
	if app.LastBlockHeight() == 0 && app.initialHeight > 1 {
		// In this case, we're validating the first block of the chain (no
		// previous commit). The height we're expecting is the initial height.
		expectedHeight = app.initialHeight
	} else {
		// This case can means two things:
		// - either there was already a previous commit in the store, in which
		// case we increment the version from there,
		// - or there was no previous commit, and initial version was not set,
		// in which case we start at version 1.
		expectedHeight = app.LastBlockHeight() + 1
	}

	if req.Header.Height != expectedHeight {
		return fmt.Errorf("invalid height: %d; expected: %d", req.Header.Height, expectedHeight)
	}

	return nil
}

// Returns the applications's deliverState if app is in runTxModeDeliver,
// otherwise it returns the application's checkstate.
func (app *BaseApp) getState(mode runTxMode) *state {
	if mode == runTxModeDeliver {
		return app.deliverState
	}

	return app.checkState
}

// retrieve the context for the tx w/ txBytes and other memoized values.
func (app *BaseApp) getContextForTx(mode runTxMode, txBytes []byte) context.Context {
	ctx := app.getState(mode).ctx.
		WithTxBytes(txBytes).
		WithVoteInfos(app.voteInfos)

	ctx = ctx.WithConsensusParams(app.GetConsensusParams(ctx))

	if mode == runTxModeReCheck {
		ctx = ctx.WithIsReCheckTx(true)
	}

	if mode == runTxModeSimulate {
		ctx, _ = ctx.CacheContext()
	}

	return sdk.WrapSDKContext(ctx)
}