package app

import (
	"encoding/json"
	"io"
	"os"

	abci "github.com/tendermint/tendermint/abci/types"
	cmn "github.com/tendermint/tendermint/libs/common"
	dbm "github.com/tendermint/tendermint/libs/db"
	"github.com/tendermint/tendermint/libs/log"
	tmtypes "github.com/tendermint/tendermint/types"

	bam "github.com/cosmos/cosmos-sdk/baseapp"
	"github.com/cosmos/cosmos-sdk/codec"
	sdk "github.com/cosmos/cosmos-sdk/types"
	"github.com/cosmos/cosmos-sdk/x/auth"
	"github.com/cosmos/cosmos-sdk/x/bank"
	distr "github.com/cosmos/cosmos-sdk/x/distribution"
	"github.com/cosmos/cosmos-sdk/x/gov"
	"github.com/cosmos/cosmos-sdk/x/params"
	"github.com/cosmos/cosmos-sdk/x/slashing"
	"github.com/cosmos/cosmos-sdk/x/stake"
)

const (
	appName = "GaiaApp"
)

// default home directories for expected binaries
var (
	DefaultCLIHome  = os.ExpandEnv("$HOME/.gaiacli")
	DefaultNodeHome = os.ExpandEnv("$HOME/.gaiad")
)

// Extended ABCI application
type GaiaApp struct {
	*bam.BaseApp
	cdc *codec.Codec

	// keys to access the substores
	keyMain          *sdk.KVStoreKey
	keyAccount       *sdk.KVStoreKey
	keyStake         *sdk.KVStoreKey
	tkeyStake        *sdk.TransientStoreKey
	keySlashing      *sdk.KVStoreKey
	keyDistr         *sdk.KVStoreKey
	tkeyDistr        *sdk.TransientStoreKey
	keyGov           *sdk.KVStoreKey
	keyFeeCollection *sdk.KVStoreKey
	keyParams        *sdk.KVStoreKey
	tkeyParams       *sdk.TransientStoreKey

	// Manage getting and setting accounts
	accountMapper       auth.AccountMapper
	feeCollectionKeeper auth.FeeCollectionKeeper
	bankKeeper          bank.Keeper
	stakeKeeper         stake.Keeper
	slashingKeeper      slashing.Keeper
	distrKeeper         distr.Keeper
	govKeeper           gov.Keeper
	paramsKeeper        params.Keeper
}

// NewGaiaApp returns a reference to an initialized GaiaApp.
func NewGaiaApp(logger log.Logger, db dbm.DB, traceStore io.Writer, baseAppOptions ...func(*bam.BaseApp)) *GaiaApp {
	cdc := MakeCodec()

	bApp := bam.NewBaseApp(appName, logger, db, auth.DefaultTxDecoder(cdc), baseAppOptions...)
	bApp.SetCommitMultiStoreTracer(traceStore)

	var app = &GaiaApp{
		BaseApp:          bApp,
		cdc:              cdc,
		keyMain:          sdk.NewKVStoreKey("main"),
		keyAccount:       sdk.NewKVStoreKey("acc"),
		keyStake:         sdk.NewKVStoreKey("stake"),
		tkeyStake:        sdk.NewTransientStoreKey("transient_stake"),
		keyDistr:         sdk.NewKVStoreKey("distr"),
		tkeyDistr:        sdk.NewTransientStoreKey("transient_distr"),
		keySlashing:      sdk.NewKVStoreKey("slashing"),
		keyGov:           sdk.NewKVStoreKey("gov"),
		keyFeeCollection: sdk.NewKVStoreKey("fee"),
		keyParams:        sdk.NewKVStoreKey("params"),
		tkeyParams:       sdk.NewTransientStoreKey("transient_params"),
	}

	// define the accountMapper
	app.accountMapper = auth.NewAccountMapper(
		app.cdc,
		app.keyAccount,        // target store
		auth.ProtoBaseAccount, // prototype
	)

	// add handlers
	app.bankKeeper = bank.NewBaseKeeper(app.accountMapper)
	app.feeCollectionKeeper = auth.NewFeeCollectionKeeper(
		app.cdc,
		app.keyFeeCollection,
	)
	app.paramsKeeper = params.NewKeeper(
		app.cdc,
		app.keyParams, app.tkeyParams,
	)
	app.stakeKeeper = stake.NewKeeper(
		app.cdc,
		app.keyStake, app.tkeyStake,
		app.bankKeeper, app.paramsKeeper.Subspace(stake.DefaultParamspace),
		app.RegisterCodespace(stake.DefaultCodespace),
	)
	app.distrKeeper = distr.NewKeeper(
		app.cdc,
		app.keyDistr,
		app.paramsKeeper.Subspace(distr.DefaultParamspace),
		app.bankKeeper, app.stakeKeeper, app.feeCollectionKeeper,
		app.RegisterCodespace(stake.DefaultCodespace),
	)
	app.slashingKeeper = slashing.NewKeeper(
		app.cdc,
		app.keySlashing,
		app.stakeKeeper, app.paramsKeeper.Subspace(slashing.DefaultParamspace),
		app.RegisterCodespace(slashing.DefaultCodespace),
	)
	app.govKeeper = gov.NewKeeper(
		app.cdc,
		app.keyGov,
		app.paramsKeeper, app.paramsKeeper.Subspace(gov.DefaultParamspace), app.bankKeeper, app.stakeKeeper,
		app.RegisterCodespace(gov.DefaultCodespace),
	)

	// register the staking hooks
	app.stakeKeeper = app.stakeKeeper.WithHooks(
		NewHooks(app.distrKeeper.Hooks(), app.slashingKeeper.Hooks()))

	// register message routes
	app.Router().
		AddRoute("bank", bank.NewHandler(app.bankKeeper)).
		AddRoute("stake", stake.NewHandler(app.stakeKeeper)).
		AddRoute("distr", distr.NewHandler(app.distrKeeper)).
		AddRoute("slashing", slashing.NewHandler(app.slashingKeeper)).
		AddRoute("gov", gov.NewHandler(app.govKeeper))

	app.QueryRouter().
		AddRoute("gov", gov.NewQuerier(app.govKeeper)).
		AddRoute("stake", stake.NewQuerier(app.stakeKeeper, app.cdc))

	// initialize BaseApp
	app.SetInitChainer(app.initChainer)
	app.SetBeginBlocker(app.BeginBlocker)
	app.SetAnteHandler(auth.NewAnteHandler(app.accountMapper, app.feeCollectionKeeper))
	app.MountStoresIAVL(app.keyMain, app.keyAccount, app.keyStake, app.keyDistr,
		app.keySlashing, app.keyGov, app.keyFeeCollection, app.keyParams)
	app.MountStoresTransient(app.tkeyParams, app.tkeyStake, app.tkeyDistr)
	app.SetEndBlocker(app.EndBlocker)

	err := app.LoadLatestVersion(app.keyMain)
	if err != nil {
		cmn.Exit(err.Error())
	}

	return app
}

// custom tx codec
func MakeCodec() *codec.Codec {
	var cdc = codec.New()
	bank.RegisterCodec(cdc)
	stake.RegisterCodec(cdc)
	distr.RegisterCodec(cdc)
	slashing.RegisterCodec(cdc)
	gov.RegisterCodec(cdc)
	auth.RegisterCodec(cdc)
	sdk.RegisterCodec(cdc)
	codec.RegisterCrypto(cdc)
	return cdc
}

// application updates every end block
func (app *GaiaApp) BeginBlocker(ctx sdk.Context, req abci.RequestBeginBlock) abci.ResponseBeginBlock {
	tags := slashing.BeginBlocker(ctx, req, app.slashingKeeper)

	// distribute rewards from previous block
	distr.BeginBlocker(ctx, req, app.distrKeeper)

	return abci.ResponseBeginBlock{
		Tags: tags.ToKVPairs(),
	}
}

// application updates every end block
// nolint: unparam
func (app *GaiaApp) EndBlocker(ctx sdk.Context, req abci.RequestEndBlock) abci.ResponseEndBlock {

	tags := gov.EndBlocker(ctx, app.govKeeper)
	validatorUpdates := stake.EndBlocker(ctx, app.stakeKeeper)

	// Add these new validators to the addr -> pubkey map.
	app.slashingKeeper.AddValidators(ctx, validatorUpdates)

	return abci.ResponseEndBlock{
		ValidatorUpdates: validatorUpdates,
		Tags:             tags,
	}
}

// custom logic for gaia initialization
func (app *GaiaApp) initChainer(ctx sdk.Context, req abci.RequestInitChain) abci.ResponseInitChain {
	stateJSON := req.AppStateBytes
	// TODO is this now the whole genesis file?

	var genesisState GenesisState
	err := app.cdc.UnmarshalJSON(stateJSON, &genesisState)
	if err != nil {
		panic(err) // TODO https://github.com/cosmos/cosmos-sdk/issues/468
		// return sdk.ErrGenesisParse("").TraceCause(err, "")
	}

	// load the accounts
	for _, gacc := range genesisState.Accounts {
		acc := gacc.ToAccount()
		acc.AccountNumber = app.accountMapper.GetNextAccountNumber(ctx)
		app.accountMapper.SetAccount(ctx, acc)
	}

	// load the initial stake information
	validators, err := stake.InitGenesis(ctx, app.stakeKeeper, genesisState.StakeData)
	if err != nil {
		panic(err) // TODO find a way to do this w/o panics
	}

	// load the address to pubkey map
	slashing.InitGenesis(ctx, app.slashingKeeper, genesisState.SlashingData, genesisState.StakeData)

	gov.InitGenesis(ctx, app.govKeeper, genesisState.GovData)
	distr.InitGenesis(ctx, app.distrKeeper, genesisState.DistrData)
	err = GaiaValidateGenesisState(genesisState)
	if err != nil {
		panic(err) // TODO find a way to do this w/o panics
	}

	return abci.ResponseInitChain{
		Validators: validators,
	}
}

// export the state of gaia for a genesis file
func (app *GaiaApp) ExportAppStateAndValidators() (appState json.RawMessage, validators []tmtypes.GenesisValidator, err error) {
	ctx := app.NewContext(true, abci.Header{})

	// iterate to get the accounts
	accounts := []GenesisAccount{}
	appendAccount := func(acc auth.Account) (stop bool) {
		account := NewGenesisAccountI(acc)
		accounts = append(accounts, account)
		return false
	}
	app.accountMapper.IterateAccounts(ctx, appendAccount)

	genState := GenesisState{
		Accounts:  accounts,
		StakeData: stake.WriteGenesis(ctx, app.stakeKeeper),
		DistrData: distr.WriteGenesis(ctx, app.distrKeeper),
		GovData:   gov.WriteGenesis(ctx, app.govKeeper),
	}
	appState, err = codec.MarshalJSONIndent(app.cdc, genState)
	if err != nil {
		return nil, nil, err
	}
	validators = stake.WriteValidators(ctx, app.stakeKeeper)
	return appState, validators, nil
}

//______________________________________________________________________________________________

// Combined Staking Hooks
type Hooks struct {
	dh distr.Hooks
	sh slashing.Hooks
}

func NewHooks(dh distr.Hooks, sh slashing.Hooks) Hooks {
	return Hooks{dh, sh}
}

var _ sdk.StakingHooks = Hooks{}

// nolint
func (h Hooks) OnValidatorCreated(ctx sdk.Context, addr sdk.ValAddress) {
	h.dh.OnValidatorCreated(ctx, addr)
}
func (h Hooks) OnValidatorCommissionChange(ctx sdk.Context, addr sdk.ValAddress) {
	h.dh.OnValidatorCommissionChange(ctx, addr)
}
func (h Hooks) OnValidatorRemoved(ctx sdk.Context, addr sdk.ValAddress) {
	h.dh.OnValidatorRemoved(ctx, addr)
}
func (h Hooks) OnValidatorBonded(ctx sdk.Context, addr sdk.ConsAddress) {
	h.sh.OnValidatorBonded(ctx, addr)
}
func (h Hooks) OnValidatorBeginUnbonding(ctx sdk.Context, addr sdk.ConsAddress) {
	h.sh.OnValidatorBeginUnbonding(ctx, addr)
}
func (h Hooks) OnDelegationCreated(ctx sdk.Context, delAddr sdk.AccAddress, valAddr sdk.ValAddress) {
	h.dh.OnDelegationCreated(ctx, delAddr, valAddr)
}
func (h Hooks) OnDelegationSharesModified(ctx sdk.Context, delAddr sdk.AccAddress, valAddr sdk.ValAddress) {
	h.dh.OnDelegationSharesModified(ctx, delAddr, valAddr)
}
func (h Hooks) OnDelegationRemoved(ctx sdk.Context, delAddr sdk.AccAddress, valAddr sdk.ValAddress) {
	h.dh.OnDelegationRemoved(ctx, delAddr, valAddr)
}