package middleware

import (
	sdk "github.com/cosmos/cosmos-sdk/types"
	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
	"github.com/cosmos/cosmos-sdk/types/tx"
	"github.com/cosmos/cosmos-sdk/types/tx/signing"
	authsigning "github.com/cosmos/cosmos-sdk/x/auth/signing"
	"github.com/cosmos/cosmos-sdk/x/auth/types"
)

// ComposeMiddlewares compose multiple middlewares on top of a tx.Handler. The
// middleware order in the variadic arguments is from outer to inner.
//
// Example: Given a base tx.Handler H, and two middlewares A and B, the
// middleware stack:
// ```
// A.pre
//   B.pre
//     H
//   B.post
// A.post
// ```
// is created by calling `ComposeMiddlewares(H, A, B)`.
func ComposeMiddlewares(txHandler tx.Handler, middlewares ...tx.Middleware) tx.Handler {
	for i := len(middlewares) - 1; i >= 0; i-- {
		txHandler = middlewares[i](txHandler)
	}

	return txHandler
}

type TxHandlerOptions struct {
	Debug 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{}

	LegacyRouter     sdk.Router
	MsgServiceRouter *MsgServiceRouter

	AccountKeeper   AccountKeeper
	BankKeeper      types.BankKeeper
	FeegrantKeeper  FeegrantKeeper
	SignModeHandler authsigning.SignModeHandler
	SigGasConsumer  func(meter sdk.GasMeter, sig signing.SignatureV2, params types.Params) error
}

// NewDefaultTxHandler defines a TxHandler middleware stacks that should work
// for most applications.
func NewDefaultTxHandler(options TxHandlerOptions) (tx.Handler, error) {
	if options.AccountKeeper == nil {
		return nil, sdkerrors.Wrap(sdkerrors.ErrLogic, "account keeper is required for compose middlewares")
	}

	if options.BankKeeper == nil {
		return nil, sdkerrors.Wrap(sdkerrors.ErrLogic, "bank keeper is required for compose middlewares")
	}

	if options.SignModeHandler == nil {
		return nil, sdkerrors.Wrap(sdkerrors.ErrLogic, "sign mode handler is required for compose middlewares")
	}

	var sigGasConsumer = options.SigGasConsumer
	if sigGasConsumer == nil {
		sigGasConsumer = DefaultSigVerificationGasConsumer
	}

	return ComposeMiddlewares(
		NewRunMsgsTxHandler(options.MsgServiceRouter, options.LegacyRouter),
		// Set a new GasMeter on sdk.Context.
		//
		// Make sure the Gas middleware is outside of all other middlewares
		// that reads the GasMeter. In our case, the Recovery middleware reads
		// the GasMeter to populate GasInfo.
		GasTxMiddleware,
		// Recover from panics. Panics outside of this middleware won't be
		// caught, be careful!
		RecoveryTxMiddleware,
		// Choose which events to index in Tendermint. Make sure no events are
		// emitted outside of this middleware.
		NewIndexEventsTxMiddleware(options.IndexEvents),
		// Reject all extension options which can optionally be included in the
		// tx.
		RejectExtensionOptionsMiddleware,
		MempoolFeeMiddleware,
		ValidateBasicMiddleware,
		TxTimeoutHeightMiddleware,
		ValidateMemoMiddleware(options.AccountKeeper),
		ConsumeTxSizeGasMiddleware(options.AccountKeeper),
		DeductFeeMiddleware(options.AccountKeeper, options.BankKeeper, options.FeegrantKeeper),
		SetPubKeyMiddleware(options.AccountKeeper),
		ValidateSigCountMiddleware(options.AccountKeeper),
		SigGasConsumeMiddleware(options.AccountKeeper, sigGasConsumer),
		SigVerificationMiddleware(options.AccountKeeper, options.SignModeHandler),
		IncrementSequenceMiddleware(options.AccountKeeper),
	), nil
}