package account

import (
	"context"
	"encoding/json"

	log "github.com/sirupsen/logrus"

	"github.com/bytom/blockchain/signers"
	"github.com/bytom/blockchain/txbuilder"
	"github.com/bytom/common"
	"github.com/bytom/consensus"
	"github.com/bytom/crypto/ed25519/chainkd"
	"github.com/bytom/errors"
	"github.com/bytom/protocol/bc"
	"github.com/bytom/protocol/bc/types"
	"github.com/bytom/protocol/vm/vmutil"
)

//DecodeSpendAction unmarshal JSON-encoded data of spend action
func (m *Manager) DecodeSpendAction(data []byte) (txbuilder.Action, error) {
	a := &spendAction{accounts: m}
	err := json.Unmarshal(data, a)
	return a, err
}

type spendAction struct {
	accounts *Manager
	bc.AssetAmount
	AccountID   string  `json:"account_id"`
	ClientToken *string `json:"client_token"`
}

func (a *spendAction) Build(ctx context.Context, b *txbuilder.TemplateBuilder) error {
	var missing []string
	if a.AccountID == "" {
		missing = append(missing, "account_id")
	}
	if a.AssetId.IsZero() {
		missing = append(missing, "asset_id")
	}
	if len(missing) > 0 {
		return txbuilder.MissingFieldsError(missing...)
	}

	acct, err := a.accounts.FindByID(ctx, a.AccountID)
	if err != nil {
		return errors.Wrap(err, "get account info")
	}

	src := source{
		AssetID:   *a.AssetId,
		AccountID: a.AccountID,
	}
	res, err := a.accounts.utxoDB.Reserve(src, a.Amount, a.ClientToken, b.MaxTime())
	if err != nil {
		return errors.Wrap(err, "reserving utxos")
	}

	// Cancel the reservation if the build gets rolled back.
	b.OnRollback(canceler(ctx, a.accounts, res.ID))

	for _, r := range res.UTXOs {
		txInput, sigInst, err := UtxoToInputs(acct.Signer, r)
		if err != nil {
			return errors.Wrap(err, "creating inputs")
		}
		err = b.AddInput(txInput, sigInst)
		if err != nil {
			return errors.Wrap(err, "adding inputs")
		}
	}

	if res.Change > 0 {
		acp, err := a.accounts.CreateAddress(ctx, a.AccountID, true)
		if err != nil {
			return errors.Wrap(err, "creating control program")
		}

		// Don't insert the control program until callbacks are executed.
		a.accounts.insertControlProgramDelayed(ctx, b, acp)

		err = b.AddOutput(types.NewTxOutput(*a.AssetId, res.Change, acp.ControlProgram))
		if err != nil {
			return errors.Wrap(err, "adding change output")
		}
	}
	return nil
}

//DecodeSpendUTXOAction unmarshal JSON-encoded data of spend utxo action
func (m *Manager) DecodeSpendUTXOAction(data []byte) (txbuilder.Action, error) {
	a := &spendUTXOAction{accounts: m}
	err := json.Unmarshal(data, a)
	return a, err
}

type spendUTXOAction struct {
	accounts *Manager
	OutputID *bc.Hash `json:"output_id"`

	ClientToken *string `json:"client_token"`
}

func (a *spendUTXOAction) Build(ctx context.Context, b *txbuilder.TemplateBuilder) error {
	if a.OutputID == nil {
		return txbuilder.MissingFieldsError("output_id")
	}

	res, err := a.accounts.utxoDB.ReserveUTXO(ctx, *a.OutputID, a.ClientToken, b.MaxTime())
	if err != nil {
		return err
	}
	b.OnRollback(canceler(ctx, a.accounts, res.ID))

	var accountSigner *signers.Signer
	if len(res.Source.AccountID) != 0 {
		account, err := a.accounts.FindByID(ctx, res.Source.AccountID)
		if err != nil {
			return err
		}
		accountSigner = account.Signer
	}

	txInput, sigInst, err := UtxoToInputs(accountSigner, res.UTXOs[0])
	if err != nil {
		return err
	}
	return b.AddInput(txInput, sigInst)
}

// Best-effort cancellation attempt to put in txbuilder.BuildResult.Rollback.
func canceler(ctx context.Context, m *Manager, rid uint64) func() {
	return func() {
		if err := m.utxoDB.Cancel(ctx, rid); err != nil {
			log.WithField("error", err).Error("Best-effort cancellation attempt to put in txbuilder.BuildResult.Rollback")
		}
	}
}

// UtxoToInputs convert an utxo to the txinput
func UtxoToInputs(signer *signers.Signer, u *UTXO) (*types.TxInput, *txbuilder.SigningInstruction, error) {
	txInput := types.NewSpendInput(nil, u.SourceID, u.AssetID, u.Amount, u.SourcePos, u.ControlProgram)
	sigInst := &txbuilder.SigningInstruction{}
	if signer == nil {
		return txInput, sigInst, nil
	}

	path := signers.Path(signer, signers.AccountKeySpace, u.ControlProgramIndex)
	if u.Address == "" {
		sigInst.AddWitnessKeys(signer.XPubs, path, signer.Quorum)
		return txInput, sigInst, nil
	}

	address, err := common.DecodeAddress(u.Address, &consensus.ActiveNetParams)
	if err != nil {
		return nil, nil, err
	}

	switch address.(type) {
	case *common.AddressWitnessPubKeyHash:
		sigInst.AddRawWitnessKeys(signer.XPubs, path, signer.Quorum)
		derivedXPubs := chainkd.DeriveXPubs(signer.XPubs, path)
		derivedPK := derivedXPubs[0].PublicKey()
		sigInst.WitnessComponents = append(sigInst.WitnessComponents, txbuilder.DataWitness([]byte(derivedPK)))

	case *common.AddressWitnessScriptHash:
		sigInst.AddRawWitnessKeys(signer.XPubs, path, signer.Quorum)
		path := signers.Path(signer, signers.AccountKeySpace, u.ControlProgramIndex)
		derivedXPubs := chainkd.DeriveXPubs(signer.XPubs, path)
		derivedPKs := chainkd.XPubKeys(derivedXPubs)
		script, err := vmutil.P2SPMultiSigProgram(derivedPKs, signer.Quorum)
		if err != nil {
			return nil, nil, err
		}
		sigInst.WitnessComponents = append(sigInst.WitnessComponents, txbuilder.DataWitness(script))

	default:
		return nil, nil, errors.New("unsupport address type")
	}

	return txInput, sigInst, nil
}

// insertControlProgramDelayed takes a template builder and an account
// control program that hasn't been inserted to the database yet. It
// registers callbacks on the TemplateBuilder so that all of the template's
// account control programs are batch inserted if building the rest of
// the template is successful.
func (m *Manager) insertControlProgramDelayed(ctx context.Context, b *txbuilder.TemplateBuilder, acp *CtrlProgram) {
	m.delayedACPsMu.Lock()
	m.delayedACPs[b] = append(m.delayedACPs[b], acp)
	m.delayedACPsMu.Unlock()

	b.OnRollback(func() {
		m.delayedACPsMu.Lock()
		delete(m.delayedACPs, b)
		m.delayedACPsMu.Unlock()
	})
	b.OnBuild(func() error {
		m.delayedACPsMu.Lock()
		acps := m.delayedACPs[b]
		delete(m.delayedACPs, b)
		m.delayedACPsMu.Unlock()

		// Insert all of the account control programs at once.
		if len(acps) == 0 {
			return nil
		}
		return m.insertAccountControlProgram(ctx, acps...)
	})
}