package state

import (
	"math/big"

	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
	"github.com/nspcc-dev/neo-go/pkg/io"
	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)

// NEP5BalanceState represents balance state of a NEP5-token.
type NEP5BalanceState struct {
	Balance big.Int
}

// NEOBalanceState represents balance state of a NEO-token.
type NEOBalanceState struct {
	NEP5BalanceState
	BalanceHeight uint32
	Votes         keys.PublicKeys
}

// NEP5BalanceStateFromBytes converts serialized NEP5BalanceState to structure.
func NEP5BalanceStateFromBytes(b []byte) (*NEP5BalanceState, error) {
	balance := new(NEP5BalanceState)
	if len(b) == 0 {
		return balance, nil
	}
	r := io.NewBinReaderFromBuf(b)
	balance.DecodeBinary(r)
	if r.Err != nil {
		return nil, r.Err
	}
	return balance, nil
}

// Bytes returns serialized NEP5BalanceState.
func (s *NEP5BalanceState) Bytes() []byte {
	w := io.NewBufBinWriter()
	s.EncodeBinary(w.BinWriter)
	if w.Err != nil {
		panic(w.Err)
	}
	return w.Bytes()
}

func (s *NEP5BalanceState) toStackItem() stackitem.Item {
	return stackitem.NewStruct([]stackitem.Item{stackitem.NewBigInteger(&s.Balance)})
}

func (s *NEP5BalanceState) fromStackItem(item stackitem.Item) {
	s.Balance = *item.(*stackitem.Struct).Value().([]stackitem.Item)[0].Value().(*big.Int)
}

// EncodeBinary implements io.Serializable interface.
func (s *NEP5BalanceState) EncodeBinary(w *io.BinWriter) {
	si := s.toStackItem()
	stackitem.EncodeBinaryStackItem(si, w)
}

// DecodeBinary implements io.Serializable interface.
func (s *NEP5BalanceState) DecodeBinary(r *io.BinReader) {
	si := stackitem.DecodeBinaryStackItem(r)
	if r.Err != nil {
		return
	}
	s.fromStackItem(si)
}

// NEOBalanceStateFromBytes converts serialized NEOBalanceState to structure.
func NEOBalanceStateFromBytes(b []byte) (*NEOBalanceState, error) {
	balance := new(NEOBalanceState)
	if len(b) == 0 {
		return balance, nil
	}
	r := io.NewBinReaderFromBuf(b)
	balance.DecodeBinary(r)

	if r.Err != nil {
		return nil, r.Err
	}
	return balance, nil
}

// Bytes returns serialized NEOBalanceState.
func (s *NEOBalanceState) Bytes() []byte {
	w := io.NewBufBinWriter()
	s.EncodeBinary(w.BinWriter)
	if w.Err != nil {
		panic(w.Err)
	}
	return w.Bytes()
}

// EncodeBinary implements io.Serializable interface.
func (s *NEOBalanceState) EncodeBinary(w *io.BinWriter) {
	si := s.toStackItem()
	stackitem.EncodeBinaryStackItem(si, w)
}

// DecodeBinary implements io.Serializable interface.
func (s *NEOBalanceState) DecodeBinary(r *io.BinReader) {
	si := stackitem.DecodeBinaryStackItem(r)
	if r.Err != nil {
		return
	}
	s.fromStackItem(si)
}

func (s *NEOBalanceState) toStackItem() stackitem.Item {
	result := s.NEP5BalanceState.toStackItem().(*stackitem.Struct)
	result.Append(stackitem.NewBigInteger(big.NewInt(int64(s.BalanceHeight))))
	votes := make([]stackitem.Item, len(s.Votes))
	for i, v := range s.Votes {
		votes[i] = stackitem.NewByteArray(v.Bytes())
	}
	result.Append(stackitem.NewArray(votes))
	return result
}

func (s *NEOBalanceState) fromStackItem(item stackitem.Item) {
	structItem := item.Value().([]stackitem.Item)
	s.Balance = *structItem[0].Value().(*big.Int)
	s.BalanceHeight = uint32(structItem[1].Value().(*big.Int).Int64())
	votes := structItem[2].Value().([]stackitem.Item)
	s.Votes = make([]*keys.PublicKey, len(votes))
	for i, v := range votes {
		s.Votes[i].DecodeBytes(v.Value().([]byte))
	}
}