// VulcanizeDB
// Copyright © 2018 Vulcanize

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.

// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package tend

import (
	"encoding/json"
	"errors"
	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared"
	"math/big"

	"github.com/ethereum/go-ethereum/core/types"
)

type TendConverter struct{}

func (TendConverter) ToModels(ethLogs []types.Log) (results []interface{}, err error) {
	for _, ethLog := range ethLogs {
		err := validateLog(ethLog)
		if err != nil {
			return nil, err
		}

		bidId := ethLog.Topics[2].Big()
		guy := shared.GetHexWithoutPrefix(ethLog.Topics[1].Bytes())
		lot := ethLog.Topics[3].Big().String()

		lastDataItemStartIndex := len(ethLog.Data) - 32
		lastItem := ethLog.Data[lastDataItemStartIndex:]
		last := big.NewInt(0).SetBytes(lastItem)
		bidValue := last.String()
		transactionIndex := ethLog.TxIndex
		logIndex := ethLog.Index

		rawLog, err := json.Marshal(ethLog)
		if err != nil {
			return nil, err
		}

		model := TendModel{
			BidId:            bidId.String(),
			Lot:              lot,
			Bid:              bidValue,
			Guy:              guy,
			LogIndex:         logIndex,
			TransactionIndex: transactionIndex,
			Raw:              rawLog,
		}
		results = append(results, model)
	}
	return results, err
}

func validateLog(ethLog types.Log) error {
	if len(ethLog.Data) <= 0 {
		return errors.New("tend log note data is empty")
	}

	if len(ethLog.Topics) < 4 {
		return errors.New("tend log does not contain expected topics")
	}

	return nil
}