package pathprocessor

import (
	"context"
	"fmt"
	"math/big"
	"strings"

	"github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/accounts/abi"
	"github.com/ethereum/go-ethereum/accounts/abi/bind"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	ethTypes "github.com/ethereum/go-ethereum/core/types"
	"github.com/status-im/status-go/account"
	"github.com/status-im/status-go/contracts/community-tokens/collectibles"
	"github.com/status-im/status-go/contracts/erc721"
	"github.com/status-im/status-go/eth-node/types"
	"github.com/status-im/status-go/params"
	"github.com/status-im/status-go/rpc"
	"github.com/status-im/status-go/services/wallet/token"
	"github.com/status-im/status-go/transactions"
)

const (
	functionNameSafeTransferFrom = "safeTransferFrom"
	functionNameTransferFrom     = "transferFrom"
)

type ERC721TxArgs struct {
	transactions.SendTxArgs
	TokenID   *hexutil.Big   `json:"tokenId"`
	Recipient common.Address `json:"recipient"`
}

type ERC721Processor struct {
	rpcClient  *rpc.Client
	transactor transactions.TransactorIface
}

func NewERC721Processor(rpcClient *rpc.Client, transactor transactions.TransactorIface) *ERC721Processor {
	return &ERC721Processor{rpcClient: rpcClient, transactor: transactor}
}

func createERC721ErrorResponse(err error) error {
	return createErrorResponse(ProcessorERC721Name, err)
}

func (s *ERC721Processor) Name() string {
	return ProcessorERC721Name
}

func (s *ERC721Processor) AvailableFor(params ProcessorInputParams) (bool, error) {
	return params.FromChain.ChainID == params.ToChain.ChainID && params.ToToken == nil, nil
}

func (s *ERC721Processor) CalculateFees(params ProcessorInputParams) (*big.Int, *big.Int, error) {
	return ZeroBigIntValue, ZeroBigIntValue, nil
}

func (s *ERC721Processor) packTxInputDataInternally(params ProcessorInputParams, functionName string) ([]byte, error) {
	abi, err := abi.JSON(strings.NewReader(erc721.Erc721MetaData.ABI))
	if err != nil {
		return []byte{}, createERC721ErrorResponse(err)
	}

	id, success := big.NewInt(0).SetString(params.FromToken.Symbol, 0)
	if !success {
		return []byte{}, createERC721ErrorResponse(fmt.Errorf("failed to convert %s to big.Int", params.FromToken.Symbol))
	}

	return abi.Pack(functionName,
		params.FromAddr,
		params.ToAddr,
		id,
	)
}

func (s *ERC721Processor) checkIfFunctionExists(params ProcessorInputParams, functionName string) error {
	data, err := s.packTxInputDataInternally(params, functionName)
	if err != nil {
		return createERC721ErrorResponse(err)
	}

	ethClient, err := s.rpcClient.EthClient(params.FromChain.ChainID)
	if err != nil {
		return createERC721ErrorResponse(err)
	}

	value := new(big.Int)
	msg := ethereum.CallMsg{
		From:  params.FromAddr,
		To:    &params.FromToken.Address,
		Value: value,
		Data:  data,
	}

	_, err = ethClient.CallContract(context.Background(), msg, nil)
	return err
}

func (s *ERC721Processor) PackTxInputData(params ProcessorInputParams) ([]byte, error) {
	err := s.checkIfFunctionExists(params, functionNameSafeTransferFrom)
	if err == nil {
		return s.packTxInputDataInternally(params, functionNameSafeTransferFrom)
	}

	return s.packTxInputDataInternally(params, functionNameTransferFrom)
}

func (s *ERC721Processor) EstimateGas(params ProcessorInputParams) (uint64, error) {
	if params.TestsMode {
		if params.TestEstimationMap != nil {
			if val, ok := params.TestEstimationMap[s.Name()]; ok {
				return val.Value, val.Err
			}
		}
		return 0, ErrNoEstimationFound
	}

	ethClient, err := s.rpcClient.EthClient(params.FromChain.ChainID)
	if err != nil {
		return 0, createERC721ErrorResponse(err)
	}

	value := new(big.Int)

	input, err := s.PackTxInputData(params)
	if err != nil {
		return 0, createERC721ErrorResponse(err)
	}

	msg := ethereum.CallMsg{
		From:  params.FromAddr,
		To:    &params.FromToken.Address,
		Value: value,
		Data:  input,
	}

	estimation, err := ethClient.EstimateGas(context.Background(), msg)
	if err != nil {
		return 0, createERC721ErrorResponse(err)
	}

	increasedEstimation := float64(estimation) * IncreaseEstimatedGasFactor
	return uint64(increasedEstimation), nil
}

func (s *ERC721Processor) sendOrBuild(sendArgs *MultipathProcessorTxArgs, signerFn bind.SignerFn, lastUsedNonce int64) (tx *ethTypes.Transaction, err error) {
	from := common.Address(sendArgs.ERC721TransferTx.From)

	useSafeTransferFrom := true
	inputParams := ProcessorInputParams{
		FromChain: &params.Network{
			ChainID: sendArgs.ChainID,
		},
		FromAddr: from,
		ToAddr:   sendArgs.ERC721TransferTx.Recipient,
		FromToken: &token.Token{
			Symbol: sendArgs.ERC721TransferTx.TokenID.String(),
		},
	}
	err = s.checkIfFunctionExists(inputParams, functionNameSafeTransferFrom)
	if err != nil {
		useSafeTransferFrom = false
	}

	ethClient, err := s.rpcClient.EthClient(sendArgs.ChainID)
	if err != nil {
		return tx, createERC721ErrorResponse(err)
	}

	contract, err := collectibles.NewCollectibles(common.Address(*sendArgs.ERC721TransferTx.To), ethClient)
	if err != nil {
		return tx, createERC721ErrorResponse(err)
	}

	var nonce uint64
	if lastUsedNonce < 0 {
		nonce, err = s.transactor.NextNonce(s.rpcClient, sendArgs.ChainID, sendArgs.ERC721TransferTx.From)
		if err != nil {
			return tx, createERC721ErrorResponse(err)
		}
	} else {
		nonce = uint64(lastUsedNonce) + 1
	}

	argNonce := hexutil.Uint64(nonce)
	sendArgs.ERC721TransferTx.Nonce = &argNonce
	txOpts := sendArgs.ERC721TransferTx.ToTransactOpts(signerFn)
	if useSafeTransferFrom {
		tx, err = contract.SafeTransferFrom(txOpts, from,
			sendArgs.ERC721TransferTx.Recipient,
			sendArgs.ERC721TransferTx.TokenID.ToInt())
	} else {
		tx, err = contract.TransferFrom(txOpts, from,
			sendArgs.ERC721TransferTx.Recipient,
			sendArgs.ERC721TransferTx.TokenID.ToInt())
	}
	if err != nil {
		return tx, createERC721ErrorResponse(err)
	}
	err = s.transactor.StoreAndTrackPendingTx(from, sendArgs.ERC721TransferTx.Symbol, sendArgs.ChainID, sendArgs.ERC721TransferTx.MultiTransactionID, tx)
	if err != nil {
		return tx, createERC721ErrorResponse(err)
	}
	return tx, nil
}

func (s *ERC721Processor) Send(sendArgs *MultipathProcessorTxArgs, lastUsedNonce int64, verifiedAccount *account.SelectedExtKey) (hash types.Hash, usedNonce uint64, err error) {
	tx, err := s.sendOrBuild(sendArgs, getSigner(sendArgs.ChainID, sendArgs.ERC721TransferTx.From, verifiedAccount), lastUsedNonce)
	if err != nil {
		return hash, 0, createERC721ErrorResponse(err)
	}
	return types.Hash(tx.Hash()), tx.Nonce(), nil
}

func (s *ERC721Processor) BuildTransaction(sendArgs *MultipathProcessorTxArgs, lastUsedNonce int64) (*ethTypes.Transaction, uint64, error) {
	tx, err := s.sendOrBuild(sendArgs, nil, lastUsedNonce)
	return tx, tx.Nonce(), err
}

func (s *ERC721Processor) CalculateAmountOut(params ProcessorInputParams) (*big.Int, error) {
	return params.AmountIn, nil
}

func (s *ERC721Processor) GetContractAddress(params ProcessorInputParams) (common.Address, error) {
	return params.FromToken.Address, nil
}