package shreder

import (
	"bytes"
	"encoding/binary"
	"fmt"

	"github.com/gagliardetto/solana-go"
)

var binanceWalletProgramID = solana.MustPublicKeyFromBase58("B3111yJCeHBcA1bizdJjUFPALfhAfSRnAbJzGUtnt56A")

const (
	binanceWalletMinDataLen = 72
	binanceWalletSolOffset  = 23
	binanceWalletTokenOff   = 39
	binanceWalletSolRepeat  = 51
	binanceWalletSideOff    = 71

	binanceWalletPumpBuy  = 0x05
	binanceWalletPumpSell = 0x06
)

var binanceWalletMarker = []byte{0x13, 0x2c, 0x82, 0x94, 0x48, 0x38, 0x2c, 0xee}

func parseBinanceWalletInstruction(tx VersionedTransaction, instructionIndex int) (TxSignalBatch, error) {
	if instructionIndex >= len(tx.Instructions) {
		return nil, fmt.Errorf("instruction index out of bounds")
	}

	instruction := tx.Instructions[instructionIndex]
	if len(instruction.Data) < len(binanceWalletMarker) || !bytes.Contains(instruction.Data, binanceWalletMarker) {
		return nil, nil
	}
	if len(instruction.Data) < binanceWalletMinDataLen {
		return nil, fmt.Errorf("data too short for binance wallet, len=%d", len(instruction.Data))
	}

	side := instruction.Data[binanceWalletSideOff]
	if side != binanceWalletPumpBuy && side != binanceWalletPumpSell {
		return nil, nil
	}

	if len(instruction.Accounts) <= 8 {
		return nil, fmt.Errorf("accounts too short")
	}

	wsolIdx := 7
	tokenIdx := 8
	if side == binanceWalletPumpSell {
		wsolIdx = 8
		tokenIdx = 7
	}

	wsolKey, err := tx.GetAccount(int(instruction.Accounts[wsolIdx]))
	if err != nil {
		return nil, err
	}
	if !wsolKey.Equals(solana.WrappedSol) {
		return nil, nil
	}
	mint, err := tx.GetAccount(int(instruction.Accounts[tokenIdx]))
	if err != nil {
		return nil, err
	}

	amountA := binary.LittleEndian.Uint64(instruction.Data[binanceWalletSolOffset : binanceWalletSolOffset+8])
	if amountA == 0 && len(instruction.Data) >= binanceWalletSolRepeat+8 {
		repeat := binary.LittleEndian.Uint64(instruction.Data[binanceWalletSolRepeat : binanceWalletSolRepeat+8])
		if repeat > 0 {
			amountA = repeat
		}
	}
	amountB := binary.LittleEndian.Uint64(instruction.Data[binanceWalletTokenOff : binanceWalletTokenOff+8])

	solAmount := amountA
	tokenAmount := amountB
	if side == binanceWalletPumpSell {
		solAmount = amountB
		tokenAmount = amountA
	}

	maker := ""
	if len(tx.StaticAccountKeys) > 0 {
		maker = tx.StaticAccountKeys[0].String()
	} else if len(instruction.Accounts) > 0 {
		key, err := tx.GetAccount(int(instruction.Accounts[0]))
		if err != nil {
			return nil, err
		}
		maker = key.String()
	}

	event := "buy"
	exactIn := true
	if side == binanceWalletPumpSell {
		event = "sell"
		exactIn = false
	}

	return TxSignalBatch{&TxSignal{
		TxHash:             tx.Signatures[0].String(),
		Label:              "binancewallet",
		Maker:              maker,
		Token0Address:      mint.String(),
		Token1Address:      wsolMint,
		Token0Amount:       formatTokenAmount(tokenAmount),
		Token1Amount:       formatSolAmount(solAmount),
		Program:            "Pump",
		Event:              event,
		IsToken2022:        false,
		IsMayhemMode:       false,
		ExactSOL:           exactIn,
		Block:              tx.Block,
		Token0AmountUint64: tokenAmount,
		Token1AmountUint64: solAmount,
	}}, nil
}