package shreder

import (
	"encoding/binary"
	"fmt"

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

var gmgnProgramID = solana.MustPublicKeyFromBase58("GMgnVFR8Jb39LoXsEVzb3DvBy3ywCmdmJquHUy1Lrkqb")
var (
	gmgnBuyTokensIX = []byte{0x66, 0x06, 0x3d, 0x12, 0x01, 0xda, 0xeb, 0xea}
)

func parseGMGNInstruction(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) == 0 {
		return nil, fmt.Errorf("data is empty")
	}
	if len(instruction.Data) < 8 {
		return nil, nil
	}

	var (
		err      error
		txSignal *TxSignal
	)
	if matchMethod(instruction.Data, gmgnBuyTokensIX) {
		txSignal, err = parseGMGNBuy(tx, instruction)
	}
	if txSignal != nil {
		return TxSignalBatch{txSignal}, err
	}
	return nil, err
}

func parseGMGNBuy(tx VersionedTransaction, instruction Instructions) (*TxSignal, error) {
	if len(instruction.Accounts) < 8 {
		return nil, fmt.Errorf("accounts too short")
	}
	if len(instruction.Data) < 24 {
		return nil, fmt.Errorf("data too short for gmgn buy args, len=%d", len(instruction.Data))
	}

	mint, err := tx.GetAccount(int(instruction.Accounts[2]))
	if err != nil {
		return nil, err
	}
	user, err := tx.GetAccount(int(instruction.Accounts[6]))
	if err != nil {
		return nil, err
	}

	solAmount := binary.LittleEndian.Uint64(instruction.Data[8:16])
	tokenAmount := binary.LittleEndian.Uint64(instruction.Data[16:24])

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