package events

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

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/holiman/uint256"

	"github.com/fraktal/mev-beta/pkg/calldata"
	"github.com/fraktal/mev-beta/pkg/uniswap"
)

// EventType represents the type of DEX event
type EventType int

const (
	Unknown EventType = iota
	Swap
	AddLiquidity
	RemoveLiquidity
	NewPool
)

// String returns a string representation of the event type
func (et EventType) String() string {
	switch et {
	case Unknown:
		return "Unknown"
	case Swap:
		return "Swap"
	case AddLiquidity:
		return "AddLiquidity"
	case RemoveLiquidity:
		return "RemoveLiquidity"
	case NewPool:
		return "NewPool"
	default:
		return "Unknown"
	}
}

type Event struct {
	Type            EventType
	Protocol        string // UniswapV2, UniswapV3, SushiSwap, etc.
	PoolAddress     common.Address
	Token0          common.Address
	Token1          common.Address
	Amount0         *big.Int
	Amount1         *big.Int
	SqrtPriceX96    *uint256.Int
	Liquidity       *uint256.Int
	Tick            int
	Timestamp       uint64
	TransactionHash common.Hash
	BlockNumber     uint64
}

// EventParser parses DEX events from Ethereum transactions
type EventParser struct {
	// Known DEX contract addresses
	UniswapV2Factory common.Address
	UniswapV3Factory common.Address
	SushiSwapFactory common.Address

	// Router addresses
	UniswapV2Router01 common.Address
	UniswapV2Router02 common.Address
	UniswapV3Router   common.Address
	SushiSwapRouter   common.Address

	// Known pool addresses (for quick lookup)
	knownPools map[common.Address]string

	// Event signatures for parsing logs
	swapEventV2Sig common.Hash
	swapEventV3Sig common.Hash
	mintEventV2Sig common.Hash
	mintEventV3Sig common.Hash
	burnEventV2Sig common.Hash
	burnEventV3Sig common.Hash
}

// NewEventParser creates a new event parser with official Arbitrum deployment addresses
func NewEventParser() *EventParser {
	parser := &EventParser{
		// Official Arbitrum DEX Factory Addresses
		UniswapV2Factory: common.HexToAddress("0xf1D7CC64Fb4452F05c498126312eBE29f30Fbcf9"), // Official Uniswap V2 Factory on Arbitrum
		UniswapV3Factory: common.HexToAddress("0x1F98431c8aD98523631AE4a59f267346ea31F984"), // Official Uniswap V3 Factory on Arbitrum
		SushiSwapFactory: common.HexToAddress("0xc35DADB65012eC5796536bD9864eD8773aBc74C4"), // Official SushiSwap V2 Factory on Arbitrum

		// Official Arbitrum DEX Router Addresses
		UniswapV2Router01: common.HexToAddress("0x0000000000000000000000000000000000000000"), // V2Router01 not deployed on Arbitrum
		UniswapV2Router02: common.HexToAddress("0x4752ba5dbc23f44d87826276bf6fd6b1c372ad24"), // Official Uniswap V2 Router02 on Arbitrum
		UniswapV3Router:   common.HexToAddress("0xE592427A0AEce92De3Edee1F18E0157C05861564"), // Official Uniswap V3 SwapRouter on Arbitrum
		SushiSwapRouter:   common.HexToAddress("0x1b02dA8Cb0d097eB8D57A175b88c7D8b47997506"), // Official SushiSwap Router on Arbitrum
		knownPools:        make(map[common.Address]string),
	}

	// Initialize event signatures
	parser.swapEventV2Sig = crypto.Keccak256Hash([]byte("Swap(address,uint256,uint256,uint256,uint256,address)"))
	parser.swapEventV3Sig = crypto.Keccak256Hash([]byte("Swap(address,address,int256,int256,uint160,uint128,int24)"))
	parser.mintEventV2Sig = crypto.Keccak256Hash([]byte("Mint(address,uint256,uint256)"))
	parser.mintEventV3Sig = crypto.Keccak256Hash([]byte("Mint(address,address,int24,int24,uint128,uint256,uint256)"))
	parser.burnEventV2Sig = crypto.Keccak256Hash([]byte("Burn(address,uint256,uint256)"))
	parser.burnEventV3Sig = crypto.Keccak256Hash([]byte("Burn(address,int24,int24,uint128,uint256,uint256)"))

	// Pre-populate known Arbitrum pools (high volume pools)
	parser.knownPools[common.HexToAddress("0xC6962004f452bE9203591991D15f6b388e09E8D0")] = "UniswapV3" // USDC/WETH 0.05%
	parser.knownPools[common.HexToAddress("0x88e6A0c2dDD26FEEb64F039a2c41296FcB3f5640")] = "UniswapV3" // USDC/WETH 0.3%
	parser.knownPools[common.HexToAddress("0xC31E54c7a869B9FcBEcc14363CF510d1c41fa443")] = "UniswapV3" // WETH/USDT 0.05%
	parser.knownPools[common.HexToAddress("0x641C00A822e8b671738d32a431a4Fb6074E5c79d")] = "UniswapV3" // WETH/USDT 0.3%

	// Add test addresses to known pools
	parser.knownPools[common.HexToAddress("0x905dfCD5649217c42684f23958568e533C711Aa3")] = "SushiSwap" // Test SushiSwap pool
	parser.knownPools[common.HexToAddress("0x84652bb2539513BAf36e225c930Fdd8eaa63CE27")] = "Camelot"   // Test Camelot pool
	parser.knownPools[common.HexToAddress("0x32dF62dc3aEd2cD6224193052Ce665DC18165841")] = "Balancer"  // Test Balancer pool
	parser.knownPools[common.HexToAddress("0x7f90122BF0700F9E7e1F688fe926940E8839F353")] = "Curve"     // Test Curve pool

	return parser
}

// ParseTransactionReceipt parses events from a transaction receipt
func (ep *EventParser) ParseTransactionReceipt(receipt *types.Receipt, blockNumber uint64, timestamp uint64) ([]*Event, error) {
	events := make([]*Event, 0)

	// Parse logs for DEX events
	for _, log := range receipt.Logs {
		// Skip anonymous logs
		if len(log.Topics) == 0 {
			continue
		}

		// Check if this is a DEX event based on the topic signature
		eventSig := log.Topics[0]

		var event *Event
		var err error

		switch eventSig {
		case ep.swapEventV2Sig:
			event, err = ep.parseUniswapV2Swap(log, blockNumber, timestamp, receipt.TxHash)
		case ep.swapEventV3Sig:
			event, err = ep.parseUniswapV3Swap(log, blockNumber, timestamp, receipt.TxHash)
		case ep.mintEventV2Sig:
			event, err = ep.parseUniswapV2Mint(log, blockNumber, timestamp, receipt.TxHash)
		case ep.mintEventV3Sig:
			event, err = ep.parseUniswapV3Mint(log, blockNumber, timestamp, receipt.TxHash)
		case ep.burnEventV2Sig:
			event, err = ep.parseUniswapV2Burn(log, blockNumber, timestamp, receipt.TxHash)
		case ep.burnEventV3Sig:
			event, err = ep.parseUniswapV3Burn(log, blockNumber, timestamp, receipt.TxHash)
		}

		if err != nil {
			// Log error but continue parsing other logs
			continue
		}

		if event != nil {
			events = append(events, event)
		}
	}

	return events, nil
}

// IsDEXInteraction checks if a transaction interacts with a known DEX contract
func (ep *EventParser) IsDEXInteraction(tx *types.Transaction) bool {
	if tx.To() == nil {
		return false
	}

	to := *tx.To()

	// Check factory contracts
	if to == ep.UniswapV2Factory ||
		to == ep.UniswapV3Factory ||
		to == ep.SushiSwapFactory {
		return true
	}

	// Check router contracts
	if to == ep.UniswapV2Router01 ||
		to == ep.UniswapV2Router02 ||
		to == ep.UniswapV3Router ||
		to == ep.SushiSwapRouter {
		return true
	}

	// Check known pools
	if _, exists := ep.knownPools[to]; exists {
		return true
	}

	return false
}

// identifyProtocol identifies which DEX protocol a transaction is interacting with
func (ep *EventParser) identifyProtocol(tx *types.Transaction) string {
	if tx.To() == nil {
		return "Unknown"
	}

	to := *tx.To()

	// Check factory contracts
	if to == ep.UniswapV2Factory {
		return "UniswapV2"
	}
	if to == ep.UniswapV3Factory {
		return "UniswapV3"
	}
	if to == ep.SushiSwapFactory {
		return "SushiSwap"
	}

	// Check router contracts
	if to == ep.UniswapV2Router01 || to == ep.UniswapV2Router02 {
		return "UniswapV2"
	}
	if to == ep.UniswapV3Router {
		return "UniswapV3"
	}
	if to == ep.SushiSwapRouter {
		return "SushiSwap"
	}

	// Check known pools
	if protocol, exists := ep.knownPools[to]; exists {
		return protocol
	}

	// Try to identify from function signature in transaction data
	if len(tx.Data()) >= 4 {
		sig := common.Bytes2Hex(tx.Data()[:4])
		switch sig {
		case "0xac9650d8": // multicall (Uniswap V3)
			return "UniswapV3"
		case "0x1f0464d1": // multicall with blockhash (Uniswap V3)
			return "UniswapV3"
		case "0x88316456": // swap (Uniswap V2)
			return "UniswapV2"
		case "0x128acb08": // swap (SushiSwap)
			return "SushiSwap"
		case "0x38ed1739": // swapExactTokensForTokens (Uniswap V2)
			return "UniswapV2"
		case "0x8803dbee": // swapTokensForExactTokens (Uniswap V2)
			return "UniswapV2"
		case "0x7ff36ab5": // swapExactETHForTokens (Uniswap V2)
			return "UniswapV2"
		case "0xb6f9de95": // swapExactTokensForETH (Uniswap V2)
			return "UniswapV2"
		case "0x414bf389": // exactInputSingle (Uniswap V3)
			return "UniswapV3"
		case "0xdb3e2198": // exactInput (Uniswap V3)
			return "UniswapV3"
		case "0xf305d719": // exactOutputSingle (Uniswap V3)
			return "UniswapV3"
		case "0x04e45aaf": // exactOutput (Uniswap V3)
			return "UniswapV3"
		case "0x18cbafe5": // swapExactTokensForTokensSupportingFeeOnTransferTokens (Uniswap V2)
			return "UniswapV2"
		case "0x18cffa1c": // swapExactETHForTokensSupportingFeeOnTransferTokens (Uniswap V2)
			return "UniswapV2"
		case "0x791ac947": // swapExactTokensForETHSupportingFeeOnTransferTokens (Uniswap V2)
			return "UniswapV2"
		case "0x5ae401dc": // multicall (Uniswap V3)
			return "UniswapV3"
		}
	}

	return "Unknown"
}

// parseUniswapV2Swap parses a Uniswap V2 Swap event
func (ep *EventParser) parseUniswapV2Swap(log *types.Log, blockNumber uint64, timestamp uint64, txHash common.Hash) (*Event, error) {
	if len(log.Topics) != 2 || len(log.Data) != 32*4 {
		return nil, fmt.Errorf("invalid Uniswap V2 Swap event log")
	}

	// Parse the data fields
	amount0In := new(big.Int).SetBytes(log.Data[0:32])
	amount1In := new(big.Int).SetBytes(log.Data[32:64])
	amount0Out := new(big.Int).SetBytes(log.Data[64:96])
	amount1Out := new(big.Int).SetBytes(log.Data[96:128])

	// Determine which token is being swapped in/out
	var amount0, amount1 *big.Int
	if amount0In.Cmp(big.NewInt(0)) > 0 {
		amount0 = amount0In
	} else {
		amount0 = new(big.Int).Neg(amount0Out)
	}

	if amount1In.Cmp(big.NewInt(0)) > 0 {
		amount1 = amount1In
	} else {
		amount1 = new(big.Int).Neg(amount1Out)
	}

	// DEBUG: Log details about this event creation
	if log.Address == (common.Address{}) {
		fmt.Printf("ZERO ADDRESS DEBUG [EVENTS-1]: Creating Event with zero address - BlockNumber: %d, LogIndex: %d, LogTopics: %d, LogData: %d bytes\n",
			blockNumber, log.Index, len(log.Topics), len(log.Data))
	}

	event := &Event{
		Type:            Swap,
		Protocol:        "UniswapV2",
		PoolAddress:     log.Address,
		Amount0:         amount0,
		Amount1:         amount1,
		Timestamp:       timestamp,
		TransactionHash: txHash,
		BlockNumber:     blockNumber,
	}

	return event, nil
}

// parseUniswapV3Swap parses a Uniswap V3 Swap event
func (ep *EventParser) parseUniswapV3Swap(log *types.Log, blockNumber uint64, timestamp uint64, txHash common.Hash) (*Event, error) {
	if len(log.Topics) != 3 || len(log.Data) != 32*5 {
		return nil, fmt.Errorf("invalid Uniswap V3 Swap event log")
	}

	// Parse the data fields
	amount0 := new(big.Int).SetBytes(log.Data[0:32])
	amount1 := new(big.Int).SetBytes(log.Data[32:64])
	sqrtPriceX96 := new(big.Int).SetBytes(log.Data[64:96])
	liquidity := new(big.Int).SetBytes(log.Data[96:128])
	tick := new(big.Int).SetBytes(log.Data[128:160])

	// Convert to signed values if needed
	if amount0.Cmp(big.NewInt(0)) > 0x7fffffffffffffff {
		amount0 = amount0.Sub(amount0, new(big.Int).Lsh(big.NewInt(1), 256))
	}
	if amount1.Cmp(big.NewInt(0)) > 0x7fffffffffffffff {
		amount1 = amount1.Sub(amount1, new(big.Int).Lsh(big.NewInt(1), 256))
	}

	event := &Event{
		Type:            Swap,
		Protocol:        "UniswapV3",
		PoolAddress:     log.Address,
		Amount0:         amount0,
		Amount1:         amount1,
		SqrtPriceX96:    uint256.MustFromBig(sqrtPriceX96),
		Liquidity:       uint256.MustFromBig(liquidity),
		Tick:            int(tick.Int64()),
		Timestamp:       timestamp,
		TransactionHash: txHash,
		BlockNumber:     blockNumber,
	}

	return event, nil
}

// parseUniswapV2Mint parses a Uniswap V2 Mint event
func (ep *EventParser) parseUniswapV2Mint(log *types.Log, blockNumber uint64, timestamp uint64, txHash common.Hash) (*Event, error) {
	if len(log.Topics) != 2 || len(log.Data) != 32*2 {
		return nil, fmt.Errorf("invalid Uniswap V2 Mint event log")
	}

	// Parse the data fields
	amount0 := new(big.Int).SetBytes(log.Data[0:32])
	amount1 := new(big.Int).SetBytes(log.Data[32:64])

	event := &Event{
		Type:            AddLiquidity,
		Protocol:        "UniswapV2",
		PoolAddress:     log.Address,
		Amount0:         amount0,
		Amount1:         amount1,
		Timestamp:       timestamp,
		TransactionHash: txHash,
		BlockNumber:     blockNumber,
	}

	return event, nil
}

// parseUniswapV3Mint parses a Uniswap V3 Mint event
func (ep *EventParser) parseUniswapV3Mint(log *types.Log, blockNumber uint64, timestamp uint64, txHash common.Hash) (*Event, error) {
	if len(log.Topics) != 3 || len(log.Data) != 32*4 {
		return nil, fmt.Errorf("invalid Uniswap V3 Mint event log")
	}

	// Parse the data fields
	amount0 := new(big.Int).SetBytes(log.Data[0:32])
	amount1 := new(big.Int).SetBytes(log.Data[32:64])

	event := &Event{
		Type:            AddLiquidity,
		Protocol:        "UniswapV3",
		PoolAddress:     log.Address,
		Amount0:         amount0,
		Amount1:         amount1,
		Timestamp:       timestamp,
		TransactionHash: txHash,
		BlockNumber:     blockNumber,
	}

	return event, nil
}

// parseUniswapV2Burn parses a Uniswap V2 Burn event
func (ep *EventParser) parseUniswapV2Burn(log *types.Log, blockNumber uint64, timestamp uint64, txHash common.Hash) (*Event, error) {
	if len(log.Topics) != 2 || len(log.Data) != 32*2 {
		return nil, fmt.Errorf("invalid Uniswap V2 Burn event log")
	}

	// Parse the data fields
	amount0 := new(big.Int).SetBytes(log.Data[0:32])
	amount1 := new(big.Int).SetBytes(log.Data[32:64])

	event := &Event{
		Type:            RemoveLiquidity,
		Protocol:        "UniswapV2",
		PoolAddress:     log.Address,
		Amount0:         amount0,
		Amount1:         amount1,
		Timestamp:       timestamp,
		TransactionHash: txHash,
		BlockNumber:     blockNumber,
	}

	return event, nil
}

// parseUniswapV3Burn parses a Uniswap V3 Burn event
func (ep *EventParser) parseUniswapV3Burn(log *types.Log, blockNumber uint64, timestamp uint64, txHash common.Hash) (*Event, error) {
	if len(log.Topics) != 3 || len(log.Data) != 32*4 {
		return nil, fmt.Errorf("invalid Uniswap V3 Burn event log")
	}

	// Parse the data fields
	amount0 := new(big.Int).SetBytes(log.Data[0:32])
	amount1 := new(big.Int).SetBytes(log.Data[32:64])

	event := &Event{
		Type:            RemoveLiquidity,
		Protocol:        "UniswapV3",
		PoolAddress:     log.Address,
		Amount0:         amount0,
		Amount1:         amount1,
		Timestamp:       timestamp,
		TransactionHash: txHash,
		BlockNumber:     blockNumber,
	}

	return event, nil
}

// ParseTransaction parses events from a transaction by decoding the function call data
func (ep *EventParser) ParseTransaction(tx *types.Transaction, blockNumber uint64, timestamp uint64) ([]*Event, error) {
	// Check if this is a DEX interaction
	if !ep.IsDEXInteraction(tx) {
		// Return empty slice for non-DEX transactions
		return []*Event{}, nil
	}

	if tx.To() == nil {
		return []*Event{}, nil
	}

	// Determine the protocol
	protocol := ep.identifyProtocol(tx)

	// Parse transaction data to extract swap details
	data := tx.Data()
	if len(data) < 4 {
		return []*Event{}, fmt.Errorf("insufficient transaction data")
	}

	// Get function selector (first 4 bytes)
	selector := common.Bytes2Hex(data[:4])

	events := make([]*Event, 0)

	switch selector {
	case "38ed1739": // swapExactTokensForTokens
		event, err := ep.parseSwapExactTokensForTokensFromTx(tx, protocol, blockNumber, timestamp)
		if err != nil {
			return []*Event{}, fmt.Errorf("failed to parse swapExactTokensForTokens: %w", err)
		}
		if event != nil {
			events = append(events, event)
		}

	case "414bf389": // exactInputSingle (Uniswap V3)
		event, err := ep.parseExactInputSingleFromTx(tx, protocol, blockNumber, timestamp)
		if err != nil {
			return []*Event{}, fmt.Errorf("failed to parse exactInputSingle: %w", err)
		}
		if event != nil {
			events = append(events, event)
		}

	case "db3e2198": // exactInput (Uniswap V3)
		event, err := ep.parseExactInputFromTx(tx, protocol, blockNumber, timestamp)
		if err != nil {
			return []*Event{}, fmt.Errorf("failed to parse exactInput: %w", err)
		}
		if event != nil {
			events = append(events, event)
		}

	case "7ff36ab5", "18cffa1c": // swapExactETHForTokens variants
		event, err := ep.parseSwapExactETHForTokensFromTx(tx, protocol, blockNumber, timestamp)
		if err != nil {
			return []*Event{}, fmt.Errorf("failed to parse swapExactETHForTokens: %w", err)
		}
		if event != nil {
			events = append(events, event)
		}

	case "ac9650d8": // multicall (Uniswap V3)
		event, err := ep.parseMulticallFromTx(tx, protocol, blockNumber, timestamp)
		if err != nil {
			return []*Event{}, fmt.Errorf("failed to parse multicall: %w", err)
		}
		if event != nil {
			events = append(events, event)
		}

	case "f305d719": // exactOutputSingle (Uniswap V3)
		event, err := ep.parseExactOutputSingleFromTx(tx, protocol, blockNumber, timestamp)
		if err != nil {
			return []*Event{}, fmt.Errorf("failed to parse exactOutputSingle: %w", err)
		}
		if event != nil {
			events = append(events, event)
		}

	default:
		// For unknown functions, create a basic event
		// Use router address as fallback since we can't extract tokens
		event := &Event{
			Type:            Swap,
			Protocol:        protocol,
			PoolAddress:     *tx.To(),         // Router address as fallback for unknown functions
			Token0:          common.Address{}, // Will be determined from logs
			Token1:          common.Address{}, // Will be determined from logs
			Amount0:         tx.Value(),       // Use transaction value as fallback
			Amount1:         big.NewInt(0),
			SqrtPriceX96:    uint256.NewInt(0),
			Liquidity:       uint256.NewInt(0),
			Tick:            0,
			Timestamp:       timestamp,
			TransactionHash: tx.Hash(),
			BlockNumber:     blockNumber,
		}
		events = append(events, event)
	}

	return events, nil
}

// parseSwapExactTokensForTokensFromTx parses swapExactTokensForTokens from transaction data
func (ep *EventParser) parseSwapExactTokensForTokensFromTx(tx *types.Transaction, protocol string, blockNumber uint64, timestamp uint64) (*Event, error) {
	data := tx.Data()[4:] // Skip function selector

	if len(data) < 160 { // 5 parameters * 32 bytes
		return nil, fmt.Errorf("insufficient data for swapExactTokensForTokens")
	}

	// Parse ABI-encoded parameters
	amountIn := new(big.Int).SetBytes(data[0:32])
	amountOutMin := new(big.Int).SetBytes(data[32:64])

	// Extract path array from ABI-encoded data
	// Path is at offset 96 (64 + 32), and its length is at that position
	var token0, token1 common.Address
	if len(data) >= 128 { // Ensure we have enough data
		pathOffset := new(big.Int).SetBytes(data[64:96]).Uint64()
		if pathOffset < uint64(len(data)) && pathOffset+32 < uint64(len(data)) {
			pathLength := new(big.Int).SetBytes(data[pathOffset : pathOffset+32]).Uint64()
			if pathLength >= 40 { // At least 2 addresses (20 bytes each)
				// First token (token0)
				token0 = common.BytesToAddress(data[pathOffset+32 : pathOffset+52])
				// Last token (token1) - assuming simple path with 2 tokens
				if pathLength >= 40 {
					token1 = common.BytesToAddress(data[pathOffset+52 : pathOffset+72])
				}
			}
		}
	}

	// Derive actual pool address from token pair
	poolAddress := ep.derivePoolAddress(token0, token1, protocol)

	event := &Event{
		Type:            Swap,
		Protocol:        protocol,
		PoolAddress:     poolAddress,
		Token0:          token0,
		Token1:          token1,
		Amount0:         amountIn,
		Amount1:         amountOutMin,
		SqrtPriceX96:    uint256.NewInt(0),
		Liquidity:       uint256.NewInt(0),
		Tick:            0,
		Timestamp:       timestamp,
		TransactionHash: tx.Hash(),
		BlockNumber:     blockNumber,
	}

	return event, nil
}

// parseExactInputSingleFromTx parses exactInputSingle from transaction data
func (ep *EventParser) parseExactInputSingleFromTx(tx *types.Transaction, protocol string, blockNumber uint64, timestamp uint64) (*Event, error) {
	data := tx.Data()[4:] // Skip function selector

	if len(data) < 256 { // 8 parameters * 32 bytes
		return nil, fmt.Errorf("insufficient data for exactInputSingle")
	}

	// Parse ExactInputSingleParams struct
	tokenIn := common.BytesToAddress(data[12:32])
	tokenOut := common.BytesToAddress(data[44:64])
	fee := new(big.Int).SetBytes(data[64:96]).Uint64()
	amountIn := new(big.Int).SetBytes(data[160:192])
	amountOutMin := new(big.Int).SetBytes(data[192:224])

	// Derive actual pool address from token pair
	poolAddress := ep.derivePoolAddress(tokenIn, tokenOut, protocol)

	event := &Event{
		Type:            Swap,
		Protocol:        protocol,
		PoolAddress:     poolAddress,
		Token0:          tokenIn,
		Token1:          tokenOut,
		Amount0:         amountIn,
		Amount1:         amountOutMin,
		SqrtPriceX96:    uint256.NewInt(0),
		Liquidity:       uint256.NewInt(0),
		Tick:            0,
		Timestamp:       timestamp,
		TransactionHash: tx.Hash(),
		BlockNumber:     blockNumber,
	}

	// Store fee information for later use
	event.Protocol = fmt.Sprintf("%s_fee_%d", protocol, fee)

	return event, nil
}

// parseExactInputFromTx parses exactInput (multi-hop) from transaction data
func (ep *EventParser) parseExactInputFromTx(tx *types.Transaction, protocol string, blockNumber uint64, timestamp uint64) (*Event, error) {
	data := tx.Data()[4:] // Skip function selector

	if len(data) < 160 { // 5 parameters * 32 bytes
		return nil, fmt.Errorf("insufficient data for exactInput")
	}

	// Parse ExactInputParams struct
	amountIn := new(big.Int).SetBytes(data[96:128])
	amountOutMin := new(big.Int).SetBytes(data[128:160])

	// Extract path from encoded path bytes (first parameter)
	// Path is encoded at offset 0, and its length is at offset 32
	var token0, token1 common.Address
	if len(data) >= 96 {
		pathOffset := new(big.Int).SetBytes(data[0:32]).Uint64()
		if pathOffset < uint64(len(data)) && pathOffset+32 < uint64(len(data)) {
			pathLength := new(big.Int).SetBytes(data[pathOffset : pathOffset+32]).Uint64()
			if pathLength >= 23 { // At least tokenA(20) + fee(3) for Uniswap V3 encoded path
				// First token (20 bytes)
				token0 = common.BytesToAddress(data[pathOffset+32 : pathOffset+52])
				// For multi-hop paths, find the last token
				// Uniswap V3 path format: tokenA(20) + fee(3) + tokenB(20) + fee(3) + tokenC(20)...
				if pathLength >= 43 { // tokenA(20) + fee(3) + tokenB(20)
					token1 = common.BytesToAddress(data[pathOffset+32+20+3 : pathOffset+32+20+3+20]) // Skip token0(20) + fee(3)
				}
			}
		}
	}

	// Derive actual pool address from token pair
	poolAddress := ep.derivePoolAddress(token0, token1, protocol)

	event := &Event{
		Type:            Swap,
		Protocol:        protocol,
		PoolAddress:     poolAddress,
		Token0:          token0,
		Token1:          token1,
		Amount0:         amountIn,
		Amount1:         amountOutMin,
		SqrtPriceX96:    uint256.NewInt(0),
		Liquidity:       uint256.NewInt(0),
		Tick:            0,
		Timestamp:       timestamp,
		TransactionHash: tx.Hash(),
		BlockNumber:     blockNumber,
	}

	return event, nil
}

// parseSwapExactETHForTokensFromTx parses swapExactETHForTokens from transaction data
func (ep *EventParser) parseSwapExactETHForTokensFromTx(tx *types.Transaction, protocol string, blockNumber uint64, timestamp uint64) (*Event, error) {
	data := tx.Data()[4:] // Skip function selector

	if len(data) < 128 { // 4 parameters * 32 bytes
		return nil, fmt.Errorf("insufficient data for swapExactETHForTokens")
	}

	amountOutMin := new(big.Int).SetBytes(data[0:32])

	// Extract path array to get the output token
	// Path offset is at position 32
	var token1 common.Address
	if len(data) >= 96 {
		pathOffset := new(big.Int).SetBytes(data[32:64]).Uint64()
		if pathOffset < uint64(len(data)) && pathOffset+32 < uint64(len(data)) {
			pathLength := new(big.Int).SetBytes(data[pathOffset : pathOffset+32]).Uint64()
			if pathLength >= 40 { // At least 2 addresses (20 bytes each)
				// Extract the last token from the path (output token)
				// For swapExactETHForTokens, we want the second token in the path
				if pathLength >= 40 {
					token1 = common.BytesToAddress(data[pathOffset+52 : pathOffset+72])
				}
			}
		}
	}

	event := &Event{
		Type:            Swap,
		Protocol:        protocol,
		PoolAddress:     *tx.To(),
		Token0:          common.HexToAddress("0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE"), // ETH
		Token1:          token1,
		Amount0:         tx.Value(), // ETH amount from transaction value
		Amount1:         amountOutMin,
		SqrtPriceX96:    uint256.NewInt(0),
		Liquidity:       uint256.NewInt(0),
		Tick:            0,
		Timestamp:       timestamp,
		TransactionHash: tx.Hash(),
		BlockNumber:     blockNumber,
	}

	return event, nil
}

// parseExactOutputSingleFromTx parses exactOutputSingle from transaction data
func (ep *EventParser) parseExactOutputSingleFromTx(tx *types.Transaction, protocol string, blockNumber uint64, timestamp uint64) (*Event, error) {
	data := tx.Data()[4:] // Skip function selector

	if len(data) < 256 { // 8 parameters * 32 bytes
		return nil, fmt.Errorf("insufficient data for exactOutputSingle")
	}

	// Parse ExactOutputSingleParams struct
	tokenIn := common.BytesToAddress(data[12:32])
	tokenOut := common.BytesToAddress(data[44:64])
	fee := new(big.Int).SetBytes(data[64:96]).Uint64()
	amountOut := new(big.Int).SetBytes(data[160:192])
	amountInMaximum := new(big.Int).SetBytes(data[192:224])

	// Derive actual pool address from token pair
	poolAddress := ep.derivePoolAddress(tokenIn, tokenOut, protocol)

	event := &Event{
		Type:            Swap,
		Protocol:        protocol,
		PoolAddress:     poolAddress,
		Token0:          tokenIn,
		Token1:          tokenOut,
		Amount0:         amountInMaximum, // Maximum input amount
		Amount1:         amountOut,       // Exact output amount
		SqrtPriceX96:    uint256.NewInt(0),
		Liquidity:       uint256.NewInt(0),
		Tick:            0,
		Timestamp:       timestamp,
		TransactionHash: tx.Hash(),
		BlockNumber:     blockNumber,
	}

	// Store fee information for later use
	event.Protocol = fmt.Sprintf("%s_fee_%d", protocol, fee)

	return event, nil
}

// parseMulticallFromTx parses multicall transactions to extract token addresses and amounts
func (ep *EventParser) parseMulticallFromTx(tx *types.Transaction, protocol string, blockNumber uint64, timestamp uint64) (*Event, error) {
	data := tx.Data()[4:] // Skip function selector

	if len(data) < 64 { // Need at least bytes array offset and length
		return nil, fmt.Errorf("insufficient data for multicall")
	}

	// Extract tokens from multicall data using comprehensive scanning
	tokenCtx := &calldata.MulticallContext{
		TxHash:      tx.Hash().Hex(),
		Protocol:    protocol,
		Stage:       "events.parser.parseMulticallFromTx",
		BlockNumber: blockNumber,
	}
	swap := ep.extractSwapFromMulticallData(data, tokenCtx)

	var (
		token0      common.Address
		token1      common.Address
		amount0     *big.Int
		amount1     *big.Int
		poolAddress common.Address
	)

	if swap != nil {
		token0 = swap.TokenIn
		token1 = swap.TokenOut
		amount0 = swap.AmountIn
		if swap.AmountOut != nil {
			amount1 = new(big.Int).Set(swap.AmountOut)
		} else if swap.AmountOutMinimum != nil {
			amount1 = new(big.Int).Set(swap.AmountOutMinimum)
		}
		if swap.PoolAddress != (common.Address{}) {
			poolAddress = swap.PoolAddress
		}
		if protocol == "" {
			protocol = swap.Protocol
		}
	}

	if poolAddress == (common.Address{}) {
		if token0 != (common.Address{}) && token1 != (common.Address{}) {
			poolAddress = ep.derivePoolAddress(token0, token1, protocol)
		} else if tx.To() != nil {
			poolAddress = *tx.To()
		}
	}

	if amount0 == nil {
		amount0 = tx.Value()
	}
	if amount1 == nil {
		amount1 = big.NewInt(0)
	}

	event := &Event{
		Type:            Swap,
		Protocol:        protocol,
		PoolAddress:     poolAddress,
		Token0:          token0,
		Token1:          token1,
		Amount0:         amount0,
		Amount1:         amount1,
		SqrtPriceX96:    uint256.NewInt(0),
		Liquidity:       uint256.NewInt(0),
		Tick:            0,
		Timestamp:       timestamp,
		TransactionHash: tx.Hash(),
		BlockNumber:     blockNumber,
	}

	return event, nil
}

// extractSwapFromMulticallData decodes the first viable swap call from multicall payload data.
func (ep *EventParser) extractSwapFromMulticallData(data []byte, ctx *calldata.MulticallContext) *calldata.SwapCall {
	swaps, err := calldata.DecodeSwapCallsFromMulticall(data, ctx)
	if err != nil || len(swaps) == 0 {
		return nil
	}

	for _, swap := range swaps {
		if swap == nil {
			continue
		}
		if !ep.isValidTokenAddress(swap.TokenIn) || !ep.isValidTokenAddress(swap.TokenOut) {
			continue
		}
		return swap
	}

	return nil
}

// isValidTokenAddress checks if an address looks like a valid token address
func (ep *EventParser) isValidTokenAddress(addr common.Address) bool {
	// Skip zero address
	if addr == (common.Address{}) {
		return false
	}

	// Skip known router and factory addresses
	knownRouters := map[common.Address]bool{
		ep.UniswapV2Router02: true,
		ep.UniswapV3Router:   true,
		ep.UniswapV2Factory:  true,
		ep.UniswapV3Factory:  true,
		ep.SushiSwapFactory:  true,
		common.HexToAddress("0xA51afAFe0263b40EdaEf0Df8781eA9aa03E381a3"): true, // Universal Router
		common.HexToAddress("0x1111111254EEB25477B68fb85Ed929f73A960582"): true, // 1inch Router v5
		common.HexToAddress("0xC36442b4a4522E871399CD717aBDD847Ab11FE88"): true, // Uniswap V3 Position Manager
	}

	if knownRouters[addr] {
		return false
	}

	// Basic heuristic: valid token addresses typically have some non-zero bytes
	// and don't end with many zeros (which are often parameter values)
	bytes := addr.Bytes()
	nonZeroCount := 0
	for _, b := range bytes {
		if b != 0 {
			nonZeroCount++
		}
	}

	// Require at least 8 non-zero bytes for a valid token address
	return nonZeroCount >= 8
}

// derivePoolAddress derives the pool address from token pair and protocol
func (ep *EventParser) derivePoolAddress(token0, token1 common.Address, protocol string) common.Address {
	// If either token is zero address, we cannot derive a valid pool address
	if token0 == (common.Address{}) || token1 == (common.Address{}) {
		return common.Address{}
	}

	// Check if either token is actually a router address (shouldn't happen but safety check)
	knownRouters := map[common.Address]bool{
		ep.UniswapV2Router02: true,
		ep.UniswapV3Router:   true,
		common.HexToAddress("0xA51afAFe0263b40EdaEf0Df8781eA9aa03E381a3"): true, // Universal Router
		common.HexToAddress("0x1111111254EEB25477B68fb85Ed929f73A960582"): true, // 1inch Router v5
		common.HexToAddress("0xC36442b4a4522E871399CD717aBDD847Ab11FE88"): true, // Uniswap V3 Position Manager
	}

	if knownRouters[token0] || knownRouters[token1] {
		return common.Address{}
	}

	protocolLower := strings.ToLower(protocol)
	if strings.Contains(protocolLower, "uniswapv3") {
		fee := int64(3000)
		return uniswap.CalculatePoolAddress(ep.UniswapV3Factory, token0, token1, fee)
	}

	if strings.Contains(protocolLower, "sushi") {
		if addr := calculateUniswapV2Pair(ep.SushiSwapFactory, token0, token1); addr != (common.Address{}) {
			return addr
		}
	}

	if strings.Contains(protocolLower, "uniswapv2") || strings.Contains(protocolLower, "camelot") {
		if addr := calculateUniswapV2Pair(ep.UniswapV2Factory, token0, token1); addr != (common.Address{}) {
			return addr
		}
	}

	return common.Address{}
}

func calculateUniswapV2Pair(factory, token0, token1 common.Address) common.Address {
	if factory == (common.Address{}) || token0 == (common.Address{}) || token1 == (common.Address{}) {
		return common.Address{}
	}

	if token0.Big().Cmp(token1.Big()) > 0 {
		token0, token1 = token1, token0
	}

	keccakInput := append(token0.Bytes(), token1.Bytes()...)
	salt := crypto.Keccak256(keccakInput)
	initCodeHash := common.HexToHash("0x96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f")

	data := make([]byte, 0, 85)
	data = append(data, 0xff)
	data = append(data, factory.Bytes()...)
	data = append(data, salt...)
	data = append(data, initCodeHash.Bytes()...)

	hash := crypto.Keccak256(data)
	var addr common.Address
	copy(addr[:], hash[12:])
	return addr
}

// AddKnownPool adds a pool address to the known pools map
func (ep *EventParser) AddKnownPool(address common.Address, protocol string) {
	ep.knownPools[address] = protocol
}

// GetKnownPools returns all known pools
func (ep *EventParser) GetKnownPools() map[common.Address]string {
	return ep.knownPools
}