package main

import (
	"context"
	"fmt"
	"math/big"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/ethereum/go-ethereum/accounts/abi/bind"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/ethclient"
	"github.com/fraktal/mev-beta/internal/config"
	"github.com/fraktal/mev-beta/internal/logger"
	"github.com/urfave/cli/v2"
)

// SwapParams represents the parameters for a swap operation
type SwapParams struct {
	TokenIn      common.Address
	TokenOut     common.Address
	AmountIn     *big.Int
	MinAmountOut *big.Int
	Recipient    common.Address
	Deadline     uint64
	Protocol     string
	Slippage     float64
}

// SwapExecutor handles the execution of swaps
type SwapExecutor struct {
	client *ethclient.Client
	logger *logger.Logger
	config *config.Config
	auth   *bind.TransactOpts
}

func main() {
	app := &cli.App{
		Name:  "swap-cli",
		Usage: "CLI tool for executing swaps on Arbitrum using various DEX protocols",
		Flags: []cli.Flag{
			&cli.StringFlag{
				Name:     "rpc-endpoint",
				Usage:    "Arbitrum RPC endpoint URL",
				EnvVars:  []string{"ARBITRUM_RPC_ENDPOINT"},
				Required: true,
			},
			&cli.StringFlag{
				Name:    "private-key",
				Usage:   "Private key for transaction signing (hex format without 0x)",
				EnvVars: []string{"PRIVATE_KEY"},
			},
			&cli.StringFlag{
				Name:    "wallet-address",
				Usage:   "Wallet address (if using external signer)",
				EnvVars: []string{"WALLET_ADDRESS"},
			},
			&cli.BoolFlag{
				Name:  "dry-run",
				Usage: "Simulate the swap without executing",
				Value: false,
			},
			&cli.StringFlag{
				Name:  "log-level",
				Usage: "Log level (debug, info, warn, error)",
				Value: "info",
			},
		},
		Commands: []*cli.Command{
			{
				Name:  "uniswap-v3",
				Usage: "Execute swap on Uniswap V3",
				Flags: getSwapFlags(),
				Action: func(c *cli.Context) error {
					return executeSwap(c, "uniswap-v3")
				},
			},
			{
				Name:  "uniswap-v2",
				Usage: "Execute swap on Uniswap V2",
				Flags: getSwapFlags(),
				Action: func(c *cli.Context) error {
					return executeSwap(c, "uniswap-v2")
				},
			},
			{
				Name:  "sushiswap",
				Usage: "Execute swap on SushiSwap",
				Flags: getSwapFlags(),
				Action: func(c *cli.Context) error {
					return executeSwap(c, "sushiswap")
				},
			},
			{
				Name:  "camelot-v3",
				Usage: "Execute swap on Camelot V3",
				Flags: getSwapFlags(),
				Action: func(c *cli.Context) error {
					return executeSwap(c, "camelot-v3")
				},
			},
			{
				Name:  "traderjoe-v2",
				Usage: "Execute swap on TraderJoe V2",
				Flags: getSwapFlags(),
				Action: func(c *cli.Context) error {
					return executeSwap(c, "traderjoe-v2")
				},
			},
			{
				Name:  "kyber-elastic",
				Usage: "Execute swap on KyberSwap Elastic",
				Flags: getSwapFlags(),
				Action: func(c *cli.Context) error {
					return executeSwap(c, "kyber-elastic")
				},
			},
			{
				Name:  "estimate-gas",
				Usage: "Estimate gas cost for a swap",
				Flags: getSwapFlags(),
				Action: func(c *cli.Context) error {
					return estimateGas(c)
				},
			},
			{
				Name:  "check-allowance",
				Usage: "Check token allowance for a protocol",
				Flags: []cli.Flag{
					&cli.StringFlag{
						Name:     "token",
						Usage:    "Token contract address",
						Required: true,
					},
					&cli.StringFlag{
						Name:     "spender",
						Usage:    "Spender contract address (router)",
						Required: true,
					},
					&cli.StringFlag{
						Name:  "owner",
						Usage: "Owner address (defaults to wallet address)",
					},
				},
				Action: func(c *cli.Context) error {
					return checkAllowance(c)
				},
			},
			{
				Name:  "approve",
				Usage: "Approve token spending for a protocol",
				Flags: []cli.Flag{
					&cli.StringFlag{
						Name:     "token",
						Usage:    "Token contract address",
						Required: true,
					},
					&cli.StringFlag{
						Name:     "spender",
						Usage:    "Spender contract address (router)",
						Required: true,
					},
					&cli.StringFlag{
						Name:     "amount",
						Usage:    "Amount to approve (use 'max' for maximum approval)",
						Required: true,
					},
				},
				Action: func(c *cli.Context) error {
					return approveToken(c)
				},
			},
		},
	}

	if err := app.Run(os.Args); err != nil {
		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
		os.Exit(1)
	}
}

func getSwapFlags() []cli.Flag {
	return []cli.Flag{
		&cli.StringFlag{
			Name:     "token-in",
			Usage:    "Input token contract address",
			Required: true,
		},
		&cli.StringFlag{
			Name:     "token-out",
			Usage:    "Output token contract address",
			Required: true,
		},
		&cli.StringFlag{
			Name:     "amount-in",
			Usage:    "Amount of input tokens (in smallest unit, e.g., wei for ETH)",
			Required: true,
		},
		&cli.StringFlag{
			Name:  "min-amount-out",
			Usage: "Minimum amount of output tokens (calculated from slippage if not provided)",
		},
		&cli.StringFlag{
			Name:  "recipient",
			Usage: "Recipient address (defaults to sender)",
		},
		&cli.Float64Flag{
			Name:  "slippage",
			Usage: "Slippage tolerance in percentage (e.g., 0.5 for 0.5%)",
			Value: 0.5,
		},
		&cli.Uint64Flag{
			Name:  "deadline",
			Usage: "Transaction deadline in seconds from now",
			Value: 300, // 5 minutes default
		},
		&cli.StringFlag{
			Name:  "pool-fee",
			Usage: "Pool fee tier for V3 swaps (500, 3000, 10000)",
			Value: "3000",
		},
		&cli.StringFlag{
			Name:  "gas-price",
			Usage: "Gas price in gwei (optional, uses network default if not specified)",
		},
		&cli.Uint64Flag{
			Name:  "gas-limit",
			Usage: "Gas limit (optional, estimated if not specified)",
		},
	}
}

func executeSwap(c *cli.Context, protocol string) error {
	// Initialize logger
	log := logger.New(c.String("log-level"), "text", "")

	// Parse swap parameters
	params, err := parseSwapParams(c)
	if err != nil {
		return fmt.Errorf("failed to parse swap parameters: %w", err)
	}

	// Initialize swap executor
	executor, err := newSwapExecutor(c, log)
	if err != nil {
		return fmt.Errorf("failed to initialize swap executor: %w", err)
	}

	log.Info("Swap Parameters",
		"protocol", protocol,
		"tokenIn", params.TokenIn.Hex(),
		"tokenOut", params.TokenOut.Hex(),
		"amountIn", params.AmountIn.String(),
		"minAmountOut", params.MinAmountOut.String(),
		"recipient", params.Recipient.Hex(),
		"slippage", fmt.Sprintf("%.2f%%", params.Slippage),
	)

	if c.Bool("dry-run") {
		return executor.simulateSwap(params, protocol)
	}

	return executor.executeSwap(params, protocol)
}

func parseSwapParams(c *cli.Context) (*SwapParams, error) {
	// Parse token addresses
	tokenIn := common.HexToAddress(c.String("token-in"))
	tokenOut := common.HexToAddress(c.String("token-out"))

	// Parse amount in
	amountInStr := c.String("amount-in")
	amountIn, ok := new(big.Int).SetString(amountInStr, 10)
	if !ok {
		return nil, fmt.Errorf("invalid amount-in: %s", amountInStr)
	}

	// Parse minimum amount out
	var minAmountOut *big.Int
	if minAmountOutStr := c.String("min-amount-out"); minAmountOutStr != "" {
		var ok bool
		minAmountOut, ok = new(big.Int).SetString(minAmountOutStr, 10)
		if !ok {
			return nil, fmt.Errorf("invalid min-amount-out: %s", minAmountOutStr)
		}
	} else {
		// Calculate from slippage (simplified - in real implementation would fetch price)
		slippage := c.Float64("slippage")
		minAmountOut = calculateMinAmountOut(amountIn, slippage)
	}

	// Parse recipient
	var recipient common.Address
	if recipientStr := c.String("recipient"); recipientStr != "" {
		recipient = common.HexToAddress(recipientStr)
	} else {
		// Use wallet address as recipient
		if walletAddr := c.String("wallet-address"); walletAddr != "" {
			recipient = common.HexToAddress(walletAddr)
		} else {
			return nil, fmt.Errorf("recipient address required")
		}
	}

	// Calculate deadline
	deadline := uint64(time.Now().Unix()) + c.Uint64("deadline")

	return &SwapParams{
		TokenIn:      tokenIn,
		TokenOut:     tokenOut,
		AmountIn:     amountIn,
		MinAmountOut: minAmountOut,
		Recipient:    recipient,
		Deadline:     deadline,
		Protocol:     "",
		Slippage:     c.Float64("slippage"),
	}, nil
}

func newSwapExecutor(c *cli.Context, log *logger.Logger) (*SwapExecutor, error) {
	// Connect to Arbitrum RPC
	client, err := ethclient.Dial(c.String("rpc-endpoint"))
	if err != nil {
		return nil, fmt.Errorf("failed to connect to Arbitrum RPC: %w", err)
	}

	// Load configuration (simplified)
	cfg := &config.Config{
		Arbitrum: config.ArbitrumConfig{
			RPCEndpoint: c.String("rpc-endpoint"),
			ChainID:     42161, // Arbitrum mainnet
		},
	}

	// Setup auth if private key is provided
	var auth *bind.TransactOpts
	if privateKeyHex := c.String("private-key"); privateKeyHex != "" {
		privateKey, err := crypto.HexToECDSA(privateKeyHex)
		if err != nil {
			return nil, fmt.Errorf("invalid private key: %w", err)
		}

		chainID := big.NewInt(42161) // Arbitrum mainnet
		auth, err = bind.NewKeyedTransactorWithChainID(privateKey, chainID)
		if err != nil {
			return nil, fmt.Errorf("failed to create transactor: %w", err)
		}

		// Set gas price if specified
		if gasPriceStr := c.String("gas-price"); gasPriceStr != "" {
			gasPriceGwei, err := strconv.ParseFloat(gasPriceStr, 64)
			if err != nil {
				return nil, fmt.Errorf("invalid gas price: %w", err)
			}
			gasPrice := new(big.Int).Mul(
				big.NewInt(int64(gasPriceGwei*1e9)),
				big.NewInt(1),
			)
			auth.GasPrice = gasPrice
		}

		// Set gas limit if specified
		if gasLimit := c.Uint64("gas-limit"); gasLimit > 0 {
			auth.GasLimit = gasLimit
		}
	}

	return &SwapExecutor{
		client: client,
		logger: log,
		config: cfg,
		auth:   auth,
	}, nil
}

func (se *SwapExecutor) simulateSwap(params *SwapParams, protocol string) error {
	se.logger.Info("🔍 SIMULATION MODE - No actual transaction will be sent")

	ctx := context.Background()

	// Check balances
	balance, err := se.getTokenBalance(ctx, params.TokenIn, params.Recipient)
	if err != nil {
		return fmt.Errorf("failed to get token balance: %w", err)
	}

	se.logger.Info("Balance Check",
		"token", params.TokenIn.Hex(),
		"balance", balance.String(),
		"required", params.AmountIn.String(),
		"sufficient", balance.Cmp(params.AmountIn) >= 0,
	)

	if balance.Cmp(params.AmountIn) < 0 {
		se.logger.Warn("⚠️  Insufficient balance for swap")
		return fmt.Errorf("insufficient balance: have %s, need %s", balance.String(), params.AmountIn.String())
	}

	// Estimate gas
	gasEstimate, err := se.estimateSwapGas(params, protocol)
	if err != nil {
		se.logger.Warn("Failed to estimate gas", "error", err.Error())
		gasEstimate = 200000 // Default estimate
	}

	se.logger.Info("Gas Estimation",
		"estimatedGas", gasEstimate,
		"protocol", protocol,
	)

	se.logger.Info("✅ Simulation completed successfully")
	return nil
}

func (se *SwapExecutor) executeSwap(params *SwapParams, protocol string) error {
	if se.auth == nil {
		return fmt.Errorf("no private key provided - cannot execute transaction")
	}

	se.logger.Info("🚀 Executing swap transaction")

	ctx := context.Background()

	// Pre-flight checks
	if err := se.preFlightChecks(ctx, params); err != nil {
		return fmt.Errorf("pre-flight checks failed: %w", err)
	}

	// Get router address for protocol
	routerAddr, err := se.getRouterAddress(protocol)
	if err != nil {
		return fmt.Errorf("failed to get router address: %w", err)
	}

	se.logger.Info("Router Information",
		"protocol", protocol,
		"router", routerAddr.Hex(),
	)

	// Execute the swap based on protocol
	switch protocol {
	case "uniswap-v3":
		return se.executeUniswapV3Swap(ctx, params, routerAddr)
	case "uniswap-v2":
		return se.executeUniswapV2Swap(ctx, params, routerAddr)
	case "sushiswap":
		return se.executeSushiSwap(ctx, params, routerAddr)
	case "camelot-v3":
		return se.executeCamelotV3Swap(ctx, params, routerAddr)
	case "traderjoe-v2":
		return se.executeTraderJoeV2Swap(ctx, params, routerAddr)
	case "kyber-elastic":
		return se.executeKyberElasticSwap(ctx, params, routerAddr)
	default:
		return fmt.Errorf("unsupported protocol: %s", protocol)
	}
}

func (se *SwapExecutor) preFlightChecks(ctx context.Context, params *SwapParams) error {
	// Check balance
	balance, err := se.getTokenBalance(ctx, params.TokenIn, params.Recipient)
	if err != nil {
		return fmt.Errorf("failed to get token balance: %w", err)
	}

	if balance.Cmp(params.AmountIn) < 0 {
		return fmt.Errorf("insufficient balance: have %s, need %s", balance.String(), params.AmountIn.String())
	}

	se.logger.Info("✅ Balance check passed",
		"balance", balance.String(),
		"required", params.AmountIn.String(),
	)

	return nil
}

// Helper functions for protocol-specific implementations
func (se *SwapExecutor) executeUniswapV3Swap(ctx context.Context, params *SwapParams, router common.Address) error {
	se.logger.Info("Executing Uniswap V3 swap")
	// Implementation would go here - this is a placeholder
	return fmt.Errorf("Uniswap V3 swap implementation pending")
}

func (se *SwapExecutor) executeUniswapV2Swap(ctx context.Context, params *SwapParams, router common.Address) error {
	se.logger.Info("Executing Uniswap V2 swap")
	// Implementation would go here - this is a placeholder
	return fmt.Errorf("Uniswap V2 swap implementation pending")
}

func (se *SwapExecutor) executeSushiSwap(ctx context.Context, params *SwapParams, router common.Address) error {
	se.logger.Info("Executing SushiSwap swap")
	// Implementation would go here - this is a placeholder
	return fmt.Errorf("SushiSwap swap implementation pending")
}

func (se *SwapExecutor) executeCamelotV3Swap(ctx context.Context, params *SwapParams, router common.Address) error {
	se.logger.Info("Executing Camelot V3 swap")
	// Implementation would go here - this is a placeholder
	return fmt.Errorf("Camelot V3 swap implementation pending")
}

func (se *SwapExecutor) executeTraderJoeV2Swap(ctx context.Context, params *SwapParams, router common.Address) error {
	se.logger.Info("Executing TraderJoe V2 swap")
	// Implementation would go here - this is a placeholder
	return fmt.Errorf("TraderJoe V2 swap implementation pending")
}

func (se *SwapExecutor) executeKyberElasticSwap(ctx context.Context, params *SwapParams, router common.Address) error {
	se.logger.Info("Executing KyberSwap Elastic swap")
	// Implementation would go here - this is a placeholder
	return fmt.Errorf("KyberSwap Elastic swap implementation pending")
}

// Utility functions
func (se *SwapExecutor) getTokenBalance(ctx context.Context, token common.Address, owner common.Address) (*big.Int, error) {
	// Implementation would call ERC20 balanceOf
	// For now, return a placeholder
	return big.NewInt(1000000000000000000), nil // 1 ETH worth
}

func (se *SwapExecutor) estimateSwapGas(params *SwapParams, protocol string) (uint64, error) {
	// Implementation would estimate gas for the specific protocol
	// For now, return reasonable estimates
	switch protocol {
	case "uniswap-v3":
		return 150000, nil
	case "uniswap-v2":
		return 120000, nil
	default:
		return 200000, nil
	}
}

func (se *SwapExecutor) getRouterAddress(protocol string) (common.Address, error) {
	// Return known router addresses for each protocol on Arbitrum
	switch protocol {
	case "uniswap-v3":
		return common.HexToAddress("0xE592427A0AEce92De3Edee1F18E0157C05861564"), nil
	case "uniswap-v2":
		return common.HexToAddress("0x4752ba5dbc23f44d87826276bf6fd6b1c372ad24"), nil
	case "sushiswap":
		return common.HexToAddress("0x1b02dA8Cb0d097eB8D57A175b88c7D8b47997506"), nil
	case "camelot-v3":
		return common.HexToAddress("0x1a3c9B1d2F0529D97f2afC5136Cc23e58f1FD35B"), nil
	case "traderjoe-v2":
		return common.HexToAddress("0x18556DA13313f3532c54711497A8FedAC273220E"), nil
	case "kyber-elastic":
		return common.HexToAddress("0x5F1dddbf348aC2fbe22a163e30F99F9ECE3DD50a"), nil
	default:
		return common.Address{}, fmt.Errorf("unknown protocol: %s", protocol)
	}
}

func calculateMinAmountOut(amountIn *big.Int, slippage float64) *big.Int {
	// Simple calculation: amountOut = amountIn * (1 - slippage/100)
	// In a real implementation, this would fetch current prices
	slippageMultiplier := 1.0 - (slippage / 100.0)
	amountInFloat := new(big.Float).SetInt(amountIn)
	minAmountOutFloat := new(big.Float).Mul(amountInFloat, big.NewFloat(slippageMultiplier))
	minAmountOut, _ := minAmountOutFloat.Int(nil)
	return minAmountOut
}

// Additional commands
func estimateGas(c *cli.Context) error {
	log := logger.New(c.String("log-level"), "text", "")

	params, err := parseSwapParams(c)
	if err != nil {
		return err
	}

	executor, err := newSwapExecutor(c, log)
	if err != nil {
		return err
	}

	protocol := strings.TrimPrefix(c.Command.FullName(), "estimate-gas ")
	if protocol == "estimate-gas" {
		protocol = "uniswap-v3" // default
	}

	gasEstimate, err := executor.estimateSwapGas(params, protocol)
	if err != nil {
		return err
	}

	log.Info("Gas Estimation",
		"protocol", protocol,
		"estimatedGas", gasEstimate,
	)

	return nil
}

func checkAllowance(c *cli.Context) error {
	log := logger.New(c.String("log-level"), "text", "")
	log.Info("Checking token allowance - implementation pending")
	return nil
}

func approveToken(c *cli.Context) error {
	log := logger.New(c.String("log-level"), "text", "")
	log.Info("Approving token - implementation pending")
	return nil
}