package exchanges

import (
	"fmt"
	"math/big"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/ethclient"

	"github.com/fraktal/mev-beta/internal/logger"
	"github.com/fraktal/mev-beta/pkg/math"
)

// DexAggregatorPoolDetector implements PoolDetector for DEX aggregators
type DexAggregatorPoolDetector struct {
	client   *ethclient.Client
	logger   *logger.Logger
	config   *ExchangeConfig
	registry *ExchangeRegistry
}

// NewDexAggregatorPoolDetector creates a new DEX aggregator pool detector
func NewDexAggregatorPoolDetector(client *ethclient.Client, logger *logger.Logger, config *ExchangeConfig, registry *ExchangeRegistry) *DexAggregatorPoolDetector {
	return &DexAggregatorPoolDetector{
		client:   client,
		logger:   logger,
		config:   config,
		registry: registry,
	}
}

// GetAllPools returns all pools containing the specified tokens across all exchanges
func (d *DexAggregatorPoolDetector) GetAllPools(token0, token1 common.Address) ([]common.Address, error) {
	// This would aggregate pools from all registered exchanges
	var allPools []common.Address

	// Get all supported exchanges for this token pair
	exchanges := d.registry.GetExchangesForPair(token0, token1)

	for _, exchangeConfig := range exchanges {
		// Get the pool detector for this exchange
		poolDetector := d.registry.GetPoolDetector(exchangeConfig.Type)
		if poolDetector != nil {
			pools, err := poolDetector.GetAllPools(token0, token1)
			if err != nil {
				d.logger.Warn(fmt.Sprintf("Error getting pools from exchange %s: %v", exchangeConfig.Name, err))
				continue
			}
			allPools = append(allPools, pools...)
		}
	}

	return allPools, nil
}

// GetPoolForPair returns the best pool address for a specific token pair across exchanges
func (d *DexAggregatorPoolDetector) GetPoolForPair(token0, token1 common.Address) (common.Address, error) {
	// In a real implementation, this would find the pool with best pricing across exchanges
	// For now, return a placeholder address
	return common.HexToAddress("0x0"), nil
}

// GetSupportedFeeTiers returns supported fee tiers for the aggregated exchanges
func (d *DexAggregatorPoolDetector) GetSupportedFeeTiers() []int64 {
	// Return a range that covers all possible fee tiers across exchanges
	return []int64{100, 250, 300, 500, 1000, 2500, 3000, 5000, 10000} // Various fee tiers
}

// GetPoolType returns the pool type
func (d *DexAggregatorPoolDetector) GetPoolType() string {
	return "dex_aggregator"
}

// DexAggregatorLiquidityFetcher implements LiquidityFetcher for DEX aggregators
type DexAggregatorLiquidityFetcher struct {
	client   *ethclient.Client
	logger   *logger.Logger
	config   *ExchangeConfig
	registry *ExchangeRegistry
	engine   *math.ExchangePricingEngine
}

// NewDexAggregatorLiquidityFetcher creates a new DEX aggregator liquidity fetcher
func NewDexAggregatorLiquidityFetcher(client *ethclient.Client, logger *logger.Logger, config *ExchangeConfig, registry *ExchangeRegistry, engine *math.ExchangePricingEngine) *DexAggregatorLiquidityFetcher {
	return &DexAggregatorLiquidityFetcher{
		client:   client,
		logger:   logger,
		config:   config,
		registry: registry,
		engine:   engine,
	}
}

// GetPoolData fetches pool information from the best available exchange for the token pair
func (f *DexAggregatorLiquidityFetcher) GetPoolData(poolAddress common.Address) (*math.PoolData, error) {
	// For aggregator, this would depend on which exchange's pool is being represented
	// For this implementation, we'll return placeholder data
	return nil, fmt.Errorf("GetPoolData not directly supported for aggregator, use GetBestPoolData instead")
}

// GetTokenReserves fetches reserves from the best available exchange for a token pair
func (f *DexAggregatorLiquidityFetcher) GetTokenReserves(poolAddress, token0, token1 common.Address) (*big.Int, *big.Int, error) {
	// This would aggregate reserves across exchanges
	// For now, return placeholder values
	return big.NewInt(0), big.NewInt(0), fmt.Errorf("not implemented for aggregator directly")
}

// GetBestPoolData fetches the best pool data across all exchanges for a token pair
func (f *DexAggregatorLiquidityFetcher) GetBestPoolData(token0, token1 common.Address) (*math.PoolData, math.ExchangeType, error) {
	// Get all supported exchanges for this token pair
	exchanges := f.registry.GetExchangesForPair(token0, token1)
	bestAmountOut := big.NewInt(0)
	var bestPoolData *math.PoolData
	var bestExchangeType math.ExchangeType

	for _, exchangeConfig := range exchanges {
		// Get the liquidity fetcher for this exchange
		liquidityFetcher := f.registry.GetLiquidityFetcher(exchangeConfig.Type)
		if liquidityFetcher != nil {
			// Get pool data for this exchange
			poolData, err := liquidityFetcher.GetPoolData(common.HexToAddress(exchangeConfig.FactoryAddress.Hex())) // This is a simplification
			if err != nil {
				f.logger.Warn(fmt.Sprintf("Error getting pool data from exchange %s: %v", exchangeConfig.Name, err))
				continue
			}

			// Calculate amount out for a standard amount to compare
			testAmount := big.NewInt(1000000000000000000) // 1 ETH equivalent
			decimalAmountIn, err := math.NewUniversalDecimal(testAmount, 18, "AMOUNT_IN")
			if err != nil {
				f.logger.Warn(fmt.Sprintf("Error creating decimal amount: %v", err))
				continue
			}

			pricer, err := f.engine.GetExchangePricer(poolData.ExchangeType)
			if err != nil {
				continue
			}

			amountOut, err := pricer.CalculateAmountOut(decimalAmountIn, poolData)
			if err != nil {
				continue
			}

			// Check if this is the best rate
			if amountOut.Value.Cmp(bestAmountOut) > 0 {
				bestAmountOut = amountOut.Value
				bestPoolData = poolData
				bestExchangeType = poolData.ExchangeType
			}
		}
	}

	if bestPoolData == nil {
		return nil, "", fmt.Errorf("no pools found for token pair")
	}

	return bestPoolData, bestExchangeType, nil
}

// GetPoolPrice calculates the best price of token1 in terms of token0 across exchanges
func (f *DexAggregatorLiquidityFetcher) GetPoolPrice(poolAddress common.Address) (*big.Float, error) {
	// For an aggregator, we'd need to look up which exchange the pool belongs to
	// For this simplified version, return an error
	return nil, fmt.Errorf("GetPoolPrice not directly supported for aggregator, use GetBestPoolPrice instead")
}

// GetBestPoolPrice calculates the best price across all exchanges for a token pair
func (f *DexAggregatorLiquidityFetcher) GetBestPoolPrice(token0, token1 common.Address) (*big.Float, math.ExchangeType, error) {
	poolData, exchangeType, err := f.GetBestPoolData(token0, token1)
	if err != nil {
		return nil, "", err
	}

	pricer, err := f.engine.GetExchangePricer(poolData.ExchangeType)
	if err != nil {
		return nil, "", err
	}

	spotPrice, err := pricer.GetSpotPrice(poolData)
	if err != nil {
		return nil, "", err
	}

	// Convert the UniversalDecimal Value to a *big.Float
	result := new(big.Float).SetInt(spotPrice.Value)
	return result, exchangeType, nil
}

// GetLiquidityDepth calculates the liquidity depth across all exchanges
func (f *DexAggregatorLiquidityFetcher) GetLiquidityDepth(poolAddress, tokenIn common.Address, amount *big.Int) (*big.Int, error) {
	// This would aggregate liquidity across exchanges
	// For now, return placeholder
	return amount, nil
}

// DexAggregatorSwapRouter implements SwapRouter for DEX aggregators
type DexAggregatorSwapRouter struct {
	client   *ethclient.Client
	logger   *logger.Logger
	config   *ExchangeConfig
	registry *ExchangeRegistry
	engine   *math.ExchangePricingEngine
}

// NewDexAggregatorSwapRouter creates a new DEX aggregator swap router
func NewDexAggregatorSwapRouter(client *ethclient.Client, logger *logger.Logger, config *ExchangeConfig, registry *ExchangeRegistry, engine *math.ExchangePricingEngine) *DexAggregatorSwapRouter {
	return &DexAggregatorSwapRouter{
		client:   client,
		logger:   logger,
		config:   config,
		registry: registry,
		engine:   engine,
	}
}

// CalculateSwap calculates the expected best output amount across all exchanges
func (r *DexAggregatorSwapRouter) CalculateSwap(tokenIn, tokenOut common.Address, amountIn *big.Int) (*big.Int, error) {
	// Get the best available rate across all exchanges
	exchanges := r.registry.GetExchangesForPair(tokenIn, tokenOut)
	bestAmountOut := big.NewInt(0)

	for _, exchangeConfig := range exchanges {
		// Get the swap router for this exchange
		swapRouter := r.registry.GetSwapRouter(exchangeConfig.Type)
		if swapRouter != nil {
			amountOut, err := swapRouter.CalculateSwap(tokenIn, tokenOut, amountIn)
			if err != nil {
				r.logger.Warn(fmt.Sprintf("Error calculating swap on exchange %s: %v", exchangeConfig.Name, err))
				continue
			}

			// Check if this is the best rate
			if amountOut.Cmp(bestAmountOut) > 0 {
				bestAmountOut = amountOut
			}
		}
	}

	if bestAmountOut.Sign() <= 0 {
		return nil, fmt.Errorf("no favorable swap route found across exchanges")
	}

	return bestAmountOut, nil
}

// CalculateMultiSwap calculates the output amount considering multiple exchanges and routing
func (r *DexAggregatorSwapRouter) CalculateMultiSwap(tokenIn, tokenOut common.Address, amountIn *big.Int) (*big.Int, []math.ExchangeType, error) {
	// Find best path across exchanges
	exchanges := r.registry.GetExchangesForPair(tokenIn, tokenOut)
	bestAmountOut := big.NewInt(0)
	var bestRoutes []math.ExchangeType

	for _, exchangeConfig := range exchanges {
		// Get the swap router for this exchange
		swapRouter := r.registry.GetSwapRouter(exchangeConfig.Type)
		if swapRouter != nil {
			amountOut, err := swapRouter.CalculateSwap(tokenIn, tokenOut, amountIn)
			if err != nil {
				r.logger.Warn(fmt.Sprintf("Error calculating swap on exchange %s: %v", exchangeConfig.Name, err))
				continue
			}

			// Check if this is the best rate
			if amountOut.Cmp(bestAmountOut) > 0 {
				bestAmountOut = amountOut
				bestRoutes = []math.ExchangeType{exchangeConfig.Type}
			}
		}
	}

	if bestAmountOut.Sign() <= 0 {
		return nil, nil, fmt.Errorf("no favorable swap route found across exchanges")
	}

	return bestAmountOut, bestRoutes, nil
}

// GenerateSwapData generates the calldata for an aggregated swap transaction
func (r *DexAggregatorSwapRouter) GenerateSwapData(tokenIn, tokenOut common.Address, amountIn, minAmountOut *big.Int, deadline *big.Int) ([]byte, error) {
	// In a real implementation, this would generate data for a complex multi-exchange swap
	// For now, return placeholder
	return []byte{}, nil
}

// GetSwapRoute returns the best route for a swap across all exchanges
func (r *DexAggregatorSwapRouter) GetSwapRoute(tokenIn, tokenOut common.Address) ([]common.Address, error) {
	// Find the best exchange for this swap
	exchanges := r.registry.GetExchangesForPair(tokenIn, tokenOut)
	if len(exchanges) == 0 {
		return nil, fmt.Errorf("no exchanges support this token pair")
	}

	// For this simplified implementation, return a direct route
	return []common.Address{tokenIn, tokenOut}, nil
}

// GetBestSwapRoute returns the best route considering multiple exchanges
func (r *DexAggregatorSwapRouter) GetBestSwapRoute(tokenIn, tokenOut common.Address) ([]common.Address, math.ExchangeType, error) {
	// Find the best exchange for this swap
	exchanges := r.registry.GetExchangesForPair(tokenIn, tokenOut)
	bestAmountOut := big.NewInt(0)
	var bestExchange math.ExchangeType

	for _, exchangeConfig := range exchanges {
		// Get the swap router for this exchange
		swapRouter := r.registry.GetSwapRouter(exchangeConfig.Type)
		if swapRouter != nil {
			amountOut, err := swapRouter.CalculateSwap(tokenIn, tokenOut, big.NewInt(1000000000000000000)) // Use 1 ETH equivalent to compare
			if err != nil {
				r.logger.Warn(fmt.Sprintf("Error calculating swap on exchange %s: %v", exchangeConfig.Name, err))
				continue
			}

			// Check if this is the best rate
			if amountOut.Cmp(bestAmountOut) > 0 {
				bestAmountOut = amountOut
				bestExchange = exchangeConfig.Type
			}
		}
	}

	if bestAmountOut.Sign() <= 0 {
		return nil, "", fmt.Errorf("no favorable swap route found across exchanges")
	}

	// Return the best route for the exchange type
	return []common.Address{tokenIn, tokenOut}, bestExchange, nil
}

// ValidateSwap validates a swap across exchanges before execution
func (r *DexAggregatorSwapRouter) ValidateSwap(tokenIn, tokenOut common.Address, amountIn *big.Int) error {
	if amountIn.Sign() <= 0 {
		return fmt.Errorf("amountIn must be positive")
	}

	if tokenIn == tokenOut {
		return fmt.Errorf("tokenIn and tokenOut cannot be the same")
	}

	if tokenIn == common.HexToAddress("0x0") || tokenOut == common.HexToAddress("0x0") {
		return fmt.Errorf("invalid token addresses")
	}

	// Check if any exchange supports this pair
	if !r.registry.IsPairSupported(tokenIn, tokenOut) {
		return fmt.Errorf("no exchange supports this token pair")
	}

	return nil
}

// RegisterDexAggregatorWithRegistry registers DEX aggregator implementation with the exchange registry
func RegisterDexAggregatorWithRegistry(registry *ExchangeRegistry) error {
	// Note: For a complete implementation, we would need to define a specific type for aggregators
	// For now, we're not registering it as it needs a dedicated ExchangeType

	// config := &ExchangeConfig{
	// 	Type:                   math.ExchangeUniswapV2, // Using a placeholder type for the aggregator
	// 	Name:                   "DEX Aggregator",
	// 	FactoryAddress:         common.HexToAddress("0x0"), // Aggregators don't have a factory address
	// 	RouterAddress:          common.HexToAddress("0x0"), // Would actually be aggregator contract address
	// 	PoolInitCodeHash:       "",
	// 	SwapSelector:           []byte{0x00, 0x00, 0x00, 0x00}, // Placeholder
	// 	StableSwapSelector:     []byte{0x00, 0x00, 0x00, 0x00}, // Placeholder
	// 	ChainID:                1, // Ethereum mainnet
	// 	SupportsFlashSwaps:     true,
	// 	RequiresApproval:       true,
	// 	MaxHops:                5, // Can route through multiple exchanges
	// 	DefaultSlippagePercent: 0.5,
	// 	Url:                    "https://dex.ag",
	// 	ApiUrl:                 "https://api.dex.ag",
	// }

	// Note: For a complete implementation, we would need to define a specific type for aggregators
	// registry.exchanges[math.ExchangeDexAggregator] = config

	return nil
}