package types

import (
	"math/big"

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

// PoolInfo contains comprehensive pool information
type PoolInfo struct {
	// Pool identification
	Address         common.Address
	Protocol        ProtocolType
	PoolType        string  // e.g., "constant-product", "stable", "weighted"

	// Token information
	Token0          common.Address
	Token1          common.Address
	Token0Decimals  uint8
	Token1Decimals  uint8
	Token0Symbol    string
	Token1Symbol    string

	// Reserves/Liquidity
	Reserve0        *big.Int
	Reserve1        *big.Int
	Liquidity       *big.Int

	// Fee information
	Fee             uint32  // Fee in basis points (e.g., 30 = 0.3%)
	FeeGrowth0      *big.Int  // UniswapV3 fee growth
	FeeGrowth1      *big.Int  // UniswapV3 fee growth

	// Protocol-specific data
	SqrtPriceX96    *big.Int  // UniswapV3/Camelot V3
	Tick            *int32    // UniswapV3/Camelot V3
	TickSpacing     int32     // UniswapV3/Camelot V3
	AmpCoefficient  *big.Int  // Curve amplification coefficient

	// Pool state
	IsActive        bool
	BlockNumber     uint64
	LastUpdate      uint64
}

// Validate checks if the pool info is valid
func (p *PoolInfo) Validate() error {
	if p.Address == (common.Address{}) {
		return ErrInvalidPoolAddress
	}

	if p.Token0 == (common.Address{}) {
		return ErrInvalidToken0Address
	}

	if p.Token1 == (common.Address{}) {
		return ErrInvalidToken1Address
	}

	if p.Token0Decimals == 0 || p.Token0Decimals > 18 {
		return ErrInvalidToken0Decimals
	}

	if p.Token1Decimals == 0 || p.Token1Decimals > 18 {
		return ErrInvalidToken1Decimals
	}

	if p.Protocol == ProtocolUnknown {
		return ErrUnknownProtocol
	}

	return nil
}

// GetTokenPair returns the token pair as a sorted tuple
func (p *PoolInfo) GetTokenPair() (common.Address, common.Address) {
	if p.Token0.Big().Cmp(p.Token1.Big()) < 0 {
		return p.Token0, p.Token1
	}
	return p.Token1, p.Token0
}

// CalculatePrice calculates the price of token0 in terms of token1
func (p *PoolInfo) CalculatePrice() *big.Float {
	if p.Reserve0 == nil || p.Reserve1 == nil || p.Reserve0.Sign() == 0 {
		return big.NewFloat(0)
	}

	// Scale reserves to 18 decimals for consistent calculation
	reserve0Scaled := ScaleToDecimals(p.Reserve0, p.Token0Decimals, 18)
	reserve1Scaled := ScaleToDecimals(p.Reserve1, p.Token1Decimals, 18)

	// Price = Reserve1 / Reserve0
	reserve0Float := new(big.Float).SetInt(reserve0Scaled)
	reserve1Float := new(big.Float).SetInt(reserve1Scaled)

	price := new(big.Float).Quo(reserve1Float, reserve0Float)
	return price
}

// ScaleToDecimals scales an amount from one decimal precision to another
func ScaleToDecimals(amount *big.Int, fromDecimals, toDecimals uint8) *big.Int {
	if fromDecimals == toDecimals {
		return new(big.Int).Set(amount)
	}

	if fromDecimals < toDecimals {
		// Scale up
		multiplier := new(big.Int).Exp(
			big.NewInt(10),
			big.NewInt(int64(toDecimals-fromDecimals)),
			nil,
		)
		return new(big.Int).Mul(amount, multiplier)
	}

	// Scale down
	divisor := new(big.Int).Exp(
		big.NewInt(10),
		big.NewInt(int64(fromDecimals-toDecimals)),
		nil,
	)
	return new(big.Int).Div(amount, divisor)
}