package selectors

import (
	"encoding/hex"
	"fmt"
	"sync"

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

type selectorCache struct {
	mu    sync.Mutex
	cache map[string]string
}

var cachedSelectors = selectorCache{
	cache: make(map[string]string),
}

// MustSelector returns the canonical 4-byte selector (prefixed with 0x) for a function signature.
// Panics if the signature cannot be hashed (should never happen for valid signatures).
func MustSelector(signature string) string {
	cachedSelectors.mu.Lock()
	defer cachedSelectors.mu.Unlock()

	if sel, ok := cachedSelectors.cache[signature]; ok {
		return sel
	}

	hash := crypto.Keccak256([]byte(signature))
	if len(hash) < 4 {
		panic(fmt.Sprintf("unable to derive selector for %s", signature))
	}

	selector := "0x" + hex.EncodeToString(hash[:4])
	cachedSelectors.cache[signature] = selector
	return selector
}

// Uniswap / Pancake / TraderJoe (Uniswap V2-style) selectors
var (
	UniswapV2SwapExactTokensForTokens              = MustSelector("swapExactTokensForTokens(uint256,uint256,address[],address,uint256)")
	UniswapV2SwapTokensForExactTokens              = MustSelector("swapTokensForExactTokens(uint256,uint256,address[],address,uint256)")
	UniswapV2SwapExactETHForTokens                 = MustSelector("swapExactETHForTokens(uint256,address[],address,uint256)")
	UniswapV2SwapTokensForExactETH                 = MustSelector("swapTokensForExactETH(uint256,uint256,address[],address,uint256)")
	UniswapV2SwapExactTokensForETH                 = MustSelector("swapExactTokensForETH(uint256,uint256,address[],address,uint256)")
	UniswapV2SwapETHForExactTokens                 = MustSelector("swapETHForExactTokens(uint256,address[],address,uint256)")
	UniswapV2SwapExactTokensForTokensSupportingFee = MustSelector("swapExactTokensForTokensSupportingFeeOnTransferTokens(uint256,uint256,address[],address,uint256)")
	UniswapV2SwapExactETHForTokensSupportingFee    = MustSelector("swapExactETHForTokensSupportingFeeOnTransferTokens(uint256,address[],address,uint256)")
	UniswapV2SwapExactTokensForETHSupportingFee    = MustSelector("swapExactTokensForETHSupportingFeeOnTransferTokens(uint256,uint256,address[],address,uint256)")
	UniswapV2AddLiquidity                          = MustSelector("addLiquidity(address,address,uint256,uint256,uint256,uint256,address,uint256)")
	UniswapV2AddLiquidityETH                       = MustSelector("addLiquidityETH(address,uint256,uint256,uint256,address,uint256)")
)

// Uniswap V3 / Algebra (Camelot V3, Kyber Elastic) selectors
var (
	UniswapV3ExactInputSingle       = MustSelector("exactInputSingle((address,address,uint24,address,uint256,uint256,uint256,uint160))")
	UniswapV3ExactInputSingleLegacy = MustSelector("exactInputSingle((address,address,uint24,address,uint256,uint256,uint160))")
	UniswapV3ExactInput             = MustSelector("exactInput((bytes,address,uint256,uint256,uint256))")
	UniswapV3ExactInputLegacy       = MustSelector("exactInput((bytes,address,uint256,uint256))")
	UniswapV3ExactOutputSingle      = MustSelector("exactOutputSingle((address,address,uint24,address,uint256,uint256,uint256,uint160))")
	UniswapV3ExactOutput            = MustSelector("exactOutput((bytes,address,uint256,uint256,uint256))")
	UniswapV3ExactOutputBytes       = MustSelector("exactOutput(bytes)")
	UniswapV3Multicall              = MustSelector("multicall(bytes[])")
	UniswapV3MulticallWithDeadline  = MustSelector("multicall(uint256,bytes[])")
	UniswapV3MulticallWithBlockhash = MustSelector("multicall(bytes32,bytes[])")
	UniversalRouterExecute          = MustSelector("execute(bytes,bytes[],uint256)")
	UniversalRouterExecutePayable   = MustSelector("execute(bytes,bytes[])")
	UniversalRouterExecuteSimple    = MustSelector("execute(bytes)")
)

// Balancer V2 selectors
var (
	BalancerSwap      = MustSelector("swap((bytes32,uint8,address,address,uint256,bytes),(address,bool,address,bool),uint256,uint256)")
	BalancerBatchSwap = MustSelector("batchSwap(uint8,(bytes32,uint256,uint256,uint256,bytes)[],address[],(address,bool,address,bool),int256[],uint256)")
	BalancerFlashLoan = MustSelector("flashLoan(address,address[],uint256[],bytes)")
)

// Curve Finance selectors
var (
	CurveExchange               = MustSelector("exchange(int128,int128,uint256,uint256)")
	CurveExchangeUnderlying     = MustSelector("exchange_underlying(int128,int128,uint256,uint256)")
	CurveExchangeUint           = MustSelector("exchange(uint256,uint256,uint256,uint256)")
	CurveExchangeUnderlyingUint = MustSelector("exchange_underlying(uint256,uint256,uint256,uint256)")
)

// Kyber Elastic (reuses Uniswap V3 style)
var (
	KyberExactInputSingleLegacy        = UniswapV3ExactInputSingleLegacy
	KyberExactInputSingle              = UniswapV3ExactInputSingle
	KyberExactInput                    = UniswapV3ExactInput
	KyberExactOutputSingle             = UniswapV3ExactOutputSingle
	KyberExactOutput                   = UniswapV3ExactOutput
	KyberMulticall                     = UniswapV3Multicall
	KyberMulticallWithDeadline         = UniswapV3MulticallWithDeadline
	KyberMulticallWithBlockhash        = UniswapV3MulticallWithBlockhash
	KyberUniversalRouterExecute        = UniversalRouterExecute
	KyberUniversalRouterExecutePayable = UniversalRouterExecutePayable
	KyberUniversalRouterExecuteSimple  = UniversalRouterExecuteSimple
)

// Kyber Classic shares the Uniswap V2 style router interface.
var (
	KyberClassicSwapExactTokensForTokens              = UniswapV2SwapExactTokensForTokens
	KyberClassicSwapTokensForExactTokens              = UniswapV2SwapTokensForExactTokens
	KyberClassicSwapExactETHForTokens                 = UniswapV2SwapExactETHForTokens
	KyberClassicSwapTokensForExactETH                 = UniswapV2SwapTokensForExactETH
	KyberClassicSwapExactTokensForETH                 = UniswapV2SwapExactTokensForETH
	KyberClassicSwapETHForExactTokens                 = UniswapV2SwapETHForExactTokens
	KyberClassicSwapExactTokensForTokensSupportingFee = UniswapV2SwapExactTokensForTokensSupportingFee
	KyberClassicSwapExactETHForTokensSupportingFee    = UniswapV2SwapExactETHForTokensSupportingFee
	KyberClassicSwapExactTokensForETHSupportingFee    = UniswapV2SwapExactTokensForETHSupportingFee
)

// PancakeSwap (BSC) uses the Uniswap V2 router interface.
var (
	PancakeSwapSwapExactTokensForTokens              = UniswapV2SwapExactTokensForTokens
	PancakeSwapSwapTokensForExactTokens              = UniswapV2SwapTokensForExactTokens
	PancakeSwapSwapExactETHForTokens                 = UniswapV2SwapExactETHForTokens
	PancakeSwapSwapTokensForExactETH                 = UniswapV2SwapTokensForExactETH
	PancakeSwapSwapExactTokensForETH                 = UniswapV2SwapExactTokensForETH
	PancakeSwapSwapETHForExactTokens                 = UniswapV2SwapETHForExactTokens
	PancakeSwapSwapExactTokensForTokensSupportingFee = UniswapV2SwapExactTokensForTokensSupportingFee
	PancakeSwapSwapExactETHForTokensSupportingFee    = UniswapV2SwapExactETHForTokensSupportingFee
	PancakeSwapSwapExactTokensForETHSupportingFee    = UniswapV2SwapExactTokensForETHSupportingFee
	PancakeSwapAddLiquidity                          = UniswapV2AddLiquidity
	PancakeSwapAddLiquidityETH                       = UniswapV2AddLiquidityETH
)

// Trader Joe V2 (AMM) mirrors the Uniswap V2 router interface.
var (
	TraderJoeSwapExactTokensForTokens              = UniswapV2SwapExactTokensForTokens
	TraderJoeSwapTokensForExactTokens              = UniswapV2SwapTokensForExactTokens
	TraderJoeSwapExactETHForTokens                 = UniswapV2SwapExactETHForTokens
	TraderJoeSwapTokensForExactETH                 = UniswapV2SwapTokensForExactETH
	TraderJoeSwapExactTokensForETH                 = UniswapV2SwapExactTokensForETH
	TraderJoeSwapETHForExactTokens                 = UniswapV2SwapETHForExactTokens
	TraderJoeSwapExactTokensForTokensSupportingFee = UniswapV2SwapExactTokensForTokensSupportingFee
	TraderJoeSwapExactETHForTokensSupportingFee    = UniswapV2SwapExactETHForTokensSupportingFee
	TraderJoeSwapExactTokensForETHSupportingFee    = UniswapV2SwapExactTokensForETHSupportingFee
	TraderJoeAddLiquidity                          = UniswapV2AddLiquidity
	TraderJoeAddLiquidityETH                       = UniswapV2AddLiquidityETH
)

// Trader Joe Liquidity Book router specific selectors.
var (
	TraderJoeLBSwapExactTokensForTokens              = MustSelector("swapExactTokensForTokens(uint256,uint256,(uint256[],uint8[],address[]),address,uint256)")
	TraderJoeLBSwapTokensForExactTokens              = MustSelector("swapTokensForExactTokens(uint256,uint256,(uint256[],uint8[],address[]),address,uint256)")
	TraderJoeLBSwapExactTokensForNative              = MustSelector("swapExactTokensForNATIVE(uint256,uint256,(uint256[],uint8[],address[]),address,uint256)")
	TraderJoeLBSwapExactNativeForTokens              = MustSelector("swapExactNATIVEForTokens(uint256,(uint256[],uint8[],address[]),address,uint256)")
	TraderJoeLBSwapTokensForExactNative              = MustSelector("swapTokensForExactNATIVE(uint256,uint256,(uint256[],uint8[],address[]),address,uint256)")
	TraderJoeLBSwapExactTokensForTokensSupportingFee = MustSelector("swapExactTokensForTokensSupportingFeeOnTransferTokens(uint256,uint256,(uint256[],uint8[],address[]),address,uint256)")
	TraderJoeLBSwapExactTokensForNativeSupportingFee = MustSelector("swapExactTokensForNATIVESupportingFeeOnTransferTokens(uint256,uint256,(uint256[],uint8[],address[]),address,uint256)")
	TraderJoeLBSwapExactNativeForTokensSupportingFee = MustSelector("swapExactNATIVEForTokensSupportingFeeOnTransferTokens(uint256,(uint256[],uint8[],address[]),address,uint256)")
	TraderJoeLBLiquidityAdd                          = MustSelector("addLiquidity((address,address,uint256,uint256,uint256,uint256,uint256,uint256,uint256,int256[],uint256[],uint256[],address,address,uint256))")
	TraderJoeLBLiquidityAddNative                    = MustSelector("addLiquidityNATIVE((address,address,uint256,uint256,uint256,uint256,uint256,uint256,uint256,int256[],uint256[],uint256[],address,address,uint256))")
	TraderJoeLBLiquidityRemove                       = MustSelector("removeLiquidity(address,address,uint16,uint256,uint256,uint256[],uint256[],address,uint256)")
	TraderJoeLBLiquidityRemoveNative                 = MustSelector("removeLiquidityNATIVE(address,uint16,uint256,uint256,uint256[],uint256[],address,uint256)")
)

// Camelot V2 uses Uniswap V2 style selectors; Camelot V3 builds on Algebra (Uniswap V3 equivalent).
var (
	CamelotV2SwapExactTokensForTokens              = UniswapV2SwapExactTokensForTokens
	CamelotV2SwapTokensForExactTokens              = UniswapV2SwapTokensForExactTokens
	CamelotV2SwapExactETHForTokens                 = UniswapV2SwapExactETHForTokens
	CamelotV2SwapTokensForExactETH                 = UniswapV2SwapTokensForExactETH
	CamelotV2SwapExactTokensForETH                 = UniswapV2SwapExactTokensForETH
	CamelotV2SwapETHForExactTokens                 = UniswapV2SwapETHForExactTokens
	CamelotV2SwapExactTokensForTokensSupportingFee = UniswapV2SwapExactTokensForTokensSupportingFee
	CamelotV2SwapExactETHForTokensSupportingFee    = UniswapV2SwapExactETHForTokensSupportingFee
	CamelotV2SwapExactTokensForETHSupportingFee    = UniswapV2SwapExactTokensForETHSupportingFee
	CamelotV2AddLiquidity                          = UniswapV2AddLiquidity
	CamelotV2AddLiquidityETH                       = UniswapV2AddLiquidityETH

	CamelotV3ExactInputSingle       = UniswapV3ExactInputSingle
	CamelotV3ExactInput             = UniswapV3ExactInput
	CamelotV3ExactOutputSingle      = UniswapV3ExactOutputSingle
	CamelotV3ExactOutput            = UniswapV3ExactOutput
	CamelotV3Multicall              = UniswapV3Multicall
	CamelotV3MulticallWithDeadline  = UniswapV3MulticallWithDeadline
	CamelotV3MulticallWithBlockhash = UniswapV3MulticallWithBlockhash
)

// Additional selectors
var (
	UniswapV2SwapExactTokensForTokensSupportingFeeLegacy = MustSelector("swapExactTokensForTokensSupportingFeeOnTransferTokens(uint256,uint256,address[],address)")
	NonfungiblePositionManagerMint                       = MustSelector("mint((address,address,uint24,int24,int24,uint256,uint256,uint256,uint256,address,uint256))")
)