package shreder

import (
	"bytes"
	"encoding/binary"
	"fmt"

	bin "github.com/gagliardetto/binary"
	"github.com/gagliardetto/solana-go"
	"github.com/shopspring/decimal"
)

var (
	dflowProgramID = solana.MustPublicKeyFromBase58("DF1ow4tspfHX9JwWJsAb9epbkA8hmpSEAtxXy1V27QBH")

	dflowSwapDisc                   = []byte{248, 198, 158, 145, 225, 117, 135, 200}
	dflowSwap2Disc                  = []byte{65, 75, 63, 76, 235, 91, 91, 136}
	dflowSwapWithDestinationDisc    = []byte{168, 172, 24, 77, 197, 156, 135, 101}
	dflowSwapWithDestinationNative  = []byte{205, 77, 127, 108, 241, 32, 196, 195}
	dflowSwap2WithDestinationDisc   = []byte{95, 123, 213, 246, 122, 1, 86, 231}
	dflowSwap2WithDestinationNative = []byte{222, 100, 184, 146, 186, 196, 105, 165}

	wrappedSOL = solana.MustPublicKeyFromBase58("So11111111111111111111111111111111111111112")
)

// Action enum tags (0-based, per dflow_idl Action variants)
const (
	ActWhirlpoolsSwap uint8 = iota
	ActClearpoolsSwap
	ActRaydiumAmmSwap
	ActLifinityV2Swap
	ActMeteoraDlmmSwap
	ActRaydiumClmmSwap
	ActRaydiumClmmSwapV2
	ActPhoenixSwap
	ActPumpFunBuy
	ActPumpFunSell
	ActGammaSwap
	ActObricV2Swap
	ActPumpFunAmmBuy
	ActPumpFunAmmSell
	ActSolFiSwap
	ActRubiconSwap
	ActMeteoraDammV1Swap
	ActRaydiumCpSwap
	ActStabbleStableSwap
	ActTesseraVSwap
	ActMeteoraDammV2Swap
	ActRaydiumLaunchlabSwap
	ActMeteoraDbcSwap
	ActHumidiFiSwap
	ActWhirlpoolsSwapV2
	ActMeteoraDlmmSwapV2
	ActZeroFiSwap
	ActAlphaQSwap
	ActTokenSwap
	ActSolFiV2Swap
	ActMozartSwap
	ActDFlowDynamicRouteV1
	ActHeavenSwap
	ActNexusSwap
	ActSarosDlmmSwap
	ActTransferFee
	ActTransferFeeWithMint
	ActRecordId
	ActRecordId2
	ActManifestSwap
	ActBisonFiSwap
	ActSanctumInfinitySwap
	ActSanctumInfinityLiquidity
	ActOpenPredictionsOrder
	ActScorchSwap
	ActIncludeAccount
)

// DynamicRouteV1CandidateAction tags
const (
	drv1SolFi uint8 = iota
	drv1Rubicon
	drv1TesseraV
	drv1HumidiFi
	drv1SolFiV2
	drv1Mozart
	drv1ObricV2
	drv1Nexus
)

// PumpFunAmmSellOptions { amount: u64, orchestrator_flags: OrchestratorFlags{flags u8} }
type pumpFunAmm struct {
	Amount uint64
	Flags  uint8
}

type dflowAction struct {
	Tag  uint8
	Pump *pumpFunAmm
}

type dflowSwapParams struct {
	Actions []dflowAction
}

// bytes to skip for Action variants before/after PumpFunAmmSell; only PumpFunAmmSell is decoded.
func skipDflowAction(dec *bin.Decoder, tag uint8) (*pumpFunAmm, error) {
	switch tag {
	case ActWhirlpoolsSwap, ActClearpoolsSwap, ActWhirlpoolsSwapV2:
		// amount u64 + bool + orchestrator_flags u8
		return nil, dec.SkipBytes(8 + 1 + 1)
	case ActRaydiumAmmSwap, ActLifinityV2Swap, ActPumpFunBuy, ActPumpFunSell, ActObricV2Swap,
		ActSolFiSwap, ActRubiconSwap, ActMeteoraDammV1Swap, ActRaydiumCpSwap,
		ActStabbleStableSwap, ActTesseraVSwap, ActMeteoraDammV2Swap, ActRaydiumLaunchlabSwap,
		ActZeroFiSwap, ActAlphaQSwap, ActTokenSwap, ActSolFiV2Swap, ActMozartSwap, ActHeavenSwap,
		ActNexusSwap, ActSarosDlmmSwap, ActManifestSwap, ActBisonFiSwap:
		// amount u64 + orchestrator_flags u8
		return nil, dec.SkipBytes(8 + 1)
	case ActMeteoraDlmmSwap, ActRaydiumClmmSwap, ActRaydiumClmmSwapV2, ActMeteoraDlmmSwapV2:
		// amount u64 + u8 + orchestrator_flags u8
		return nil, dec.SkipBytes(8 + 1 + 1)
	case ActPhoenixSwap:
		// amount u64 + side u8 + orchestrator_flags u8
		return nil, dec.SkipBytes(8 + 1 + 1)
	case ActGammaSwap:
		// amount u64 + endorsed bool + orchestrator_flags u8
		return nil, dec.SkipBytes(8 + 1 + 1)
	case ActPumpFunAmmSell, ActPumpFunAmmBuy:
		amt, err := dec.ReadUint64(binary.LittleEndian)
		if err != nil {
			return nil, err
		}
		flg, err := dec.ReadUint8()
		if err != nil {
			return nil, err
		}
		return &pumpFunAmm{Amount: amt, Flags: flg}, nil
	case ActMeteoraDbcSwap:
		// amount u64 + is_rate_limiter_applied bool + orchestrator_flags u8
		return nil, dec.SkipBytes(8 + 1 + 1)
	case ActHumidiFiSwap:
		// amount u64 + swap_id u64 + orchestrator_flags u8
		return nil, dec.SkipBytes(8 + 8 + 1)
	case ActDFlowDynamicRouteV1:
		// candidate_actions Vec<DynamicRouteV1CandidateAction> + amount u64 + orchestrator_flags u8
		ln, err := dec.ReadUint32(binary.LittleEndian)
		if err != nil {
			return nil, err
		}
		for j := uint32(0); j < ln; j++ {
			t, err := dec.ReadUint8()
			if err != nil {
				return nil, err
			}
			if t == drv1HumidiFi {
				if err := dec.SkipBytes(8); err != nil {
					return nil, err
				}
			}
			// other variants carry no payload
		}
		if err := dec.SkipBytes(8); err != nil { // amount
			return nil, err
		}
		return nil, dec.SkipBytes(1) // orchestrator_flags
	case ActTransferFee, ActTransferFeeWithMint:
		return nil, dec.SkipBytes(8)
	case ActRecordId:
		return nil, dec.SkipBytes(76)
	case ActRecordId2:
		return nil, dec.SkipBytes(4)
	case ActSanctumInfinitySwap:
		// amount u64 + src_lst_value_calc_accs u8 + dst_lst_value_calc_accs u8 + src_lst_index u32 + dst_lst_index u32 + orchestrator_flags u8
		return nil, dec.SkipBytes(8 + 1 + 1 + 4 + 4 + 1)
	case ActSanctumInfinityLiquidity:
		// amount u64 + lst_value_calc_accs u8 + lst_index u32 + orchestrator_flags u8
		return nil, dec.SkipBytes(8 + 1 + 4 + 1)
	case ActOpenPredictionsOrder:
		// nonce u64 + order_outcome u8 + quoted_out_amount u64 + slippage_bps u16 + platform_fee_recipient_vault pubkey(32) + platform_fee_scale u16
		return nil, dec.SkipBytes(8 + 1 + 8 + 2 + 32 + 2)
	case ActScorchSwap:
		// amount u64 + id u128 + orchestrator_flags u8
		return nil, dec.SkipBytes(8 + 16 + 1)
	case ActIncludeAccount:
		return nil, nil
	default:
		return nil, fmt.Errorf("unsupported action tag %d", tag)
	}
}

// SwapParams: actions Vec<Action>, quoted_out_amount u64, slippage_bps u16, platform_fee_bps u16
func decodeSwapParams(data []byte) (*dflowSwapParams, error) {
	dec := bin.NewBorshDecoder(data)
	out := &dflowSwapParams{}
	ln, err := dec.ReadUint32(binary.LittleEndian)
	if err != nil {
		return nil, err
	}
	out.Actions = make([]dflowAction, 0, ln)
	for i := uint32(0); i < ln; i++ {
		tag, err := dec.ReadUint8()
		if err != nil {
			return nil, fmt.Errorf("actions[%d] tag: %w", i, err)
		}
		pump, err := skipDflowAction(dec, tag)
		if err != nil {
			return nil, fmt.Errorf("actions[%d]: %w", i, err)
		}
		out.Actions = append(out.Actions, dflowAction{Tag: tag, Pump: pump})
	}
	return out, nil
}

// Swap2Params: actions Vec<Action>, quoted_out_amount u64, slippage_bps u16, platform_fee_bps u16, positive_slippage_fee_limit_pct u8
func decodeSwap2Params(data []byte) (*dflowSwapParams, error) {
	dec := bin.NewBorshDecoder(data)
	out := &dflowSwapParams{}
	ln, err := dec.ReadUint32(binary.LittleEndian)
	if err != nil {
		return nil, err
	}
	out.Actions = make([]dflowAction, 0, ln)
	for i := uint32(0); i < ln; i++ {
		tag, err := dec.ReadUint8()
		if err != nil {
			return nil, fmt.Errorf("actions[%d] tag: %w", i, err)
		}
		pump, err := skipDflowAction(dec, tag)
		if err != nil {
			return nil, fmt.Errorf("actions[%d]: %w", i, err)
		}
		out.Actions = append(out.Actions, dflowAction{Tag: tag, Pump: pump})
	}
	return out, nil
}

func parseDFlowInstruction(tx *versionedTransaction, instructionIndex int) (*TxSignal, error) {
	msg := tx.Message
	if instructionIndex >= len(msg.Instructions) {
		return nil, fmt.Errorf("instruction index out of bounds")
	}
	ix := msg.Instructions[instructionIndex]
	if len(ix.Data) < 8 {
		return nil, nil
	}

	var err error
	disc := ix.Data[:8]
	payload := ix.Data[8:]

	var params *dflowSwapParams
	switch {
	case bytes.Equal(disc, dflowSwapDisc), bytes.Equal(disc, dflowSwapWithDestinationDisc), bytes.Equal(disc, dflowSwapWithDestinationNative):
		params, err = decodeSwapParams(payload)
	case bytes.Equal(disc, dflowSwap2Disc), bytes.Equal(disc, dflowSwap2WithDestinationDisc), bytes.Equal(disc, dflowSwap2WithDestinationNative):
		params, err = decodeSwap2Params(payload)
	default:
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	if params == nil {
		return nil, nil
	}

	var pump *pumpFunAmm
	for _, act := range params.Actions {
		if act.Tag == ActPumpFunAmmSell && act.Pump != nil {
			pump = act.Pump
			break
		}
	}
	if pump == nil {
		return nil, nil // only care about PumpFunAmmSell
	}

	// Require WSOL pair when destination mint is provided.
	var (
		srcIdx uint8
	)
	for i, acctIdx := range ix.Accounts {
		if i < 6 {
			continue
		}
		key, err := getStaticKey(tx.Message.StaticAccountKeys, int(acctIdx))
		if err != nil {
			return nil, err
		}
		if key.Equals(pumpAmmProgramID) {
			srcIdx = uint8(i + 4)
			break
		}
	}
	if srcIdx == 0 || srcIdx+1 >= uint8(len(ix.Accounts)) {
		return nil, nil
	}

	baseMint, err := getStaticKey(tx.Message.StaticAccountKeys, int(ix.Accounts[srcIdx]))
	if err != nil {
		return nil, err
	}
	quoteMint, err := getStaticKey(tx.Message.StaticAccountKeys, int(ix.Accounts[srcIdx+1]))
	if err != nil {
		return nil, err
	}
	if !quoteMint.Equals(solana.WrappedSol) {
		return nil, nil
	}

	// Build TxSignal
	sig := &TxSignal{
		Label:              "dflow",
		TxHash:             tx.Signatures[0].String(),
		Maker:              tx.Message.StaticAccountKeys[0].String(),
		Program:            "PumpAMM",
		Event:              "sell",
		Token0Address:      baseMint.String(),
		Token1Address:      wsolMint,
		Token0Amount:       formatTokenAmount(pump.Amount),
		Token1Amount:       decimal.Zero,
		Token0AmountUint64: uint64(pump.Amount),
		Token1AmountUint64: 0,
	}
	return sig, nil
}