package exchange

import (
	"context"
	"crypto/ecdsa"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"math"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/ethereum/go-ethereum/crypto"
	hl "github.com/sonirico/go-hyperliquid"
)

// HyperLiquidTrade handles order placement on HyperLiquid using the SDK.
type HyperLiquidTrade struct {
	exchange    *hl.Exchange
	info        *hl.Info
	privateKey  *ecdsa.PrivateKey
	mainAddress string
	nonceMu     sync.Mutex
	lastNonce   int64
	configured  bool
}

func NewHyperLiquidTrade(privateKeyHex, mainAddress, apiAddress string) (*HyperLiquidTrade, error) {
	if privateKeyHex == "" {
		return &HyperLiquidTrade{}, nil
	}

	keyHex := strings.TrimPrefix(privateKeyHex, "0x")
	keyBytes, err := hex.DecodeString(keyHex)
	if err != nil {
		return nil, fmt.Errorf("decode private key: %w", err)
	}

	privKey, err := crypto.ToECDSA(keyBytes)
	if err != nil {
		return nil, fmt.Errorf("convert to ECDSA: %w", err)
	}

	// Initialize SDK Info (auto-fetches meta + spotMeta)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	info := hl.NewInfo(ctx, hl.TestnetAPIURL, true, nil, nil, nil)

	t := &HyperLiquidTrade{
		privateKey:  privKey,
		mainAddress: mainAddress,
		info:        info,
		configured:  true,
	}

	// Initialize exchange lazily on first order
	return t, nil
}

func (h *HyperLiquidTrade) initExchange() error {
	if h.exchange != nil {
		return nil
	}
	if !h.configured {
		return fmt.Errorf("HyperLiquid not configured")
	}

	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()

	meta, err := h.info.Meta(ctx)
	if err != nil {
		return fmt.Errorf("fetch meta: %w", err)
	}

	spotMeta, err := h.info.SpotMeta(ctx)
	if err != nil {
		return fmt.Errorf("fetch spot meta: %w", err)
	}

	h.exchange = hl.NewExchange(
		ctx,
		h.privateKey,
		hl.TestnetAPIURL,
		meta,
		"",
		h.mainAddress,
		spotMeta,
		nil,
	)

	return nil
}

func (h *HyperLiquidTrade) IsConfigured() bool {
	return h.configured
}

// PlaceMarketOrder places a market (IOC) order on HyperLiquid.
func (h *HyperLiquidTrade) PlaceMarketOrder(coin, side, sz string) (string, error) {
	if !h.configured {
		return "", fmt.Errorf("HyperLiquid not configured")
	}

	if err := h.initExchange(); err != nil {
		return "", fmt.Errorf("init exchange: %w", err)
	}

	isBuy := side == "buy"
	size, err := strconv.ParseFloat(sz, 64)
	if err != nil {
		return "", fmt.Errorf("parse size %s: %w", sz, err)
	}

	// Get current price for slippage
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	mids, err := h.info.AllMids(ctx)
	if err != nil {
		return "", fmt.Errorf("fetch mids: %w", err)
	}

	priceStr, ok := mids[coin]
	if !ok {
		return "", fmt.Errorf("coin %s not found", coin)
	}
	midPx, _ := strconv.ParseFloat(priceStr, 64)

	// Aggressive IOC: buy above market, sell below
	limitPx := midPx * 2.0
	if !isBuy {
		limitPx = midPx * 0.5
	}

	result, err := h.exchange.MarketOpen(ctx, coin, isBuy, size, &limitPx, 0.05, nil, nil)
	if err != nil {
		return "", fmt.Errorf("market open: %w", err)
	}

	// Marshal response
	respJSON, _ := json.Marshal(result)
	return string(respJSON), nil
}

// GetHLSize calculates size for a given USD amount on HyperLiquid.
func GetHLSize(coin string, amountUSD, price float64) string {
	sz := amountUSD / price
	switch coin {
	case "DOGE":
		sz = math.Floor(sz)
		if sz < 1 {
			sz = 1
		}
		return fmt.Sprintf("%.0f", sz)
	case "LINK":
		sz = math.Floor(sz*10) / 10
		if sz < 0.1 {
			sz = 0.1
		}
		return fmt.Sprintf("%.1f", sz)
	case "ONDO":
		sz = math.Floor(sz)
		if sz < 1 {
			sz = 1
		}
		return fmt.Sprintf("%.0f", sz)
	case "OP":
		sz = math.Floor(sz*10) / 10
		if sz < 0.1 {
			sz = 0.1
		}
		return fmt.Sprintf("%.1f", sz)
	case "WIF":
		sz = math.Floor(sz)
		if sz < 1 {
			sz = 1
		}
		return fmt.Sprintf("%.0f", sz)
	case "ARB":
		sz = math.Floor(sz*10) / 10
		if sz < 0.1 {
			sz = 0.1
		}
		return fmt.Sprintf("%.1f", sz)
	default:
		return fmt.Sprintf("%.4f", sz)
	}
}