Initial commit

exchange/bitget_trade.go

@@ -0,0 +1,138 @@
+package exchange
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// BitgetTrade handles order placement on Bitget.
+type BitgetTrade struct {
+	APIKey     string
+	APISecret  string
+	Passphrase string
+	client     *http.Client
+}
+
+func NewBitgetTrade(apiKey, apiSecret, passphrase string) *BitgetTrade {
+	return &BitgetTrade{
+		APIKey:     apiKey,
+		APISecret:  apiSecret,
+		Passphrase: passphrase,
+		client:     &http.Client{Timeout: 10 * time.Second},
+	}
+}
+
+// PlaceMarketOrder places a market order on Bitget.
+// side: "buy" or "sell"
+// symbol: "BTCUSDT" (we use UMCBL perpetual)
+// size: contract size in coin units (e.g. 0.001 for BTC)
+func (b *BitgetTrade) PlaceMarketOrder(side, symbol, size string) (string, error) {
+	ts := fmt.Sprintf("%d", time.Now().UnixMilli())
+	method := "POST"
+	requestPath := "/api/v2/mix/order/place"
+
+	body := map[string]interface{}{
+		"symbol":      symbol + "_UMCBL",
+		"marginCoin":  "USDT",
+		"side":        side,
+		"orderType":   "market",
+		"size":        size,
+		"timeInForce": "IOC", // immediate-or-cancel for market orders
+	}
+	bodyJSON, _ := json.Marshal(body)
+
+	sign := b.sign(method, requestPath, ts, string(bodyJSON))
+
+	url := "https://api.bitget.com" + requestPath
+	req, err := http.NewRequest(method, url, strings.NewReader(string(bodyJSON)))
+	if err != nil {
+		return "", fmt.Errorf("create request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("ACCESS-KEY", b.APIKey)
+	req.Header.Set("ACCESS-SIGN", sign)
+	req.Header.Set("ACCESS-TIMESTAMP", ts)
+	req.Header.Set("ACCESS-PASSPHRASE", b.Passphrase)
+
+	resp, err := b.client.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("http request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	respBody, _ := io.ReadAll(resp.Body)
+
+	var result struct {
+		Code string `json:"code"`
+		Msg  string `json:"msg"`
+		Data struct {
+			OrderID string `json:"orderId"`
+		} `json:"data"`
+	}
+	if err := json.Unmarshal(respBody, &result); err != nil {
+		return "", fmt.Errorf("parse response: %s", string(respBody))
+	}
+	if result.Code != "00000" {
+		return "", fmt.Errorf("bitget error: %s - %s", result.Code, result.Msg)
+	}
+	return result.Data.OrderID, nil
+}
+
+func (b *BitgetTrade) sign(method, requestPath, timestamp, body string) string {
+	raw := timestamp + method + requestPath + body
+	mac := hmac.New(sha256.New, []byte(b.APISecret))
+	mac.Write([]byte(raw))
+	return base64.StdEncoding.EncodeToString(mac.Sum(nil))
+}
+
+// GetBitgetSize calculates the contract size for a given USD amount.
+// Returns size as a decimal string complying with Bitget's USDT-FUTURES precision.
+// Enforces the exchange's minimum: minTradeNum contracts AND $5 min notional.
+func GetBitgetSize(symbol string, amountUSD, price float64) string {
+	if amountUSD < 5 {
+		amountUSD = 5 // Bitget minimum notional
+	}
+	sz := amountUSD / price // raw coin count
+
+	switch symbol {
+	case "DOGEUSDT":
+		if sz < 1 {
+			sz = 1
+		}
+		return fmt.Sprintf("%.0f", sz) // minTradeNum=1, sizeMultiplier=1
+	case "LINKUSDT":
+		if sz < 1 {
+			sz = 1
+		}
+		return fmt.Sprintf("%.0f", sz) // minTradeNum=1, sizeMultiplier=1
+	case "ONDOUSDT":
+		if sz < 0.1 {
+			sz = 0.1
+		}
+		return fmt.Sprintf("%.1f", sz) // minTradeNum=0.1, sizeMultiplier=0.1
+	case "OPUSDT":
+		if sz < 0.1 {
+			sz = 0.1
+		}
+		return fmt.Sprintf("%.1f", sz) // minTradeNum=0.1, sizeMultiplier=0.1
+	case "WIFUSDT":
+		if sz < 0.1 {
+			sz = 0.1
+		}
+		return fmt.Sprintf("%.1f", sz) // minTradeNum=0.1, sizeMultiplier=0.1
+	case "ARBUSDT":
+		if sz < 0.01 {
+			sz = 0.01
+		}
+		return fmt.Sprintf("%.2f", sz) // minTradeNum=0.01, sizeMultiplier=0.01
+	default:
+		return fmt.Sprintf("%.4f", sz)
+	}
+}