Telegram Webhookによるボット操作機能を追加（課題の追加・完了・一覧・スヌーズ対応）

internal/handler/telegram_handler.go

@@ -0,0 +1,57 @@
+package handler
+
+import (
+	"crypto/subtle"
+	"log"
+	"net/http"
+
+	"homework-manager/internal/service"
+
+	"github.com/gin-gonic/gin"
+)
+
+// TelegramHandler handles incoming Telegram webhook requests.
+type TelegramHandler struct {
+	telegramService *service.TelegramService
+	webhookSecret   string
+}
+
+// NewTelegramHandler creates a TelegramHandler.
+func NewTelegramHandler(telegramService *service.TelegramService, webhookSecret string) *TelegramHandler {
+	return &TelegramHandler{
+		telegramService: telegramService,
+		webhookSecret:   webhookSecret,
+	}
+}
+
+// Webhook is the endpoint registered as the Telegram bot webhook.
+// POST /api/telegram/webhook
+func (h *TelegramHandler) Webhook(c *gin.Context) {
+	if h.webhookSecret == "" {
+		c.Status(http.StatusServiceUnavailable)
+		return
+	}
+	secret := c.GetHeader("X-Telegram-Bot-Api-Secret-Token")
+	if subtle.ConstantTimeCompare([]byte(secret), []byte(h.webhookSecret)) != 1 {
+		c.Status(http.StatusUnauthorized)
+		return
+	}
+
+	var update service.TelegramUpdate
+	if err := c.ShouldBindJSON(&update); err != nil {
+		c.Status(http.StatusBadRequest)
+		return
+	}
+
+	// Process asynchronously so Telegram gets a 200 within its timeout window.
+	go func() {
+		defer func() {
+			if r := recover(); r != nil {
+				log.Printf("telegram HandleUpdate panic: %v", r)
+			}
+		}()
+		h.telegramService.HandleUpdate(update)
+	}()
+
+	c.Status(http.StatusOK)
+}