Phase 1 MVP — echo bot factory

handler_echo.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"strings"
+)
+
+type EchoHandler struct {
+	tg *TelegramClient
+}
+
+func (e *EchoHandler) Handle(ctx context.Context, update Update, bot Bot) error {
+	chatID, ok := update.ChatID()
+	if !ok {
+		return nil
+	}
+	text := strings.TrimSpace(update.Text())
+	if text == "" {
+		return nil
+	}
+	reply := text
+	if strings.HasPrefix(text, "/echo") {
+		reply = strings.TrimSpace(strings.TrimPrefix(text, "/echo"))
+		if reply == "" {
+			reply = "echo bot online — send me anything"
+		}
+	}
+	if err := e.tg.SendMessage(ctx, bot.Token, SendMessageParams{ChatID: chatID, Text: reply}); err != nil {
+		return fmt.Errorf("sendMessage: %w", err)
+	}
+	return nil
+}