feat: initial project setup

- Add bot.py with core Telegram Contact Bot logic
- Add Dockerfile and docker-compose for containerization
- Add requirements.txt for dependency management
- Add .env.example for environment configuration

bot.py

@@ -0,0 +1,100 @@
+import os
+import logging
+import aiosqlite
+from telegram import Update
+from telegram.ext import Application, MessageHandler, CommandHandler, filters, ContextTypes
+
+# --- 从环境变量读取配置 ---
+BOT_TOKEN = os.getenv('BOT_TOKEN')
+ADMIN_ID = int(os.getenv('ADMIN_ID', '0'))
+DB_FILE = os.getenv('DB_PATH', '/app/data/messages.db')
+
+# 启用日志
+logging.basicConfig(
+    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s', 
+    level=logging.INFO
+)
+logger = logging.getLogger(__name__)
+
+# 初始化数据库
+async def init_db():
+    async with aiosqlite.connect(DB_FILE) as db:
+        await db.execute('''CREATE TABLE IF NOT EXISTS msg_map 
+                          (admin_msg_id INTEGER PRIMARY KEY, user_id INTEGER)''')
+        await db.commit()
+
+# 处理 /start 命令
+async def start(update: Update, context: ContextTypes.DEFAULT_TYPE):
+    user_id = update.effective_chat.id
+    if user_id != ADMIN_ID:
+        await update.message.reply_text("Hello!\n\nYou can contact us using this bot.")
+    else:
+        await update.message.reply_text("你好，管理员！有人给机器人发消息时，我会转发给你。你直接【回复】该消息即可回信。")
+
+# 处理所有普通消息（文字、图片、语音、文件等）
+async def handle_message(update: Update, context: ContextTypes.DEFAULT_TYPE):
+    if not update.message:
+        return
+    
+    user_id = update.effective_chat.id
+    message = update.message
+
+    # 1. 用户发给机器人 -> 转发给管理员
+    if user_id != ADMIN_ID:
+        try:
+            forwarded_msg = await context.bot.forward_message(
+                chat_id=ADMIN_ID,
+                from_chat_id=user_id,
+                message_id=message.message_id
+            )
+            
+            # 记录对应关系到数据库
+            async with aiosqlite.connect(DB_FILE) as db:
+                await db.execute("INSERT INTO msg_map VALUES (?, ?)", 
+                                 (forwarded_msg.message_id, user_id))
+                await db.commit()
+        except Exception as e:
+            logger.error(f"转发失败: {e}")
+
+    # 2. 管理员回复转发的消息 -> 回传给用户
+    else:
+        if message.reply_to_message:
+            reply_id = message.reply_to_message.message_id
+            
+            async with aiosqlite.connect(DB_FILE) as db:
+                async with db.execute("SELECT user_id FROM msg_map WHERE admin_msg_id = ?", (reply_id,)) as cursor:
+                    row = await cursor.fetchone()
+            
+            if row:
+                target_user_id = row[0]
+                try:
+                    # 使用 copy_message 原样复制回复的内容
+                    await context.bot.copy_message(
+                        chat_id=target_user_id,
+                        from_chat_id=ADMIN_ID,
+                        message_id=message.message_id
+                    )
+                except Exception as e:
+                    await message.reply_text(f"回复发送失败，可能用户已停用机器人: {e}")
+            else:
+                await message.reply_text("找不到该消息的来源记录，无法回复。")
+        # 如果管理员没用回复功能，而是直接发消息，不执行任何操作
+
+async def post_init(application: Application):
+    await init_db()
+
+if __name__ == '__main__':
+    # 检查配置
+    if not BOT_TOKEN or ADMIN_ID == 0:
+        print("错误: 请确保环境变量 BOT_TOKEN 和 ADMIN_ID 已正确设置！")
+        exit(1)
+
+    # 构建应用
+    application = Application.builder().token(BOT_TOKEN).post_init(post_init).build()
+    
+    # 处理器注册
+    application.add_handler(CommandHandler("start", start))
+    application.add_handler(MessageHandler(filters.ALL & ~filters.COMMAND, handle_message))
+    
+    print(f"机器人已启动... 管理员ID: {ADMIN_ID}")
+    application.run_polling()