from fastapi import FastAPI, Request, HTTPException
from linebot import LineBotApi, WebhookHandler
from linebot.exceptions import InvalidSignatureError
from linebot.models import MessageEvent, TextMessage, TextSendMessage

import os

# 設定 LINE Channel Access Token 和 Channel Secret
LINE_CHANNEL_ACCESS_TOKEN = os.getenv("LINE_CHANNEL_ACCESS_TOKEN")
LINE_CHANNEL_SECRET = os.getenv("LINE_CHANNEL_SECRET")

line_bot_api = LineBotApi(LINE_CHANNEL_ACCESS_TOKEN)
handler = WebhookHandler(LINE_CHANNEL_SECRET)

app = FastAPI()

# Webhook endpoint for LINE messages
@app.post("/callback")
async def callback(request: Request):
    signature = request.headers['X-Line-Signature']
    body = await request.body()

    try:
        handler.handle(body.decode('utf-8'), signature)
    except InvalidSignatureError:
        raise HTTPException(status_code=400, detail="Invalid signature")

    return 'OK'

# 處理文字訊息的事件
@handler.add(MessageEvent, message=TextMessage)
def handle_text_message(event):
    # 回應同樣的訊息給使用者
    reply_text = event.message.text
    line_bot_api.reply_message(
        event.reply_token,
        TextSendMessage(text=reply_text)
    )

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)