from fastapi.middleware.cors import CORSMiddleware
from fastapi import FastAPI, Request,  Header, BackgroundTasks, HTTPException, status
from fastapi.staticfiles import StaticFiles

import google.generativeai as genai_gen

from linebot import LineBotApi, WebhookHandler
from linebot.exceptions import InvalidSignatureError
from linebot.models import MessageEvent, TextMessage, TextSendMessage, ImageSendMessage, AudioMessage, ImageMessage

import json, os
import io
import PIL.Image

from Image_text_generation import Image_text_Generator
from Uploading_images_file import get_image_url, store_user_message, analyze_with_gemini, get_previous_message

#==========================
#  API 金鑰
#==========================

# 設定 Google AI API 金鑰
google_api = os.environ["GOOGLE_API_KEY"]
genai_gen.configure(api_key=google_api)

# 設定生成文字的參數
generation_config = genai_gen.types.GenerationConfig(max_output_tokens=1000, temperature=0.2, top_p=0.5, top_k=16) #2048

# 使用 gemini-2.0-flash-exp 模型
model = genai_gen.GenerativeModel('gemini-2.0-flash', system_instruction="主要用繁體中文回答，但如果用戶使用詢問英文問題，就用英文回應。你現在是個專業助理，職稱為OPEN小助理，個性活潑、樂觀，願意回答所有問題", generation_config=generation_config)

# 設定 Line Bot 的 API 金鑰和秘密金鑰
line_bot_api = LineBotApi(os.environ["CHANNEL_ACCESS_TOKEN"])
line_handler = WebhookHandler(os.environ["CHANNEL_SECRET"])

# 設定是否正在與使用者交談
working_status = os.getenv("DEFALUT_TALKING", default = "true").lower() == "true"

# 建立 FastAPI 應用程式
app = FastAPI()
app.mount("/static", StaticFiles(directory="static"), name="static")

# 設定 CORS，允許跨域請求
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# 處理根路徑請求
@app.get("/")
def root():
    return {"title": "Line Bot"}

# 處理 Line Webhook 請求
@app.post("/webhook")
async def webhook(
    request: Request,
    background_tasks: BackgroundTasks,
    x_line_signature=Header(None),
):
    # 取得請求內容
    body = await request.body()
    try:
        # 將處理 Line 事件的任務加入背景工作
        background_tasks.add_task(
            line_handler.handle, body.decode("utf-8"), x_line_signature
        )
    except InvalidSignatureError:
        # 處理無效的簽章錯誤
        raise HTTPException(status_code=400, detail="Invalid signature")
    return "ok"
    

#==========================
# 主程式(圖片與文字)
#==========================
# 建立 chat_sessions 字典
chat_sessions = {}
@line_handler.add(MessageEvent, message=(ImageMessage, TextMessage))
def handle_image_message(event):
    user_id = event.source.user_id
    chat = chat_sessions.get(user_id) or model.start_chat(history=[])
    chat_sessions[user_id] = chat

    # ========
    # 生成圖片
    # ========
    user_text = event.message.text if event.message.type == "text" else None
    image_url = None
    if user_text and user_text.startswith("生成圖片"):
        prompt = user_text.replace("生成圖片", "").strip()

         # 先立即回覆避免token過期
        line_bot_api.reply_message(event.reply_token, TextSendMessage(text="圖片生成中～ 請稍候.....✨"))
        image_generator = Image_text_Generator(user_id)
        # 生成圖片
        image_binary = image_generator.generate_image_with_gemini(prompt)

        if image_binary:
            image_url = 'https://alanchen1115-linebot.hf.space/'+image_generator.upload_image_to_tmp(image_binary)

            if image_url:
                # 使用 push message 發送圖片，避免 reply token 超時
                line_bot_api.push_message(
                    event.source.user_id,
                    [
                        TextSendMessage(text="✨ 這是我為你生成的圖片喔～"),
                        ImageSendMessage(original_content_url=image_url, preview_image_url=image_url)
                    ]
                )
            else:
                line_bot_api.push_message(
                    event.source.user_id,
                    TextSendMessage(text="⚠️ 圖片上傳失敗，請稍後再試~")
                )
        else:
            line_bot_api.push_message(
                event.source.user_id,
                TextSendMessage(text="⚠️ 圖片生成失敗，請稍後再試~")
            )
        return
        
    # ========
    # 上傳圖片
    # ========
    if event.message.type == "image":
        image_path = get_image_url(event.message.id)
        if image_path:
            store_user_message(user_id, "image", image_path)
            line_bot_api.reply_message(event.reply_token, TextSendMessage(text="圖片已接收成功囉，幫我輸入你想詢問的問題喔~"))
        else:
            line_bot_api.reply_message(event.reply_token, TextSendMessage(text="沒有接收到圖片~"))
        return

    previous_message = get_previous_message(user_id)
    if previous_message and previous_message["type"] == "image" and event.message.type == "text":
        image_path = previous_message["content"]
        user_text = event.message.text
        store_user_message(user_id, "text", user_text)
        try:
            if not os.path.exists(image_path):
                raise FileNotFoundError(f"圖片路徑無效：{image_path}")
            organ = PIL.Image.open(image_path)
            completion = chat.send_message([user_text, organ])
            out = completion.text
        except Exception as e:
            out = f"發生錯誤: {e}"

    # ========
    # 純文字
    # ========
    else:
        if event.message.type != "text":
            line_bot_api.reply_message(event.reply_token, TextSendMessage(text="請輸入文字或圖片~"))
            return
        if event.message.text == "再見":
            line_bot_api.reply_message(event.reply_token, TextSendMessage(text="Bye!"))
            return
        if working_status:
            try:
                prompt = event.message.text
                store_user_message(user_id, "text", prompt)
                completion = chat.send_message(prompt)
                out = completion.text if completion.text else "我不太懂什麼意思也~"
            except:
                out = "執行出錯!請換個說法！"

    line_bot_api.reply_message(event.reply_token, TextSendMessage(text=out))


if __name__ == "__main__":
    # 啟動 FastAPI 應用程式
    uvicorn.run("main:app", host="0.0.0.0", port=7860, reload=True)