✨ feat: Add LLM integration for LeetCode problems

Adds LLM translation and inspire features to the bot.

- Integrates Google Gemini for problem translation and insight generation.
- Introduces buttons for problem description, LLM translation, and inspiration.
- Implements caching for LLM results to improve response times and reduce API usage.
- Enhances .env with Google Gemini API key.

Author: cxyfer

.env.example

@@ -5,4 +5,7 @@ DISCORD_TOKEN=your_discord_bot_token_here
 POST_TIME=00:00 
 
 # Default timezone (Example: UTC, Asia/Taipei, America/New_York)
-TIMEZONE=UTC
+TIMEZONE=UTC
+
+# Google Gemini API Key
+GOOGLE_GEMINI_API_KEY=your_google_gemini_api_key_here

bot.py

@@ -12,20 +12,25 @@
 from utils.logger import setup_logging, get_logger
 
 from leetcode import LeetCodeClient, html_to_text
+from llms import GeminiLLM
 from utils import SettingsDatabaseManager
+from utils.database import LLMTranslateDatabaseManager, LLMInspireDatabaseManager
 from discord.ui import View, Button
 
 # Set up logging
 setup_logging()
 logger = get_logger("bot")
 
+# Load environment variables
 load_dotenv(dotenv_path='.env', verbose=True, override=True)
 DISCORD_TOKEN = os.getenv('DISCORD_TOKEN')
 POST_TIME = os.getenv('POST_TIME', '00:00')  # Default to 00:00
 TIMEZONE = os.getenv('TIMEZONE', 'UTC')  # Default to UTC
 
 # Initialize the database manager
 db = SettingsDatabaseManager()
+llm_translate_db = LLMTranslateDatabaseManager()
+llm_inspire_db = LLMInspireDatabaseManager()
 
 # Initialize LeetCode client
 lcus = LeetCodeClient()
@@ -36,22 +41,178 @@
 intents.message_content = True  # Enable message content permission
 bot = commands.Bot(command_prefix="!", intents=intents)
 
+# LLM
+try:
+    llm = GeminiLLM(model="gemini-2.0-flash")
+    llm_pro = GeminiLLM(model="gemini-2.5-pro-preview-03-25")
+except Exception as e:
+    logger.error(f"Error while initializing LLM: {e}")
+    llm = None
+    llm_pro = None
+
 # Schedule tasks are stored here to be cancelled later
 schedule_tasks = {}
 
 # Define a fixed custom ID prefix
-LEETCODE_BUTTON_PREFIX = "leetcode_problem_"
-
+# LEETCODE_DISCRIPTION_BUTTON_PREFIX = "leetcode_problem_"
+LEETCODE_DISCRIPTION_BUTTON_PREFIX = "leetcode_problem_"
+LEETCODE_TRANSLATE_BUTTON_PREFIX = "leetcode_translate_"
+LEETCODE_INSPIRE_BUTTON_PREFIX = "leetcode_inspire_"
 # Global interaction event handler
 @bot.event
 async def on_interaction(interaction):
     # Ignore non-button interactions
     if interaction.type != discord.InteractionType.component:
         return
-    
-    # Check if it's our LeetCode button
+
     custom_id = interaction.data.get("custom_id", "")
-    if custom_id.startswith(LEETCODE_BUTTON_PREFIX):
+
+    # Button for LLM translation
+    if custom_id.startswith(LEETCODE_TRANSLATE_BUTTON_PREFIX):
+        logger.debug(f"接收到LeetCode LLM翻譯按鈕交互: custom_id={custom_id}")
+        try:
+            # 先 defer，避免 interaction 過期
+            await interaction.response.defer(ephemeral=True)
+            parts = custom_id.split("_")
+            # 格式: leetcode_translate_{problem_id}_{domain}
+            problem_id = parts[2]
+            domain = parts[3] if len(parts) > 3 else "com"
+
+            logger.debug(f"嘗試獲取題目並進行LLM翻譯: problem_id={problem_id}, domain={domain}")
+
+            client = lcus if domain == "com" else lccn
+
+            if problem_id and problem_id.isdigit():
+                # 先查詢 DB cache
+                translation = llm_translate_db.get_translation(int(problem_id), domain)
+                if translation:
+                    logger.debug(f"從DB取得LLM翻譯: problem_id={problem_id}")
+                    await interaction.followup.send(translation, ephemeral=True)
+                    return
+
+                problem_info = await client.get_problem(problem_id=problem_id)
+                if problem_info and problem_info.get("content"):
+                    problem_content = html_to_text(problem_info["content"])
+                    # LLM 翻譯
+                    try:
+                        translation = llm.translate(problem_content, "zh-TW")
+                        # 長度限制
+                        if len(translation) > 1900:
+                            translation = translation[:1900] + "...\n(翻譯內容已截斷)"
+                        # 寫入 DB
+                        llm_translate_db.save_translation(int(problem_id), domain, translation)
+                        await interaction.followup.send(translation, ephemeral=True)
+                        logger.debug(f"成功發送LLM翻譯並寫入DB: problem_id={problem_id}")
+                    except Exception as llm_e:
+                        logger.error(f"LLM 翻譯失敗: {llm_e}", exc_info=True)
+                        await interaction.followup.send(f"LLM 翻譯失敗：{str(llm_e)}", ephemeral=True)
+                else:
+                    logger.warning(f"題目沒有內容: problem_id={problem_id}")
+                    await interaction.followup.send("無法獲取題目描述，請前往 LeetCode 網站查看。", ephemeral=True)
+            else:
+                logger.warning(f"無效的題目ID: {problem_id}")
+                await interaction.followup.send("無效的題目ID，無法顯示翻譯。", ephemeral=True)
+        except discord.errors.InteractionResponded:
+            await interaction.followup.send("已經回應過此交互，請重新點擊按鈕。", ephemeral=True)
+        except Exception as e:
+            logger.error(f"處理LLM翻譯按鈕交互時發生錯誤: {e}", exc_info=True)
+            try:
+                await interaction.followup.send(f"LLM 翻譯時發生錯誤：{str(e)}", ephemeral=True)
+            except:
+                pass
+        return
+    
+    # Button for LLM inspire
+    def format_inspire_field(val):
+        if isinstance(val, list):
+            return '\n'.join(f"- {x}" for x in val)
+        return str(val)
+
+    INSPIRE_FIELDS = [
+        ("thinking", "🧠 思路"),
+        ("traps", "⚠️ 陷阱"),
+        ("algorithms", "🛠️ 推薦演算法"),
+        ("inspiration", "✨ 其他靈感"),
+    ]
+
+    if custom_id.startswith(LEETCODE_INSPIRE_BUTTON_PREFIX):
+        logger.debug(f"接收到LeetCode 靈感啟發按鈕交互: custom_id={custom_id}")
+        try:
+            await interaction.response.defer(ephemeral=True)
+            parts = custom_id.split("_")
+            # 格式: leetcode_inspire_{problem_id}_{domain}
+            problem_id = parts[2]
+            domain = parts[3] if len(parts) > 3 else "com"
+
+            logger.debug(f"嘗試獲取題目並進行LLM靈感啟發: problem_id={problem_id}, domain={domain}")
+
+            if not problem_id or not problem_id.isdigit():
+                logger.warning(f"無效的題目ID: {problem_id}")
+                await interaction.followup.send("無效的題目ID，無法顯示靈感啟發。", ephemeral=True)
+                return
+
+            inspire_result = llm_inspire_db.get_inspire(int(problem_id), domain)
+            if inspire_result:
+                logger.debug(f"Get inspire result from DB: problem_id={problem_id}")
+            else:
+                client = lcus if domain == "com" else lccn
+                problem_info = await client.get_problem(problem_id=problem_id)
+                if problem_info and problem_info.get("content"):
+                    problem_content = html_to_text(problem_info["content"])
+                    tags = problem_info.get("tags", [])
+                    difficulty = problem_info.get("difficulty", "")
+                else:
+                    logger.warning(f"題目沒有內容: problem_id={problem_id}")
+                    await interaction.followup.send("無法獲取題目資訊。", ephemeral=True)
+                    return
+                
+                # Get inspire result from LLM
+                try:
+                    inspire_result = llm_pro.inspire(problem_content, tags, difficulty)
+                    if not isinstance(inspire_result, dict) or not all(k in inspire_result for k in ["thinking", "traps", "algorithms", "inspiration"]):
+                        # 回傳原始 LLM 回覆
+                        raw = inspire_result.get("raw", inspire_result)
+                        if len(str(raw)) > 1900:
+                            raw = str(raw)[:1900] + "...\n(內容已截斷)"
+                        await interaction.followup.send(str(raw), ephemeral=True)
+                        logger.debug(f"發送原始 LLM 靈感回覆: problem_id={problem_id}")
+                        return
+                    # --- DB cache: save inspire result ---
+                    formatted_fields = [format_inspire_field(inspire_result[k]) for k, _ in INSPIRE_FIELDS]
+                    llm_inspire_db.save_inspire(
+                        int(problem_id), domain,
+                        *formatted_fields
+                    )
+                except Exception as llm_e:
+                    logger.error(f"LLM 靈感啟發失敗: {llm_e}", exc_info=True)
+                    await interaction.followup.send(f"LLM 靈感啟發失敗：{str(llm_e)}", ephemeral=True)
+                    return
+            
+            embed = discord.Embed(
+                title="💡 靈感啟發",
+                color=0x8e44ad,
+            )
+            total_len = 0
+            for key, field_name in INSPIRE_FIELDS:
+                val = format_inspire_field(inspire_result.get(key, ""))
+                embed.add_field(name=field_name, value=val, inline=False)
+                total_len += len(val)
+            if total_len > 1800:
+                embed.set_footer(text="內容已截斷，請嘗試更精簡提示。")
+            await interaction.followup.send(embed=embed, ephemeral=True)
+           
+        except discord.errors.InteractionResponded:
+            await interaction.followup.send("已經回應過此交互，請重新點擊按鈕。", ephemeral=True)
+        except Exception as e:
+            logger.error(f"處理LLM靈感啟發按鈕交互時發生錯誤: {e}", exc_info=True)
+            try:
+                await interaction.followup.send(f"LLM 靈感啟發時發生錯誤：{str(e)}", ephemeral=True)
+            except:
+                pass
+        return
+
+    # Button for displaying LeetCode problem description
+    if custom_id.startswith(LEETCODE_DISCRIPTION_BUTTON_PREFIX):
         logger.debug(f"接收到LeetCode按鈕交互: custom_id={custom_id}")
 
         # Parse problem ID and domain
@@ -297,21 +458,38 @@ async def send_daily_challenge(channel_id=None, role_id=None, interaction=None,
             embed.add_field(name="🔍 Similar Questions", value="\n".join(similar_questions), inline=False)
 
         embed.set_footer(text=f"LeetCode Daily Challenge ｜ {info['date']}", icon_url="https://leetcode.com/static/images/LeetCode_logo.png")
-        
-        # 創建一個自訂ID，包含問題ID和域名
-        custom_id = f"{LEETCODE_BUTTON_PREFIX}{info['id']}_{domain}"
-        
-        # 創建按鈕組件
-        button = discord.ui.Button(
+
+        # Create a view containing the button
+        view = discord.ui.View(timeout=None)
+
+        # Create a button for displaying the problem description
+        description_button = discord.ui.Button(
             style=discord.ButtonStyle.primary,
-            label="顯示題目描述（僅自己可見）",
+            label="題目描述",
             emoji="📖",
-            custom_id=custom_id
+            custom_id=f"{LEETCODE_DISCRIPTION_BUTTON_PREFIX}{info['id']}_{domain}"
         )
-        
-        # 創建包含按鈕的視圖
-        view = discord.ui.View(timeout=None)
-        view.add_item(button)
+        view.add_item(description_button)
+
+        # Add LLM translation button
+        translate_custom_id = f"{LEETCODE_TRANSLATE_BUTTON_PREFIX}{info['id']}_{domain}"
+        translate_button = discord.ui.Button(
+            style=discord.ButtonStyle.success,
+            label="LLM 翻譯",
+            emoji="🌐",
+            custom_id=translate_custom_id
+        )
+        view.add_item(translate_button)
+    
+        # Add LLM inspire button
+        inspire_custom_id = f"{LEETCODE_INSPIRE_BUTTON_PREFIX}{info['id']}_{domain}"
+        inspire_button = discord.ui.Button(
+            style=discord.ButtonStyle.danger,
+            label="靈感啟發",
+            emoji="💡",
+            custom_id=inspire_custom_id
+        )
+        view.add_item(inspire_button)
 
         # Determine how to send the message
         if interaction:

llms/__init__.py

@@ -0,0 +1,2 @@
+from .base import LLMBase
+from .gemini import GeminiLLM

llms/base.py

@@ -0,0 +1,81 @@
+from abc import ABC, abstractmethod
+from langchain_core.output_parsers import SimpleJsonOutputParser
+
+from llms.templates import *
+
+class LLMBase(ABC):
+    """
+    LLMBase is the abstract base class for all LLM implementations.
+    All subclasses must implement the generate method.
+
+    Methods:
+        generate(prompt: str) -> str
+            Generate a response from the LLM based on the input prompt.
+    """
+    def __init__(self):
+        self.llm = None
+
+    @abstractmethod
+    def generate(self, prompt: str) -> str:
+        """
+        Generate a response from the LLM based on the input prompt.
+
+        Args:
+            prompt (str): The input prompt.
+
+        Returns:
+            str: The generated response.
+        """
+        pass
+
+    def translate(self, content: str, target_language: str, from_lang: str = "auto") -> str:
+        """
+        Translate the input content to the target language using the LLM.
+
+        Args:
+            content (str): The text to be translated.
+            from_lang (str): The source language for translation., default is "auto"
+            target_language (str): The target language for translation, default is "zh-TW"
+
+        Returns:
+            str: The translated text, or the original LLM response if parsing fails.
+        """
+
+        prompt = TRANSLATION_JSON_PROMPT_TEMPLATE.format(
+            to=target_language,
+            from_lang=from_lang,
+            text=content,
+        )
+
+        response = self.generate(prompt)
+        parser = SimpleJsonOutputParser()
+        try:
+            parsed = parser.parse(response)
+            return parsed["translation"]
+        except Exception:
+            return response
+
+    def inspire(self, content: str, tags: list, difficulty: str) -> dict:
+        """
+        根據題目描述、tags、難度，產生解題靈感（僅繁體中文，禁止程式碼），回傳 JSON dict。
+        Args:
+            content (str): 題目描述
+            tags (list): 題目標籤
+            difficulty (str): 題目難度
+        Returns:
+            dict: { "thinking": ..., "traps": ..., "algorithms": ..., "inspiration": ... }
+                  若解析失敗則回傳 {"raw": response}
+        """
+        prompt = INSPIRE_JSON_PROMPT_TEMPLATE.format(
+            text=content,
+            tags=", ".join(tags) if tags else "",
+            difficulty=difficulty
+        )
+        response = self.generate(prompt)
+        parser = SimpleJsonOutputParser()
+        try:
+            parsed = parser.parse(response)
+            return parsed
+        except Exception:
+            return {"raw": response}
+