"""
聊天历史API路由
"""
from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.orm import Session
from pydantic import BaseModel, validator
from typing import List, Optional
from datetime import datetime
from enum import Enum

from backend.core.database import get_db
from backend.core.models import User, ChatHistory, ChatMessage
from backend.core.auth import get_current_user

router = APIRouter(tags=["chat"], prefix="/chat-history")

# 添加角色枚举类型
class MessageRole(str, Enum):
    USER = "user"
    ASSISTANT = "assistant" 
    SYSTEM = "system"

class MessageCreate(BaseModel):
    role: MessageRole  # 使用枚举类型替代字符串
    content: str
    
    # 添加额外验证器
    @validator('content')
    def content_must_not_be_empty(cls, v):
        if not v or not v.strip():
            raise ValueError('消息内容不能为空')
        return v
        
    # 添加角色验证器，尝试将字符串转换为枚举
    @validator('role', pre=True)
    def validate_role(cls, v):
        if isinstance(v, MessageRole):
            return v
            
        if isinstance(v, str):
            # 尝试将字符串匹配到枚举值
            if v.lower() == "user":
                return MessageRole.USER
            elif v.lower() == "assistant":
                return MessageRole.ASSISTANT
            elif v.lower() == "system":
                return MessageRole.SYSTEM
        
        # 如果无法匹配，默认返回USER
        return MessageRole.USER

class MessageResponse(BaseModel):
    id: int
    role: str
    content: str
    timestamp: datetime
    
    class Config:
        orm_mode = True

class ChatHistoryCreate(BaseModel):
    title: str
    messages: List[MessageCreate]
    
class ChatHistoryResponse(BaseModel):
    id: int
    title: str
    created_at: datetime
    updated_at: datetime
    messages: List[MessageResponse]
    
    class Config:
        orm_mode = True
        
class ChatHistorySummary(BaseModel):
    id: int
    title: str
    created_at: datetime
    updated_at: datetime
    
    class Config:
        orm_mode = True

class ChatHistoryUpdate(BaseModel):
    title: Optional[str] = None

@router.post("/", response_model=ChatHistoryResponse)
async def create_chat_history(
    chat_data: ChatHistoryCreate,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """创建新的聊天历史"""
    try:
        # 打印接收到的数据
        print("收到的聊天历史数据:", chat_data)
        
        # 创建聊天历史
        chat = ChatHistory(
            user_id=current_user.id,
            title=chat_data.title
        )
        db.add(chat)
        db.commit()
        db.refresh(chat)
        
        # 添加消息
        for msg_data in chat_data.messages:
            message = ChatMessage(
                chat_id=chat.id,
                role=msg_data.role,
                content=msg_data.content
            )
            db.add(message)
        
        db.commit()
        db.refresh(chat)
        
        return chat
    except Exception as e:
        # 打印详细错误信息
        print("保存聊天历史出错:", str(e))
        raise

@router.get("/", response_model=List[ChatHistorySummary])
async def get_chat_histories(
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """获取用户的所有聊天历史摘要"""
    # 获取基本聊天历史记录
    chats_query = db.query(ChatHistory)\
        .filter(ChatHistory.user_id == current_user.id)\
        .order_by(ChatHistory.updated_at.desc())
    
    chats = chats_query.all()
    
    # 增强聊天记录信息
    for chat in chats:
        # 获取消息数量
        message_count = db.query(ChatMessage)\
            .filter(ChatMessage.chat_id == chat.id)\
            .count()
        chat.message_count = message_count
        
        # 获取最新的用户消息作为预览
        last_user_message = db.query(ChatMessage)\
            .filter(ChatMessage.chat_id == chat.id, ChatMessage.role == "user")\
            .order_by(ChatMessage.timestamp.desc())\
            .first()
        
        if last_user_message:
            # 截取前100个字符作为预览
            preview = last_user_message.content[:100]
            if len(last_user_message.content) > 100:
                preview += "..."
            chat.preview = preview
        else:
            chat.preview = ""
        
        # 检查是否包含代码
        has_code = db.query(ChatMessage)\
            .filter(
                ChatMessage.chat_id == chat.id,
                ChatMessage.content.like("%```%")
            ).count() > 0
        chat.has_code = has_code
    
    return chats

@router.get("/{chat_id}", response_model=ChatHistoryResponse)
async def get_chat_history(
    chat_id: int,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """获取特定聊天历史的详情"""
    chat = db.query(ChatHistory)\
        .filter(ChatHistory.id == chat_id, ChatHistory.user_id == current_user.id)\
        .first()
    
    if not chat:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="聊天历史不存在或无权访问"
        )
    
    return chat

@router.post("/{chat_id}/messages", response_model=MessageResponse)
async def add_message(
    chat_id: int,
    message: MessageCreate,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """向现有聊天添加新消息"""
    # 检查聊天是否存在且属于当前用户
    chat = db.query(ChatHistory)\
        .filter(ChatHistory.id == chat_id, ChatHistory.user_id == current_user.id)\
        .first()
    
    if not chat:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="聊天历史不存在或无权访问"
        )
    
    # 创建新消息
    db_message = ChatMessage(
        chat_id=chat_id,
        role=message.role,
        content=message.content
    )
    
    # 更新聊天的更新时间
    chat.updated_at = datetime.utcnow()
    
    db.add(db_message)
    db.commit()
    db.refresh(db_message)
    
    return db_message

@router.delete("/{chat_id}")
async def delete_chat_history(
    chat_id: int,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """删除聊天历史"""
    chat = db.query(ChatHistory)\
        .filter(ChatHistory.id == chat_id, ChatHistory.user_id == current_user.id)\
        .first()
    
    if not chat:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="聊天历史不存在或无权访问"
        )
    
    # 删除聊天相关的所有消息
    db.query(ChatMessage).filter(ChatMessage.chat_id == chat_id).delete()
    
    # 删除聊天
    db.delete(chat)
    db.commit()
    
    return {"message": "聊天历史已删除"}

@router.put("/{chat_id}", response_model=ChatHistoryResponse)
async def update_chat_history(
    chat_id: int,
    update_data: ChatHistoryUpdate,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """更新聊天历史的标题"""
    chat = db.query(ChatHistory)\
        .filter(ChatHistory.id == chat_id, ChatHistory.user_id == current_user.id)\
        .first()
    
    if not chat:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="聊天历史不存在或无权访问"
        )
    
    # 更新标题
    if update_data.title:
        chat.title = update_data.title
    
    chat.updated_at = datetime.utcnow()
    db.commit()
    db.refresh(chat)
    
    return chat