"""
会话管理服务
"""
from typing import List, Optional
from datetime import datetime
from sqlalchemy.orm import Session
import uuid

from models import User, Conversation, Message


class ConversationService:
    def __init__(self, db: Session):
        self.db = db
    
    def get_or_create_user(self, user_id: str, display_name: str = None, user_type: str = 'web', matrix_user_id: str = None) -> User:
        """获取或创建用户"""
        user = self.db.query(User).filter(User.user_id == user_id).first()
        if not user:
            user = User(
                user_id=user_id,
                display_name=display_name or user_id,
                user_type=user_type,
                matrix_user_id=matrix_user_id
            )
            self.db.add(user)
            self.db.commit()
            self.db.refresh(user)
        else:
            user.last_active_at = datetime.utcnow()
            self.db.commit()
        return user
    
    def create_conversation(self, user_id: int, title: str = None) -> Conversation:
        """创建新会话"""
        conversation_id = f"conv_{uuid.uuid4().hex[:12]}"
        conversation = Conversation(
            conversation_id=conversation_id,
            user_id=user_id,
            title=title
        )
        self.db.add(conversation)
        self.db.commit()
        self.db.refresh(conversation)
        return conversation
    
    def get_conversation(self, conversation_id: str) -> Optional[Conversation]:
        """获取会话"""
        return self.db.query(Conversation).filter(
            Conversation.conversation_id == conversation_id
        ).first()
    
    def get_user_conversations(self, user_id: int) -> List[Conversation]:
        """获取用户的所有会话"""
        return self.db.query(Conversation).filter(
            Conversation.user_id == user_id,
            Conversation.is_active == True
        ).order_by(Conversation.updated_at.desc()).all()
    
    def add_message(self, conversation_id: int, role: str, content: str, source: str = 'web', extra_data: dict = None) -> Message:
        """添加消息"""
        message = Message(
            conversation_id=conversation_id,
            role=role,
            content=content,
            source=source,
            extra_data=extra_data
        )
        self.db.add(message)
        
        # 更新会话时间
        conversation = self.db.query(Conversation).filter(Conversation.id == conversation_id).first()
        if conversation:
            conversation.updated_at = datetime.utcnow()
            # 如果没有标题，用第一条用户消息作为标题
            if not conversation.title and role == 'user':
                conversation.title = content[:50] + ('...' if len(content) > 50 else '')
        
        self.db.commit()
        self.db.refresh(message)
        return message
    
    def get_messages(self, conversation_id: int, limit: int = 50) -> List[Message]:
        """获取会话消息"""
        return self.db.query(Message).filter(
            Message.conversation_id == conversation_id
        ).order_by(Message.created_at.asc()).limit(limit).all()
    
    def get_conversation_history(self, conversation_id: str, limit: int = 20) -> List[dict]:
        """获取会话历史（用于AI上下文）"""
        conversation = self.get_conversation(conversation_id)
        if not conversation:
            return []
        
        messages = self.db.query(Message).filter(
            Message.conversation_id == conversation.id
        ).order_by(Message.created_at.desc()).limit(limit).all()
        
        # 反转顺序，最早的在前
        messages.reverse()
        
        return [{"role": m.role, "content": m.content} for m in messages]
    
    def delete_conversation(self, conversation_id: str):
        """删除会话（软删除）"""
        conversation = self.get_conversation(conversation_id)
        if conversation:
            conversation.is_active = False
            self.db.commit()
            return True
        return False