"""
会话管理服务 - v2.0 兼容版
支持思考内容、Agent追踪等新字段
"""
from typing import List, Optional
from datetime import datetime
from sqlalchemy.orm import Session
import uuid

# 兼容v1和v2模型
try:
    from models_v2 import User, Conversation, Message, Agent
    USE_V2 = True
except ImportError:
    from models import User, Conversation, Message
    USE_V2 = False


class ConversationService:
    def __init__(self, db: Session):
        self.db = db
        self.use_v2 = USE_V2
    
    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, channel_id: int = None) -> Conversation:
        """创建新会话"""
        conversation_id = f"conv_{uuid.uuid4().hex[:12]}"
        
        if self.use_v2:
            conversation = Conversation(
                conversation_id=conversation_id,
                user_id=user_id,
                title=title,
                channel_id=channel_id
            )
        else:
            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,
        thinking_content: str = None,  # v2新增
        agent_id: int = None,  # v2新增
        model_used: str = None  # v2新增
    ) -> Message:
        """添加消息"""
        
        if self.use_v2:
            message = Message(
                conversation_id=conversation_id,
                role=role,
                content=content,
                source=source,
                extra_data=extra_data,
                thinking_content=thinking_content,
                agent_id=agent_id,
                model_used=model_used
            )
        else:
            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 '')
            
            # v2: 更新当前Agent
            if self.use_v2 and agent_id:
                conversation.current_agent_id = agent_id
        
        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,
            Message.role.in_(['user', 'assistant', 'system'])  # 排除thinking
        ).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
    
    def set_conversation_agent(self, conversation_id: str, agent_id: int):
        """设置会话使用的Agent（v2）"""
        if not self.use_v2:
            return False
        
        conversation = self.get_conversation(conversation_id)
        if conversation:
            conversation.current_agent_id = agent_id
            self.db.commit()
            return True
        return False