"""
前端状态管理模块
使用 Streamlit Session State 管理应用状态
"""

import uuid
from typing import List, Dict, Any
import streamlit as st

from frontend.config import config


class AppState:
    """应用状态管理器 - 统一管理所有 session_state"""
    
    @staticmethod
    def init():
        """初始化所有状态变量"""
        # 用户状态
        if "user_id" not in st.session_state:
            st.session_state.user_id = config.default_user_id
        if "logged_in" not in st.session_state:
            st.session_state.logged_in = False
        
        # 对话状态
        if "current_thread_id" not in st.session_state:
            st.session_state.current_thread_id = str(uuid.uuid4())
        if "messages" not in st.session_state:
            st.session_state.messages = []
        
        # 历史列表
        if "threads" not in st.session_state:
            st.session_state.threads = []
        if "loading_history" not in st.session_state:
            st.session_state.loading_history = False
        
        # 模型选择
        if "selected_model" not in st.session_state:
            st.session_state.selected_model = config.default_model
    
    # ==================== 用户相关 ====================
    
    @staticmethod
    def get_user_id() -> str:
        """获取当前用户 ID"""
        return st.session_state.user_id
    
    @staticmethod
    def is_logged_in() -> bool:
        """检查是否已登录"""
        return st.session_state.logged_in
    
    @staticmethod
    def login(username: str):
        """
        用户登录
        
        Args:
            username: 用户名，为空则使用默认用户
        """
        st.session_state.user_id = username.strip() if username.strip() else config.default_user_id
        st.session_state.logged_in = True
        # 登录后必须开启一个干净的新对话
        AppState.start_new_thread()
    
    @staticmethod
    def logout():
        """用户登出，重置为默认用户"""
        st.session_state.logged_in = False
        st.session_state.user_id = config.default_user_id
        st.session_state.threads = []
        # 登出后必须开启一个干净的新对话
        AppState.start_new_thread()
    
    # ==================== 线程相关 ====================
    
    @staticmethod
    def get_current_thread_id() -> str:
        """获取当前线程 ID"""
        return st.session_state.current_thread_id
    
    @staticmethod
    def set_current_thread_id(thread_id: str):
        """
        设置当前线程 ID
        
        Args:
            thread_id: 线程 ID
        """
        st.session_state.current_thread_id = thread_id
    
    @staticmethod
    def start_new_thread():
        """开始新对话，生成新线程 ID 并清空消息"""
        st.session_state.current_thread_id = str(uuid.uuid4())
        st.session_state.messages = []
    
    # ==================== 消息相关 ====================
    
    @staticmethod
    def get_messages() -> List[Dict[str, str]]:
        """获取消息列表"""
        return st.session_state.messages
    
    @staticmethod
    def add_message(role: str, content: str):
        """
        添加消息
        
        Args:
            role: 消息角色 (user/assistant)
            content: 消息内容
        """
        st.session_state.messages.append({"role": role, "content": content})
    
    @staticmethod
    def clear_messages():
        """清空消息列表"""
        st.session_state.messages = []
    
    @staticmethod
    def get_message_stats() -> Dict[str, int]:
        """
        获取消息统计
        
        Returns:
            包含 user 和 assistant 消息数量的字典
        """
        messages = st.session_state.messages
        return {
            "user": len([m for m in messages if m["role"] == "user"]),
            "assistant": len([m for m in messages if m["role"] == "assistant"])
        }
    
    # ==================== 历史列表相关 ====================
    
    @staticmethod
    def get_threads() -> List[Dict[str, Any]]:
        """获取历史线程列表"""
        return st.session_state.threads
    
    @staticmethod
    def set_threads(threads: List[Dict[str, Any]]):
        """
        设置历史线程列表
        
        Args:
            threads: 线程列表
        """
        st.session_state.threads = threads
    
    # ==================== 模型相关 ====================
    
    @staticmethod
    def get_selected_model() -> str:
        """获取选中的模型"""
        return st.session_state.selected_model
    
    @staticmethod
    def set_selected_model(model: str):
        """
        设置选中的模型
        
        Args:
            model: 模型标识符
        """
        st.session_state.selected_model = model