"""
状态基类工具模块
提供类型安全的 LangGraph 状态基类和常用状态操作工具

功能：
1. BaseState - 基础状态基类，包含通用字段（消息、token统计、耗时等）
2. StateUtils - 状态操作工具类，提供常用的状态访问和修改方法
3. TypedStateBuilder - 类型化状态构建器，支持链式创建自定义状态
4. StateValidation - 状态验证工具，确保状态完整性
"""

from typing import Dict, Any, List, Optional
from dataclasses import dataclass, field
from datetime import datetime
from enum import Enum, auto


class Phase(Enum):
    """执行阶段枚举"""
    INIT = auto()
    INTENT_PARSING = auto()
    EXECUTING = auto()
    FORMATTING = auto()
    COMPLETED = auto()
    ERROR = auto()


@dataclass
class TokenUsage:
    """Token 使用统计"""
    prompt_tokens: int = 0
    completion_tokens: int = 0
    total_tokens: int = 0
    
    def add(self, other: 'TokenUsage') -> 'TokenUsage':
        """累加另一个统计"""
        return TokenUsage(
            prompt_tokens=self.prompt_tokens + other.prompt_tokens,
            completion_tokens=self.completion_tokens + other.completion_tokens,
            total_tokens=self.total_tokens + other.total_tokens
        )


@dataclass
class BaseState:
    """
    基础状态基类
    所有子图的状态都应继承此类
    """
    # 核心字段
    user_query: str = ""
    user_id: str = "default"
    thread_id: Optional[str] = None
    
    # 执行阶段
    current_phase: Phase = Phase.INIT
    phase_history: List[Phase] = field(default_factory=list)
    
    # 结果
    final_result: str = ""
    success: bool = True
    error_message: str = ""
    
    # 统计
    token_usage: TokenUsage = field(default_factory=TokenUsage)
    start_time: Optional[datetime] = None
    end_time: Optional[datetime] = None
    
    # 元数据
    metadata: Dict[str, Any] = field(default_factory=dict)
    
    def __post_init__(self):
        """初始化后调用"""
        if self.start_time is None:
            self.start_time = datetime.now()
        if not self.phase_history:
            self.phase_history.append(self.current_phase)
    
    def transition_to(self, phase: Phase) -> None:
        """转换到新阶段"""
        self.current_phase = phase
        self.phase_history.append(phase)
    
    def complete(self, result: str, success: bool = True) -> None:
        """完成执行"""
        self.final_result = result
        self.success = success
        self.end_time = datetime.now()
        self.transition_to(Phase.COMPLETED)
    
    def fail(self, error: str) -> None:
        """执行失败"""
        self.error_message = error
        self.success = False
        self.end_time = datetime.now()
        self.transition_to(Phase.ERROR)
    
    @property
    def elapsed_time(self) -> float:
        """获取耗时（秒）"""
        if self.start_time and self.end_time:
            return (self.end_time - self.start_time).total_seconds()
        return 0.0


class StateUtils:
    """状态操作工具类"""
    
    @staticmethod
    def merge_metadata(base: Dict[str, Any], overlay: Dict[str, Any]) -> Dict[str, Any]:
        """合并元数据"""
        result = base.copy()
        result.update(overlay)
        return result
    
    @staticmethod
    def create_snapshot(state: BaseState) -> Dict[str, Any]:
        """创建状态快照（用于调试）"""
        return {
            "user_query": state.user_query,
            "user_id": state.user_id,
            "current_phase": state.current_phase.name,
            "success": state.success,
            "elapsed_time": state.elapsed_time
        }