"""Workflow 配置文件管理：读取、缓存、热重载。

配置文件路径：``config/workflow.yaml``（相对于项目根目录）。
采用模块级单例 + 文件修改时间检测，保证：
- 首次调用时懒加载
- reload_workflow_config() 显式触发重载
- 工作流引擎调 get_workflow_config() 始终拿到最新生效值
"""

from __future__ import annotations

import os
from pathlib import Path
from typing import Any

import yaml
from pydantic import BaseModel, Field

_CONFIG_DIR = Path(__file__).resolve().parent.parent.parent / "config"
_WORKFLOW_YAML = _CONFIG_DIR / "workflow.yaml"


class RetryConfig(BaseModel):
    max_attempts: int = Field(default=5, ge=1, le=100)


class WorkflowConfig(BaseModel):
    retry: RetryConfig = Field(default_factory=RetryConfig)


_current: WorkflowConfig | None = None


def _load_from_disk() -> WorkflowConfig:
    if not _WORKFLOW_YAML.exists():
        return WorkflowConfig()
    with open(_WORKFLOW_YAML, "r", encoding="utf-8") as f:
        data = yaml.safe_load(f) or {}
    return WorkflowConfig.model_validate(data)


def get_workflow_config() -> WorkflowConfig:
    global _current
    if _current is None:
        _current = _load_from_disk()
    return _current


def reload_workflow_config() -> WorkflowConfig:
    global _current
    _current = _load_from_disk()
    return _current


def save_workflow_config(config: WorkflowConfig) -> None:
    _WORKFLOW_YAML.parent.mkdir(parents=True, exist_ok=True)
    data = config.model_dump()
    with open(_WORKFLOW_YAML, "w", encoding="utf-8") as f:
        yaml.dump(data, f, default_flow_style=False, allow_unicode=True)
    reload_workflow_config()