# -*- coding: utf-8 -*-
# @Time    : 2024/6/7
# @Author  : 魏志亮
import os

import yaml
from typing import Any, Optional, Dict


def load_yaml_config(file_path: str, encoding: str = 'utf-8') -> Dict[str, Any]:
    """
    加载YAML配置文件
    
    Args:
        file_path: YAML文件路径
        encoding: 文件编码，默认为utf-8
        
    Returns:
        解析后的配置字典
        
    Raises:
        FileNotFoundError: 文件不存在时抛出
        yaml.YAMLError: YAML解析错误时抛出
    """
    try:
        with open(file_path, 'r', encoding=encoding) as f:
            data = yaml.safe_load(f)
            # 确保返回字典类型，防止YAML文件为空时返回None
            return data if isinstance(data, dict) else {}
    except FileNotFoundError:
        raise FileNotFoundError(f"配置文件不存在: {file_path}")
    except yaml.YAMLError as e:
        raise yaml.YAMLError(f"YAML解析错误: {e}")


def get_config_value(config: Dict[str, Any], key: str, default: Optional[Any] = None) -> Any:
    """
    从配置字典中安全地获取值
    
    Args:
        config: 配置字典
        key: 配置键名
        default: 默认值，当键不存在或值为None时返回
        
    Returns:
        配置值或默认值
    """
    # 处理config为None的情况
    if config is None:
        return default
    
    # 支持嵌套键，如 "database.host"
    keys = key.split('.')
    value = config
    
    for k in keys:
        if isinstance(value, dict) and k in value:
            value = value[k]
        else:
            value = None
            break
    
    # 如果值为None且提供了默认值，返回默认值
    if value is None and default is not None:
        return default
    
    return value


def merge_configs(base_config: Dict[str, Any], override_config: Dict[str, Any]) -> Dict[str, Any]:
    """
    合并配置字典
    
    Args:
        base_config: 基础配置
        override_config: 覆盖配置
        
    Returns:
        合并后的配置
    """
    result = base_config.copy()
    
    for key, value in override_config.items():
        if key in result and isinstance(result[key], dict) and isinstance(value, dict):
            # 递归合并嵌套字典
            result[key] = merge_configs(result[key], value)
        else:
            # 直接覆盖
            result[key] = value
    
    return result


def load_config_with_env(file_path: str, encoding: str = 'utf-8') -> Dict[str, Any]:
    """
    加载配置文件并支持环境变量覆盖
    
    Args:
        file_path: YAML文件路径
        encoding: 文件编码，默认为utf-8
        
    Returns:
        解析后的配置字典
    """
    # 加载基础配置
    base_config = load_yaml_config(file_path, encoding)
    
    # 检查是否有环境变量覆盖
    env_prefix = "ETL_"
    override_config = {}
    
    for key, value in os.environ.items():
        if key.startswith(env_prefix):
            # 转换环境变量名到配置键名
            config_key = key[len(env_prefix):].lower().replace('_', '.')
            
            # 解析值
            if value.lower() == 'true':
                parsed_value = True
            elif value.lower() == 'false':
                parsed_value = False
            elif value.isdigit():
                parsed_value = int(value)
            elif '.' in value and all(part.isdigit() for part in value.split('.')):
                parsed_value = float(value)
            else:
                parsed_value = value
            
            # 构建嵌套配置
            keys = config_key.split('.')
            current = override_config
            for k in keys[:-1]:
                if k not in current:
                    current[k] = {}
                current = current[k]
            current[keys[-1]] = parsed_value
    
    # 合并配置
    if override_config:
        base_config = merge_configs(base_config, override_config)
    
    return base_config


# 为了保持向后兼容，保留原函数名（可选）
yaml_conf = load_yaml_config
read_conf = get_config_value