"""
配置管理模块
提供统一的配置管理功能，支持从配置文件、环境变量加载配置
"""

import json
import os
from pathlib import Path
from typing import Any, Dict, Optional, Union
from .logger import get_logger

logger = get_logger("taskflow.config")


class Config:
    """
    配置管理类
    
    支持从多种来源加载配置：
    1. 默认配置
    2. 配置文件（JSON）
    3. 环境变量
    
    配置优先级：环境变量 > 配置文件 > 默认配置
    
    使用示例:
        >>> config = Config()
        >>> config.load_from_file("config.json")
        >>> value = config.get("task.state_file")
    """
    
    def __init__(self, default_config: Optional[Dict] = None):
        """
        初始化配置管理器
        
        Args:
            default_config: 默认配置字典
        """
        self._config: Dict[str, Any] = {}
        self._default_config = default_config or self._get_default_config()
        self._load_defaults()
    
    def _get_default_config(self) -> Dict[str, Any]:
        """
        获取默认配置
        
        Returns:
            默认配置字典
        """
        return {
            "task": {
                "state_file": "task_state.json",
                "cache_dir": "task_cache",
                "auto_save": True,
                "save_interval": 1,  # 每N个步骤保存一次状态
            },
            "logging": {
                "level": "INFO",
                "format": "%(asctime)s - %(name)s - %(levelname)s - %(message)s",
                "date_format": "%Y-%m-%d %H:%M:%S",
                "console_output": True,
                "file_output": False,
                "log_file": None,
            },
            "run": {
                "base_output_dir": "output",
                "run_id_format": "run_{timestamp}",
                "timestamp_format": "%Y%m%d_%H%M%S",
            },
            "io": {
                "encoding": "utf-8",
                "json_indent": 2,
                "create_dirs": True,
            },
            "api": {
                "ark": {
                    "api_key": None,
                    "base_url": "https://ark.cn-beijing.volces.com",
                    "model": "doubao-seed-1-6-251015",
                    "image_model": "doubao-seedream-4-0-250828",
                    "timeout": 60,
                }
            }
        }
    
    def _load_defaults(self):
        """加载默认配置"""
        self._config = self._deep_copy(self._default_config)
    
    def _deep_copy(self, source: Dict) -> Dict:
        """深拷贝字典"""
        return json.loads(json.dumps(source))
    
    def load_from_file(self, config_file: Union[str, Path]) -> bool:
        """
        从配置文件加载配置
        
        Args:
            config_file: 配置文件路径（JSON格式）
        
        Returns:
            是否成功加载
        """
        config_path = Path(config_file)
        
        if not config_path.exists():
            logger.warning(f"配置文件不存在: {config_file}")
            return False
        
        try:
            with open(config_path, 'r', encoding='utf-8') as f:
                file_config = json.load(f)
            
            self._merge_config(self._config, file_config)
            logger.info(f"成功加载配置文件: {config_file}")
            return True
            
        except json.JSONDecodeError as e:
            logger.error(f"配置文件格式错误: {e}")
            return False
        except Exception as e:
            logger.error(f"加载配置文件失败: {e}")
            return False
    
    def load_from_env(self, prefix: str = "TASKFLOW_"):
        """
        从环境变量加载配置
        
        环境变量命名规则：
        - TASKFLOW_TASK_STATE_FILE -> task.state_file
        - TASKFLOW_LOGGING_LEVEL -> logging.level
        
        Args:
            prefix: 环境变量前缀
        """
        env_config = {}
        
        for key, value in os.environ.items():
            if key.startswith(prefix):
                # 移除前缀并转换为配置路径
                config_key = key[len(prefix):].lower()
                # 将下划线分隔的键转换为嵌套字典路径
                keys = config_key.split('_')
                
                # 构建嵌套字典
                current = env_config
                for k in keys[:-1]:
                    if k not in current:
                        current[k] = {}
                    current = current[k]
                
                # 设置值（尝试转换为合适的类型）
                final_key = keys[-1]
                current[final_key] = self._parse_env_value(value)
        
        if env_config:
            self._merge_config(self._config, env_config)
            logger.info(f"从环境变量加载了 {len(env_config)} 个配置项")
    
    def _parse_env_value(self, value: str) -> Any:
        """
        解析环境变量值，尝试转换为合适的类型
        
        Args:
            value: 环境变量值
        
        Returns:
            转换后的值
        """
        # 尝试转换为布尔值
        if value.lower() in ('true', '1', 'yes', 'on'):
            return True
        if value.lower() in ('false', '0', 'no', 'off'):
            return False
        
        # 尝试转换为数字
        try:
            if '.' in value:
                return float(value)
            return int(value)
        except ValueError:
            pass
        
        # 返回字符串
        return value
    
    def _merge_config(self, base: Dict, override: Dict):
        """
        合并配置（深度合并）
        
        Args:
            base: 基础配置（会被修改）
            override: 覆盖配置
        """
        for key, value in override.items():
            if key in base and isinstance(base[key], dict) and isinstance(value, dict):
                self._merge_config(base[key], value)
            else:
                base[key] = value
    
    def get(self, key: str, default: Any = None) -> Any:
        """
        获取配置值
        
        支持点号分隔的嵌套键，如 "task.state_file"
        
        Args:
            key: 配置键（支持点号分隔的嵌套路径）
            default: 默认值
        
        Returns:
            配置值
        
        示例:
            >>> config.get("task.state_file")
            >>> config.get("logging.level", "DEBUG")
        """
        keys = key.split('.')
        current = self._config
        
        try:
            for k in keys:
                current = current[k]
            return current
        except (KeyError, TypeError):
            return default
    
    def set(self, key: str, value: Any):
        """
        设置配置值
        
        支持点号分隔的嵌套键，如 "task.state_file"
        
        Args:
            key: 配置键（支持点号分隔的嵌套路径）
            value: 配置值
        
        示例:
            >>> config.set("task.state_file", "custom_state.json")
        """
        keys = key.split('.')
        current = self._config
        
        # 创建嵌套字典结构
        for k in keys[:-1]:
            if k not in current:
                current[k] = {}
            elif not isinstance(current[k], dict):
                current[k] = {}
            current = current[k]
        
        # 设置值
        current[keys[-1]] = value
    
    def has(self, key: str) -> bool:
        """
        检查配置键是否存在
        
        Args:
            key: 配置键（支持点号分隔的嵌套路径）
        
        Returns:
            是否存在
        """
        keys = key.split('.')
        current = self._config
        
        try:
            for k in keys:
                current = current[k]
            return True
        except (KeyError, TypeError):
            return False
    
    def get_section(self, section: str) -> Dict[str, Any]:
        """
        获取配置节
        
        Args:
            section: 配置节名称（如 "task", "logging"）
        
        Returns:
            配置节字典
        """
        return self._config.get(section, {})
    
    def to_dict(self) -> Dict[str, Any]:
        """
        获取完整配置字典
        
        Returns:
            配置字典的深拷贝
        """
        return self._deep_copy(self._config)
    
    def save_to_file(self, config_file: Union[str, Path], indent: int = 2):
        """
        保存配置到文件
        
        Args:
            config_file: 配置文件路径
            indent: JSON缩进空格数
        """
        config_path = Path(config_file)
        config_path.parent.mkdir(parents=True, exist_ok=True)
        
        try:
            with open(config_path, 'w', encoding='utf-8') as f:
                json.dump(self._config, f, ensure_ascii=False, indent=indent)
            logger.info(f"配置已保存到: {config_file}")
        except Exception as e:
            logger.error(f"保存配置失败: {e}")
    
    def reset(self):
        """重置为默认配置"""
        self._load_defaults()
        logger.info("配置已重置为默认值")
    
    def validate(self):
        """
        验证配置的有效性
        
        Returns:
            (是否有效, 错误列表)
        """
        errors = []
        
        # 验证task配置
        if not isinstance(self.get("task.state_file"), str):
            errors.append("task.state_file 必须是字符串")
        
        if not isinstance(self.get("task.cache_dir"), str):
            errors.append("task.cache_dir 必须是字符串")
        
        # 验证logging配置
        valid_log_levels = ["DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"]
        log_level = self.get("logging.level")
        if log_level not in valid_log_levels:
            errors.append(f"logging.level 必须是以下之一: {valid_log_levels}")
        
        # 验证run配置
        if not isinstance(self.get("run.base_output_dir"), str):
            errors.append("run.base_output_dir 必须是字符串")
        
        return len(errors) == 0, errors


# 全局配置实例
_global_config: Optional[Config] = None


def get_config(config_file: Optional[Union[str, Path]] = None) -> Config:
    """
    获取全局配置实例
    
    如果全局配置不存在，会创建一个新的配置实例。
    如果提供了配置文件路径，会尝试加载。
    
    Args:
        config_file: 可选的配置文件路径
    
    Returns:
        配置实例
    """
    global _global_config
    
    if _global_config is None:
        _global_config = Config()
        
        # 尝试从环境变量加载
        _global_config.load_from_env()
        
        # 如果提供了配置文件路径，尝试加载
        if config_file:
            _global_config.load_from_file(config_file)
        else:
            # 尝试加载默认配置文件
            default_config_files = [
                "./config/taskflow_config.example.json",
                "./config/taskflow_config.json",
                "./config/.taskflow_config.json"
            ]
            
            for config_file_path in default_config_files:
                if Path(config_file_path).exists():
                    _global_config.load_from_file(config_file_path)
                    break
    
    return _global_config


def reset_config():
    """重置全局配置"""
    global _global_config
    _global_config = None