#!/usr/bin/env python3
# -*- coding: utf-8 -*-

"""
引擎注册表
负责引擎的自动发现、注册和管理
"""

import logging
import importlib
import pkgutil
from typing import Dict, Type, Optional, List, Any
from pathlib import Path

from .engines.base import BaseAIGCEngine

logger = logging.getLogger(__name__)


class EngineRegistry:
    """
    引擎注册表
    
    支持：
    - 自动发现 engines 目录下的所有引擎
    - 手动注册引擎
    - 按 ID 获取引擎实例
    - 列出所有可用引擎
    """
    
    _instance: Optional['EngineRegistry'] = None
    
    def __new__(cls):
        """单例模式"""
        if cls._instance is None:
            cls._instance = super().__new__(cls)
            cls._instance._initialized = False
        return cls._instance
    
    def __init__(self):
        if self._initialized:
            return
            
        self._engines: Dict[str, Type[BaseAIGCEngine]] = {}
        self._instances: Dict[str, BaseAIGCEngine] = {}
        self._shared_components: Optional[Dict[str, Any]] = None
        self._initialized = True
        
        logger.info("引擎注册表初始化")
    
    def set_shared_components(self, components: Dict[str, Any]):
        """
        设置共享组件
        
        Args:
            components: 共享组件字典 (db, llm, prompt, image, storage, paths, config)
        """
        self._shared_components = components
        
        # 为已实例化的引擎注入组件
        for engine in self._instances.values():
            engine.initialize(components)
        
        logger.info("共享组件已设置")
    
    def auto_discover(self, package_path: str = "domain.aigc.engines"):
        """
        自动发现并注册引擎
        
        Args:
            package_path: 引擎包路径
        """
        logger.info(f"开始自动发现引擎: {package_path}")
        
        try:
            package = importlib.import_module(package_path)
            package_dir = Path(package.__file__).parent
            
            # 遍历包中的所有模块
            for _, module_name, is_pkg in pkgutil.iter_modules([str(package_dir)]):
                # 跳过 base 模块和私有模块
                if module_name.startswith('_') or module_name == 'base':
                    continue
                
                # 跳过子包（如 _future）
                if is_pkg:
                    continue
                
                try:
                    module = importlib.import_module(f"{package_path}.{module_name}")
                    
                    # 查找模块中的引擎类
                    for attr_name in dir(module):
                        attr = getattr(module, attr_name)
                        
                        # 检查是否是 BaseAIGCEngine 的子类
                        if (isinstance(attr, type) and 
                            issubclass(attr, BaseAIGCEngine) and 
                            attr is not BaseAIGCEngine and
                            hasattr(attr, 'engine_id') and
                            attr.engine_id):
                            
                            self.register(attr)
                            
                except Exception as e:
                    logger.warning(f"加载模块 {module_name} 失败: {e}")
                    
        except Exception as e:
            logger.error(f"自动发现引擎失败: {e}")
        
        logger.info(f"自动发现完成，共注册 {len(self._engines)} 个引擎")
    
    def register(self, engine_class: Type[BaseAIGCEngine]):
        """
        注册引擎
        
        Args:
            engine_class: 引擎类
        """
        engine_id = engine_class.engine_id
        
        if not engine_id:
            logger.warning(f"引擎类 {engine_class.__name__} 未定义 engine_id，跳过注册")
            return
        
        if engine_id in self._engines:
            logger.warning(f"引擎 {engine_id} 已存在，将被覆盖")
        
        self._engines[engine_id] = engine_class
        logger.info(f"注册引擎: {engine_id} ({engine_class.engine_name})")
    
    def get(self, engine_id: str) -> Optional[BaseAIGCEngine]:
        """
        获取引擎实例
        
        Args:
            engine_id: 引擎 ID
            
        Returns:
            引擎实例，不存在返回 None
        """
        # 检查是否已实例化
        if engine_id in self._instances:
            return self._instances[engine_id]
        
        # 检查是否已注册
        if engine_id not in self._engines:
            logger.warning(f"引擎 {engine_id} 未注册")
            return None
        
        # 创建实例
        try:
            engine_class = self._engines[engine_id]
            engine = engine_class()
            
            # 注入共享组件
            if self._shared_components:
                engine.initialize(self._shared_components)
            
            self._instances[engine_id] = engine
            return engine
            
        except Exception as e:
            logger.error(f"创建引擎 {engine_id} 实例失败: {e}")
            return None
    
    def has(self, engine_id: str) -> bool:
        """
        检查引擎是否存在
        
        Args:
            engine_id: 引擎 ID
            
        Returns:
            是否存在
        """
        return engine_id in self._engines
    
    def list_engines(self) -> List[Dict[str, Any]]:
        """
        列出所有可用引擎
        
        Returns:
            引擎信息列表
        """
        engines = []
        for engine_id, engine_class in self._engines.items():
            engines.append({
                "id": engine_id,
                "name": engine_class.engine_name,
                "version": engine_class.version,
                "description": engine_class.description,
            })
        return engines
    
    def get_engine_info(self, engine_id: str) -> Optional[Dict[str, Any]]:
        """
        获取引擎详细信息
        
        Args:
            engine_id: 引擎 ID
            
        Returns:
            引擎信息，包含参数 Schema
        """
        engine = self.get(engine_id)
        if engine:
            return engine.get_info()
        return None
    
    def clear(self):
        """清空注册表（主要用于测试）"""
        self._engines.clear()
        self._instances.clear()
        logger.info("引擎注册表已清空")