"""
适配器工厂模块

根据 DEPLOYMENT_MODE 配置自动选择本地或服务器适配器。

Example:
    >>> from app.core.adapters import get_database_adapter, get_storage_adapter
    >>> db = get_database_adapter()
    >>> storage = get_storage_adapter()
"""

from functools import lru_cache
from typing import TYPE_CHECKING

from project_config import settings

if TYPE_CHECKING:
    from ..adapters.base import (
        DatabaseAdapter,
        ProgressAdapter,
        StorageAdapter,
        TaskQueueAdapter,
    )


class AdapterFactory:
    """
    适配器工厂
    
    根据 DEPLOYMENT_MODE 配置创建对应的适配器实例。
    
    - local 模式: SQLite + 本地文件系统 + asyncio.subprocess
    - server 模式: PostgreSQL + S3/MinIO + Celery (Phase 2)
    """
    
    @staticmethod
    def create_storage_adapter() -> "StorageAdapter":
        """
        创建存储适配器
        
        Returns:
            本地模式返回 LocalStorageAdapter
            服务器模式返回 S3StorageAdapter (Phase 2)
        """
        if settings.DEPLOYMENT_MODE == "local":
            from ..adapters.local.storage import LocalStorageAdapter
            return LocalStorageAdapter(base_path=str(settings.DATA_DIR / "files"))
        else:
            # Phase 2: 服务器模式
            raise NotImplementedError("Server mode storage adapter not implemented yet")
    
    @staticmethod
    def create_database_adapter() -> "DatabaseAdapter":
        """
        创建数据库适配器
        
        Returns:
            本地模式返回 SQLiteAdapter
            服务器模式返回 PostgreSQLAdapter (Phase 2)
        """
        if settings.DEPLOYMENT_MODE == "local":
            from ..adapters.local.database import SQLiteAdapter
            return SQLiteAdapter(db_path=str(settings.SQLITE_PATH))
        else:
            # Phase 2: 服务器模式
            raise NotImplementedError("Server mode database adapter not implemented yet")
    
    @staticmethod
    def create_task_queue_adapter(database_adapter: "DatabaseAdapter" = None) -> "TaskQueueAdapter":
        """
        创建任务队列适配器
        
        Args:
            database_adapter: 数据库适配器，用于同步任务状态到 tasks 表。
                              如果未提供，将自动创建一个实例。
        
        Returns:
            本地模式返回 AsyncTrainingManager
            服务器模式返回 CeleryTaskQueueAdapter (Phase 2)
        """
        if settings.DEPLOYMENT_MODE == "local":
            from ..adapters.local.task_queue import AsyncTrainingManager
            from ..adapters.local.database import SQLiteAdapter
            
            # 如果未提供 database_adapter，创建一个新实例用于状态同步
            if database_adapter is None:
                database_adapter = SQLiteAdapter(db_path=str(settings.SQLITE_PATH))
            
            return AsyncTrainingManager(
                db_path=str(settings.SQLITE_PATH),
                database_adapter=database_adapter
            )
        else:
            # Phase 2: 服务器模式
            raise NotImplementedError("Server mode task queue adapter not implemented yet")
    
    @staticmethod
    def create_progress_adapter() -> "ProgressAdapter":
        """
        创建进度管理适配器
        
        Returns:
            本地模式返回 LocalProgressAdapter
            服务器模式返回 RedisProgressAdapter (Phase 2)
        """
        if settings.DEPLOYMENT_MODE == "local":
            from ..adapters.local.progress import LocalProgressAdapter
            return LocalProgressAdapter()
        else:
            # Phase 2: 服务器模式
            raise NotImplementedError("Server mode progress adapter not implemented yet")


# ============================================================
# 全局单例获取函数（使用 lru_cache 缓存实例）
# ============================================================

@lru_cache()
def get_storage_adapter() -> "StorageAdapter":
    """
    获取存储适配器单例
    
    Returns:
        StorageAdapter 实例
    """
    return AdapterFactory.create_storage_adapter()


@lru_cache()
def get_database_adapter() -> "DatabaseAdapter":
    """
    获取数据库适配器单例
    
    Returns:
        DatabaseAdapter 实例
    """
    return AdapterFactory.create_database_adapter()


@lru_cache()
def get_task_queue_adapter() -> "TaskQueueAdapter":
    """
    获取任务队列适配器单例
    
    使用共享的数据库适配器实例来确保状态同步一致性。
    
    Returns:
        TaskQueueAdapter 实例
    """
    # 使用共享的数据库适配器实例
    db_adapter = get_database_adapter()
    return AdapterFactory.create_task_queue_adapter(database_adapter=db_adapter)


@lru_cache()
def get_progress_adapter() -> "ProgressAdapter":
    """
    获取进度管理适配器单例
    
    Returns:
        ProgressAdapter 实例
    """
    return AdapterFactory.create_progress_adapter()


# ============================================================
# 便捷别名（向后兼容）
# ============================================================

# 延迟初始化的全局变量，在首次访问时创建
# 注意：这些是函数调用的结果，不是直接的实例引用
# 如果需要在模块级别使用，请调用对应的 get_*_adapter() 函数

__all__ = [
    "AdapterFactory",
    "get_storage_adapter",
    "get_database_adapter",
    "get_task_queue_adapter",
    "get_progress_adapter",
]