from functools import wraps
import torch
import os
import logging

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

class DeviceManager:
    _instance = None
    
    def __new__(cls):
        if cls._instance is None:
            cls._instance = super(DeviceManager, cls).__new__(cls)
            cls._instance._initialized = False
        return cls._instance
    
    def __init__(self):
        if self._initialized:
            return
            
        self._initialized = True
        self._current_device = None
        self.initialize_zero_gpu()
        
    def initialize_zero_gpu(self):
        """初始化 ZeroGPU"""
        try:
            # 檢查是否在 Hugging Face Spaces 環境中
            if os.environ.get('SPACE_ID'):
                # 嘗試初始化 ZeroGPU
                os.environ['CUDA_VISIBLE_DEVICES'] = '0'
                # 設置必要的環境變數
                os.environ['ZERO_GPU'] = '1'
                logger.info("ZeroGPU environment initialized")
        except Exception as e:
            logger.warning(f"Failed to initialize ZeroGPU environment: {e}")
    
    def check_zero_gpu_availability(self):
        """檢查 ZeroGPU 是否可用"""
        try:
            if os.environ.get('SPACE_ID') and os.environ.get('ZERO_GPU') == '1':
                # 確保 CUDA 運行時環境正確設置
                if torch.cuda.is_available():
                    torch.cuda.init()
                    return True
        except Exception as e:
            logger.warning(f"ZeroGPU check failed: {e}")
        return False
    
    def get_optimal_device(self):
        """獲取最佳可用設備"""
        if self._current_device is None:
            if self.check_zero_gpu_availability():
                try:
                    self._current_device = torch.device('cuda')
                    logger.info("Using ZeroGPU")
                    # 嘗試進行一次小規模的 CUDA 操作來驗證
                    torch.zeros(1).cuda()
                except Exception as e:
                    logger.warning(f"Failed to use ZeroGPU: {e}")
                    self._current_device = torch.device('cpu')
                    logger.info("Fallback to CPU")
            else:
                self._current_device = torch.device('cpu')
                logger.info("Using CPU (ZeroGPU not available)")
        return self._current_device

    def move_to_device(self, tensor_or_model):
        """將張量或模型移動到最佳設備"""
        device = self.get_optimal_device()
        try:
            if hasattr(tensor_or_model, 'to'):
                return tensor_or_model.to(device)
        except Exception as e:
            logger.warning(f"Failed to move to {device}, falling back to CPU: {e}")
            self._current_device = torch.device('cpu')
            if hasattr(tensor_or_model, 'to'):
                return tensor_or_model.to('cpu')
        return tensor_or_model