import os
import sys

def get_size_format(b, factor=1024, suffix="B"):
    """
    将字节大小转换为更易读的格式 (KB, MB, GB, 等)
    """
    for unit in ["", "K", "M", "G", "T", "P", "E", "Z"]:
        if b < factor:
            return f"{b:.2f} {unit}{suffix}"
        b /= factor
    return f"{b:.2f} Y{suffix}"

def get_directory_size(directory):
    """
    递归获取文件夹总大小（字节）
    使用 os.scandir 比 os.walk 更快
    """
    total = 0
    try:
        for entry in os.scandir(directory):
            if entry.is_file(follow_symlinks=False):
                total += entry.stat(follow_symlinks=False).st_size
            elif entry.is_dir(follow_symlinks=False):
                total += get_directory_size(entry.path)
    except PermissionError:
        # 跳过无权限访问的文件夹/文件
        pass
    except FileNotFoundError:
        pass
    except Exception:
        pass
    return total

def scan_folders(target_dir):
    """
    扫描目标目录下的子文件夹和文件，并按大小降序输出
    """
    print(f"开始扫描目录: {target_dir}\n")
    if not os.path.exists(target_dir):
        print(f"路径不存在: {target_dir}")
        return

    items_sizes = []
    
    try:
        for entry in os.scandir(target_dir):
            if entry.is_dir(follow_symlinks=False):
                size = get_directory_size(entry.path)
                items_sizes.append({'name': entry.name, 'size': size, 'path': entry.path, 'type': '文件夹'})
            elif entry.is_file(follow_symlinks=False):
                size = entry.stat(follow_symlinks=False).st_size
                items_sizes.append({'name': entry.name, 'size': size, 'path': entry.path, 'type': '文件'})
    except PermissionError:
        print(f"警告: 没有权限访问目录 '{target_dir}'。")
        return

    # 按大小降序排序
    items_sizes.sort(key=lambda x: x['size'], reverse=True)

    # 打印结果表头
    # 由于中文宽度问题，简单格式化可能无法完美对齐，这里尽量保证可读性
    print(f"{'类型':<5} | {'大小':<12} | {'名称'}")
    print("-" * 60)
    
    total_size = 0
    for item in items_sizes:
        size_str = get_size_format(item['size'])
        print(f"{item['type']:<5} | {size_str:<12} | {item['name']}")
        total_size += item['size']
        
    print("-" * 60)
    print(f"当前目录总大小: {get_size_format(total_size)}")

if __name__ == "__main__":
    # 如果通过命令行传入参数，则使用参数作为路径，否则提示用户输入或默认扫描当前目录
    if len(sys.argv) > 1:
        target = sys.argv[1]
    else:
        target = input("请输入要扫描的文件夹路径 (按回车扫描当前目录): ").strip()
        if not target:
            target = "."
    
    # 获取绝对路径并执行扫描
    target_abs = os.path.abspath(target)
    scan_folders(target_abs)