import os
import shutil

ROOT = "./"
MAX_FILES = 8000  # 每个子目录最多文件数

def split_directory(dirpath):
    """
    将 dirpath 下的直接文件分成 part_xxx 子目录
    """
    print(f"→ Splitting directory: {dirpath}")

    files = [
        f for f in os.listdir(dirpath)
        if os.path.isfile(os.path.join(dirpath, f))
    ]

    total = len(files)
    print(f"  Found {total} files.")

    # 按 MAX_FILES 分块
    for idx in range(0, total, MAX_FILES):
        part = idx // MAX_FILES
        subdir = os.path.join(dirpath, f"part_{part:03d}")
        os.makedirs(subdir, exist_ok=True)

        for filename in files[idx: idx + MAX_FILES]:
            src = os.path.join(dirpath, filename)
            dst = os.path.join(subdir, filename)
            shutil.move(src, dst)

        print(f"  - Created {subdir}")

    print(f"✔ Completed: {dirpath}\n")


def walk_and_process(root):
    """
    递归遍历整个目录树，发现需要拆分的目录就拆分
    """
    for dirpath, dirnames, filenames in os.walk(root):
        # 过滤掉我们自己创建的 part_000/part_001 目录，避免再次处理
        dirnames[:] = [d for d in dirnames if not d.startswith("part_")]

        file_count = len([
            f for f in filenames
            if os.path.isfile(os.path.join(dirpath, f))
        ])

        if file_count > 10000:
            print(f"▶ Found big directory: {dirpath} ({file_count} files)")
            split_directory(dirpath)


if __name__ == "__main__":
    walk_and_process(ROOT)
    print("🎉 All oversized directories processed.")