#!/usr/bin/env python3

import os
import sys
import tempfile

from posix_parity import fail
from posix_parity import join
from posix_parity import mergerfs_get_option
from posix_parity import mergerfs_set_option
from posix_parity import touch


def list_and_stat(dirpath):
    out = {}
    for name in os.listdir(dirpath):
        if name in (".", ".."):
            continue
        st = os.lstat(os.path.join(dirpath, name))
        out[name] = (st.st_mode & 0xF000, st.st_size)
    return out


def main():
    if len(sys.argv) != 2:
        print("usage: TEST_posix_readdir_plus <mountpoint>", file=sys.stderr)
        return 1

    mount = sys.argv[1]

    with tempfile.TemporaryDirectory() as native:
        merge_dir = join(mount, "posix-readdir-plus/dir")
        native_dir = join(native, "posix-readdir-plus/dir")

        for i in range(40):
            touch(join(merge_dir, f"f{i:03d}"), bytes(str(i), "ascii"))
            touch(join(native_dir, f"f{i:03d}"), bytes(str(i), "ascii"))

        # Exercise mapping from readdir entries to immediate getattr calls.
        m_map = list_and_stat(merge_dir)
        n_map = list_and_stat(native_dir)
        if m_map != n_map:
            return fail("readdir+getattr map mismatch between mergerfs and native")

        # Optionally toggle readdir policy and ensure semantic output stays stable.
        try:
            orig = mergerfs_get_option(mount, "func.readdir")
        except (PermissionError, FileNotFoundError, OSError):
            return 0

        try:
            for mode in ("seq", "cosr:2:2", "cor:2:2"):
                mergerfs_set_option(mount, "func.readdir", mode)
                got = list_and_stat(merge_dir)
                if got != m_map:
                    return fail(f"func.readdir={mode} changed readdir+getattr semantic output")
        except (PermissionError, FileNotFoundError, OSError):
            return 0
        finally:
            try:
                mergerfs_set_option(mount, "func.readdir", orig)
            except OSError:
                pass

        return 0


if __name__ == "__main__":
    raise SystemExit(main())