#!/usr/bin/env python3

import os
import sys
import tempfile

from posix_parity import cleanup_dir
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 temp_dir
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_base = temp_dir(mount)
        try:
            native_base = join(native, os.path.basename(merge_base))
            os.makedirs(native_base, exist_ok=True)

            merge_dir = join(merge_base, "dir")
            native_dir = join(native_base, "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
        finally:
            cleanup_dir(merge_base)


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