#!/usr/bin/env python3

import os
import sys

from posix_parity import fail
from posix_parity import mergerfs_get_option
from posix_parity import mergerfs_set_option


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

    mount = sys.argv[1]

    try:
        orig_statfs = mergerfs_get_option(mount, "statfs")
        orig_ignore = mergerfs_get_option(mount, "statfs-ignore")
    except (PermissionError, FileNotFoundError, OSError):
        return 0

    try:
        mergerfs_set_option(mount, "statfs", "base")

        mergerfs_set_option(mount, "statfs-ignore", "none")
        s_none = os.statvfs(mount)

        mergerfs_set_option(mount, "statfs-ignore", "nc")
        s_nc = os.statvfs(mount)

        mergerfs_set_option(mount, "statfs-ignore", "ro")
        s_ro = os.statvfs(mount)

        # Ignoring additional branch classes should never increase available blocks.
        if s_nc.f_bavail > s_none.f_bavail:
            return fail(
                f"statfs-ignore=nc increased bavail unexpectedly nc={s_nc.f_bavail} none={s_none.f_bavail}"
            )
        if s_ro.f_bavail > s_nc.f_bavail:
            return fail(
                f"statfs-ignore=ro increased bavail unexpectedly ro={s_ro.f_bavail} nc={s_nc.f_bavail}"
            )

        mergerfs_set_option(mount, "statfs", "full")
        s_full = os.statvfs(mount)
        if s_full.f_bsize <= 0 or s_full.f_frsize <= 0:
            return fail(
                f"statfs=full invalid block sizes bsize={s_full.f_bsize} frsize={s_full.f_frsize}"
            )
    except (PermissionError, FileNotFoundError, OSError):
        return 0
    finally:
        try:
            mergerfs_set_option(mount, "statfs", orig_statfs)
            mergerfs_set_option(mount, "statfs-ignore", orig_ignore)
        except OSError:
            pass

    return 0


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