#!/usr/bin/env python3

import os
import select
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_mount
from posix_parity import temp_dir
from posix_parity import touch


def poll_mask(fd, timeout_ms=25):
    p = select.poll()
    p.register(fd, select.POLLIN | select.POLLOUT | select.POLLERR | select.POLLHUP)
    events = p.poll(timeout_ms)
    mask = 0
    for _fd, ev in events:
        mask |= ev
    return mask


def main():
    try:
        with mergerfs_mount() as (mount, _):
            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_file = join(merge_base, "file")
                    native_file = join(native_base, "file")
                    touch(merge_file, b"abcdef")
                    touch(native_file, b"abcdef")

                    mfd = os.open(merge_file, os.O_RDONLY)
                    nfd = os.open(native_file, os.O_RDONLY)
                    try:
                        mmask = poll_mask(mfd)
                        nmask = poll_mask(nfd)

                        if bool(mmask & select.POLLIN) != bool(nmask & select.POLLIN):
                            return fail(f"poll POLLIN mismatch mergerfs_mask=0x{mmask:x} native_mask=0x{nmask:x}")
                        if bool(mmask & select.POLLOUT) != bool(nmask & select.POLLOUT):
                            return fail(f"poll POLLOUT mismatch mergerfs_mask=0x{mmask:x} native_mask=0x{nmask:x}")
                    finally:
                        os.close(mfd)
                        os.close(nfd)

                    return 0
                finally:
                    cleanup_dir(merge_base)
    except RuntimeError as exc:
        print(str(exc), end="")
        return 77


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