#!/usr/bin/env python3

import os
import select
import sys
import tempfile

from posix_parity import fail
from posix_parity import join
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():
    if len(sys.argv) != 2:
        print("usage: TEST_posix_poll <mountpoint>", file=sys.stderr)
        return 1

    mount = sys.argv[1]

    with tempfile.TemporaryDirectory() as native:
        merge_file = join(mount, "posix-poll/file")
        native_file = join(native, "posix-poll/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)

            # For regular files POLLIN and POLLOUT are typically ready.
            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


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