#! /usr/bin/env python3

# Copyright © 2020, RedHat Inc.

#

# This program is free software; you can redistribute it and/or

# modify it under the terms of the GNU Lesser General Public

# License as published by the Free Software Foundation; either

# version 2.1 of the License, or (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

# Lesser General Public License for more details.

#

# You should have received a copy of the GNU Lesser General Public

# License along with this library. If not, see <http://www.gnu.org/licenses/>.

# Authors:

#       Benjamin Berg <bberg@redhat.com>

import os

import sys

import fcntl

import io

import re

import time

import threading

class OutputChecker(object):

    def __init__(self, out=sys.stdout):

        self._output = out

        self._pipe_fd_r, self._pipe_fd_w = os.pipe()

        self._partial_buf = b''

        self._lines_sem = threading.Semaphore()

        self._lines = []

        self._reader_io = io.StringIO()

        # Just to be sure, shouldn't be a problem even if we didn't set it

        fcntl.fcntl(self._pipe_fd_r, fcntl.F_SETFL,

                    fcntl.fcntl(self._pipe_fd_r, fcntl.F_GETFL) | os.O_CLOEXEC)

        fcntl.fcntl(self._pipe_fd_w, fcntl.F_SETFL,

                    fcntl.fcntl(self._pipe_fd_w, fcntl.F_GETFL) | os.O_CLOEXEC)

        # Start copier thread

        self._thread = threading.Thread(target=self._copy)

        self._thread.start()

    def _copy(self):

        while True:

            r = os.read(self._pipe_fd_r, 1024)

            if not r:

                return

            l = r.split(b'\n')

            l[0] = self._partial_buf + l[0]

            self._lines.extend(l[:-1])

            self._partial_buf = l[-1]

            self._lines_sem.release()

            os.write(self._output.fileno(), r)

    def check_line_re(self, needle_re, timeout=0, failmsg=None):

        deadline = time.time() + timeout

        if isinstance(needle_re, str):

            needle_re = needle_re.encode('ascii')

        r = re.compile(needle_re)

        ret = []

        while True:

            try:

                l = self._lines.pop(0)

            except IndexError:

                # Check if should wake up

                if not self._lines_sem.acquire(timeout = deadline - time.time()):

                    if failmsg:

                        raise AssertionError(failmsg)

                    else:

                        raise AssertionError('Timed out waiting for needle %s (timeout: %0.2f)' % (str(needle_re), timeout))

                continue

            ret.append(l)

            if r.search(l):

                return ret

    def check_line(self, needle, timeout=0, failmsg=None):

        if isinstance(needle, str):

            needle = needle.encode('ascii')

        needle_re = re.escape(needle)

        return self.check_line_re(needle_re, timeout=timeout, failmsg=failmsg)

    def check_no_line_re(self, needle_re, wait=0, failmsg=None):

        deadline = time.time() + wait

        if isinstance(needle_re, str):

            needle_re = needle_re.encode('ascii')

        r = re.compile(needle_re)

        ret = []

        while True:

            try:

                l = self._lines.pop(0)

            except IndexError:

                # Check if should wake up

                if not self._lines_sem.acquire(timeout = deadline - time.time()):

                    # Timed out, so everything is good

                    break

                continue

            ret.append(l)

            if r.search(l):

                if failmsg:

                    raise AssertionError(failmsg)

                else:

                    raise AssertionError('Found needle %s but shouldn\'t have been there (timeout: %0.2f)' % (str(needle_re), timeout))

        return ret

    def check_no_line(self, needle, wait=0, failmsg=None):

        if isinstance(needle, str):

            needle = needle.encode('ascii')

        needle_re = re.escape(needle)

        return self.check_no_line_re(needle_re, wait=wait, failmsg=failmsg)

    def clear(self):

        ret = self._lines

        self._lines = []

        return ret

    def assert_closed(self, timeout=1):

        self._thread.join(timeout)

        if self._thread.is_alive() != False:

            raise AssertionError("OutputCheck: Write side has not been closed yet!")

    @property

    def fd(self):

        return self._pipe_fd_w

    def writer_attached(self):

        os.close(self._pipe_fd_w)

        self._pipe_fd_w = -1