#!/usr/bin/env python
#
# Copyright (C) 2020 GNS3 Technologies Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import pytest
import asyncio
from unittest.mock import MagicMock


from gns3server.utils.file_watcher import FileWatcher


@pytest.mark.parametrize("strategy", ['mtime', 'hash'])
@pytest.mark.asyncio
async def test_file_watcher(tmpdir, strategy):

    file = tmpdir / "test"
    file.write("a")
    callback = MagicMock()
    FileWatcher(file, callback, delay=0.1, strategy=strategy)
    await asyncio.sleep(0.5)
    assert not callback.called
    file.write("b")
    await asyncio.sleep(0.5)
    callback.assert_called_with(str(file))


@pytest.mark.parametrize("strategy", ['mtime', 'hash'])
@pytest.mark.asyncio
async def test_file_watcher_not_existing(tmpdir, strategy):

    file = tmpdir / "test"
    callback = MagicMock()
    FileWatcher(file, callback, delay=0.1, strategy=strategy)
    await asyncio.sleep(0.5)
    assert not callback.called
    file.write("b")
    await asyncio.sleep(0.5)
    callback.assert_called_with(str(file))


@pytest.mark.parametrize("strategy", ['mtime', 'hash'])
@pytest.mark.asyncio
async def test_file_watcher_list(tmpdir, strategy):

    file = tmpdir / "test"
    file.write("a")
    file2 = tmpdir / "test2"
    callback = MagicMock()
    FileWatcher([file, file2], callback, delay=0.1, strategy=strategy)
    await asyncio.sleep(0.5)
    assert not callback.called
    file2.write("b")
    await asyncio.sleep(0.5)
    callback.assert_called_with(str(file2))


@pytest.mark.asyncio
async def test_file_watcher_callback_exception_does_not_stop_polling(tmpdir):

    file = tmpdir / "test"
    file.write("a")
    callback = MagicMock(side_effect=ValueError("callback error"))
    FileWatcher(file, callback, delay=0.1)
    await asyncio.sleep(0.5)
    assert callback.call_count == 0
    file.write("b")
    await asyncio.sleep(0.5)
    assert callback.call_count == 1  # raised, but must not kill the polling loop
    file.write("c")
    await asyncio.sleep(0.5)
    assert callback.call_count == 2  # polling survived the exception