# This file is part of the MapProxy project.
# Copyright (C) 2012 Omniscale <http://omniscale.de>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import multiprocessing
import time
import sys

import pytest

from mapproxy.seed.cachelock import CacheLocker, CacheLockedError


@pytest.mark.skipif(sys.platform == "win32", reason="test not supported for Windows")
@pytest.mark.skipif(sys.platform == "darwin", reason="test not supported for MacOS")
class TestCacheLock(object):

    @pytest.fixture
    def lock_file(self, tmpdir):
        return (tmpdir / "lock").strpath

    def test_free_lock(self, lock_file):
        locker = CacheLocker(lock_file)
        with locker.lock("foo"):
            assert True

    def test_locked_by_process_no_block(self, lock_file):
        ctx = multiprocessing.get_context('fork')

        proc_is_locked = ctx.Event()

        def lock():
            locker = CacheLocker(lock_file)
            with locker.lock("foo"):
                proc_is_locked.set()
                time.sleep(10)

        p = ctx.Process(target=lock)
        p.start()
        # wait for process to start
        proc_is_locked.wait()

        locker = CacheLocker(lock_file)

        # test unlocked bar
        with locker.lock("bar", no_block=True):
            assert True

        # test locked foo
        try:
            with locker.lock("foo", no_block=True):
                assert False
        except CacheLockedError:
            pass
        finally:
            p.terminate()
            p.join()

    def test_locked_by_process_waiting(self, lock_file):
        ctx = multiprocessing.get_context('fork')

        proc_is_locked = ctx.Event()

        def lock():
            locker = CacheLocker(lock_file)
            with locker.lock("foo"):
                proc_is_locked.set()
                time.sleep(.1)

        p = ctx.Process(target=lock)
        start_time = time.time()
        p.start()
        # wait for process to start
        proc_is_locked.wait()

        locker = CacheLocker(lock_file, polltime=0.02)
        try:
            with locker.lock("foo", no_block=False):
                diff = time.time() - start_time
                assert diff > 0.1
        finally:
            p.terminate()
            p.join()
