/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

#include <gtest/gtest.h>

#include <list>
#include <string>

#include <process/gmock.hpp>
#include <process/gtest.hpp>

#include <stout/os.hpp>
#include <stout/strings.hpp>

#include "configurator/configurator.hpp"

#ifdef __linux__
#include "linux/cgroups.hpp"
#endif

#include "tests/environment.hpp"

using std::list;
using std::string;

namespace mesos {
namespace internal {
namespace tests {

// Returns true if we should enable the provided test. Similar to how
// tests can be disabled using the 'DISABLED_' prefix on a test case
// name or test name, we use:
//
//   'ROOT_' : Disable test if current user isn't root.
//   'CGROUPS_' : Disable test if cgroups support isn't present.
//   'NOHIERARCHY_' : Disable test if there is already a cgroups
//       hierarchy mounted.
//
// These flags can be composed in any order, but must come after
// 'DISABLED_'. In addition, we disable tests that attempt to use the
// CgroupsIsolator type parameter if the current user is not root or
// cgroups is not supported.
// TODO(benh): Provide a generic way to enable/disable tests by
// registering "filter" functions.
static bool enable(const ::testing::TestInfo& test)
{
  // First check the test case name and test name.
  list<string> names;
  names.push_back(test.test_case_name());
  names.push_back(test.name());

  foreach (const string& name, names) {
    if (strings::contains(name, "ROOT_") && os::user() != "root") {
      return false;
    }

    if (strings::contains(name, "CGROUPS_") && !os::exists("/proc/cgroups")) {
      return false;
    }

#ifdef __linux__
    if (strings::contains(name, "NOHIERARCHY_")) {
      Try<std::set<std::string> > hierarchies = cgroups::hierarchies();
      CHECK(hierarchies.isSome());
      if (!hierarchies.get().empty()) {
        std::cerr
          << "-------------------------------------------------------------\n"
          << "We cannot run any cgroups tests that require mounting\n"
          << "hierarchies because you have the following hierarchies mounted:\n"
          << strings::trim(stringify(hierarchies.get()), " {},") << "\n"
          << "You can either unmount those hierarchies, or disable\n"
          << "this test case (i.e., --gtest_filter=-CgroupsNoHierarchyTest.*).\n"
          << "-------------------------------------------------------------"
          << std::endl;

        return false;
      }
    }
#endif
  }

  // Now check the type parameter.
  if (test.type_param() != NULL) {
    const string& type = test.type_param();
    if (strings::contains(type, "CgroupsIsolator") &&
        (os::user() != "root" || !os::exists("/proc/cgroups"))) {
      return false;
    }
  }

  return true;
}


// We use the constructor to setup specific tests by updating the
// gtest filter. We do this so that we can selectively run tests that
// require root or specific OS support (e.g., cgroups). Note that this
// should not effect any other filters that have been put in place
// either on the command line or via an environment variable.
// N.B. This MUST be done _before_ invoking RUN_ALL_TESTS.
Environment::Environment()
{
  // First we split the current filter into enabled and disabled tests
  // (which are separated by a '-').
  const string& filter = ::testing::GTEST_FLAG(filter);
  string enabled;
  string disabled;

  size_t dash = filter.find('-');
  if (dash != string::npos) {
    enabled = filter.substr(0, dash);
    disabled = filter.substr(dash + 1);
  } else {
    enabled = filter;
  }

  // Use universal filter if not specified.
  if (enabled.empty()) {
    enabled = "*";
  }

  // Ensure disabled tests end with ":" separator before we add more.
  if (!disabled.empty() && !strings::endsWith(disabled, ":")) {
    disabled += ":";
  }

  // Construct the filter string to handle system or platform specific tests.
  ::testing::UnitTest* unitTest = ::testing::UnitTest::GetInstance();
  for (int i = 0; i < unitTest->total_test_case_count(); i++) {
    const ::testing::TestCase* testCase = unitTest->GetTestCase(i);
    for (int j = 0; j < testCase->total_test_count(); j++) {
      const ::testing::TestInfo* testInfo = testCase->GetTestInfo(j);

      if (!enable(*testCase->GetTestInfo(j))) {
        // Append 'TestCase.TestName:'.
        disabled.append(testInfo->test_case_name());
        disabled.append(".");
        disabled.append(testInfo->name());
        disabled.append(":");
      }
    }
  }

  // Now update the gtest flag.
  ::testing::GTEST_FLAG(filter) = enabled + "-" + disabled;

  // Add our test event listeners.
  ::testing::TestEventListeners& listeners =
    ::testing::UnitTest::GetInstance()->listeners();

  listeners.Append(process::FilterTestEventListener::instance());
  listeners.Append(process::ClockTestEventListener::instance());
}


void Environment::SetUp()
{
  // Clear any MESOS_ environment variables so they don't affect our tests.
  Configurator::clearMesosEnvironmentVars();
}


void Environment::TearDown() {}

} // namespace tests {
} // namespace internal {
} // namespace mesos {