// Copyright 2020 Google LLC
//
// 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
//
//     https://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 "platform/impl/windows/executor.h"

#include <utility>

#include "gtest/gtest.h"

TEST(ExecutorTests, SingleThreadedExecutorSucceeds) {
  // Arrange
  std::string expected("runnable 1");

  std::unique_ptr<location::nearby::windows::Executor> executor =
      std::make_unique<location::nearby::windows::Executor>();
  std::string output = std::string();
  // Container to note threads that ran
  std::unique_ptr<std::vector<DWORD>> threadIds =
      std::make_unique<std::vector<DWORD>>();

  threadIds->push_back(GetCurrentThreadId());

  // Act
  executor->Execute([&output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output.append("runnable 1");
  });

  Sleep(1);  //  Yield the thread

  //  Assert
  //  We should've run 1 time on the main thread, and 5 times on the
  //  workerThread
  ASSERT_EQ(threadIds->size(), 2);
  //  We should still be on the main thread
  ASSERT_EQ(GetCurrentThreadId(), threadIds->at(0));
  //  We should've run all runnables on the worker thread
  ASSERT_EQ(output, expected);

  executor->Shutdown();
}

TEST(ExecutorTests, SingleThreadedExecutorAfterShutdownFails) {
  // Arrange
  std::string expected("");

  std::unique_ptr<location::nearby::windows::Executor> executor =
      std::make_unique<location::nearby::windows::Executor>();
  std::unique_ptr<std::string> output = std::make_unique<std::string>();
  // Container to note threads that ran
  std::unique_ptr<std::vector<DWORD>> threadIds =
      std::make_unique<std::vector<DWORD>>();

  threadIds->push_back(GetCurrentThreadId());
  executor->Shutdown();

  // Act
  executor->Execute([&output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output->append("runnable 1");
  });

  Sleep(1);  //  Yield the thread

  //  Assert
  //  We should've run 1 time on the main thread, and 5 times on the
  //  workerThread
  ASSERT_EQ(threadIds->size(), 1);
  //  We should still be on the main thread
  ASSERT_EQ(GetCurrentThreadId(), threadIds->at(0));
  //  We should've run all runnables on the worker thread
  ASSERT_EQ(*output.get(), expected);
}

TEST(ExecutorTests, SingleThreadedExecutorExecuteNullSucceeds) {
  // Arrange
  std::string expected("runnable 1");

  std::unique_ptr<location::nearby::windows::Executor> executor =
      std::make_unique<location::nearby::windows::Executor>();
  std::string output = std::string();
  // Container to note threads that ran
  std::unique_ptr<std::vector<DWORD>> threadIds =
      std::make_unique<std::vector<DWORD>>();

  threadIds->push_back(GetCurrentThreadId());

  // Act
  executor->Execute(nullptr);
  executor->Execute([&output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output.append("runnable 1");
  });
  executor->Execute(nullptr);

  Sleep(1);  //  Yield the thread

  //  Assert
  //  We should've run 1 time on the main thread, and 5 times on the
  //  workerThread
  ASSERT_EQ(threadIds->size(), 2);
  //  We should still be on the main thread
  ASSERT_EQ(GetCurrentThreadId(), threadIds->at(0));
  //  We should've run all runnables on the worker thread
  ASSERT_EQ(output, expected);

  executor->Shutdown();
}

TEST(ExecutorTests, SingleThreadedExecutorMultipleTasksSucceeds) {
  // Arrange
  std::string expected(
      "runnable 1, runnable 2, runnable 3, runnable 4, runnable 5");

  std::unique_ptr<location::nearby::windows::Executor> executor =
      std::make_unique<location::nearby::windows::Executor>();
  std::string output = std::string();
  // Container to note threads that ran
  std::unique_ptr<std::vector<DWORD>> threadIds =
      std::make_unique<std::vector<DWORD>>();

  threadIds->push_back(GetCurrentThreadId());

  // Act
  executor->Execute([&output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output.append("runnable 1, ");
  });
  executor->Execute([&output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output.append("runnable 2, ");
  });
  executor->Execute([&output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output.append("runnable 3, ");
  });
  executor->Execute([&output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output.append("runnable 4, ");
  });
  executor->Execute([&output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output.append("runnable 5");
  });

  Sleep(1);  //  Yield the thread

  //  Assert
  //  We should've run 1 time on the main thread, and 5 times on the
  //  workerThread
  ASSERT_EQ(threadIds->size(), 6);
  //  We should still be on the main thread
  ASSERT_EQ(GetCurrentThreadId(), threadIds->at(0));
  //  We should've run all runnables on the worker thread
  auto workerThreadId = threadIds->at(1);
  for (int index = 1; index < threadIds->size(); index++) {
    ASSERT_EQ(threadIds->at(index), workerThreadId);
  }

  //  We should of run them in the order submitted
  ASSERT_EQ(output, expected);

  executor->Shutdown();
}

TEST(ExecutorTests, MultiThreadedExecutorSingleTaskSucceeds) {
  //  Arrange
  std::string expected("runnable 1");

  std::unique_ptr<location::nearby::windows::Executor> executor =
      std::make_unique<location::nearby::windows::Executor>(2);

  //  Container to note threads that ran
  std::unique_ptr<std::vector<DWORD>> threadIds =
      std::make_unique<std::vector<DWORD>>();

  std::shared_ptr<std::string> output = std::make_shared<std::string>();

  threadIds->push_back(GetCurrentThreadId());

  //  Act
  executor->Execute([output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output->append("runnable 1");
  });

  Sleep(1);  //  Yield the processor

  //  Assert
  //  We should've run 1 time on the main thread, and 5 times on the
  //  workerThread
  ASSERT_EQ(threadIds->size(), 2);
  //  We should still be on the main thread
  ASSERT_EQ(GetCurrentThreadId(), threadIds->at(0));
  //  We should've run the task
  ASSERT_EQ(*output.get(), expected);

  executor->Shutdown();
}

TEST(ExecutorTests, MultiThreadedExecutorMultipleTasksSucceeds) {
  //  Arrange
  std::unique_ptr<location::nearby::windows::Executor> executor =
      std::make_unique<location::nearby::windows::Executor>(2);

  //  Container to note threads that ran
  std::unique_ptr<std::vector<DWORD>> threadIds =
      std::make_unique<std::vector<DWORD>>();

  std::shared_ptr<std::string> output = std::make_shared<std::string>();

  threadIds->push_back(GetCurrentThreadId());

  //  Act
  executor->Execute([output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output->append("runnable 1, ");
  });
  executor->Execute([output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output->append("runnable 2, ");
  });
  executor->Execute([output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output->append("runnable 3, ");
  });
  executor->Execute([output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output->append("runnable 4, ");
  });
  executor->Execute([output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output->append("runnable 5");
  });

  Sleep(1);  //  Yield the processor

  //  Assert
  //  We should've run 1 time on the main thread, and 5 times on the
  //  workerThread
  ASSERT_EQ(threadIds->size(), 6);
  //  We should still be on the main thread
  ASSERT_EQ(GetCurrentThreadId(), threadIds->at(0));

  executor->Shutdown();
}

TEST(ExecutorTests, MultiThreadedExecutorSingleTaskAfterShutdownFails) {
  //  Arrange
  std::string expected("");

  std::unique_ptr<location::nearby::windows::Executor> executor =
      std::make_unique<location::nearby::windows::Executor>(2);

  //  Container to note threads that ran
  std::unique_ptr<std::vector<DWORD>> threadIds =
      std::make_unique<std::vector<DWORD>>();

  std::shared_ptr<std::string> output = std::make_shared<std::string>();

  threadIds->push_back(GetCurrentThreadId());

  executor->Shutdown();

  //  Act
  executor->Execute([output, &threadIds]() {
    threadIds->push_back(GetCurrentThreadId());
    output->append("runnable 1");
  });

  Sleep(1);  //  Yield the processor

  //  Assert
  //  We should've run 1 time on the main thread, and 5 times on the
  //  workerThread
  ASSERT_EQ(threadIds->size(), 1);
  //  We should still be on the main thread
  ASSERT_EQ(GetCurrentThreadId(), threadIds->at(0));
  //  We should've run the task
  ASSERT_EQ(*output.get(), expected);
}

TEST(ExecutorTests, MultiThreadedExecutorNegativeThreadsThrows) {
  //  Arrange
  //  Act
  //  Assert
  EXPECT_THROW(
      {
        try {
          auto result =
              std::make_unique<location::nearby::windows::Executor>(-1);
        } catch (const std::invalid_argument::exception& e) {
          // and this tests that it has the correct message
          EXPECT_STREQ("max_concurrency", e.what());
          throw;
        }
      },
      std::invalid_argument);
}