// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "lib/gtest/test_loop_fixture.h"

#include <lib/async/cpp/task.h>
#include <lib/async/default.h>

#include <cstdlib>

#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "src/lib/fxl/command_line.h"
#include "src/lib/fxl/logging.h"
#include "src/lib/fxl/test/test_settings.h"

namespace gtest {
namespace {

using TestLoopFixtureTest = TestLoopFixture;

TEST_F(TestLoopFixtureTest, DefaultDispatcherIsSet) {
  EXPECT_EQ(async_get_default_dispatcher(), dispatcher());
}

TEST_F(TestLoopFixtureTest, TimeIsAdvanced) {
  EXPECT_EQ(Now(), zx::time(0));

  RunLoopUntil(zx::time(0) + zx::sec(15));
  EXPECT_EQ(Now(), zx::time(0) + zx::sec(15));

  RunLoopFor(zx::sec(5));
  EXPECT_EQ(Now(), zx::time(0) + zx::sec(20));

  // RunLoopUntilIdle() should not advance the time.
  RunLoopUntilIdle();
  EXPECT_EQ(Now(), zx::time(0) + zx::sec(20));
}

TEST_F(TestLoopFixtureTest, WorkBeingDoneIsReported) {
  EXPECT_FALSE(RunLoopUntilIdle());
  EXPECT_FALSE(RunLoopUntil(zx::time(0) + zx::sec(5)));
  EXPECT_FALSE(RunLoopFor(zx::sec(5)));

  async::PostTask(dispatcher(), [] {});
  EXPECT_TRUE(RunLoopUntilIdle());

  async::PostTaskForTime(
      dispatcher(), [] {}, zx::time(0) + zx::sec(15));
  EXPECT_TRUE(RunLoopUntil(zx::time(0) + zx::sec(15)));

  async::PostDelayedTask(
      dispatcher(), [] {}, zx::sec(5));
  EXPECT_TRUE(RunLoopFor(zx::sec(5)));
}

TEST_F(TestLoopFixtureTest, LoopCanQuitAndReset) {
  async::PostDelayedTask(
      dispatcher(), [] {}, zx::sec(1));
  QuitLoop();

  // Loop has quit, so time does not advance and no work is done.
  EXPECT_FALSE(RunLoopFor(zx::sec(1)));
  EXPECT_EQ(Now(), zx::time(0));

  // Loop has reset, so time does advance and work is done.
  EXPECT_TRUE(RunLoopFor(zx::sec(1)));
  EXPECT_EQ(Now(), zx::time(0) + zx::sec(1));

  // Quit task is posted, followed by another task. The quit task is
  // dispatched and work is reported.
  async::PostTask(dispatcher(), QuitLoopClosure());
  async::PostTask(dispatcher(), [] {});
  EXPECT_TRUE(RunLoopUntilIdle());

  // Loop was quit, but it is now reset  the remaining task will be dispatched
  // on the next run.
  EXPECT_TRUE(RunLoopUntilIdle());
}

TEST_F(TestLoopFixtureTest, LoopRunsRepeatedly) {
  for (int i = 0; i <= 60; ++i) {
    async::PostDelayedTask(
        dispatcher(), [] {}, zx::sec(i));
  }
  // Run the loop repeatedly at ten second intervals until the delayed tasks
  // are all dispatched.
  RunLoopRepeatedlyFor(zx::sec(10));
  EXPECT_GE(Now(), zx::time(0) + zx::min(1));

  // There should be nothing further to dispatch.
  EXPECT_FALSE(RunLoopUntilIdle());
}

// Test that --test_loop_seed correctly propagates the random seed to the test
// loop. This must be done before the test fixture is instanciated, hence the
// use of |SetUpTestSuite| to set the flag (and restore the environment variable
// to its original value once done).
class RandomSeedTest : public TestLoopFixture {
 public:
  static void SetUpTestSuite() {
    random_seed_ = getenv("TEST_LOOP_RANDOM_SEED");
    FXL_CHECK(fxl::SetTestSettings(
        fxl::CommandLineFromInitializerList({"argv0", "--test_loop_seed=1234"})));
  }

  static void TearDownTestSuite() {
    if (random_seed_) {
      setenv("TEST_LOOP_RANDOM_SEED", random_seed_, /*overwrite=*/true);
      random_seed_ = nullptr;
    } else {
      unsetenv("TEST_LOOP_RANDOM_SEED");
    }
  }

 private:
  static char *random_seed_;
};

char *RandomSeedTest::random_seed_;

TEST_F(RandomSeedTest, RandomSeedFromFlag) { EXPECT_EQ(test_loop().initial_state(), 1234u); }

}  // namespace
}  // namespace gtest