// Copyright 2026 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 "tracing/thread_context.h"

#include <thread>  // NOLINT(build/c++11)

#include "gtest/gtest.h"
#include "tracing/noop_tracing.h"

namespace credentio_tracing {
namespace {

TEST(ThreadContextTest, InitialStateIsNull) {
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);
}

TEST(ThreadContextTest, SetAndGetCurrentSpan) {
  NoopSpan span1;
  NoopSpan span2;

  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);

  ThreadContext::SetCurrentSpan(&span1);
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), &span1);

  ThreadContext::SetCurrentSpan(&span2);
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), &span2);

  ThreadContext::SetCurrentSpan(nullptr);
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);
}

TEST(ThreadContextTest, ThreadLocalIsolation) {
  NoopSpan main_span;

  ThreadContext::SetCurrentSpan(&main_span);

  std::thread worker([&]() {
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);

    NoopSpan worker_span;

    ThreadContext::SetCurrentSpan(&worker_span);

    EXPECT_EQ(ThreadContext::GetCurrentSpan(), &worker_span);
  });

  worker.join();

  EXPECT_EQ(ThreadContext::GetCurrentSpan(), &main_span);

  ThreadContext::SetCurrentSpan(nullptr);
}

TEST(ThreadContextTest, SetNullWhenAlreadyNull) {
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);

  ThreadContext::SetCurrentSpan(nullptr);

  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);
}

}  // namespace
}  // namespace credentio_tracing