// 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/scoped_span.h"

#include <memory>
#include <optional>
#include <string>
#include <utility>

#include "absl/status/status.h"
#include "absl/strings/string_view.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "tracing/span.h"
#include "tracing/thread_context.h"

namespace credentio_tracing {
namespace {

using ::testing::InSequence;
using ::testing::StrictMock;

class MockSpan : public Span {
 public:
  MOCK_METHOD(void, SetAttribute, (absl::string_view key, AttributeValue value),
              (override));
  MOCK_METHOD(void, AddEvent, (absl::string_view name), (override));
  MOCK_METHOD(void, SetStatus, (const absl::Status& status), (override));
  MOCK_METHOD(void, End, (), (override));
};

TEST(ScopedSpanTest, CallsEndOnDestruction) {
  auto mock_span = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span = mock_span.get();

  EXPECT_CALL(*raw_span, End());
  {
    ScopedSpan scoped_span(std::move(mock_span));
    EXPECT_EQ(scoped_span.get(), raw_span);
    EXPECT_EQ(scoped_span.operator->(), raw_span);
  }
}

TEST(ScopedSpanTest, ForwardsSetStatus) {
  auto mock_span = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span = mock_span.get();

  absl::Status test_status = absl::InternalError("test error");
  EXPECT_CALL(*raw_span, SetStatus(test_status));
  EXPECT_CALL(*raw_span, End());

  ScopedSpan scoped_span(std::move(mock_span));
  scoped_span.SetStatus(test_status);
}

TEST(ScopedSpanTest, MoveConstructorTransfersOwnership) {
  auto mock_span = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span = mock_span.get();

  EXPECT_CALL(*raw_span, End());
  {
    ScopedSpan scoped1(std::move(mock_span));
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span);

    ScopedSpan scoped2(std::move(scoped1));

    EXPECT_EQ(scoped1.get(), nullptr);  // NOLINT(bugprone-use-after-move)
    EXPECT_EQ(scoped2.get(), raw_span);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span);
  }
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);
}

TEST(ScopedSpanTest, MoveAssignmentTransfersOwnership) {
  auto mock_span1 = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span1 = mock_span1.get();

  auto mock_span2 = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span2 = mock_span2.get();

  EXPECT_CALL(*raw_span1, End());
  EXPECT_CALL(*raw_span2, End());

  {
    ScopedSpan scoped1(std::move(mock_span1));
    ScopedSpan scoped2(std::move(mock_span2));
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span2);

    scoped2 = std::move(scoped1);
    EXPECT_EQ(scoped1.get(), nullptr);  // NOLINT(bugprone-use-after-move)
    EXPECT_EQ(scoped2.get(), raw_span1);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span1);
  }
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);
}

TEST(ScopedSpanTest, MoveAssignmentOrderAndSequence) {
  auto mock_span1 = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span1 = mock_span1.get();

  auto mock_span2 = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span2 = mock_span2.get();

  InSequence seq;
  EXPECT_CALL(*raw_span2, End());
  EXPECT_CALL(*raw_span1, End());

  {
    ScopedSpan scoped1(std::move(mock_span1));
    ScopedSpan scoped2(std::move(mock_span2));

    scoped2 = std::move(scoped1);
  }
}

TEST(ScopedSpanTest, MoveAssignmentToNullSpan) {
  auto mock_span = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span = mock_span.get();

  EXPECT_CALL(*raw_span, End());

  {
    ScopedSpan scoped1(std::move(mock_span));
    ScopedSpan scoped2(nullptr);

    scoped2 = std::move(scoped1);
    EXPECT_EQ(scoped1.get(), nullptr);  // NOLINT(bugprone-use-after-move)
    EXPECT_EQ(scoped2.get(), raw_span);
  }
}

TEST(ScopedSpanTest, SelfMoveAssignment) {
  auto mock_span = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span = mock_span.get();

  EXPECT_CALL(*raw_span, End()).Times(1);

  {
    ScopedSpan scoped(std::move(mock_span));
    ScopedSpan& scoped_ref = scoped;
    scoped = std::move(scoped_ref);
    EXPECT_EQ(scoped.get(), raw_span);
  }
}

TEST(ScopedSpanTest, NullPointerSafe) {
  ScopedSpan null_scoped(nullptr);
  EXPECT_EQ(null_scoped.get(), nullptr);

  // SetStatus on null span should not crash
  null_scoped.SetStatus(absl::OkStatus());
  // Destruction of null span should not crash
}

TEST(ScopedSpanTest, NestedSpanHierarchyRestoresParent) {
  auto mock_outer = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_outer = mock_outer.get();

  auto mock_inner = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_inner = mock_inner.get();

  EXPECT_CALL(*raw_inner, End());
  EXPECT_CALL(*raw_outer, End());

  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);
  {
    ScopedSpan outer(std::move(mock_outer));
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_outer);

    {
      ScopedSpan inner(std::move(mock_inner));
      EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_inner);
    }

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

TEST(ScopedSpanTest, MovedFromScopedSpanDestructionDoesNotRestoreSpan) {
  MockSpan outer_span;
  ThreadContext::SetCurrentSpan(&outer_span);

  auto mock_span = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span = mock_span.get();
  EXPECT_CALL(*raw_span, End());

  {
    std::optional<ScopedSpan> scoped2;
    {
      ScopedSpan scoped1(std::move(mock_span));
      EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span);

      scoped2.emplace(std::move(scoped1));
      EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span);
      // scoped1 is destroyed here at end of inner scope.
    }
    // Destruction of moved-from scoped1 must not unbind raw_span or restore
    // outer_span.
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span);
  }

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

TEST(ScopedSpanTest, MoveAssignmentIntoInactiveScopedSpanActivatesTarget) {
  auto mock_span = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span = mock_span.get();
  EXPECT_CALL(*raw_span, End());

  ScopedSpan target(nullptr);
  {
    ScopedSpan sink(std::move(target));
  }
  // target is now inactive.
  EXPECT_EQ(target.get(), nullptr);  // NOLINT(bugprone-use-after-move)
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);

  {
    ScopedSpan source(std::move(mock_span));
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span);

    // Assigning active source into inactive target must activate target.
    target = std::move(source);
    EXPECT_EQ(target.get(), raw_span);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span);
  }
  // source went out of scope (inactive).
  // target remains active in outer scope with raw_span.
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span);
}

TEST(ScopedSpanTest, MoveAssignmentFromInactiveScopedSpanDeactivatesTarget) {
  MockSpan outer_span;
  ThreadContext::SetCurrentSpan(&outer_span);

  auto mock_span = std::make_unique<StrictMock<MockSpan>>();
  MockSpan* raw_span = mock_span.get();
  EXPECT_CALL(*raw_span, End());

  {
    ScopedSpan inactive_scoped(nullptr);
    {
      ScopedSpan sink(std::move(inactive_scoped));
    }
    // inactive_scoped is now inactive.
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), &outer_span);

    ScopedSpan active_scoped(std::move(mock_span));
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), raw_span);

    // Assigning inactive into active must end active_scoped's span,
    // restore outer_span, and deactivate active_scoped.
    active_scoped =
        std::move(inactive_scoped);  // NOLINT(bugprone-use-after-move)
    EXPECT_EQ(active_scoped.get(), nullptr);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), &outer_span);
  }

  // Destruction of deactivated active_scoped must not change ThreadContext.
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), &outer_span);
  ThreadContext::SetCurrentSpan(nullptr);
}

TEST(ScopedSpanTest, RawSpanConstructorBindsAndUnbindsWithoutCallingEnd) {
  StrictMock<MockSpan> raw_span;
  // No End() call expected for non-owning ScopedSpan(Span*).

  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);
  {
    ScopedSpan scoped(&raw_span);
    EXPECT_EQ(scoped.get(), &raw_span);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), &raw_span);
  }
  EXPECT_EQ(ThreadContext::GetCurrentSpan(), nullptr);
}

TEST(ScopedSpanTest, RawSpanConstructorWithNullAndActiveContext) {
  StrictMock<MockSpan> outer_span;
  ThreadContext::SetCurrentSpan(&outer_span);

  {
    ScopedSpan null_scoped(static_cast<Span*>(nullptr));
    EXPECT_EQ(null_scoped.get(), nullptr);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), &outer_span);
  }

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

TEST(ScopedSpanTest, UniquePtrConstructorWithNullAndActiveContext) {
  StrictMock<MockSpan> outer_span;
  ThreadContext::SetCurrentSpan(&outer_span);

  {
    ScopedSpan null_scoped(std::unique_ptr<Span>(nullptr));
    EXPECT_EQ(null_scoped.get(), nullptr);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), &outer_span);
  }

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

TEST(ScopedSpanTest, MoveConstructorWithRawSpan) {
  StrictMock<MockSpan> raw_span;

  {
    ScopedSpan scoped1(&raw_span);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), &raw_span);

    ScopedSpan scoped2(std::move(scoped1));
    EXPECT_EQ(scoped1.get(), nullptr);  // NOLINT(bugprone-use-after-move)
    EXPECT_EQ(scoped2.get(), &raw_span);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), &raw_span);
  }

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

TEST(ScopedSpanTest, MoveAssignmentWithRawSpan) {
  StrictMock<MockSpan> raw_span1;
  StrictMock<MockSpan> raw_span2;

  {
    ScopedSpan scoped1(&raw_span1);
    ScopedSpan scoped2(&raw_span2);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), &raw_span2);

    scoped2 = std::move(scoped1);
    EXPECT_EQ(scoped1.get(), nullptr);  // NOLINT(bugprone-use-after-move)
    EXPECT_EQ(scoped2.get(), &raw_span1);
    EXPECT_EQ(ThreadContext::GetCurrentSpan(), &raw_span1);
  }

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

}  // namespace
}  // namespace credentio_tracing