// 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/test_tracing.h"

#include <cstdint>
#include <memory>
#include <optional>
#include <string>
#include <thread>  // NOLINT(build/c++11)
#include <vector>

#include "absl/status/status.h"
#include "absl/strings/string_view.h"
#include "absl/time/clock.h"
#include "absl/time/time.h"
#include "gtest/gtest.h"
#include "tracing/scoped_span.h"
#include "tracing/span.h"
#include "tracing/tracer.h"
#include "tracing/tracer_factory.h"

namespace credentio_tracing {
namespace {

TEST(TestRecordedSpanTest, GetAttributeAndGetAttributeAs) {
  TestRecordedSpan span;
  span.SetAttribute("string_key", std::string("val"));
  span.SetAttribute("int_key", int64_t{42});
  span.SetAttribute("double_key", 3.14);
  span.SetAttribute("bool_key", true);

  EXPECT_NE(span.GetAttribute("string_key"), std::nullopt);
  EXPECT_EQ(span.GetAttribute("nonexistent"), std::nullopt);

  EXPECT_EQ(span.GetAttributeAs<std::string>("string_key"), "val");
  EXPECT_EQ(span.GetAttributeAs<int64_t>("int_key"), 42);
  EXPECT_EQ(span.GetAttributeAs<double>("double_key"), 3.14);
  EXPECT_EQ(span.GetAttributeAs<bool>("bool_key"), true);

  // Type mismatch returns std::nullopt
  EXPECT_EQ(span.GetAttributeAs<int64_t>("string_key"), std::nullopt);
  EXPECT_EQ(span.GetAttributeAs<std::string>("nonexistent"), std::nullopt);
}

TEST(TestSpanTest, RecordsAttributesEventsStatusAndEnded) {
  auto recorded = std::make_shared<TestRecordedSpan>();
  TestSpan span(recorded);

  span.SetAttribute("attr1", std::string("val1"));
  span.SetAttribute("attr2", int64_t{100});
  // Overwrite existing attribute
  span.SetAttribute("attr1", std::string("new_val1"));

  span.AddEvent("event1");
  span.AddEvent("event2");

  span.SetStatus(absl::InvalidArgumentError("bad input"));
  span.End();

  EXPECT_TRUE(recorded->ended());
  EXPECT_EQ(recorded->status(), absl::InvalidArgumentError("bad input"));

  ASSERT_EQ(recorded->events().size(), 2);
  EXPECT_EQ(recorded->events()[0].name, "event1");
  EXPECT_EQ(recorded->events()[1].name, "event2");

  EXPECT_EQ(recorded->GetAttributeAs<std::string>("attr1"), "new_val1");
  EXPECT_EQ(recorded->GetAttributeAs<int64_t>("attr2"), 100);
}

TEST(TestTracerTest, StartSpanRecordsOptionsAndParent) {
  TestTracer tracer;
  TestSpan parent_span(std::make_shared<TestRecordedSpan>());

  StartSpanOptions options;
  options.parent = &parent_span;
  options.attributes.push_back({"init_key", std::string("init_val")});

  std::unique_ptr<Span> span = tracer.StartSpan("child_span", options);
  ASSERT_NE(span, nullptr);

  auto spans = tracer.GetSpans();
  ASSERT_EQ(spans.size(), 1);
  EXPECT_EQ(spans[0]->name_, "child_span");
  EXPECT_EQ(spans[0]->parent_, &parent_span);
  EXPECT_EQ(spans[0]->GetAttributeAs<std::string>("init_key"), "init_val");

  span->End();
  EXPECT_TRUE(spans[0]->ended());
}

TEST(TestTracerTest, QueryingSpansByName) {
  TestTracer tracer;
  tracer.StartSpan("op_a", {});
  tracer.StartSpan("op_b", {});
  tracer.StartSpan("op_a", {});

  EXPECT_EQ(tracer.GetSpans().size(), 3);

  auto span_a = tracer.GetSpan("op_a");
  ASSERT_NE(span_a, nullptr);
  EXPECT_EQ(span_a->name_, "op_a");

  EXPECT_EQ(tracer.GetSpan("nonexistent"), nullptr);

  auto spans_a = tracer.GetSpansByName("op_a");
  EXPECT_EQ(spans_a.size(), 2);

  tracer.Clear();
  EXPECT_TRUE(tracer.GetSpans().empty());
}

TEST(TestTracerTest, IntegrationWithScopedSpan) {
  TestTracer tracer;
  {
    ScopedSpan scoped_span(tracer.StartSpan("scoped_op", {}));
    ASSERT_NE(scoped_span.get(), nullptr);
    scoped_span->SetAttribute("key", std::string("value"));
    scoped_span.SetStatus(absl::OkStatus());
  }

  auto spans = tracer.GetSpans();
  ASSERT_EQ(spans.size(), 1);
  EXPECT_EQ(spans[0]->name_, "scoped_op");
  EXPECT_TRUE(spans[0]->ended());
  EXPECT_EQ(spans[0]->GetAttributeAs<std::string>("key"), "value");
}

TEST(TestTracerFactoryTest, GetTracerAndRegisterGlobalFactory) {
  auto factory = std::make_shared<TestTracerFactory>();
  TestTracerFactory::Register(factory);

  auto current_factory = TracerFactory::GetGlobalFactory();
  EXPECT_EQ(current_factory, factory);

  auto tracer1 = factory->GetTracer("component_1");
  auto tracer2 = factory->GetTracer("component_1");
  EXPECT_EQ(tracer1, tracer2);

  tracer1->StartSpan("span_1", {});

  auto test_tracer = factory->GetTestTracer("component_1");
  ASSERT_NE(test_tracer, nullptr);
  EXPECT_EQ(test_tracer->GetSpans().size(), 1);

  EXPECT_EQ(factory->GetAllSpans().size(), 1);

  factory->Clear();
  EXPECT_TRUE(factory->GetAllSpans().empty());

  TestTracerFactory::Unregister();
  EXPECT_NE(TracerFactory::GetGlobalFactory(), factory);
}

TEST(TestTracerFactoryTest, RegisterStaticHelper) {
  auto factory = TestTracerFactory::Register();
  EXPECT_EQ(TracerFactory::GetGlobalFactory(), factory);

  auto tracer = TracerFactory::GetGlobalFactory()->GetTracer("test_comp");
  tracer->StartSpan("span", {});
  EXPECT_EQ(factory->GetAllSpans().size(), 1);

  TestTracerFactory::Unregister();
  EXPECT_NE(TracerFactory::GetGlobalFactory(), factory);
}

TEST(TestTracerFactoryTest, RegisterThisMemberMethod) {
  auto factory = std::make_shared<TestTracerFactory>();
  factory->RegisterThis();
  EXPECT_EQ(TracerFactory::GetGlobalFactory(), factory);

  factory->Unregister();
  EXPECT_NE(TracerFactory::GetGlobalFactory(), factory);
}

TEST(TestTracerTest, MultithreadedSpanCreation) {
  TestTracer tracer;
  constexpr int kNumThreads = 4;
  constexpr int kSpansPerThread = 50;

  std::vector<std::thread> threads;
  threads.reserve(kNumThreads);

  for (int t = 0; t < kNumThreads; ++t) {
    threads.emplace_back([&tracer, t]() {
      for (int i = 0; i < kSpansPerThread; ++i) {
        auto span = tracer.StartSpan("mt_span", {});
        span->SetAttribute("thread", int64_t{t});
        span->SetAttribute("iter", int64_t{i});
        span->AddEvent("tick");
        span->SetStatus(absl::OkStatus());
        span->End();
      }
    });
  }

  for (auto& thread : threads) {
    thread.join();
  }

  EXPECT_EQ(tracer.GetSpans().size(), kNumThreads * kSpansPerThread);
}

TEST(TestTracerTest, ImplicitParentLinkingWithScopedSpan) {
  TestTracer tracer;
  {
    ScopedSpan outer_span(tracer.StartSpan("outer", {}));
    {
      ScopedSpan inner_span(tracer.StartSpan("inner", {}));
    }
  }

  auto spans = tracer.GetSpans();
  ASSERT_EQ(spans.size(), 2);

  EXPECT_EQ(spans[0]->name_, "outer");
  EXPECT_EQ(spans[1]->name_, "inner");

  EXPECT_FALSE(spans[0]->trace_id_.empty());
  EXPECT_EQ(spans[0]->trace_id_, spans[1]->trace_id_);
  EXPECT_EQ(spans[1]->parent_span_id_, spans[0]->span_id_);
}

TEST(TestRecordedEventTest, EqualityOperator) {
  TestRecordedEvent event1{"event_name"};
  TestRecordedEvent event2{"event_name"};
  TestRecordedEvent event3{"different_name"};

  EXPECT_EQ(event1, event2);
  EXPECT_NE(event1.name, event3.name);
}

TEST(TestRecordedSpanTest, EndTimeAndAttributesAccessors) {
  TestRecordedSpan span;
  EXPECT_FALSE(span.ended());

  absl::Time start = absl::Now();
  span.SetAttribute("key1", std::string("val1"));
  span.SetAttribute("key2", int64_t{50});
  span.End();

  EXPECT_TRUE(span.ended());
  EXPECT_GE(span.end_time(), start);

  auto attrs = span.attributes();
  ASSERT_EQ(attrs.size(), 2);
  EXPECT_EQ(attrs[0].first, "key1");
  EXPECT_EQ(std::get<std::string>(attrs[0].second), "val1");
  EXPECT_EQ(attrs[1].first, "key2");
  EXPECT_EQ(std::get<int64_t>(attrs[1].second), 50);
}

TEST(TestSpanTest, NullTestRecordedSpanHandledSafely) {
  TestSpan span(nullptr);
  EXPECT_EQ(span.recorded_span(), nullptr);

  // Calling methods on TestSpan with null recorded_span should not crash
  span.SetAttribute("key", std::string("val"));
  span.AddEvent("event");
  span.SetStatus(absl::OkStatus());
  span.End();
}

TEST(TestTracerTest, NonTestSpanParentHandling) {
  TestTracer tracer;
  class NonTestSpan : public Span {
   public:
    void SetAttribute(absl::string_view, AttributeValue) override {}
    void AddEvent(absl::string_view) override {}
    void SetStatus(const absl::Status&) override {}
    void End() override {}
  };

  NonTestSpan custom_parent;
  StartSpanOptions options;
  options.parent = &custom_parent;

  auto span = tracer.StartSpan("span_with_custom_parent", options);
  ASSERT_NE(span, nullptr);

  auto spans = tracer.GetSpans();
  ASSERT_EQ(spans.size(), 1);
  EXPECT_EQ(spans[0]->parent_, &custom_parent);
  EXPECT_TRUE(spans[0]->parent_span_id_.empty());
  EXPECT_FALSE(spans[0]->trace_id_.empty());
}

TEST(TestTracerTest, ParentTestSpanWithoutTestRecordedSpanStartsNewTrace) {
  TestTracer tracer;
  TestSpan parent_without_recording(nullptr);

  StartSpanOptions options;
  options.parent = &parent_without_recording;
  tracer.StartSpan("orphan_op", options);

  auto spans = tracer.GetSpans();
  ASSERT_EQ(spans.size(), 1);
  EXPECT_EQ(spans[0]->parent_, &parent_without_recording);
  EXPECT_TRUE(spans[0]->parent_span_id_.empty());
  EXPECT_FALSE(spans[0]->trace_id_.empty());
}

TEST(TestTracerFactoryTest, GetTestTracerReturnsNullForNonexistent) {
  TestTracerFactory factory;
  EXPECT_EQ(factory.GetTestTracer("nonexistent_tracer"), nullptr);
}

}  // namespace
}  // namespace credentio_tracing