// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0

#include <gtest/gtest.h>
#include <stdint.h>
#include <map>
#include <string>
#include <utility>

#include "opentelemetry/context/context.h"
#include "opentelemetry/context/context_value.h"
#include "opentelemetry/nostd/string_view.h"
#include "opentelemetry/nostd/variant.h"

using namespace opentelemetry;

// Tests that the context constructor accepts an std::map.
TEST(ContextTest, ContextIterableAcceptsMap)
{
  std::map<std::string, context::ContextValue> map_test = {{"test_key", static_cast<int64_t>(123)}};
  context::Context test_context                         = context::Context(map_test);
}

// Tests that the GetValue method returns the expected value.
TEST(ContextTest, ContextGetValueReturnsExpectedValue)
{
  std::map<std::string, context::ContextValue> map_test = {{"test_key", static_cast<int64_t>(123)},
                                                           {"foo_key", static_cast<int64_t>(456)}};
  const context::Context test_context                   = context::Context(map_test);
  EXPECT_EQ(nostd::get<int64_t>(test_context.GetValue("test_key")), 123);
  EXPECT_EQ(nostd::get<int64_t>(test_context.GetValue("foo_key")), 456);
}

// Tests that the SetValues method accepts an std::map.
TEST(ContextTest, ContextSetValuesAcceptsMap)
{
  std::map<std::string, context::ContextValue> map_test = {{"test_key", static_cast<int64_t>(123)}};
  std::map<std::string, context::ContextValue> map_test_write = {
      {"foo_key", static_cast<int64_t>(456)}};

  context::Context test_context = context::Context(map_test);
  context::Context foo_context  = test_context.SetValues(map_test_write);

  EXPECT_EQ(nostd::get<int64_t>(foo_context.GetValue("test_key")), 123);
  EXPECT_EQ(nostd::get<int64_t>(foo_context.GetValue("foo_key")), 456);
}

// Tests that the SetValues method accepts a nostd::string_view and
// context::ContextValue.
TEST(ContextTest, ContextSetValuesAcceptsStringViewContextValue)
{
  nostd::string_view string_view_test      = "string_view";
  context::ContextValue context_value_test = static_cast<int64_t>(123);

  context::Context test_context = context::Context(string_view_test, context_value_test);
  context::Context foo_context  = test_context.SetValue(string_view_test, context_value_test);

  EXPECT_EQ(nostd::get<int64_t>(foo_context.GetValue(string_view_test)), 123);
}

// Tests that the original context does not change when a value is
// written to it.
TEST(ContextTest, ContextImmutability)
{
  std::map<std::string, context::ContextValue> map_test = {{"test_key", static_cast<int64_t>(123)}};

  context::Context context_test = context::Context(map_test);
  context::Context context_foo  = context_test.SetValue("foo_key", static_cast<int64_t>(456));

  EXPECT_FALSE(nostd::holds_alternative<int64_t>(context_test.GetValue("foo_key")));
}

// Tests that writing the same to a context overwrites the original value.
TEST(ContextTest, ContextKeyOverwrite)
{
  std::map<std::string, context::ContextValue> map_test = {{"test_key", static_cast<int64_t>(123)}};

  context::Context context_test = context::Context(map_test);
  context::Context context_foo  = context_test.SetValue("test_key", static_cast<int64_t>(456));

  EXPECT_EQ(nostd::get<int64_t>(context_foo.GetValue("test_key")), 456);
}

// Tests that the new Context Objects inherits the keys and values
// of the original context object.
TEST(ContextTest, ContextInheritance)
{
  using M = std::map<std::string, context::ContextValue>;

  M m1 = {{"test_key", static_cast<int64_t>(123)}, {"foo_key", static_cast<int64_t>(321)}};
  M m2 = {{"other_key", static_cast<int64_t>(789)}, {"another_key", static_cast<int64_t>(987)}};

  context::Context test_context = context::Context(m1);
  context::Context foo_context  = test_context.SetValues(m2);

  EXPECT_EQ(nostd::get<int64_t>(foo_context.GetValue("test_key")), 123);
  EXPECT_EQ(nostd::get<int64_t>(foo_context.GetValue("foo_key")), 321);
  EXPECT_EQ(nostd::get<int64_t>(foo_context.GetValue("other_key")), 789);
  EXPECT_EQ(nostd::get<int64_t>(foo_context.GetValue("another_key")), 987);

  EXPECT_TRUE(nostd::holds_alternative<nostd::monostate>(test_context.GetValue("other_key")));
  EXPECT_TRUE(nostd::holds_alternative<nostd::monostate>(test_context.GetValue("another_key")));
}

// Tests that copying a context copies the key value pairs as expected.
TEST(ContextTest, ContextCopyOperator)
{
  std::map<std::string, context::ContextValue> test_map = {
      {"test_key", static_cast<int64_t>(123)},
      {"foo_key", static_cast<int64_t>(456)},
      {"other_key", static_cast<int64_t>(789)}};

  context::Context test_context          = context::Context(test_map);
  const context::Context &copied_context = test_context;

  EXPECT_EQ(nostd::get<int64_t>(copied_context.GetValue("test_key")), 123);
  EXPECT_EQ(nostd::get<int64_t>(copied_context.GetValue("foo_key")), 456);
  EXPECT_EQ(nostd::get<int64_t>(copied_context.GetValue("other_key")), 789);
}

// Tests that the Context accepts an empty map.
TEST(ContextTest, ContextEmptyMap)
{
  std::map<std::string, context::ContextValue> map_test = {};
  context::Context test_context                         = context::Context(map_test);
}

// Tests that if a key exists within a context has key will return true
// false if not.
TEST(ContextTest, ContextHasKey)
{
  std::map<std::string, context::ContextValue> map_test = {{"test_key", static_cast<int64_t>(123)}};
  const context::Context context_test                   = context::Context(map_test);
  EXPECT_TRUE(context_test.HasKey("test_key"));
  EXPECT_FALSE(context_test.HasKey("foo_key"));
}

// Tests that a copied context returns true when compared
TEST(ContextTest, ContextCopyCompare)
{
  std::map<std::string, context::ContextValue> map_test = {{"test_key", static_cast<int64_t>(123)}};
  context::Context context_test                         = context::Context(map_test);
  const context::Context &copied_test                   = context_test;
  EXPECT_TRUE(context_test == copied_test);
}

// Tests that two differently constructed contexts return false when compared
TEST(ContextTest, ContextDiffCompare)
{
  std::map<std::string, context::ContextValue> map_test = {{"test_key", static_cast<int64_t>(123)}};
  std::map<std::string, context::ContextValue> map_foo  = {{"foo_key", static_cast<int64_t>(123)}};
  context::Context context_test                         = context::Context(map_test);
  context::Context foo_test                             = context::Context(map_foo);
  EXPECT_FALSE(context_test == foo_test);
}
