// Copyright 2026 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <memory>
#include <utility>
#include <vector>

#include "base/functional/bind.h"
#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/run_loop.h"
#include "base/test/bind.h"
#include "base/test/gmock_callback_support.h"
#include "base/test/task_environment.h"
#include "base/types/expected.h"
#include "components/private_ai/client_impl.h"
#include "components/private_ai/common/private_ai_logger.h"
#include "components/private_ai/connection_basic.h"
#include "components/private_ai/connection_factory_impl.h"
#include "components/private_ai/connection_metrics.h"
#include "components/private_ai/connection_timeout.h"
#include "components/private_ai/connection_token_attestation.h"
#include "components/private_ai/private_ai_common.h"
#include "components/private_ai/private_ai_network_driver.h"
#include "components/private_ai/private_ai_oak_session_driver.h"
#include "components/private_ai/proto/private_ai.pb.h"
#include "components/private_ai/secure_channel.h"
#include "components/private_ai/status_code.h"
#include "components/private_ai/testing/fake_private_ai_network_driver.h"
#include "components/private_ai/testing/fake_private_ai_oak_session_driver.h"
#include "components/private_ai/testing/fake_secure_channel.h"
#include "components/private_ai/testing/fake_token_manager.h"
#include "components/version_info/channel.h"
#include "services/network/test/test_network_context.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace private_ai {

namespace {

using ::testing::_;
using ::testing::Invoke;

}  // namespace

class ClientImplIntegrationTest : public testing::Test {
 public:
  void SetUp() override {
    GURL url("wss://example.com?key=test-api-key");

    auto factory = std::make_unique<ConnectionFactoryImpl>(
        url, &test_network_context_, &logger_, &oak_session_driver_,
        &network_driver_, version_info::Channel::UNKNOWN);
    factory_ptr_ = factory.get();
    factory->EnableTokenAttestation(&token_manager_);
    factory->SetSecureChannelFactoryForTesting(base::BindLambdaForTesting(
        [this]() -> std::unique_ptr<SecureChannel::Factory> {
          return std::make_unique<FakeSecureChannelFactory>(
              base::BindRepeating(
                  &ClientImplIntegrationTest::on_secure_channel_created,
                  base::Unretained(this)),
              base::BindRepeating(
                  &ClientImplIntegrationTest::on_secure_channel_destroyed,
                  base::Unretained(this)));
        }));

    client_ = std::make_unique<ClientImpl>(std::move(factory), &logger_);
  }

  void TearDown() override {
    // Ensure that all SecureChannels are destroyed.
    factory_ptr_ = nullptr;
    client_.reset();
    ASSERT_TRUE(secure_channels_.empty());
  }

  void on_secure_channel_created(FakeSecureChannel* secure_channel) {
    secure_channels_.push_back(secure_channel);
  }

  void on_secure_channel_destroyed(FakeSecureChannel* secure_channel) {
    std::erase(secure_channels_, secure_channel);
  }

  FakeSecureChannel* last_secure_channel() {
    if (secure_channels_.empty()) {
      return nullptr;
    }
    return secure_channels_.back();
  }

 protected:
  base::test::TaskEnvironment task_environment_{
      base::test::TaskEnvironment::TimeSource::MOCK_TIME};

  PrivateAiLogger logger_;
  network::TestNetworkContext test_network_context_;
  FakeTokenManager token_manager_;
  FakePrivateAiOakSessionDriver oak_session_driver_;
  FakePrivateAiNetworkDriver network_driver_;
  std::vector<raw_ptr<FakeSecureChannel>> secure_channels_;
  std::unique_ptr<ClientImpl> client_;
  raw_ptr<ConnectionFactoryImpl> factory_ptr_ = nullptr;
};

TEST_F(ClientImplIntegrationTest, FullStackSuccess) {
  base::test::TestFuture<base::expected<std::string, StatusCode>> future;
  client_->SendTextRequest(
      proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION, "hello",
      future.GetCallback(), /*options=*/{});

  // 1. Attestation starts. FakeTokenManager gets a request.
  token_manager_.RunPendingCallbacks();

  // 2. SecureChannel (Basic) is created and gets the attestation request.
  auto* channel = last_secure_channel();
  ASSERT_TRUE(channel);

  // 3. Now the original text request should be sent immediately after
  // attestation.
  ASSERT_EQ(channel->written_requests().size(), 2u);
  EXPECT_TRUE(channel->written_requests()[0].has_anonymous_token_request());
  EXPECT_EQ(channel->written_requests()[0].feature_name(),
            proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION);
  EXPECT_TRUE(channel->written_requests()[1].has_generate_content_request());

  // 4. Respond to text request.
  proto::PrivateAiResponse text_response;
  text_response.set_request_id(channel->written_requests()[1].request_id());
  text_response.mutable_generate_content_response()
      ->add_candidates()
      ->mutable_content()
      ->add_parts()
      ->set_text("world");
  channel->send_back_response(text_response);

  // 6. Verify final result.
  auto result = future.Get();
  ASSERT_TRUE(result.has_value());
  EXPECT_EQ(result.value(), "world");
}

TEST_F(ClientImplIntegrationTest, AttestationFailure) {
  base::test::TestFuture<base::expected<std::string, StatusCode>> future;
  client_->SendTextRequest(
      proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION, "hello",
      future.GetCallback(), /*options=*/{});

  // 1. Attestation starts.
  // Simulate token fetch failure.
  token_manager_.RespondToGetAuthToken(std::nullopt);

  // 2. Client should receive an error.
  auto result = future.Get();
  ASSERT_FALSE(result.has_value());
  EXPECT_EQ(result.error(), StatusCode::kClientAttestationTokenFetchFailed);
}

TEST_F(ClientImplIntegrationTest, Timeout) {
  base::test::TestFuture<base::expected<std::string, StatusCode>> future;
  client_->SendTextRequest(
      proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION, "hello",
      future.GetCallback(), {.timeout = base::Seconds(5)});

  // Provide the token.
  token_manager_.RunPendingCallbacks();
  auto* channel = last_secure_channel();
  ASSERT_TRUE(channel);

  // Text request is sent immediately after attestation.
  ASSERT_EQ(channel->written_requests().size(), 2u);
  EXPECT_TRUE(channel->written_requests()[0].has_anonymous_token_request());
  EXPECT_EQ(channel->written_requests()[0].feature_name(),
            proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION);
  EXPECT_TRUE(channel->written_requests()[1].has_generate_content_request());

  // Wait for timeout.
  task_environment_.FastForwardBy(base::Seconds(6));

  // Verify timeout error.
  auto result = future.Get();
  ASSERT_FALSE(result.has_value());
  EXPECT_EQ(result.error(), StatusCode::kTimeout);
}

TEST_F(ClientImplIntegrationTest, ConcurrentRequestsDuringAttestation) {
  base::test::TestFuture<base::expected<std::string, StatusCode>> future1;
  base::test::TestFuture<base::expected<std::string, StatusCode>> future2;

  client_->SendTextRequest(
      proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION, "request1",
      future1.GetCallback(), /*options=*/{});
  client_->SendTextRequest(
      proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION, "request2",
      future2.GetCallback(), /*options=*/{});

  // 1. Attestation starts (only one token fetch should be triggered).
  token_manager_.RunPendingCallbacks();

  auto* channel = last_secure_channel();
  ASSERT_TRUE(channel);

  // 2. Now both requests should be sent immediately after attestation.
  ASSERT_EQ(channel->written_requests().size(), 3u);
  EXPECT_TRUE(channel->written_requests()[0].has_anonymous_token_request());
  EXPECT_EQ(channel->written_requests()[0].feature_name(),
            proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION);

  // Handle request 1
  EXPECT_EQ(channel->written_requests()[1]
                .generate_content_request()
                .contents(0)
                .parts(0)
                .text(),
            "request1");
  int32_t id1 = channel->written_requests()[1].request_id();
  proto::PrivateAiResponse resp1;
  resp1.set_request_id(id1);
  resp1.mutable_generate_content_response()
      ->add_candidates()
      ->mutable_content()
      ->add_parts()
      ->set_text("response1");
  channel->send_back_response(resp1);

  // Handle request 2
  EXPECT_EQ(channel->written_requests()[2]
                .generate_content_request()
                .contents(0)
                .parts(0)
                .text(),
            "request2");
  int32_t id2 = channel->written_requests()[2].request_id();
  proto::PrivateAiResponse resp2;
  resp2.set_request_id(id2);
  resp2.mutable_generate_content_response()
      ->add_candidates()
      ->mutable_content()
      ->add_parts()
      ->set_text("response2");
  channel->send_back_response(resp2);

  // 4. Verify both results.
  EXPECT_EQ(future1.Get().value(), "response1");
  EXPECT_EQ(future2.Get().value(), "response2");
}

TEST_F(ClientImplIntegrationTest, DisconnectDuringAttestation) {
  base::test::TestFuture<base::expected<std::string, StatusCode>> future;
  client_->SendTextRequest(
      proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION, "hello",
      future.GetCallback(), /*options=*/{});

  // 1. Attestation starts.
  token_manager_.RunPendingCallbacks();
  auto* channel = last_secure_channel();
  ASSERT_TRUE(channel);

  // 2. Simulate channel disconnect before responding to attestation.
  channel->send_back_error(StatusCode::kNetworkError);

  // 3. The original request should fail with the disconnect error.
  ASSERT_TRUE(future.IsReady());
  auto result = future.Get();
  ASSERT_FALSE(result.has_value());
  // Our heuristic correctly rewrites this early error (before first successful
  // response) into kClientAttestationFailed.
  EXPECT_EQ(result.error(), StatusCode::kClientAttestationFailed);
}

TEST_F(ClientImplIntegrationTest, ClientDestroyedDuringAttestation) {
  base::test::TestFuture<base::expected<std::string, StatusCode>> future;
  client_->SendTextRequest(
      proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION, "hello",
      future.GetCallback(), /*options=*/{});

  // 1. Attestation starts.
  token_manager_.RunPendingCallbacks();

  // 2. Destroy the client while attestation is pending.
  factory_ptr_ = nullptr;
  client_.reset();

  // 3. The request should be resolved with kDestroyed.
  ASSERT_TRUE(future.IsReady());
  auto result = future.Get();
  ASSERT_FALSE(result.has_value());
  EXPECT_EQ(result.error(), StatusCode::kDestroyed);
}

TEST_F(ClientImplIntegrationTest, AttestationTimedOut) {
  base::test::TestFuture<base::expected<std::string, StatusCode>> future;
  client_->SendTextRequest(
      proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION, "hello",
      future.GetCallback(), {.timeout = base::Seconds(5)});

  // 1. Attestation starts.
  token_manager_.RunPendingCallbacks();
  auto* channel = last_secure_channel();
  ASSERT_TRUE(channel);

  // 2. Wait for the request to time out.
  task_environment_.FastForwardBy(base::Seconds(10));

  // 3. Result should be kTimeout because the actual request timed out.
  ASSERT_TRUE(future.IsReady());
  auto result = future.Get();
  ASSERT_FALSE(result.has_value());
  EXPECT_EQ(result.error(), StatusCode::kTimeout);
}

TEST_F(ClientImplIntegrationTest, ProxySuccess) {
  // 1. Enable proxy.
  ASSERT_TRUE(secure_channels_.empty());
  factory_ptr_->EnableProxy(GURL("https://proxy.example.com"));

  base::test::TestFuture<base::expected<std::string, StatusCode>> future;
  client_->SendTextRequest(
      proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION, "hello",
      future.GetCallback(), /*options=*/{});

  // 2. Respond to token requests.
  token_manager_.RunPendingProxyCallbacks();
  token_manager_.RunPendingCallbacks();

  auto* channel = last_secure_channel();
  ASSERT_TRUE(channel);

  // 3. Now the original text request should be sent immediately after
  // attestation.
  ASSERT_EQ(channel->written_requests().size(), 2u);
  EXPECT_TRUE(channel->written_requests()[0].has_anonymous_token_request());
  EXPECT_EQ(channel->written_requests()[0].feature_name(),
            proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION);
  EXPECT_TRUE(channel->written_requests()[1].has_generate_content_request());

  // 4. Respond to text request.
  proto::PrivateAiResponse text_response;
  text_response.set_request_id(channel->written_requests()[1].request_id());
  text_response.mutable_generate_content_response()
      ->add_candidates()
      ->mutable_content()
      ->add_parts()
      ->set_text("world");
  channel->send_back_response(text_response);

  // 5. Verify final result is success.
  ASSERT_TRUE(future.IsReady());
  auto result = future.Get();
  ASSERT_TRUE(result.has_value());
  EXPECT_EQ(result.value(), "world");
}

TEST_F(ClientImplIntegrationTest, ProxyConfigFailure) {
  // 1. Enable proxy.
  ASSERT_TRUE(secure_channels_.empty());
  factory_ptr_->EnableProxy(GURL("https://proxy.example.com"));

  base::test::TestFuture<base::expected<std::string, StatusCode>> future;
  client_->SendTextRequest(
      proto::FeatureName::FEATURE_NAME_CHROME_ZERO_STATE_SUGGESTION, "hello",
      future.GetCallback(), /*options=*/{});

  // 2. Respond to proxy token request with invalid token.
  token_manager_.RespondToGetAuthTokenForProxy(phosphor::BlindSignedAuthToken{
      .token = "invalid base64!!!",
      .encoded_extensions = "cHJveHlfZXh0ZW5zaW9ucw=="});

  // 3. Verify final result is kProxyConfigFailed.
  ASSERT_TRUE(future.IsReady());
  auto result = future.Get();
  ASSERT_FALSE(result.has_value());
  EXPECT_EQ(result.error(), StatusCode::kProxyConfigFailed);
}

}  // namespace private_ai