// Copyright 2012 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 <vector>

#include "base/functional/bind.h"
#include "base/location.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/run_loop.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/task/single_thread_task_runner.h"
#include "base/test/task_environment.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "net/base/address_family.h"
#include "net/base/net_errors.h"
#include "net/base/test_completion_callback.h"
#include "net/dns/mock_host_resolver.h"
#include "net/log/net_log.h"
#include "net/log/net_log_event_type.h"
#include "net/log/test_net_log.h"
#include "net/log/test_net_log_util.h"
#include "net/proxy_resolution/dhcp_pac_file_fetcher.h"
#include "net/proxy_resolution/mock_pac_file_fetcher.h"
#include "net/proxy_resolution/pac_file_decider.h"
#include "net/proxy_resolution/pac_file_fetcher.h"
#include "net/proxy_resolution/proxy_config.h"
#include "net/proxy_resolution/proxy_resolver.h"
#include "net/test/gtest_util.h"
#include "net/test/test_with_task_environment.h"
#include "net/traffic_annotation/network_traffic_annotation_test_helper.h"
#include "net/url_request/url_request_context.h"
#include "net/url_request/url_request_context_builder.h"
#include "net/url_request/url_request_test_util.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

using net::test::IsError;
using net::test::IsOk;

namespace net {
namespace {

enum Error {
  kFailedDownloading = ERR_CONNECTION_CLOSED,
  kFailedParsing = ERR_PAC_SCRIPT_FAILED,
};

class Rules {
 public:
  struct Rule {
    Rule(const GURL& url, int fetch_error, bool is_valid_script)
        : url(url),
          fetch_error(fetch_error),
          is_valid_script(is_valid_script) {}

    std::u16string text() const {
      if (is_valid_script)
        return base::UTF8ToUTF16(url.spec() + "!FindProxyForURL");
      if (fetch_error == OK)
        return base::UTF8ToUTF16(url.spec() + "!invalid-script");
      return std::u16string();
    }

    GURL url;
    int fetch_error;
    bool is_valid_script;
  };

  Rule AddSuccessRule(const char* url) {
    Rule rule(GURL(url), OK /*fetch_error*/, true);
    rules_.push_back(rule);
    return rule;
  }

  void AddFailDownloadRule(const char* url) {
    rules_.push_back(
        Rule(GURL(url), kFailedDownloading /*fetch_error*/, false));
  }

  void AddFailParsingRule(const char* url) {
    rules_.push_back(Rule(GURL(url), OK /*fetch_error*/, false));
  }

  const Rule& GetRuleByUrl(const GURL& url) const {
    for (const auto& rule : rules_) {
      if (rule.url == url)
        return rule;
    }
    LOG(FATAL) << "Rule not found for " << url;
  }

 private:
  typedef std::vector<Rule> RuleList;
  RuleList rules_;
};

class RuleBasedPacFileFetcher : public PacFileFetcher {
 public:
  explicit RuleBasedPacFileFetcher(const Rules* rules) : rules_(rules) {}

  virtual void SetRequestContext(URLRequestContext* context) {
    request_context_ = context;
  }

  // PacFileFetcher implementation.
  int Fetch(const GURL& url,
            std::u16string* text,
            CompletionOnceCallback callback,
            const NetworkTrafficAnnotationTag traffic_annotation) override {
    const Rules::Rule& rule = rules_->GetRuleByUrl(url);
    int rv = rule.fetch_error;
    EXPECT_NE(ERR_UNEXPECTED, rv);
    if (rv == OK)
      *text = rule.text();
    return rv;
  }

  void Cancel() override {}

  void OnShutdown() override { request_context_ = nullptr; }

  URLRequestContext* GetRequestContext() const override {
    return request_context_;
  }

 private:
  raw_ptr<const Rules> rules_;
  raw_ptr<URLRequestContext, DanglingUntriaged> request_context_ = nullptr;
};

// A mock retriever, returns asynchronously when CompleteRequests() is called.
class MockDhcpPacFileFetcher : public DhcpPacFileFetcher {
 public:
  MockDhcpPacFileFetcher();

  MockDhcpPacFileFetcher(const MockDhcpPacFileFetcher&) = delete;
  MockDhcpPacFileFetcher& operator=(const MockDhcpPacFileFetcher&) = delete;

  ~MockDhcpPacFileFetcher() override;

  int Fetch(std::u16string* utf16_text,
            CompletionOnceCallback callback,
            const NetLogWithSource& net_log,
            const NetworkTrafficAnnotationTag traffic_annotation) override;
  void Cancel() override;
  void OnShutdown() override;
  const GURL& GetPacURL() const override;

  virtual void SetPacURL(const GURL& url);

  virtual void CompleteRequests(int result, const std::u16string& script);

 private:
  CompletionOnceCallback callback_;
  raw_ptr<std::u16string> utf16_text_;
  GURL gurl_;
};

MockDhcpPacFileFetcher::MockDhcpPacFileFetcher() = default;

MockDhcpPacFileFetcher::~MockDhcpPacFileFetcher() = default;

int MockDhcpPacFileFetcher::Fetch(
    std::u16string* utf16_text,
    CompletionOnceCallback callback,
    const NetLogWithSource& net_log,
    const NetworkTrafficAnnotationTag traffic_annotation) {
  utf16_text_ = utf16_text;
  callback_ = std::move(callback);
  return ERR_IO_PENDING;
}

void MockDhcpPacFileFetcher::Cancel() {}

void MockDhcpPacFileFetcher::OnShutdown() {}

const GURL& MockDhcpPacFileFetcher::GetPacURL() const {
  return gurl_;
}

void MockDhcpPacFileFetcher::SetPacURL(const GURL& url) {
  gurl_ = url;
}

void MockDhcpPacFileFetcher::CompleteRequests(int result,
                                              const std::u16string& script) {
  *utf16_text_ = script;
  std::move(callback_).Run(result);
}

// Succeed using custom PAC script.
TEST(PacFileDeciderTest, CustomPacSucceeds) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_pac_url(GURL("http://custom/proxy.pac"));

  Rules::Rule rule = rules.AddSuccessRule("http://custom/proxy.pac");

  TestCompletionCallback callback;
  RecordingNetLogObserver observer;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, net::NetLog::Get());
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsOk());
  EXPECT_EQ(rule.text(), decider.script_data().data->utf16());
  EXPECT_FALSE(decider.script_data().from_auto_detect);

  // Check the NetLog was filled correctly.
  auto entries = observer.GetEntries();

  EXPECT_EQ(4u, entries.size());
  EXPECT_TRUE(
      LogContainsBeginEvent(entries, 0, NetLogEventType::PAC_FILE_DECIDER));
  EXPECT_TRUE(LogContainsBeginEvent(
      entries, 1, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(LogContainsEndEvent(
      entries, 2, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(
      LogContainsEndEvent(entries, 3, NetLogEventType::PAC_FILE_DECIDER));

  EXPECT_TRUE(decider.effective_config().value().has_pac_url());
  EXPECT_EQ(config.pac_url(), decider.effective_config().value().pac_url());
}

// Fail downloading the custom PAC script.
TEST(PacFileDeciderTest, CustomPacFails1) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_pac_url(GURL("http://custom/proxy.pac"));

  rules.AddFailDownloadRule("http://custom/proxy.pac");

  TestCompletionCallback callback;
  RecordingNetLogObserver observer;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, net::NetLog::Get());
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsError(kFailedDownloading));
  EXPECT_FALSE(decider.script_data().data);

  // Check the NetLog was filled correctly.
  auto entries = observer.GetEntries();

  EXPECT_EQ(4u, entries.size());
  EXPECT_TRUE(
      LogContainsBeginEvent(entries, 0, NetLogEventType::PAC_FILE_DECIDER));
  EXPECT_TRUE(LogContainsBeginEvent(
      entries, 1, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(LogContainsEndEvent(
      entries, 2, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(
      LogContainsEndEvent(entries, 3, NetLogEventType::PAC_FILE_DECIDER));

  EXPECT_FALSE(decider.effective_config().value().has_pac_url());
}

// Fail parsing the custom PAC script.
TEST(PacFileDeciderTest, CustomPacFails2) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_pac_url(GURL("http://custom/proxy.pac"));

  rules.AddFailParsingRule("http://custom/proxy.pac");

  TestCompletionCallback callback;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, nullptr);
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsError(kFailedParsing));
  EXPECT_FALSE(decider.script_data().data);
}

// Fail downloading the custom PAC script, because the fetcher was NULL.
TEST(PacFileDeciderTest, HasNullPacFileFetcher) {
  Rules rules;
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_pac_url(GURL("http://custom/proxy.pac"));

  TestCompletionCallback callback;
  PacFileDecider decider(nullptr, &dhcp_fetcher, nullptr);
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsError(ERR_UNEXPECTED));
  EXPECT_FALSE(decider.script_data().data);
}

// Succeeds in choosing autodetect (WPAD DNS).
TEST(PacFileDeciderTest, AutodetectSuccess) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_auto_detect(true);

  Rules::Rule rule = rules.AddSuccessRule("http://wpad/wpad.dat");

  TestCompletionCallback callback;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, nullptr);
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsOk());
  EXPECT_EQ(rule.text(), decider.script_data().data->utf16());
  EXPECT_TRUE(decider.script_data().from_auto_detect);

  EXPECT_TRUE(decider.effective_config().value().has_pac_url());
  EXPECT_EQ(rule.url, decider.effective_config().value().pac_url());
}

class PacFileDeciderQuickCheckTest : public ::testing::Test,
                                     public WithTaskEnvironment {
 public:
  PacFileDeciderQuickCheckTest()
      : WithTaskEnvironment(base::test::TaskEnvironment::TimeSource::MOCK_TIME),
        rule_(rules_.AddSuccessRule("http://wpad/wpad.dat")),
        fetcher_(&rules_) {
    auto builder = CreateTestURLRequestContextBuilder();
    builder->set_host_resolver(std::make_unique<MockHostResolver>());
    request_context_ = builder->Build();
  }

  void SetUp() override {
    fetcher_.SetRequestContext(request_context_.get());
    config_.set_auto_detect(true);
    decider_ =
        std::make_unique<PacFileDecider>(&fetcher_, &dhcp_fetcher_, nullptr);
  }

  int StartDecider() {
    return decider_->Start(
        ProxyConfigWithAnnotation(config_, TRAFFIC_ANNOTATION_FOR_TESTS),
        base::TimeDelta(), true, callback_.callback());
  }

  MockHostResolver& host_resolver() {
    // This cast is safe because we set a MockHostResolver in the constructor.
    return *static_cast<MockHostResolver*>(request_context_->host_resolver());
  }

 protected:
  Rules rules_;
  Rules::Rule rule_;
  TestCompletionCallback callback_;
  RuleBasedPacFileFetcher fetcher_;
  ProxyConfig config_;
  DoNothingDhcpPacFileFetcher dhcp_fetcher_;
  std::unique_ptr<PacFileDecider> decider_;

 private:
  std::unique_ptr<URLRequestContext> request_context_;
};

// Fails if a synchronous DNS lookup success for wpad causes QuickCheck to fail.
TEST_F(PacFileDeciderQuickCheckTest, SyncSuccess) {
  host_resolver().set_synchronous_mode(true);
  host_resolver().rules()->AddRule("wpad", "1.2.3.4");

  EXPECT_THAT(StartDecider(), IsOk());
  EXPECT_EQ(rule_.text(), decider_->script_data().data->utf16());
  EXPECT_TRUE(decider_->script_data().from_auto_detect);

  EXPECT_TRUE(decider_->effective_config().value().has_pac_url());
  EXPECT_EQ(rule_.url, decider_->effective_config().value().pac_url());
}

// Fails if an asynchronous DNS lookup success for wpad causes QuickCheck to
// fail.
TEST_F(PacFileDeciderQuickCheckTest, AsyncSuccess) {
  host_resolver().set_ondemand_mode(true);
  host_resolver().rules()->AddRule("wpad", "1.2.3.4");

  EXPECT_THAT(StartDecider(), IsError(ERR_IO_PENDING));
  ASSERT_TRUE(host_resolver().has_pending_requests());

  // The DNS lookup should be pending, and be using the same
  // NetworkAnonymizationKey as the PacFileFetcher, so wpad fetches can reuse
  // the DNS lookup result from the wpad quick check, if it succeeds.
  ASSERT_EQ(1u, host_resolver().last_id());
  EXPECT_EQ(fetcher_.isolation_info().network_anonymization_key(),
            host_resolver().request_network_anonymization_key(1));

  host_resolver().ResolveAllPending();
  callback_.WaitForResult();
  EXPECT_FALSE(host_resolver().has_pending_requests());
  EXPECT_EQ(rule_.text(), decider_->script_data().data->utf16());
  EXPECT_TRUE(decider_->script_data().from_auto_detect);
  EXPECT_TRUE(decider_->effective_config().value().has_pac_url());
  EXPECT_EQ(rule_.url, decider_->effective_config().value().pac_url());
}

// Fails if an asynchronous DNS lookup failure (i.e. an NXDOMAIN) still causes
// PacFileDecider to yield a PAC URL.
TEST_F(PacFileDeciderQuickCheckTest, AsyncFail) {
  host_resolver().set_ondemand_mode(true);
  host_resolver().rules()->AddRule("wpad", ERR_NAME_NOT_RESOLVED);
  EXPECT_THAT(StartDecider(), IsError(ERR_IO_PENDING));
  ASSERT_TRUE(host_resolver().has_pending_requests());

  // The DNS lookup should be pending, and be using the same
  // NetworkAnonymizationKey as the PacFileFetcher, so wpad fetches can reuse
  // the DNS lookup result from the wpad quick check, if it succeeds.
  ASSERT_EQ(1u, host_resolver().last_id());
  EXPECT_EQ(fetcher_.isolation_info().network_anonymization_key(),
            host_resolver().request_network_anonymization_key(1));

  host_resolver().ResolveAllPending();
  callback_.WaitForResult();
  EXPECT_FALSE(decider_->effective_config().value().has_pac_url());
}

// Fails if a DNS lookup timeout either causes PacFileDecider to yield a PAC
// URL or causes PacFileDecider not to cancel its pending resolution.
TEST_F(PacFileDeciderQuickCheckTest, AsyncTimeout) {
  host_resolver().set_ondemand_mode(true);
  EXPECT_THAT(StartDecider(), IsError(ERR_IO_PENDING));
  ASSERT_TRUE(host_resolver().has_pending_requests());
  FastForwardUntilNoTasksRemain();
  callback_.WaitForResult();
  EXPECT_FALSE(host_resolver().has_pending_requests());
  EXPECT_FALSE(decider_->effective_config().value().has_pac_url());
}

// Fails if DHCP check doesn't take place before QuickCheck.
TEST_F(PacFileDeciderQuickCheckTest, QuickCheckInhibitsDhcp) {
  MockDhcpPacFileFetcher dhcp_fetcher;
  const char* kPac = "function FindProxyForURL(u,h) { return \"DIRECT\"; }";
  std::u16string pac_contents = base::UTF8ToUTF16(kPac);
  GURL url("http://foobar/baz");
  dhcp_fetcher.SetPacURL(url);
  decider_ =
      std::make_unique<PacFileDecider>(&fetcher_, &dhcp_fetcher, nullptr);
  EXPECT_THAT(StartDecider(), IsError(ERR_IO_PENDING));
  dhcp_fetcher.CompleteRequests(OK, pac_contents);
  EXPECT_TRUE(decider_->effective_config().value().has_pac_url());
  EXPECT_EQ(decider_->effective_config().value().pac_url(), url);
}

// Fails if QuickCheck still happens when disabled. To ensure QuickCheck is not
// happening, we add a synchronous failing resolver, which would ordinarily
// mean a QuickCheck failure, then ensure that our PacFileFetcher is still
// asked to fetch.
TEST_F(PacFileDeciderQuickCheckTest, QuickCheckDisabled) {
  const char* kPac = "function FindProxyForURL(u,h) { return \"DIRECT\"; }";
  host_resolver().set_synchronous_mode(true);
  MockPacFileFetcher fetcher;
  decider_ =
      std::make_unique<PacFileDecider>(&fetcher, &dhcp_fetcher_, nullptr);
  EXPECT_THAT(StartDecider(), IsError(ERR_IO_PENDING));
  EXPECT_TRUE(fetcher.has_pending_request());
  fetcher.NotifyFetchCompletion(OK, kPac);
}

TEST_F(PacFileDeciderQuickCheckTest, ExplicitPacUrl) {
  const char* kCustomUrl = "http://custom/proxy.pac";
  config_.set_pac_url(GURL(kCustomUrl));
  Rules::Rule rule = rules_.AddSuccessRule(kCustomUrl);
  host_resolver().rules()->AddRule("wpad", ERR_NAME_NOT_RESOLVED);
  host_resolver().rules()->AddRule("custom", "1.2.3.4");
  EXPECT_THAT(StartDecider(), IsError(ERR_IO_PENDING));
  callback_.WaitForResult();
  EXPECT_TRUE(decider_->effective_config().value().has_pac_url());
  EXPECT_EQ(rule.url, decider_->effective_config().value().pac_url());
}

TEST_F(PacFileDeciderQuickCheckTest, ShutdownDuringResolve) {
  host_resolver().set_ondemand_mode(true);

  EXPECT_THAT(StartDecider(), IsError(ERR_IO_PENDING));
  EXPECT_TRUE(host_resolver().has_pending_requests());

  decider_->OnShutdown();
  EXPECT_FALSE(host_resolver().has_pending_requests());
  base::RunLoop().RunUntilIdle();
  EXPECT_FALSE(callback_.have_result());
}

// Regression test for http://crbug.com/409698.
// This test lets the state machine get into state QUICK_CHECK_COMPLETE, then
// destroys the decider, causing a cancel.
TEST_F(PacFileDeciderQuickCheckTest, CancelPartway) {
  host_resolver().set_ondemand_mode(true);
  EXPECT_THAT(StartDecider(), IsError(ERR_IO_PENDING));
  decider_.reset(nullptr);
}

// Fails at WPAD (downloading), but succeeds in choosing the custom PAC.
TEST(PacFileDeciderTest, AutodetectFailCustomSuccess1) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_auto_detect(true);
  config.set_pac_url(GURL("http://custom/proxy.pac"));

  rules.AddFailDownloadRule("http://wpad/wpad.dat");
  Rules::Rule rule = rules.AddSuccessRule("http://custom/proxy.pac");

  TestCompletionCallback callback;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, nullptr);
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsOk());
  EXPECT_EQ(rule.text(), decider.script_data().data->utf16());
  EXPECT_FALSE(decider.script_data().from_auto_detect);

  EXPECT_TRUE(decider.effective_config().value().has_pac_url());
  EXPECT_EQ(rule.url, decider.effective_config().value().pac_url());
}

// Fails at WPAD (no DHCP config, DNS PAC fails parsing), but succeeds in
// choosing the custom PAC.
TEST(PacFileDeciderTest, AutodetectFailCustomSuccess2) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_auto_detect(true);
  config.set_pac_url(GURL("http://custom/proxy.pac"));
  config.proxy_rules().ParseFromString("unused-manual-proxy:99");

  rules.AddFailParsingRule("http://wpad/wpad.dat");
  Rules::Rule rule = rules.AddSuccessRule("http://custom/proxy.pac");

  TestCompletionCallback callback;
  RecordingNetLogObserver observer;

  PacFileDecider decider(&fetcher, &dhcp_fetcher, net::NetLog::Get());
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsOk());
  EXPECT_EQ(rule.text(), decider.script_data().data->utf16());
  EXPECT_FALSE(decider.script_data().from_auto_detect);

  // Verify that the effective configuration no longer contains auto detect or
  // any of the manual settings.
  EXPECT_TRUE(decider.effective_config().value().Equals(
      ProxyConfig::CreateFromCustomPacURL(GURL("http://custom/proxy.pac"))));

  // Check the NetLog was filled correctly.
  // (Note that various states are repeated since both WPAD and custom
  // PAC scripts are tried).
  auto entries = observer.GetEntries();

  EXPECT_EQ(10u, entries.size());
  EXPECT_TRUE(
      LogContainsBeginEvent(entries, 0, NetLogEventType::PAC_FILE_DECIDER));
  // This is the DHCP phase, which fails fetching rather than parsing, so
  // there is no pair of SET_PAC_SCRIPT events.
  EXPECT_TRUE(LogContainsBeginEvent(
      entries, 1, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(LogContainsEndEvent(
      entries, 2, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(LogContainsEvent(
      entries, 3,
      NetLogEventType::PAC_FILE_DECIDER_FALLING_BACK_TO_NEXT_PAC_SOURCE,
      NetLogEventPhase::NONE));
  // This is the DNS phase, which attempts a fetch but fails.
  EXPECT_TRUE(LogContainsBeginEvent(
      entries, 4, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(LogContainsEndEvent(
      entries, 5, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(LogContainsEvent(
      entries, 6,
      NetLogEventType::PAC_FILE_DECIDER_FALLING_BACK_TO_NEXT_PAC_SOURCE,
      NetLogEventPhase::NONE));
  // Finally, the custom PAC URL phase.
  EXPECT_TRUE(LogContainsBeginEvent(
      entries, 7, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(LogContainsEndEvent(
      entries, 8, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(
      LogContainsEndEvent(entries, 9, NetLogEventType::PAC_FILE_DECIDER));
}

// Fails at WPAD (downloading), and fails at custom PAC (downloading).
TEST(PacFileDeciderTest, AutodetectFailCustomFails1) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_auto_detect(true);
  config.set_pac_url(GURL("http://custom/proxy.pac"));

  rules.AddFailDownloadRule("http://wpad/wpad.dat");
  rules.AddFailDownloadRule("http://custom/proxy.pac");

  TestCompletionCallback callback;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, nullptr);
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsError(kFailedDownloading));
  EXPECT_FALSE(decider.script_data().data);
}

// Fails at WPAD (downloading), and fails at custom PAC (parsing).
TEST(PacFileDeciderTest, AutodetectFailCustomFails2) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_auto_detect(true);
  config.set_pac_url(GURL("http://custom/proxy.pac"));

  rules.AddFailDownloadRule("http://wpad/wpad.dat");
  rules.AddFailParsingRule("http://custom/proxy.pac");

  TestCompletionCallback callback;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, nullptr);
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsError(kFailedParsing));
  EXPECT_FALSE(decider.script_data().data);
}

// This is a copy-paste of CustomPacFails1, with the exception that we give it
// a 1 millisecond delay. This means it will now complete asynchronously.
// Moreover, we test the NetLog to make sure it logged the pause.
TEST(PacFileDeciderTest, CustomPacFails1_WithPositiveDelay) {
  base::test::TaskEnvironment task_environment;

  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_pac_url(GURL("http://custom/proxy.pac"));

  rules.AddFailDownloadRule("http://custom/proxy.pac");

  TestCompletionCallback callback;

  RecordingNetLogObserver observer;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, net::NetLog::Get());
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::Milliseconds(1), true, callback.callback()),
              IsError(ERR_IO_PENDING));

  EXPECT_THAT(callback.WaitForResult(), IsError(kFailedDownloading));
  EXPECT_FALSE(decider.script_data().data);

  // Check the NetLog was filled correctly.
  auto entries = observer.GetEntries();

  EXPECT_EQ(6u, entries.size());
  EXPECT_TRUE(
      LogContainsBeginEvent(entries, 0, NetLogEventType::PAC_FILE_DECIDER));
  EXPECT_TRUE(LogContainsBeginEvent(entries, 1,
                                    NetLogEventType::PAC_FILE_DECIDER_WAIT));
  EXPECT_TRUE(
      LogContainsEndEvent(entries, 2, NetLogEventType::PAC_FILE_DECIDER_WAIT));
  EXPECT_TRUE(LogContainsBeginEvent(
      entries, 3, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(LogContainsEndEvent(
      entries, 4, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(
      LogContainsEndEvent(entries, 5, NetLogEventType::PAC_FILE_DECIDER));
}

// This is a copy-paste of CustomPacFails1, with the exception that we give it
// a -5 second delay instead of a 0 ms delay. This change should have no effect
// so the rest of the test is unchanged.
TEST(PacFileDeciderTest, CustomPacFails1_WithNegativeDelay) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  DoNothingDhcpPacFileFetcher dhcp_fetcher;

  ProxyConfig config;
  config.set_pac_url(GURL("http://custom/proxy.pac"));

  rules.AddFailDownloadRule("http://custom/proxy.pac");

  TestCompletionCallback callback;
  RecordingNetLogObserver observer;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, net::NetLog::Get());
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::Seconds(-5), true, callback.callback()),
              IsError(kFailedDownloading));
  EXPECT_FALSE(decider.script_data().data);

  // Check the NetLog was filled correctly.
  auto entries = observer.GetEntries();

  EXPECT_EQ(4u, entries.size());
  EXPECT_TRUE(
      LogContainsBeginEvent(entries, 0, NetLogEventType::PAC_FILE_DECIDER));
  EXPECT_TRUE(LogContainsBeginEvent(
      entries, 1, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(LogContainsEndEvent(
      entries, 2, NetLogEventType::PAC_FILE_DECIDER_FETCH_PAC_SCRIPT));
  EXPECT_TRUE(
      LogContainsEndEvent(entries, 3, NetLogEventType::PAC_FILE_DECIDER));
}

class SynchronousSuccessDhcpFetcher : public DhcpPacFileFetcher {
 public:
  explicit SynchronousSuccessDhcpFetcher(const std::u16string& expected_text)
      : gurl_("http://dhcppac/"), expected_text_(expected_text) {}

  SynchronousSuccessDhcpFetcher(const SynchronousSuccessDhcpFetcher&) = delete;
  SynchronousSuccessDhcpFetcher& operator=(
      const SynchronousSuccessDhcpFetcher&) = delete;

  int Fetch(std::u16string* utf16_text,
            CompletionOnceCallback callback,
            const NetLogWithSource& net_log,
            const NetworkTrafficAnnotationTag traffic_annotation) override {
    *utf16_text = expected_text_;
    return OK;
  }

  void Cancel() override {}

  void OnShutdown() override {}

  const GURL& GetPacURL() const override { return gurl_; }

  const std::u16string& expected_text() const { return expected_text_; }

 private:
  GURL gurl_;
  std::u16string expected_text_;
};

// All of the tests above that use PacFileDecider have tested
// failure to fetch a PAC file via DHCP configuration, so we now test
// success at downloading and parsing, and then success at downloading,
// failure at parsing.

TEST(PacFileDeciderTest, AutodetectDhcpSuccess) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  SynchronousSuccessDhcpFetcher dhcp_fetcher(u"http://bingo/!FindProxyForURL");

  ProxyConfig config;
  config.set_auto_detect(true);

  rules.AddSuccessRule("http://bingo/");
  rules.AddFailDownloadRule("http://wpad/wpad.dat");

  TestCompletionCallback callback;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, nullptr);
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsOk());
  EXPECT_EQ(dhcp_fetcher.expected_text(), decider.script_data().data->utf16());
  EXPECT_TRUE(decider.script_data().from_auto_detect);

  EXPECT_TRUE(decider.effective_config().value().has_pac_url());
  EXPECT_EQ(GURL("http://dhcppac/"),
            decider.effective_config().value().pac_url());
}

TEST(PacFileDeciderTest, AutodetectDhcpFailParse) {
  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);
  SynchronousSuccessDhcpFetcher dhcp_fetcher(u"http://bingo/!invalid-script");

  ProxyConfig config;
  config.set_auto_detect(true);

  rules.AddFailParsingRule("http://bingo/");
  rules.AddFailDownloadRule("http://wpad/wpad.dat");

  TestCompletionCallback callback;
  PacFileDecider decider(&fetcher, &dhcp_fetcher, nullptr);
  // Since there is fallback to DNS-based WPAD, the final error will be that
  // it failed downloading, not that it failed parsing.
  EXPECT_THAT(decider.Start(ProxyConfigWithAnnotation(
                                config, TRAFFIC_ANNOTATION_FOR_TESTS),
                            base::TimeDelta(), true, callback.callback()),
              IsError(kFailedDownloading));
  EXPECT_FALSE(decider.script_data().data);

  EXPECT_FALSE(decider.effective_config().value().has_pac_url());
}

class AsyncFailDhcpFetcher final : public DhcpPacFileFetcher {
 public:
  AsyncFailDhcpFetcher() = default;
  ~AsyncFailDhcpFetcher() override = default;

  int Fetch(std::u16string* utf16_text,
            CompletionOnceCallback callback,
            const NetLogWithSource& net_log,
            const NetworkTrafficAnnotationTag traffic_annotation) override {
    callback_ = std::move(callback);
    base::SingleThreadTaskRunner::GetCurrentDefault()->PostTask(
        FROM_HERE, base::BindOnce(&AsyncFailDhcpFetcher::CallbackWithFailure,
                                  weak_ptr_factory_.GetWeakPtr()));
    return ERR_IO_PENDING;
  }

  void Cancel() override { callback_.Reset(); }

  void OnShutdown() override {}

  const GURL& GetPacURL() const override { return dummy_gurl_; }

  void CallbackWithFailure() {
    if (!callback_.is_null())
      std::move(callback_).Run(ERR_PAC_NOT_IN_DHCP);
  }

 private:
  GURL dummy_gurl_;
  CompletionOnceCallback callback_;
  base::WeakPtrFactory<AsyncFailDhcpFetcher> weak_ptr_factory_{this};
};

TEST(PacFileDeciderTest, DhcpCancelledByDestructor) {
  // This regression test would crash before
  // http://codereview.chromium.org/7044058/
  // Thus, we don't care much about actual results (hence no EXPECT or ASSERT
  // macros below), just that it doesn't crash.
  base::test::TaskEnvironment task_environment;

  Rules rules;
  RuleBasedPacFileFetcher fetcher(&rules);

  auto dhcp_fetcher = std::make_unique<AsyncFailDhcpFetcher>();

  ProxyConfig config;
  config.set_auto_detect(true);
  rules.AddFailDownloadRule("http://wpad/wpad.dat");

  TestCompletionCallback callback;

  // Scope so PacFileDecider gets destroyed early.
  {
    PacFileDecider decider(&fetcher, dhcp_fetcher.get(), nullptr);
    decider.Start(
        ProxyConfigWithAnnotation(config, TRAFFIC_ANNOTATION_FOR_TESTS),
        base::TimeDelta(), true, callback.callback());
  }

  // Run the message loop to let the DHCP fetch complete and post the results
  // back. Before the fix linked to above, this would try to invoke on
  // the callback object provided by PacFileDecider after it was
  // no longer valid.
  base::RunLoop().RunUntilIdle();
}

}  // namespace
}  // namespace net