// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <stddef.h>

#include <memory>
#include <sstream>
#include <unordered_map>
#include <utility>

#include "base/command_line.h"
#include "base/containers/id_map.h"
#include "base/files/file_util.h"
#include "base/files/scoped_temp_dir.h"
#include "base/functional/bind.h"
#include "base/location.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/scoped_refptr.h"
#include "base/run_loop.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/task/single_thread_task_runner.h"
#include "base/threading/thread_restrictions.h"
#include "components/dom_distiller/content/browser/distiller_javascript_utils.h"
#include "components/dom_distiller/content/browser/distiller_page_web_contents.h"
#include "components/dom_distiller/content/browser/test/test_util.h"
#include "components/dom_distiller/core/article_entry.h"
#include "components/dom_distiller/core/distilled_page_prefs.h"
#include "components/dom_distiller/core/distiller.h"
#include "components/dom_distiller/core/dom_distiller_service.h"
#include "components/dom_distiller/core/proto/distilled_article.pb.h"
#include "components/dom_distiller/core/proto/distilled_page.pb.h"
#include "components/dom_distiller/core/task_tracker.h"
#include "components/leveldb_proto/public/proto_database.h"
#include "components/leveldb_proto/public/proto_database_provider.h"
#include "components/sync_preferences/testing_pref_service_syncable.h"
#include "content/public/browser/browser_context.h"
#include "content/public/browser/storage_partition.h"
#include "content/public/common/isolated_world_ids.h"
#include "content/public/test/browser_test.h"
#include "content/public/test/content_browser_test.h"
#include "content/shell/browser/shell.h"
#include "google/protobuf/io/coded_stream.h"
#include "google/protobuf/io/zero_copy_stream_impl_lite.h"
#include "net/dns/mock_host_resolver.h"
#include "third_party/dom_distiller_js/dom_distiller.pb.h"

using content::ContentBrowserTest;

namespace dom_distiller {

// Factory for creating a Distiller that creates different DomDistillerOptions
// for different URLs, i.e. a specific kOriginalUrl option for each URL.
class TestDistillerFactoryImpl : public DistillerFactory {
 public:
  TestDistillerFactoryImpl(
      std::unique_ptr<DistillerURLFetcherFactory> distiller_url_fetcher_factory,
      const dom_distiller::proto::DomDistillerOptions& dom_distiller_options)
      : distiller_url_fetcher_factory_(
            std::move(distiller_url_fetcher_factory)),
        dom_distiller_options_(dom_distiller_options) {}

  ~TestDistillerFactoryImpl() override = default;

  std::unique_ptr<Distiller> CreateDistiller() override {
    return std::make_unique<DistillerImpl>(
        *distiller_url_fetcher_factory_,
        DistillerOptions(dom_distiller_options_));
  }

 private:
  std::unique_ptr<DistillerURLFetcherFactory> distiller_url_fetcher_factory_;
  dom_distiller::proto::DomDistillerOptions dom_distiller_options_;
};

namespace {

// The url to distill.
const char* kUrlSwitch = "url";

// A space-separated list of urls to distill.
const char* kUrlsSwitch = "urls";

// Indicates that DNS resolution should be disabled for this test.
const char* kDisableDnsSwitch = "disable-dns";

// Will write the distilled output to the given file instead of to stdout.
const char* kOutputFile = "output-file";

// Indicates to output a serialized protocol buffer instead of human-readable
// output.
const char* kShouldOutputBinary = "output-binary";

// Indicates to output only the text of the article and not the enclosing html.
const char* kExtractTextOnly = "extract-text-only";

// Indicates to include debug output.
const char* kDebugLevel = "debug-level";

// A semi-colon-separated (i.e. ';') list of original URLs corresponding to
// "kUrlsSwitch".
const char* kOriginalUrls = "original-urls";

// The pagination algorithm to use, one of "next", "pagenum".
const char* kPaginationAlgo = "pagination-algo";

// Maximum number of concurrent started extractor requests.
const int kMaxExtractorTasks = 8;

std::unique_ptr<DomDistillerService> CreateDomDistillerService(
    content::BrowserContext* context,
    sync_preferences::TestingPrefServiceSyncable* pref_service) {
  // Setting up PrefService for DistilledPagePrefs.
  DistilledPagePrefs::RegisterProfilePrefs(pref_service->registry());

  auto distiller_page_factory =
      std::make_unique<DistillerPageWebContentsFactory>(context);
  auto distiller_url_fetcher_factory =
      std::make_unique<DistillerURLFetcherFactory>(
          context->GetDefaultStoragePartition()
              ->GetURLLoaderFactoryForBrowserProcess());

  dom_distiller::proto::DomDistillerOptions options;
  if (base::CommandLine::ForCurrentProcess()->HasSwitch(kExtractTextOnly)) {
    options.set_extract_text_only(true);
  }
  int debug_level = 0;
  if (base::CommandLine::ForCurrentProcess()->HasSwitch(kDebugLevel) &&
      base::StringToInt(
          base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
              kDebugLevel),
          &debug_level)) {
    options.set_debug_level(debug_level);
  }
  // Options for pagination algorithm:
  // - "next": detect anchors with "next" text
  // - "pagenum": detect anchors with numeric page numbers
  // Default is "next".
  if (base::CommandLine::ForCurrentProcess()->HasSwitch(kPaginationAlgo)) {
      options.set_pagination_algo(
          base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
              kPaginationAlgo));
  }

  auto distiller_factory = std::make_unique<TestDistillerFactoryImpl>(
      std::move(distiller_url_fetcher_factory), options);

  return std::make_unique<DomDistillerService>(
      std::move(distiller_factory), std::move(distiller_page_factory),
      std::make_unique<DistilledPagePrefs>(pref_service),
      /* distiller_ui_handle */ nullptr);
}

bool WriteProtobufWithSize(
    const google::protobuf::MessageLite& message,
    google::protobuf::io::ZeroCopyOutputStream* output_stream) {
  google::protobuf::io::CodedOutputStream coded_output(output_stream);

  // Write the size.
  const int size = message.ByteSizeLong();
  coded_output.WriteLittleEndian32(size);
  message.SerializeWithCachedSizes(&coded_output);
  return !coded_output.HadError();
}

std::string GetReadableArticleString(
    const DistilledArticleProto& article_proto) {
  std::stringstream output;
  output << "Article Title: " << article_proto.title() << std::endl;
  output << "# of pages: " << article_proto.pages_size() << std::endl;
  for (int i = 0; i < article_proto.pages_size(); ++i) {
    if (i > 0) output << std::endl;
    const DistilledPageProto& page = article_proto.pages(i);
    output << "Page " << i << std::endl;
    output << "URL: " << page.url() << std::endl;
    output << "Content: " << page.html() << std::endl;
    if (page.has_debug_info() && page.debug_info().has_log())
      output << "Log: " << page.debug_info().log() << std::endl;
    if (page.has_pagination_info()) {
      if (page.pagination_info().has_next_page()) {
        output << "Next Page: " << page.pagination_info().next_page()
               << std::endl;
      }
      if (page.pagination_info().has_prev_page()) {
        output << "Prev Page: " << page.pagination_info().prev_page()
               << std::endl;
      }
    }
  }
  return output.str();
}

}  // namespace

class ContentExtractionRequest : public ViewRequestDelegate {
 public:
  ContentExtractionRequest(const GURL& url) : url_(url) {}

  void Start(DomDistillerService* service,
             const gfx::Size& render_view_size,
             base::OnceClosure finished_callback) {
    finished_callback_ = std::move(finished_callback);
    viewer_handle_ =
        service->ViewUrl(this,
                         service->CreateDefaultDistillerPage(render_view_size),
                         url_);
  }

  DistilledArticleProto GetArticleCopy() {
    return *article_proto_;
  }

  static std::vector<std::unique_ptr<ContentExtractionRequest>>
  CreateForCommandLine(const base::CommandLine& command_line) {
    std::vector<std::unique_ptr<ContentExtractionRequest>> requests;
    if (command_line.HasSwitch(kUrlSwitch)) {
      GURL url;
      std::string url_string = command_line.GetSwitchValueASCII(kUrlSwitch);
      url = GURL(url_string);
      if (url.is_valid()) {
        requests.push_back(std::make_unique<ContentExtractionRequest>(url));
      }
    } else if (command_line.HasSwitch(kUrlsSwitch)) {
      std::string urls_string = command_line.GetSwitchValueASCII(kUrlsSwitch);
      std::vector<std::string> urls = base::SplitString(
          urls_string, " ", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
      // Check for original-urls switch, which must exactly pair up with
      // |kUrlsSwitch| i.e. number of original urls must be same as that of
      // urls.
      std::vector<std::string> original_urls;
      if (command_line.HasSwitch(kOriginalUrls)) {
        std::string original_urls_string =
            command_line.GetSwitchValueASCII(kOriginalUrls);
        original_urls = base::SplitString(
            original_urls_string, " ",
            base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
        if (original_urls.size() != urls.size())
          original_urls.clear();
      }
      for (size_t i = 0; i < urls.size(); ++i) {
        GURL url(urls[i]);
        if (url.is_valid()) {
          requests.push_back(std::make_unique<ContentExtractionRequest>(url));
        } else {
          ADD_FAILURE() << "Bad url";
        }
      }
    }
    if (requests.empty()) {
      ADD_FAILURE() << "No valid url provided";
    }

    return requests;
  }

 private:
  void OnArticleUpdated(ArticleDistillationUpdate article_update) override {}

  void OnArticleReady(const DistilledArticleProto* article_proto) override {
    article_proto_ = article_proto;
    CHECK(article_proto->pages_size()) << "Failed extracting " << url_;
    base::SingleThreadTaskRunner::GetCurrentDefault()->PostTask(
        FROM_HERE, std::move(finished_callback_));
  }

  raw_ptr<const DistilledArticleProto> article_proto_;
  std::unique_ptr<ViewerHandle> viewer_handle_;
  GURL url_;
  base::OnceClosure finished_callback_;
};

class ContentExtractor : public ContentBrowserTest {
 public:
  ContentExtractor()
      : pending_tasks_(0),
        max_tasks_(kMaxExtractorTasks),
        next_request_(0),
        output_data_(),
        protobuf_output_stream_(
            std::make_unique<google::protobuf::io::StringOutputStream>(
                &output_data_)) {}

  // Change behavior of the default host resolver to avoid DNS lookup errors, so
  // we can make network calls.
  void SetUpOnMainThread() override {
    if (!base::CommandLine::ForCurrentProcess()->HasSwitch(kDisableDnsSwitch)) {
      EnableDNSLookupForThisTest();
    }
    AddComponentsResources();
  }

  void TearDownOnMainThread() override { DisableDNSLookupForThisTest(); }

 protected:
  // Creates the DomDistillerService and creates and starts the extraction
  // request.
  void Start(base::OnceClosure quit_closure) {
    quit_closure_ = std::move(quit_closure);
    const base::CommandLine& command_line =
        *base::CommandLine::ForCurrentProcess();
    requests_ = ContentExtractionRequest::CreateForCommandLine(command_line);
    content::BrowserContext* context =
        shell()->web_contents()->GetBrowserContext();
    pref_service_ =
        std::make_unique<sync_preferences::TestingPrefServiceSyncable>();

    service_ = CreateDomDistillerService(context, pref_service_.get());
    PumpQueue();
  }

  void PumpQueue() {
    while (pending_tasks_ < max_tasks_ && next_request_ < requests_.size()) {
      requests_[next_request_]->Start(
          service_.get(), shell()->web_contents()->GetContainerBounds().size(),
          base::BindOnce(&ContentExtractor::FinishRequest,
                         base::Unretained(this)));
      ++next_request_;
      ++pending_tasks_;
    }
  }

 private:
  // Change behavior of the default host resolver to allow DNS lookup
  // to proceed instead of being blocked by the test infrastructure.
  void EnableDNSLookupForThisTest() {
    // mock_host_resolver_override_ takes ownership of the resolver.
    auto resolver =
        base::MakeRefCounted<net::RuleBasedHostResolverProc>(host_resolver());
    resolver->AllowDirectLookup("*");
    mock_host_resolver_override_ =
        std::make_unique<net::ScopedDefaultHostResolverProc>(resolver.get());
  }

  // We need to reset the DNS lookup when we finish, or the test will fail.
  void DisableDNSLookupForThisTest() {
    mock_host_resolver_override_.reset();
  }

  void FinishRequest() {
    --pending_tasks_;
    if (next_request_ == requests_.size() && pending_tasks_ == 0) {
      Finish();
    } else {
      PumpQueue();
    }
  }

  void DoArticleOutput() {
    base::ScopedAllowBlockingForTesting allow_blocing;
    const base::CommandLine& command_line =
        *base::CommandLine::ForCurrentProcess();
    for (size_t i = 0; i < requests_.size(); ++i) {
      const DistilledArticleProto& article = requests_[i]->GetArticleCopy();
      if (command_line.HasSwitch(kShouldOutputBinary)) {
        WriteProtobufWithSize(article, protobuf_output_stream_.get());
      } else {
        output_data_ += GetReadableArticleString(article) + "\n";
      }
    }

    if (command_line.HasSwitch(kOutputFile)) {
      base::FilePath filename = command_line.GetSwitchValuePath(kOutputFile);
      ASSERT_TRUE(base::WriteFile(filename, output_data_));
    } else {
      VLOG(0) << output_data_;
    }
  }

  void Finish() {
    DoArticleOutput();
    requests_.clear();
    service_.reset();
    base::SingleThreadTaskRunner::GetCurrentDefault()->PostTask(
        FROM_HERE, std::move(quit_closure_));
  }

  size_t pending_tasks_;
  size_t max_tasks_;
  size_t next_request_;

  std::unique_ptr<net::ScopedDefaultHostResolverProc>
      mock_host_resolver_override_;
  std::unique_ptr<sync_preferences::TestingPrefServiceSyncable> pref_service_;
  std::unique_ptr<DomDistillerService> service_;
  std::vector<std::unique_ptr<ContentExtractionRequest>> requests_;

  std::string output_data_;
  std::unique_ptr<google::protobuf::io::StringOutputStream>
      protobuf_output_stream_;

  base::OnceClosure quit_closure_;
};

IN_PROC_BROWSER_TEST_F(ContentExtractor, MANUAL_ExtractUrl) {
  base::RunLoop loop;
  SetDistillerJavaScriptWorldId(content::ISOLATED_WORLD_ID_CONTENT_END);
  Start(loop.QuitWhenIdleClosure());
  loop.Run();
}

}  // namespace dom_distiller