// 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 "chrome/browser/ui/webui/about/about_ui.h"

#include <stddef.h>
#include <stdint.h>

#include <algorithm>
#include <memory>
#include <string>
#include <string_view>
#include <utility>
#include <vector>

#include "base/command_line.h"
#include "base/containers/to_vector.h"
#include "base/feature_list.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/format_macros.h"
#include "base/functional/bind.h"
#include "base/functional/callback.h"
#include "base/functional/callback_helpers.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/ref_counted_memory.h"
#include "base/strings/escape.h"
#include "base/strings/strcat.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/task/thread_pool.h"
#include "base/threading/scoped_blocking_call.h"
#include "base/threading/thread.h"
#include "base/values.h"
#include "build/build_config.h"
#include "chrome/browser/about_flags.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/ui/webui/chrome_urls/chrome_urls_ui.h"
#include "chrome/common/chrome_paths.h"
#include "chrome/common/url_constants.h"
#include "chrome/grit/branded_strings.h"
#include "chrome/grit/browser_resources.h"
#include "chrome/grit/generated_resources.h"
#include "components/grit/components_resources.h"
#include "components/strings/grit/components_locale_settings.h"
#include "components/strings/grit/components_strings.h"
#include "components/webui/about/credit_utils.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/url_data_source.h"
#include "content/public/browser/web_contents.h"
#include "content/public/browser/webui_config_map.h"
#include "content/public/common/url_constants.h"
#include "net/base/filename_util.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/base/webui/web_ui_util.h"
#include "url/gurl.h"

#if !BUILDFLAG(IS_ANDROID)
#include "chrome/browser/ui/webui/theme_source.h"
#endif

#if BUILDFLAG(IS_CHROMEOS)
#include <map>

#include "ash/constants/webui_url_constants.h"
#include "ash/strings/grit/ash_strings.h"
#include "base/base64.h"
#include "base/strings/strcat.h"
#include "chrome/browser/ash/crostini/crostini_features.h"
#include "chrome/browser/ash/crostini/crostini_manager.h"
#include "chrome/browser/ash/customization/customization_document.h"
#include "chrome/browser/ash/login/demo_mode/demo_setup_controller.h"
#include "chrome/browser/ash/login/wizard_controller.h"
#include "chrome/browser/browser_process_platform_part_ash.h"
#include "chrome/common/webui_url_constants.h"
#include "chromeos/ash/components/system/statistics_provider.h"
#include "components/component_updater/ash/component_manager_ash.h"
#include "components/language/core/common/locale_util.h"
#include "third_party/cros_system_api/dbus/service_constants.h"
#include "third_party/zlib/google/compression_utils.h"
#endif

using content::BrowserThread;

namespace {

constexpr char kCreditsJsPath[] = "credits.js";
constexpr char kCreditsCssPath[] = "credits.css";
constexpr char kStatsJsPath[] = "stats.js";
constexpr char kStringsJsPath[] = "strings.js";

#if BUILDFLAG(IS_CHROMEOS)

constexpr char kTerminaCreditsPath[] = "about_os_credits.html";

// Source for chrome://os-credits. On some devices, this will be compressed.
// Check both.
constexpr char kChromeOSCreditsPath[] =
    "/opt/google/chrome/resources/about_os_credits.html";
constexpr char kChromeOSCreditsCompressedPath[] =
    "/opt/google/chrome/resources/about_os_credits.html.gz";

// Loads bundled terms of service contents (Eula, OEM Eula, Play Store Terms).
// The online version of terms is fetched in OOBE screen javascript. This is
// intentional because chrome://terms runs in a privileged webui context and
// should never load from untrusted places.
class ChromeOSTermsHandler
    : public base::RefCountedThreadSafe<ChromeOSTermsHandler> {
 public:
  ChromeOSTermsHandler(const ChromeOSTermsHandler&) = delete;
  ChromeOSTermsHandler& operator=(const ChromeOSTermsHandler&) = delete;

  static void Start(const std::string& path,
                    content::URLDataSource::GotDataCallback callback) {
    scoped_refptr<ChromeOSTermsHandler> handler(
        new ChromeOSTermsHandler(path, std::move(callback)));
    handler->StartOnUIThread();
  }

 private:
  friend class base::RefCountedThreadSafe<ChromeOSTermsHandler>;

  ChromeOSTermsHandler(const std::string& path,
                       content::URLDataSource::GotDataCallback callback)
      : path_(path),
        callback_(std::move(callback)),
        // Previously we were using "initial locale" http://crbug.com/40915798
        locale_(g_browser_process->GetApplicationLocale()) {}

  virtual ~ChromeOSTermsHandler() = default;

  void StartOnUIThread() {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    if (path_ == ash::kChromeUITermsOemEulaURLPath) {
      // Load local OEM EULA from the disk.
      base::ThreadPool::PostTaskAndReply(
          FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_VISIBLE},
          base::BindOnce(&ChromeOSTermsHandler::LoadOemEulaFileAsync, this),
          base::BindOnce(&ChromeOSTermsHandler::ResponseOnUIThread, this));
    } else if (path_ == ash::kChromeUITermsArcTermsURLPath) {
      LOG(WARNING) << "Could not load offline Play Store ToS.";
    } else if (path_ == ash::kChromeUITermsArcPrivacyPolicyURLPath) {
      LOG(WARNING) << "Could not load offline Play Store privacy policy.";
    } else {
      NOTREACHED();
    }
  }

  void LoadOemEulaFileAsync() {
    base::ScopedBlockingCall scoped_blocking_call(
        FROM_HERE, base::BlockingType::MAY_BLOCK);

    const ash::StartupCustomizationDocument* customization =
        ash::StartupCustomizationDocument::GetInstance();
    if (!customization->IsReady()) {
      return;
    }

    base::FilePath oem_eula_file_path;
    if (net::FileURLToFilePath(GURL(customization->GetEULAPage(locale_)),
                               &oem_eula_file_path)) {
      if (!base::ReadFileToString(oem_eula_file_path, &contents_)) {
        contents_.clear();
      }
    }
  }

  void ResponseOnUIThread() {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    // If we fail to load Chrome OS EULA from disk, load it from resources.
    // Do nothing if OEM EULA or Play Store ToS load failed.
    if (contents_.empty() && path_.empty()) {
      contents_ =
          ui::ResourceBundle::GetSharedInstance().LoadLocalizedResourceString(
              IDS_TERMS_HTML);
    }
    std::move(callback_).Run(
        base::MakeRefCounted<base::RefCountedString>(std::move(contents_)));
  }

  // Path in the URL.
  const std::string path_;

  // Callback to run with the response.
  content::URLDataSource::GotDataCallback callback_;

  // Locale of the EULA.
  const std::string locale_;

  // EULA contents that was loaded from file.
  std::string contents_;
};

class ChromeOSCreditsHandler
    : public base::RefCountedThreadSafe<ChromeOSCreditsHandler> {
 public:
  ChromeOSCreditsHandler(const ChromeOSCreditsHandler&) = delete;
  ChromeOSCreditsHandler& operator=(const ChromeOSCreditsHandler&) = delete;

  // |prefix| allows tests to specify different location for the credits files.
  static void Start(const std::string& path,
                    content::URLDataSource::GotDataCallback callback,
                    const base::FilePath& prefix) {
    scoped_refptr<ChromeOSCreditsHandler> handler(
        new ChromeOSCreditsHandler(path, std::move(callback), prefix));
    handler->StartOnUIThread();
  }

 private:
  friend class base::RefCountedThreadSafe<ChromeOSCreditsHandler>;

  ChromeOSCreditsHandler(const std::string& path,
                         content::URLDataSource::GotDataCallback callback,
                         const base::FilePath& prefix)
      : path_(path), callback_(std::move(callback)), prefix_(prefix) {}

  virtual ~ChromeOSCreditsHandler() = default;

  void StartOnUIThread() {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    // Load local Chrome OS credits from the disk.
    base::ThreadPool::PostTaskAndReply(
        FROM_HERE, {base::MayBlock(), base::TaskPriority::BEST_EFFORT},
        base::BindOnce(&ChromeOSCreditsHandler::LoadCreditsFileAsync, this),
        base::BindOnce(&ChromeOSCreditsHandler::ResponseOnUIThread, this));
  }

  // LoadCreditsFileAsync first attempts to load the uncompressed credits file.
  // Then, if that's not present, it attempts to load and decompress the
  // compressed credits file.
  // If both fails, fall back to default contents as handled in
  // ResponseOnUIThread.
  void LoadCreditsFileAsync() {
    if (prefix_.empty()) {
      prefix_ = base::FilePath(kChromeOSCreditsPath).DirName();
    }
    base::FilePath credits =
        prefix_.Append(base::FilePath(kChromeOSCreditsPath).BaseName());
    if (base::ReadFileToString(credits, &contents_)) {
      // Decompressed present; return.
      return;
    }

    // Decompressed not present; load compressed.
    base::FilePath compressed_credits = prefix_.Append(
        base::FilePath(kChromeOSCreditsCompressedPath).BaseName());
    std::string compressed;
    if (!base::ReadFileToString(compressed_credits, &compressed)) {
      // File with credits not found, ResponseOnUIThread will load credits
      // from resources if contents_ is empty.
      contents_.clear();
      return;
    }

    // Decompress.
    if (!compression::GzipUncompress(compressed, &contents_)) {
      LOG(DFATAL) << "Decompressing os credits failed";
      contents_.clear();
      return;
    }
  }

  void ResponseOnUIThread() {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    // If we fail to load Chrome OS credits from disk, load it from resources.
    if (contents_.empty()) {
      contents_ =
          ui::ResourceBundle::GetSharedInstance().LoadDataResourceString(
              IDR_OS_CREDITS_HTML);
    }
    std::move(callback_).Run(
        base::MakeRefCounted<base::RefCountedString>(std::move(contents_)));
  }

  // Path in the URL.
  const std::string path_;

  // Callback to run with the response.
  content::URLDataSource::GotDataCallback callback_;

  // Chrome OS credits contents that was loaded from file.
  std::string contents_;

  // Directory containing files to read.
  base::FilePath prefix_;
};

class CrostiniCreditsHandler
    : public base::RefCountedThreadSafe<CrostiniCreditsHandler> {
 public:
  CrostiniCreditsHandler(const CrostiniCreditsHandler&) = delete;
  CrostiniCreditsHandler& operator=(const CrostiniCreditsHandler&) = delete;

  static void Start(Profile* profile,
                    const std::string& path,
                    content::URLDataSource::GotDataCallback callback) {
    scoped_refptr<CrostiniCreditsHandler> handler(
        new CrostiniCreditsHandler(profile, path, std::move(callback)));
    handler->StartOnUIThread();
  }

 private:
  friend class base::RefCountedThreadSafe<CrostiniCreditsHandler>;

  CrostiniCreditsHandler(Profile* profile,
                         const std::string& path,
                         content::URLDataSource::GotDataCallback callback)
      : path_(path), callback_(std::move(callback)), profile_(profile) {}

  virtual ~CrostiniCreditsHandler() = default;

  void StartOnUIThread() {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    if (crostini::CrostiniFeatures::Get()->IsAllowedNow(profile_)) {
      crostini::CrostiniManager::GetForProfile(profile_)->GetInstallLocation(
          base::BindOnce(&CrostiniCreditsHandler::LoadCredits, this));
    } else {
      RespondWithPlaceholder();
    }
  }

  void LoadCredits(base::FilePath path) {
    if (path.empty()) {
      RespondWithPlaceholder();
      return;
    }

    // Load crostini credits from the disk.
    base::ThreadPool::PostTaskAndReply(
        FROM_HERE, {base::MayBlock(), base::TaskPriority::BEST_EFFORT},
        base::BindOnce(&CrostiniCreditsHandler::LoadCrostiniCreditsFileAsync,
                       this, path.Append(kTerminaCreditsPath)),
        base::BindOnce(&CrostiniCreditsHandler::RespondOnUIThread, this));
  }

  void LoadCrostiniCreditsFileAsync(base::FilePath credits_file_path) {
    if (!base::ReadFileToString(credits_file_path, &contents_)) {
      // File with credits not found, RespondOnUIThread will load a placeholder
      // if contents_ is empty.
      contents_.clear();
    }
  }

  void RespondWithPlaceholder() {
    contents_.clear();
    RespondOnUIThread();
  }

  void RespondOnUIThread() {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    // If we fail to load Linux credits from disk, use the placeholder.
    if (contents_.empty()) {
      contents_ = l10n_util::GetStringUTF8(IDS_CROSTINI_CREDITS_PLACEHOLDER);
    }
    std::move(callback_).Run(
        base::MakeRefCounted<base::RefCountedString>(std::move(contents_)));
  }

  // Path in the URL.
  const std::string path_;

  // Callback to run with the response.
  content::URLDataSource::GotDataCallback callback_;

  // Linux credits contents that was loaded from file.
  std::string contents_;

  raw_ptr<Profile> profile_;
};
#endif

}  // namespace

// Individual about handlers ---------------------------------------------------

namespace about_ui {

void AppendHeader(std::string* output, const std::string& unescaped_title) {
  output->append("<!DOCTYPE HTML>\n<html>\n<head>\n");
  output->append("<meta charset='utf-8'>\n");
  output->append("<meta name='color-scheme' content='light dark'>\n");
  if (!unescaped_title.empty()) {
    output->append("<title>");
    output->append(base::EscapeForHTML(unescaped_title));
    output->append("</title>\n");
  }
}

void AppendBody(std::string* output) {
  output->append("</head>\n<body>\n");
}

void AppendFooter(std::string* output) {
  output->append("</body>\n</html>\n");
}

}  // namespace about_ui

using about_ui::AppendBody;
using about_ui::AppendFooter;
using about_ui::AppendHeader;

namespace {

#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_OPENBSD)
std::string AboutLinuxProxyConfig() {
  std::string data;
  AppendHeader(&data,
               l10n_util::GetStringUTF8(IDS_ABOUT_LINUX_PROXY_CONFIG_TITLE));
  data.append("<style>body { max-width: 70ex; padding: 2ex 5ex; }</style>");
  AppendBody(&data);
  base::FilePath binary = base::CommandLine::ForCurrentProcess()->GetProgram();
  data.append(
      l10n_util::GetStringFUTF8(IDS_ABOUT_LINUX_PROXY_CONFIG_BODY,
                                l10n_util::GetStringUTF16(IDS_PRODUCT_NAME),
                                base::ASCIIToUTF16(binary.BaseName().value())));
  AppendFooter(&data);
  return data;
}
#endif

}  // namespace

AboutUIConfigBase::AboutUIConfigBase(std::string_view host)
    : DefaultWebUIConfig(content::kChromeUIScheme, host) {}

CreditsUIConfig::CreditsUIConfig()
    : AboutUIConfigBase(chrome::kChromeUICreditsHost) {}

#if !BUILDFLAG(IS_ANDROID)
TermsUIConfig::TermsUIConfig()
    : AboutUIConfigBase(chrome::kChromeUITermsHost) {}
#endif

#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_OPENBSD)
LinuxProxyConfigUI::LinuxProxyConfigUI()
    : AboutUIConfigBase(chrome::kChromeUILinuxProxyConfigHost) {}
#endif

#if BUILDFLAG(IS_CHROMEOS)
OSCreditsUI::OSCreditsUI() : AboutUIConfigBase(ash::kChromeUIOSCreditsHost) {}

CrostiniCreditsUI::CrostiniCreditsUI()
    : AboutUIConfigBase(ash::kChromeUICrostiniCreditsHost) {}
#endif

// AboutUIHTMLSource ----------------------------------------------------------

AboutUIHTMLSource::AboutUIHTMLSource(const std::string& source_name,
                                     Profile* profile)
    : source_name_(source_name), profile_(profile) {}

AboutUIHTMLSource::~AboutUIHTMLSource() = default;

std::string AboutUIHTMLSource::GetSource() {
  return source_name_;
}

void AboutUIHTMLSource::StartDataRequest(
    const GURL& url,
    const content::WebContents::Getter& wc_getter,
    content::URLDataSource::GotDataCallback callback) {
  // TODO(crbug.com/40050262): Simplify usages of |path| since |url| is
  // available.
  const std::string path = content::URLDataSource::URLToRequestPath(url);
  std::string response;
  // Add your data source here, in alphabetical order.
  if (source_name_ == chrome::kChromeUICreditsHost) {
    int idr = IDR_ABOUT_UI_CREDITS_HTML;
    if (path == kCreditsJsPath) {
      idr = IDR_ABOUT_UI_CREDITS_JS;
    } else if (path == kCreditsCssPath) {
      idr = IDR_ABOUT_UI_CREDITS_CSS;
    }
    if (idr == IDR_ABOUT_UI_CREDITS_HTML) {
      response = about_ui::GetCredits(true /*include_scripts*/);
    } else {
      response =
          ui::ResourceBundle::GetSharedInstance().LoadDataResourceString(idr);
    }
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_OPENBSD)
  } else if (source_name_ == chrome::kChromeUILinuxProxyConfigHost) {
    response = AboutLinuxProxyConfig();
#endif
#if BUILDFLAG(IS_CHROMEOS)
  } else if (source_name_ == ash::kChromeUIOSCreditsHost ||
             source_name_ == ash::kChromeUICrostiniCreditsHost) {
    int idr = IDR_ABOUT_UI_CREDITS_HTML;
    if (path == kCreditsJsPath) {
      idr = IDR_ABOUT_UI_CREDITS_JS;
    } else if (path == kCreditsCssPath) {
      idr = IDR_ABOUT_UI_CREDITS_CSS;
    }
    if (idr == IDR_ABOUT_UI_CREDITS_HTML) {
      if (source_name_ == ash::kChromeUIOSCreditsHost) {
        ChromeOSCreditsHandler::Start(path, std::move(callback),
                                      os_credits_prefix_);
      } else if (source_name_ == ash::kChromeUICrostiniCreditsHost) {
        CrostiniCreditsHandler::Start(profile(), path, std::move(callback));
      } else {
        NOTREACHED();
      }
      return;
    }

    response =
        ui::ResourceBundle::GetSharedInstance().LoadDataResourceString(idr);
#endif
#if !BUILDFLAG(IS_ANDROID)
  } else if (source_name_ == chrome::kChromeUITermsHost) {
#if BUILDFLAG(IS_CHROMEOS)
    if (!path.empty()) {
      ChromeOSTermsHandler::Start(path, std::move(callback));
      return;
    }
#endif
    response =
        ui::ResourceBundle::GetSharedInstance().LoadLocalizedResourceString(
            IDS_TERMS_HTML);
#endif
  }

  FinishDataRequest(response, std::move(callback));
}

void AboutUIHTMLSource::FinishDataRequest(
    const std::string& html,
    content::URLDataSource::GotDataCallback callback) {
  std::move(callback).Run(base::MakeRefCounted<base::RefCountedString>(html));
}

std::string AboutUIHTMLSource::GetMimeType(const GURL& url) {
  const std::string_view path = url.path().substr(1);
  if (path == kCreditsJsPath || path == kStatsJsPath ||
      path == kStringsJsPath) {
    return "application/javascript";
  }

  if (path == kCreditsCssPath) {
    return "text/css";
  }

  return "text/html";
}

std::string AboutUIHTMLSource::GetAccessControlAllowOriginForOrigin(
    const std::string& origin) {
#if BUILDFLAG(IS_CHROMEOS)
  // Allow chrome://oobe to load chrome://terms via XHR.
  if (source_name_ == chrome::kChromeUITermsHost &&
      base::StartsWith(ash::kChromeUIOobeURL, origin,
                       base::CompareCase::SENSITIVE)) {
    return origin;
  }
#endif
  return content::URLDataSource::GetAccessControlAllowOriginForOrigin(origin);
}

AboutUI::AboutUI(content::WebUI* web_ui, const GURL& url)
    : WebUIController(web_ui) {
  Profile* profile = Profile::FromWebUI(web_ui);

#if !BUILDFLAG(IS_ANDROID)
  // Set up the chrome://theme/ source.
  content::URLDataSource::Add(profile, std::make_unique<ThemeSource>(profile));
#endif

  content::URLDataSource::Add(
      profile, std::make_unique<AboutUIHTMLSource>(url.GetHost(), profile));
}