// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/plugins/plugin_prefs.h"

#include <stddef.h>

#include <memory>

#include "base/bind.h"
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/path_service.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/values.h"
#include "build/build_config.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/plugins/plugin_finder.h"
#include "chrome/browser/plugins/plugin_metadata.h"
#include "chrome/browser/plugins/plugin_prefs_factory.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/common/chrome_constants.h"
#include "chrome/common/chrome_content_client.h"
#include "chrome/common/chrome_paths.h"
#include "chrome/common/pref_names.h"
#include "components/keyed_service/core/keyed_service.h"
#include "components/prefs/scoped_user_pref_update.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/plugin_service.h"
#include "content/public/common/webplugininfo.h"

using content::BrowserThread;

namespace {

bool IsPDFViewerPlugin(const std::u16string& plugin_name) {
  return (plugin_name ==
          base::ASCIIToUTF16(ChromeContentClient::kPDFExtensionPluginName)) ||
         (plugin_name ==
          base::ASCIIToUTF16(ChromeContentClient::kPDFInternalPluginName));
}

}  // namespace

// static
scoped_refptr<PluginPrefs> PluginPrefs::GetForProfile(Profile* profile) {
  return PluginPrefsFactory::GetPrefsForProfile(profile);
}

// static
scoped_refptr<PluginPrefs> PluginPrefs::GetForTestingProfile(
    Profile* profile) {
  return static_cast<PluginPrefs*>(
      PluginPrefsFactory::GetInstance()
          ->SetTestingFactoryAndUse(
              profile,
              base::BindRepeating(&PluginPrefsFactory::CreateForTestingProfile))
          .get());
}

PluginPrefs::PolicyStatus PluginPrefs::PolicyStatusForPlugin(
    const std::u16string& name) const {
  // Special handling for PDF based on its specific policy.
  if (IsPDFViewerPlugin(name) && always_open_pdf_externally_)
    return POLICY_DISABLED;

  return NO_POLICY;
}

bool PluginPrefs::IsPluginEnabled(const content::WebPluginInfo& plugin) const {
  std::unique_ptr<PluginMetadata> plugin_metadata(
      PluginFinder::GetInstance()->GetPluginMetadata(plugin));
  std::u16string group_name = plugin_metadata->name();

  // Check if the plugin or its group is enabled by policy.
  PolicyStatus plugin_status = PolicyStatusForPlugin(plugin.name);
  PolicyStatus group_status = PolicyStatusForPlugin(group_name);
  if (plugin_status == POLICY_ENABLED || group_status == POLICY_ENABLED)
    return true;

  // Check if the plugin or its group is disabled by policy.
  if (plugin_status == POLICY_DISABLED || group_status == POLICY_DISABLED)
    return false;

  // Default to enabled.
  return true;
}

void PluginPrefs::UpdatePdfPolicy(const std::string& pref_name) {
  always_open_pdf_externally_ =
      prefs_->GetBoolean(prefs::kPluginsAlwaysOpenPdfExternally);

  content::PluginService::GetInstance()->PurgePluginListCache(profile_, false);
  std::vector<Profile*> otr_profiles = profile_->GetAllOffTheRecordProfiles();
  for (Profile* otr : otr_profiles)
    content::PluginService::GetInstance()->PurgePluginListCache(otr, false);
}

void PluginPrefs::SetPrefs(PrefService* prefs) {
  prefs_ = prefs;
  bool update_internal_dir = false;
  base::FilePath last_internal_dir =
      prefs_->GetFilePath(prefs::kPluginsLastInternalDirectory);
  base::FilePath cur_internal_dir;
  if (base::PathService::Get(chrome::DIR_INTERNAL_PLUGINS, &cur_internal_dir) &&
      cur_internal_dir != last_internal_dir) {
    update_internal_dir = true;
    prefs_->SetFilePath(
        prefs::kPluginsLastInternalDirectory, cur_internal_dir);
  }

  {  // Scoped update of prefs::kPluginsPluginsList.
    ListPrefUpdate update(prefs_, prefs::kPluginsPluginsList);
    base::ListValue* saved_plugins_list = update.Get();
    if (saved_plugins_list && !saved_plugins_list->empty()) {
      for (auto& plugin_value : *saved_plugins_list) {
        base::DictionaryValue* plugin;
        if (!plugin_value.GetAsDictionary(&plugin)) {
          LOG(WARNING) << "Invalid entry in " << prefs::kPluginsPluginsList;
          continue;  // Oops, don't know what to do with this item.
        }

        std::string path;
        // The plugin list constains all the plugin files in addition to the
        // plugin groups.
        if (plugin->GetString("path", &path)) {
          // Files have a path attribute, groups don't.
          base::FilePath plugin_path = base::FilePath::FromUTF8Unsafe(path);

          // The path to the internal plugin directory changes everytime Chrome
          // is auto-updated, since it contains the current version number. For
          // example, it changes from foobar\Chrome\Application\21.0.1180.83 to
          // foobar\Chrome\Application\21.0.1180.89.
          // However, we would like the settings of internal plugins to persist
          // across Chrome updates. Therefore, we need to recognize those paths
          // that are within the previous internal plugin directory, and update
          // them in the prefs accordingly.
          if (update_internal_dir) {
            base::FilePath relative_path;

            // Extract the part of |plugin_path| that is relative to
            // |last_internal_dir|. For example, |relative_path| will be
            // foo\bar.dll if |plugin_path| is <last_internal_dir>\foo\bar.dll.
            //
            // Every iteration the last path component from |plugin_path| is
            // removed and prepended to |relative_path| until we get up to
            // |last_internal_dir|.
            while (last_internal_dir.IsParent(plugin_path)) {
              relative_path = plugin_path.BaseName().Append(relative_path);

              base::FilePath old_path = plugin_path;
              plugin_path = plugin_path.DirName();
              // To be extra sure that we won't end up in an infinite loop.
              if (old_path == plugin_path) {
                NOTREACHED();
                break;
              }
            }

            // If |relative_path| is empty, |plugin_path| is not within
            // |last_internal_dir|. We don't need to update it.
            if (!relative_path.empty()) {
              plugin_path = cur_internal_dir.Append(relative_path);
              path = plugin_path.AsUTF8Unsafe();
              plugin->SetString("path", path);
            }
          }
        }
      }
    }
  }  // Scoped update of prefs::kPluginsPluginsList.

  UpdatePdfPolicy(prefs::kPluginsAlwaysOpenPdfExternally);
  registrar_.Init(prefs_);
  registrar_.Add(prefs::kPluginsAlwaysOpenPdfExternally,
                 base::BindRepeating(&PluginPrefs::UpdatePdfPolicy,
                                     base::Unretained(this)));
}

void PluginPrefs::ShutdownOnUIThread() {
  prefs_ = nullptr;
  registrar_.RemoveAll();
}

PluginPrefs::PluginPrefs() = default;
PluginPrefs::~PluginPrefs() = default;

void PluginPrefs::SetAlwaysOpenPdfExternallyForTests(
    bool always_open_pdf_externally) {
  always_open_pdf_externally_ = always_open_pdf_externally;
}