// 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/chromeos/accessibility/accessibility_util.h"

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/logging.h"
#include "chrome/browser/accessibility/accessibility_extension_api.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/extensions/extension_tts_api_platform.h"
#include "chrome/browser/extensions/component_loader.h"
#include "chrome/browser/extensions/extension_service.h"
#include "chrome/browser/extensions/file_reader.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/profiles/profile_manager.h"
#include "chrome/common/extensions/extension_messages.h"
#include "chrome/common/extensions/extension_resource.h"
#include "chrome/common/pref_names.h"
#include "content/browser/accessibility/browser_accessibility_state.h"
#include "content/browser/renderer_host/render_view_host.h"
#include "content/public/browser/web_contents.h"
#include "content/public/browser/web_ui.h"
#include "grit/browser_resources.h"
#include "grit/generated_resources.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/base/resource/resource_bundle.h"

namespace chromeos {
namespace accessibility {

// Helper class that directly loads an extension's content scripts into
// all of the frames corresponding to a given RenderViewHost.
class ContentScriptLoader {
 public:
  // Initialize the ContentScriptLoader with the ID of the extension
  // and the RenderViewHost where the scripts should be loaded.
  ContentScriptLoader(const std::string& extension_id,
                      RenderViewHost* render_view_host)
      : extension_id_(extension_id),
        render_view_host_(render_view_host) {}

  // Call this once with the ExtensionResource corresponding to each
  // content script to be loaded.
  void AppendScript(ExtensionResource resource) {
    resources_.push(resource);
  }

  // Fianlly, call this method once to fetch all of the resources and
  // load them. This method will delete this object when done.
  void Run() {
    if (resources_.empty()) {
      delete this;
      return;
    }

    ExtensionResource resource = resources_.front();
    resources_.pop();
    scoped_refptr<FileReader> reader(new FileReader(resource, base::Bind(
        &ContentScriptLoader::OnFileLoaded, base::Unretained(this))));
    reader->Start();
  }

 private:
  void OnFileLoaded(bool success, const std::string& data) {
    if (success) {
      ExtensionMsg_ExecuteCode_Params params;
      params.request_id = 0;
      params.extension_id = extension_id_;
      params.is_javascript = true;
      params.code = data;
      params.all_frames = true;
      params.in_main_world = false;
      render_view_host_->Send(new ExtensionMsg_ExecuteCode(
          render_view_host_->routing_id(), params));
    }
    Run();
  }

  std::string extension_id_;
  RenderViewHost* render_view_host_;
  std::queue<ExtensionResource> resources_;
};

void EnableAccessibility(bool enabled, content::WebUI* login_web_ui) {
  bool accessibility_enabled = g_browser_process &&
      g_browser_process->local_state()->GetBoolean(
          prefs::kSpokenFeedbackEnabled);
  if (accessibility_enabled == enabled) {
    LOG(INFO) << "Accessibility is already " <<
        (enabled ? "enabled" : "disabled") << ".  Going to do nothing.";
    return;
  }

  g_browser_process->local_state()->SetBoolean(
      prefs::kSpokenFeedbackEnabled, enabled);
  g_browser_process->local_state()->CommitPendingWrite();
  ExtensionAccessibilityEventRouter::GetInstance()->
      SetAccessibilityEnabled(enabled);
  BrowserAccessibilityState::GetInstance()->OnAccessibilityEnabledManually();

  Speak(enabled ?
        l10n_util::GetStringUTF8(IDS_CHROMEOS_ACC_ACCESS_ENABLED).c_str() :
        l10n_util::GetStringUTF8(IDS_CHROMEOS_ACC_ACCESS_DISABLED).c_str());

  // Load/Unload ChromeVox
  Profile* profile = ProfileManager::GetDefaultProfile();
  ExtensionService* extension_service =
      profile->GetExtensionService();
  FilePath path = FilePath(extension_misc::kAccessExtensionPath)
      .AppendASCII(extension_misc::kChromeVoxDirectoryName);
  if (enabled) { // Load ChromeVox
    const Extension* extension =
        extension_service->component_loader()->Add(IDR_CHROMEVOX_MANIFEST,
                                                   path);

    if (login_web_ui) {
      RenderViewHost* render_view_host =
          login_web_ui->GetWebContents()->GetRenderViewHost();
      // Set a flag to tell ChromeVox that it's just been enabled,
      // so that it won't interrupt our speech feedback enabled message.
      ExtensionMsg_ExecuteCode_Params params;
      params.request_id = 0;
      params.extension_id = extension->id();
      params.is_javascript = true;
      params.code = "window.INJECTED_AFTER_LOAD = true;";
      params.all_frames = true;
      params.in_main_world = false;
      render_view_host->Send(new ExtensionMsg_ExecuteCode(
          render_view_host->routing_id(), params));

      // Inject ChromeVox' content scripts.
      ContentScriptLoader* loader = new ContentScriptLoader(
          extension->id(), render_view_host);

      for (size_t i = 0; i < extension->content_scripts().size(); i++) {
        const UserScript& script = extension->content_scripts()[i];
        for (size_t j = 0; j < script.js_scripts().size(); ++j) {
          const UserScript::File &file = script.js_scripts()[j];
          ExtensionResource resource = extension->GetResource(
              file.relative_path());
          loader->AppendScript(resource);
        }
      }
      loader->Run();  // It cleans itself up when done.
    }

    LOG(INFO) << "ChromeVox was Loaded.";
  } else { // Unload ChromeVox
    extension_service->component_loader()->Remove(path);
    LOG(INFO) << "ChromeVox was Unloaded.";
  }
}

void EnableHighContrast(bool enabled) {
  PrefService* pref_service = g_browser_process->local_state();
  pref_service->SetBoolean(prefs::kHighContrastEnabled, enabled);
  pref_service->CommitPendingWrite();
}

void EnableScreenMagnifier(bool enabled) {
  PrefService* pref_service = g_browser_process->local_state();
  pref_service->SetBoolean(prefs::kScreenMagnifierEnabled, enabled);
  pref_service->CommitPendingWrite();
}

void EnableVirtualKeyboard(bool enabled) {
  PrefService* pref_service = g_browser_process->local_state();
  pref_service->SetBoolean(prefs::kVirtualKeyboardEnabled, enabled);
  pref_service->CommitPendingWrite();
}

void ToggleAccessibility(content::WebUI* login_web_ui) {
  bool accessibility_enabled = g_browser_process &&
      g_browser_process->local_state()->GetBoolean(
          prefs::kSpokenFeedbackEnabled);
  accessibility_enabled = !accessibility_enabled;
  EnableAccessibility(accessibility_enabled, login_web_ui);
};

void Speak(const char* utterance) {
  UtteranceContinuousParameters params;
  ExtensionTtsPlatformImpl::GetInstance()->Speak(
      -1,  // No utterance ID because we don't need a callback when it finishes.
      utterance,
      g_browser_process->GetApplicationLocale(),
      params);
}

bool IsAccessibilityEnabled() {
  if (!g_browser_process) {
    return false;
  }
  PrefService* prefs = g_browser_process->local_state();
  bool accessibility_enabled = prefs &&
      prefs->GetBoolean(prefs::kSpokenFeedbackEnabled);
  return accessibility_enabled;
}

}  // namespace accessibility
}  // namespace chromeos