// Copyright 2014 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.

#ifndef CHROME_BROWSER_ASH_APP_MODE_KIOSK_APP_EXTERNAL_LOADER_H_
#define CHROME_BROWSER_ASH_APP_MODE_KIOSK_APP_EXTERNAL_LOADER_H_

#include <memory>

#include "base/callback_forward.h"
#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "chrome/browser/extensions/external_loader.h"

namespace ash {

// An extensions::ExternalLoader that loads apps and extensions for a kiosk
// session. It is used to either load primary kiosk app, or secondary kiosk
// apps (or extensions). Single instance cannot load both primary and secondary
// apps.
// It registers a callback with KioskAppManager that is called when the kiosk
// app information is updated - when run, the callback will finish extension
// load handled by |this|.
// Note that |this| might call extensions::ExternalLoader::OnUpdated(), because
// in certain cases kiosk app properties might get updated.
// This lives on the UI thread, even though it's ref counted as a subclass
// of |extensions::ExternalLoader|.
class KioskAppExternalLoader : public extensions::ExternalLoader {
 public:
  enum class AppClass { kPrimary, kSecondary };

  explicit KioskAppExternalLoader(AppClass app_class);

  // extensions::ExternalLoader:
  void StartLoading() override;

 protected:
  ~KioskAppExternalLoader() override;

 private:
  enum class State { kInitial, kLoading, kLoaded };

  // Gets prefs describing appropriate set of external extensions (depending
  // on the class of kiosk apps handled by |this|) from KioskAppManager.
  std::unique_ptr<base::DictionaryValue> GetAppsPrefs();

  // Registers callback for handling kiosk apps prefs changes.
  void SetPrefsChangedHandler(base::RepeatingClosure handler);

  // If prefs for the set of kiosk apps handled by |this| are available, sends
  // them to the external loader owner (using extensions::ExternalLoader
  // interface).
  void SendPrefsIfAvailable();

  // The class of kiosk apps this external extensions loader handles.
  const AppClass app_class_;

  State state_ = State::kInitial;

  base::WeakPtrFactory<KioskAppExternalLoader> weak_ptr_factory_{this};

  DISALLOW_COPY_AND_ASSIGN(KioskAppExternalLoader);
};

}  // namespace ash

#endif  // CHROME_BROWSER_ASH_APP_MODE_KIOSK_APP_EXTERNAL_LOADER_H_