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 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-

  * This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 package org.mozilla.gecko.home;

 import java.util.ArrayList;

 import java.util.List;

 import java.util.Set;

 import java.util.concurrent.atomic.AtomicInteger;

 import org.json.JSONArray;

 import org.json.JSONException;

 import org.json.JSONObject;

 import org.mozilla.gecko.GeckoAppShell;

 import org.mozilla.gecko.GeckoEvent;

 import org.mozilla.gecko.home.HomeConfig.PanelConfig;

 import org.mozilla.gecko.util.GeckoEventListener;

 import org.mozilla.gecko.util.ThreadUtils;

 import android.util.Log;

 import android.util.SparseArray;

 public class PanelInfoManager implements GeckoEventListener {

     private static final String LOGTAG = "GeckoPanelInfoManager";

     public class PanelInfo {

         private final String mId;

         private final String mTitle;

         private final JSONObject mJSONData;

         public PanelInfo(String id, String title, JSONObject jsonData) {

             mId = id;

             mTitle = title;

             mJSONData = jsonData;

         }

         public String getId() {

             return mId;

         }

         public String getTitle() {

             return mTitle;

         }

         public PanelConfig toPanelConfig() {

             try {

                 return new PanelConfig(mJSONData);

             } catch (Exception e) {

                 Log.e(LOGTAG, "Failed to convert PanelInfo to PanelConfig", e);

                 return null;

             }

         }

     }

     public interface RequestCallback {

         public void onComplete(List<PanelInfo> panelInfos);

     }

     private static AtomicInteger sRequestId = new AtomicInteger(0);

     // Stores set of pending request callbacks.

     private static final SparseArray<RequestCallback> sCallbacks = new SparseArray<RequestCallback>();

     /**

      * Asynchronously fetches list of available panels from Gecko

      * for the given IDs.

      *

      * @param ids list of panel ids to be fetched. A null value will fetch all

      *        available panels.

      * @param callback onComplete will be called on the UI thread.

      */

     public void requestPanelsById(Set<String> ids, RequestCallback callback) {

         final int requestId = sRequestId.getAndIncrement();

         synchronized(sCallbacks) {

             // If there are no pending callbacks, register the event listener.

             if (sCallbacks.size() == 0) {

                 GeckoAppShell.getEventDispatcher().registerEventListener("HomePanels:Data", this);

             }

             sCallbacks.put(requestId, callback);

         }

         final JSONObject message = new JSONObject();

         try {

             message.put("requestId", requestId);

             if (ids != null && ids.size() > 0) {

                 JSONArray idsArray = new JSONArray();

                 for (String id : ids) {

                     idsArray.put(id);

                 }

                 message.put("ids", idsArray);

             }

         } catch (JSONException e) {

             Log.e(LOGTAG, "Failed to build event to request panels by id", e);

             return;

         }

         GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent("HomePanels:Get", message.toString()));

     }

     /**

      * Asynchronously fetches list of available panels from Gecko.

      *

      * @param callback onComplete will be called on the UI thread.

      */

     public void requestAvailablePanels(RequestCallback callback) {

         requestPanelsById(null, callback);

     }

     /**

      * Handles "HomePanels:Data" events.

      */

     @Override

     public void handleMessage(String event, JSONObject message) {

         final ArrayList<PanelInfo> panelInfos = new ArrayList<PanelInfo>();

         try {

             final JSONArray panels = message.getJSONArray("panels");

             final int count = panels.length();

             for (int i = 0; i < count; i++) {

                 final PanelInfo panelInfo = getPanelInfoFromJSON(panels.getJSONObject(i));

                 panelInfos.add(panelInfo);

             }

             final RequestCallback callback;

             final int requestId = message.getInt("requestId");

             synchronized(sCallbacks) {

                 callback = sCallbacks.get(requestId);

                 sCallbacks.delete(requestId);

                 // Unregister the event listener if there are no more pending callbacks.

                 if (sCallbacks.size() == 0) {

                     GeckoAppShell.getEventDispatcher().unregisterEventListener("HomePanels:Data", this);

                 }

             }

             ThreadUtils.postToUiThread(new Runnable() {

                 @Override

                 public void run() {

                     callback.onComplete(panelInfos);

                 }

             });

         } catch (JSONException e) {

             Log.e(LOGTAG, "Exception handling " + event + " message", e);

         }

     }

     private PanelInfo getPanelInfoFromJSON(JSONObject jsonPanelInfo) throws JSONException {

         final String id = jsonPanelInfo.getString("id");

         final String title = jsonPanelInfo.getString("title");

         return new PanelInfo(id, title, jsonPanelInfo);

     }

 }