/*

 * Copyright (C) 2005-2010 Alfresco Software Limited.

 *

 * This file is part of Alfresco

 *

 * Alfresco is free software: you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * Alfresco is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.

 */

package org.alfresco.util.json;



import java.lang.reflect.Constructor;

import java.util.Arrays;

import java.util.Collections;

import java.util.List;



import org.alfresco.error.AlfrescoRuntimeException;

import org.alfresco.service.cmr.transfer.TransferException;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;



public class ExceptionJsonSerializer implements JsonSerializer<Throwable, JSONObject>

{

    private final static Log log = LogFactory.getLog(ExceptionJsonSerializer.class);

    

    @Override

    public Throwable deserialize(JSONObject errorJSON)

    {

        if (errorJSON == null)

        {

            return null;

        }

        

        Throwable result = null;

        Object createdObject = null;

        

        try

        {

            //errorType and errorMessage should always be reported

            String errorType = errorJSON.getString("errorType");

            String errorMessage = errorJSON.getString("errorMessage");

            

            if (errorType == null)

            {

                errorType = Exception.class.getName();

            }

            if (errorMessage == null)

            {

                errorMessage = "";

            }

            //alfrescoErrorId and alfrescoErrorParams will only appear if the

            //throwable object was of a subclass of AlfrescoRuntimeException

            String errorId = errorJSON.optString("alfrescoMessageId", null);

            Object[] errorParams = new Object[0];

            JSONArray errorParamArray = errorJSON.optJSONArray("alfrescoMessageParams");

            if (errorParamArray != null)

            {

                int length = errorParamArray.length();

                errorParams = new Object[length];

                for (int i = 0; i < length; ++i) 

                {

                    errorParams[i] = errorParamArray.getString(i);

                }

            }

            Class<?> errorClass;

            try

            {

                errorClass = Class.forName(errorType);

            }

            catch (ClassNotFoundException e)

            {

                errorClass = Exception.class;

            }

            Constructor<?> constructor = null;

            try

            {

                try

                {

                    constructor = errorClass.getConstructor(String.class, Object[].class);

                    createdObject = constructor.newInstance(errorId, errorParams);

                }

                catch (NoSuchMethodException e)

                {

                    try

                    {

                        constructor = errorClass.getConstructor(String.class);

                        createdObject = constructor.newInstance(errorId == null ? errorMessage : errorId);

                    }

                    catch (NoSuchMethodException e1)

                    {

                        try

                        {

                            constructor = errorClass.getConstructor();

                            createdObject = constructor.newInstance();

                        }

                        catch (NoSuchMethodException e2)

                        {

                        }

                    }

                }

            }

            catch(Exception ex)

            {

                //We don't need to do anything here. Code below will fix things up

            }

            if (createdObject == null || !Throwable.class.isAssignableFrom(createdObject.getClass()))

            {

                result = new TransferException(errorId == null ? errorMessage : errorId, errorParams);

            }

            else

            {

                result = (Throwable)createdObject;

            }

        }

        catch(JSONException ex)

        {

            if (log.isDebugEnabled())

            {

                log.debug("Failed to deserialize Throwable object from JSON object", ex);

            }

        }

        return result;

    }



    @Override

    public JSONObject serialize(Throwable object)

    {

        JSONObject errorObject = new JSONObject();

        

        try

        {

            errorObject.put("errorType", object.getClass().getName());

            errorObject.put("errorMessage", object.getMessage());

            if (AlfrescoRuntimeException.class.isAssignableFrom(object.getClass()))

            {

                AlfrescoRuntimeException alfEx = (AlfrescoRuntimeException)object;

                errorObject.put("alfrescoMessageId", alfEx.getMsgId());

                Object[] msgParams = alfEx.getMsgParams();

                List<Object> params = msgParams == null ? Collections.emptyList() : Arrays.asList(msgParams);

                errorObject.put("alfrescoMessageParams", params);

            }

        }

        catch (JSONException e)

        {

            if (log.isDebugEnabled())

            {

                log.debug("Failed to serialize Throwable object into JSON object", e);

            }

        }

        return errorObject;

    }

}