/*
*  Copyright 2016 Anyware Services
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.ametys.workspaces.repository.maintenance;

import java.util.Map;

import javax.jcr.RepositoryException;

import org.apache.commons.lang.StringUtils;
import org.apache.jackrabbit.core.config.RepositoryConfig;
import org.slf4j.Logger;

import org.ametys.core.util.DateUtils;
import org.ametys.plugins.repositoryapp.RepositoryProvider;
import org.ametys.runtime.plugin.component.LogEnabled;

/**
 * Jackrabbit maintenance tasks implementations should extends this class.
 */
public abstract class AbstractMaintenanceTask implements LogEnabled
{
    /** TaskProgress */
    protected TaskProgress _progress;

    /** The repository config */
    protected RepositoryConfig _repositoryConfig;

    /** The repository provider. */
    protected RepositoryProvider _repositoryProvider;
    
    /** Logger for traces */
    protected Logger _logger;
    
    private boolean _isFinished;
    
    /**
     * Execute the task
     * @param repositoryConfig The RepositoryConfig object, used to create new Repository instance.
     * @throws RepositoryException If an error with the repository occurs while the task is executed.
     */
    public void execute(RepositoryConfig repositoryConfig) throws RepositoryException 
    {
        _repositoryConfig = repositoryConfig;

        long startTime = System.currentTimeMillis();
        
        setLogger();

        _logger.info("Executing task.");

        try
        {
            // task specific initialization.
            initialize();

            // Mark the task as running.
            setRunning();

            // Perform the task.
            apply();

            // Mark the task as finished.
            setFinished();
        }
        catch (Exception e)
        {
            setInErrorState(e);
            throw e;
        }
        finally
        {
            close();

            _logger.info("End of the task.");

            long elapsedTime = System.currentTimeMillis() - startTime;
            _logger.info("Done in " + _getFormattedDuration(elapsedTime));
        }
    }

    /**
     * Initialize the tasks.
     * This method can also create the {@link TaskProgress} object bounded to the task.
     * @throws RepositoryException If a repository exception
     */
    protected void initialize() throws RepositoryException
    {
        return;
    }
    
    /**
     * Set the tasks logger.
     */
    protected abstract void setLogger();
    
    @Override
    public void setLogger(Logger logger)
    {
        _logger = logger;
    }

    /**
     * Apply the tasks (within the execute method()).
     * @throws RepositoryException If a repository exception
     */
    protected abstract void apply() throws RepositoryException;

    /**
     * Close the tasks
     * @throws RepositoryException If a repository exception
     */
    protected void close() throws RepositoryException
    {
        return;
    }

    /**
     * Get progress information.
     * @return a map containing information on the progress status.
     */
    public Map<String, Object> getProgressInfo() 
    {
        if (_progress != null)
        {
            return _progress.getProgressInfo();
        }
        else
        {
            return null;
        }
    }

    /**
     * Is the execution of the task finished?
     * @return true if finished
     */
    public boolean isFinished()
    {
        return _isFinished;
    }

    private synchronized void setRunning()
    {
        if (_progress != null)
        {
            _progress.setRunning();
        }
    }

    private synchronized void setFinished()
    {
        if (_progress != null)
        {
            _progress.setFinished();
        }

        _isFinished = true;
    }

    private synchronized void setInErrorState(Exception e)
    {
        _logger.error(e.getLocalizedMessage(), e);

        if (_progress != null)
        {
            _progress.setInErrorState(e);
        }

        _isFinished = true;
    }

    /**
     * Transforms millisecond to a formatted string representing a duration.
     * @param elapsedTime milleseconds corresponding to the duration.
     * @return Pretty formatted string.
     */
    protected String _getFormattedDuration(long elapsedTime)
    {
        String formatted = DateUtils.formatDuration(elapsedTime);
        return StringUtils.defaultIfEmpty(formatted, "0s");
    }
}