/*
 *  Copyright 2010 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.web.skin;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.avalon.framework.configuration.DefaultConfigurationBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.ametys.runtime.i18n.I18nizableText;

/**
 * A skin
 */
public class Skin
{
    private static Logger _logger = LoggerFactory.getLogger(Skin.class);
    
    /** The skin id (e.g. the directory name) */
    protected String _id;
    /** The skin directory */
    protected File _file;
    /** The skin name */
    protected I18nizableText _label;
    /** The skin description */
    protected I18nizableText _description;
    /** The skin thumbnail 16x16 */
    protected String _smallImage;
    /** The skin thumbnail 32x32 */
    protected String _mediumImage;
    /** The skin thumbnail 48x48 */
    protected String _largeImage;
    /** The map of templates id and associated templates */
    protected Map<String, SkinTemplate> _templates = new HashMap<>();
    
    /** The last time the file was loaded */
    protected long _lastConfUpdate; 
    
    /**
     * Creates a skin
     * @param id The id of the skin (e.g. the directory name)
     * @param file The skin file
     */
    public Skin(String id, File file)
    {
        this._id = id;
        this._file = file;
    }
    
    /**
     * Get the list of existing templates
     * @return A set of skin names. Can be null if there is an error.
     */
    public Set<String> getTemplates()
    {
        try
        {
            Set<String> template = new HashSet<>();

            File tplDir = new File (_file, "/templates");
            
            for (File child : tplDir.listFiles())
            {
                if (_templateExists(child.getName()))
                {
                    template.add(child.getName());
                }
            }
            
            return template;
        }
        catch (Exception e)
        {
            _logger.error("Can not determine the list of skins available", e);
            return null;
        }
    }
    
    /**
     * Get a template
     * @param id The id of the template
     * @return The template or null if the template doesn't exists
     */
    @SuppressWarnings("null")
    public SkinTemplate getTemplate(String id)
    {
        try
        {
            boolean templateDirExists = _templateExists(id);
            SkinTemplate template = _templates.get(id);
            if (template == null && templateDirExists)
            {
                template = new SkinTemplate(this._id, id, new File (_file, "/templates/" + id));
                _templates.put(id, template);
            }
            else if (!templateDirExists)
            {
                _templates.put(id, null);
                return null;
            }
            
            template.refreshValues();
            return template;
        }
        catch (Exception e)
        {
            throw new IllegalStateException("Can not create the template DAO for skin '" + this._id + "' and the template '" + id + "'", e);
        }
    }
    
    private boolean _templateExists(String id)
    {
        File tplFile = new File (_file, "/templates/" + id + "/stylesheets/template.xsl");
        return tplFile.exists();
    }
    
    /**
     * The configuration default values (if configuration file does not exist or is unreadable)
     */
    protected void _defaultValues()
    {
        _lastConfUpdate = new Date().getTime();
        
        this._label = new I18nizableText(this._id);
        this._description = new I18nizableText("");
        this._smallImage = "/plugins/web/resources/img/skin/skin_16.png";
        this._mediumImage = "/plugins/web/resources/img/skin/skin_32.png";
        this._largeImage = "/plugins/web/resources/img/skin/skin_48.png";
    }
    
    /**
     * Refresh the conf values
     */
    public void refreshValues()
    {
        File configurationFile = null;

        try
        {
            configurationFile = new File (_file, "/conf/skin.xml");
            if (configurationFile.exists())
            {
                
                if (_lastConfUpdate < configurationFile.lastModified())
                {
                    _lastConfUpdate = configurationFile.lastModified();
                    try (InputStream is = new FileInputStream(configurationFile))
                    {
                        Configuration configuration = new DefaultConfigurationBuilder().build(is);
                        
                        this._label = _configureI18n(configuration.getChild("label", false), new I18nizableText(this._id));
                        this._description = _configureI18n(configuration.getChild("description", false), new I18nizableText(""));
                        this._smallImage = _configureThumbnail(configuration.getChild("thumbnail").getChild("small").getValue(null), "/plugins/web/resources/img/skin/skin_16.png");
                        this._mediumImage = _configureThumbnail(configuration.getChild("thumbnail").getChild("medium").getValue(null), "/plugins/web/resources/img/skin/skin_32.png");
                        this._largeImage = _configureThumbnail(configuration.getChild("thumbnail").getChild("large").getValue(null), "/plugins/web/resources/img/skin/skin_48.png");
                    }
                }
            }
            else
            {
                _defaultValues();
            }
        }
        catch (Exception e)
        {
            _defaultValues();
            if (_logger.isWarnEnabled())
            {
                _logger.warn("Cannot read the configuration file conf/skin.xml for the skin '" + this._id + "'. Continue as if file was not existing", e);
            }
        }
    }
    
    private String _configureThumbnail(String value, String defaultImage)
    {
        if (value == null)
        {
            return defaultImage;
        }
        else
        {
            return "/skins/" + this._id + "/resources/" + value;
        }
    }

    private I18nizableText _configureI18n(Configuration child, I18nizableText defaultValue) throws ConfigurationException
    {
        if (child != null)
        {
            String value = child.getValue();
            if (child.getAttributeAsBoolean("i18n", false))
            {
                return new I18nizableText("skin." + this._id, value);
            }
            else
            {
                return new I18nizableText(value);
            }
        }
        else
        {
            return defaultValue;
        }
    }

    /**
     * The skin id
     * @return the id
     */
    public String getId()
    {
        return _id;
    }
    
    /**
     * The skin label
     * @return The label
     */
    public I18nizableText getLabel()
    {
        return _label;
    }
    /**
     * The skin description
     * @return The description. Can not be null but can be empty
     */
    public I18nizableText getDescription()
    {
        return _description;
    }
    
    /**
     * The small image file uri
     * @return The small image file uri
     */
    public String getSmallImage()
    {
        return _smallImage;
    }

    /**
     * The medium image file uri
     * @return The medium image file uri
     */
    public String getMediumImage()
    {
        return _mediumImage;
    }
    
    /**
     * The large image file uri
     * @return The large image file uri
     */
    public String getLargeImage()
    {
        return _largeImage;
    }

    /**
     * Get the skin's file directory
     * @return the skin's file directory
     */
    public File getFile ()
    {
        return _file;
    }
    
    /**
     * Get the absolute path of the skin's file directory
     * @return the absolute path of the skin's file directory
     */
    public String getLocation ()
    {
        return _file.getAbsolutePath();
    }
}