/**
 * Licensed to Apereo under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright ownership. Apereo
 * licenses this file to you 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 the
 * following location:
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>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.apereo.portal.rendering.xslt;

import java.io.IOException;
import java.io.Serializable;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import org.apereo.portal.IUserPreferencesManager;
import org.apereo.portal.layout.dao.IStylesheetDescriptorDao;
import org.apereo.portal.layout.om.IStylesheetDescriptor;
import org.apereo.portal.user.IUserInstance;
import org.apereo.portal.user.IUserInstanceManager;
import org.apereo.portal.utils.cache.CacheKey;
import org.apereo.portal.xml.XmlUtilities;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;

/**
 * Common logic for getting a {@link Transformer} for a stylesheet specified by a {@link
 * CoreStylesheetDescription} Implementations have to provide the appropriate {@link
 * CoreStylesheetDescription} from the {@link IUserPreferencesManager}
 *
 */
public abstract class BaseTransformerSource implements TransformerSource, ResourceLoaderAware {
    private IUserInstanceManager userInstanceManager;
    private XmlUtilities xmlUtilities;
    private ResourceLoader resourceLoader;
    protected IStylesheetDescriptorDao stylesheetDescriptorDao;

    @Autowired
    public void setStylesheetDescriptorDao(IStylesheetDescriptorDao stylesheetDescriptorDao) {
        this.stylesheetDescriptorDao = stylesheetDescriptorDao;
    }

    @Autowired
    public void setUserInstanceManager(IUserInstanceManager userInstanceManager) {
        this.userInstanceManager = userInstanceManager;
    }

    @Autowired
    public void setXmlUtilities(XmlUtilities xmlUtilities) {
        this.xmlUtilities = xmlUtilities;
    }

    @Override
    public void setResourceLoader(ResourceLoader resourceLoader) {
        this.resourceLoader = resourceLoader;
    }

    /* (non-Javadoc)
     * @see org.apereo.portal.rendering.xslt.TransformerSource#getCacheKey(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
     */
    @Override
    public final CacheKey getCacheKey(HttpServletRequest request, HttpServletResponse response) {
        final Resource stylesheetResource = this.getStylesheetResource(request);
        final Serializable stylesheetCacheKey;
        try {
            stylesheetCacheKey = this.xmlUtilities.getStylesheetCacheKey(stylesheetResource);
        } catch (TransformerConfigurationException e) {
            throw new RuntimeException(
                    "Failed to get Transformer for stylesheet: " + stylesheetResource, e);
        } catch (IOException e) {
            throw new RuntimeException("Failed to load stylesheet: " + stylesheetResource, e);
        }

        return CacheKey.build(stylesheetResource.getDescription(), stylesheetCacheKey);
    }

    /* (non-Javadoc)
     * @see org.apereo.portal.rendering.xslt.TransformerSource#getTransformer(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
     */
    @Override
    public final Transformer getTransformer(
            HttpServletRequest request, HttpServletResponse response) {
        final Resource stylesheetResource = this.getStylesheetResource(request);
        try {
            return this.xmlUtilities.getTransformer(stylesheetResource);
        } catch (TransformerConfigurationException e) {
            throw new RuntimeException(
                    "Failed to get Transformer for stylesheet: " + stylesheetResource, e);
        } catch (IOException e) {
            throw new RuntimeException("Failed to load stylesheet: " + stylesheetResource, e);
        }
    }

    /** Get the stylesheet description from the user preferences */
    protected abstract long getStylesheetDescriptorId(IUserPreferencesManager preferencesManager);

    protected IStylesheetDescriptor getStylesheetDescriptor(HttpServletRequest request) {
        final IUserInstance userInstance = this.userInstanceManager.getUserInstance(request);
        final IUserPreferencesManager preferencesManager = userInstance.getPreferencesManager();
        final long id = this.getStylesheetDescriptorId(preferencesManager);
        return this.stylesheetDescriptorDao.getStylesheetDescriptor(id);
    };

    private Resource getStylesheetResource(HttpServletRequest request) {
        final IStylesheetDescriptor stylesheetDescriptor = this.getStylesheetDescriptor(request);
        final String stylesheetResource = stylesheetDescriptor.getStylesheetResource();
        return this.resourceLoader.getResource(stylesheetResource);
    }
}