/**
 * 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 com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import java.io.Serializable;
import java.util.Collections;
import java.util.Map;
import java.util.Set;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apereo.portal.layout.IStylesheetUserPreferencesService;
import org.apereo.portal.layout.IStylesheetUserPreferencesService.PreferencesScope;
import org.apereo.portal.layout.om.IStylesheetDescriptor;
import org.apereo.portal.utils.cache.CacheKey;
import org.jasig.resourceserver.aggr.om.Included;
import org.jasig.resourceserver.utils.aggr.ResourcesElementsProvider;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.annotation.Autowired;

/**
 * Maps a user attribute to a skin. The user's attribute named by {@link
 * #setSkinAttributeName(String)} is used to look up a skin name via the {@link
 * #setAttributeToSkinMap(Map)} map and the skin name is set to in the transformer using the {@link
 * #setSkinParameterName(String)} parameter.
 *
 */
public abstract class SkinMappingTransformerConfigurationSource
        extends TransformerConfigurationSourceAdapter implements BeanNameAware {
    private IStylesheetUserPreferencesService stylesheetUserPreferencesService;
    private ResourcesElementsProvider resourcesElementsProvider;
    private String skinNameAttribute;
    private String skinParameterName = "skin";
    private Set<String> stylesheetDescriptorNames;
    private boolean cacheSkinResolution = true;

    /** The name of the transformer parameter used for the skin name, defaults to "skin" */
    public void setSkinParameterName(String skinParameterName) {
        this.skinParameterName = skinParameterName;
    }

    @Autowired
    public void setResourcesElementsProvider(ResourcesElementsProvider resourcesElementsProvider) {
        this.resourcesElementsProvider = resourcesElementsProvider;
    }

    @Autowired
    public void setStylesheetUserPreferencesService(
            IStylesheetUserPreferencesService stylesheetUserPreferencesService) {
        this.stylesheetUserPreferencesService = stylesheetUserPreferencesService;
    }

    /**
     * If true the result of {@link #getSkinName(HttpServletRequest)} will be cached in the user's
     * session and re-used. If false {@link #getSkinName(HttpServletRequest)} will be called on
     * every execution.
     */
    public void setCacheSkinResolution(boolean cacheSkinResolution) {
        this.cacheSkinResolution = cacheSkinResolution;
    }

    /**
     * Set of theme stylesheet descriptor names that the skin-default should be set for. If not set
     * the skin-default will be set for all stylesheets
     */
    public void setStylesheetDescriptorNames(Set<String> stylesheetDescriptorNames) {
        this.stylesheetDescriptorNames = ImmutableSet.copyOf(stylesheetDescriptorNames);
    }

    @Override
    public void setBeanName(String name) {
        this.skinNameAttribute = name + ".SKIN_NAME";
    }

    @Override
    public final Map<String, Object> getParameters(
            HttpServletRequest request, HttpServletResponse response) {
        final String skinName = this.getSkinNameInternal(request);
        if (skinName == null) {
            return Collections.emptyMap();
        }

        return ImmutableMap.<String, Object>of(this.skinParameterName, skinName);
    }

    @Override
    public final CacheKey getCacheKey(HttpServletRequest request, HttpServletResponse response) {
        final String skinName = this.getSkinNameInternal(request);
        return CacheKey.build(this.getClass().getName(), skinName);
    }

    private String getSkinNameInternal(HttpServletRequest request) {
        if (!this.cacheSkinResolution
                || Included.PLAIN == this.resourcesElementsProvider.getDefaultIncludedType()) {
            if (!this.shouldOverrideSkin(request)) {
                return null;
            }

            return this.getSkinName(request);
        }

        final HttpSession session = request.getSession();
        SkinNameHolder skinNameHolder = (SkinNameHolder) session.getAttribute(skinNameAttribute);
        if (skinNameHolder == null) {
            final String skinName;
            if (this.shouldOverrideSkin(request)) {
                skinName = this.getSkinName(request);
            } else {
                skinName = null;
            }

            skinNameHolder = new SkinNameHolder(skinName);
            session.setAttribute(skinNameAttribute, skinNameHolder);
        }

        return skinNameHolder.skinName;
    }

    protected boolean shouldOverrideSkin(HttpServletRequest request) {
        if (this.stylesheetDescriptorNames == null || this.stylesheetDescriptorNames.isEmpty()) {
            return true;
        }

        final IStylesheetDescriptor stylesheetDescriptor =
                stylesheetUserPreferencesService.getStylesheetDescriptor(
                        request, PreferencesScope.THEME);
        return this.stylesheetDescriptorNames.contains(stylesheetDescriptor.getName());
    }

    /** @return The skin name to use for this request */
    protected abstract String getSkinName(HttpServletRequest request);

    private static final class SkinNameHolder implements Serializable {
        private static final long serialVersionUID = 1L;
        private final String skinName;

        public SkinNameHolder(String skinName) {
            this.skinName = skinName;
        }
    }
}