/*
 * #%L
 * BroadleafCommerce CMS Module
 * %%
 * Copyright (C) 2009 - 2013 Broadleaf Commerce
 * %%
 * 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.
 * #L%
 */
package org.broadleafcommerce.cms.web.processor;

import org.broadleafcommerce.cms.file.service.StaticAssetService;
import org.broadleafcommerce.common.file.service.StaticAssetPathService;
import org.broadleafcommerce.common.web.BroadleafRequestContext;
import org.thymeleaf.Arguments;
import org.thymeleaf.dom.Element;
import org.thymeleaf.processor.attr.AbstractAttributeModifierAttrProcessor;
import org.thymeleaf.standard.expression.Expression;
import org.thymeleaf.standard.expression.StandardExpressions;

import java.util.HashMap;
import java.util.Map;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;

/**
 * A Thymeleaf processor that processes the given url through the StaticAssetService's
 * {@link StaticAssetService#convertAssetPath(String, String, boolean)} method to determine
 * the appropriate URL for the asset to be served from.
 * 
 * @author apazzolini
 */
public class UrlRewriteProcessor extends AbstractAttributeModifierAttrProcessor {
    
    @Resource(name = "blStaticAssetPathService")
    protected StaticAssetPathService staticAssetPathService;

    /**
     * Sets the name of this processor to be used in Thymeleaf template
     */
    public UrlRewriteProcessor() {
        this("src");
    }
    
    protected UrlRewriteProcessor(final String attributeName) {
        super(attributeName);
    }

    @Override
    public int getPrecedence() {
        return 1000;
    }
    
    /**
     * @return true if the current request.scheme = HTTPS or if the request.isSecure value is true.
     */
    protected boolean isRequestSecure(HttpServletRequest request) {
        return ("HTTPS".equalsIgnoreCase(request.getScheme()) || request.isSecure());
    } 

    
    @Override
    protected Map<String, String> getModifiedAttributeValues(Arguments arguments, Element element, String attributeName) {
        Map<String, String> attrs = new HashMap<String, String>();
        HttpServletRequest request = BroadleafRequestContext.getBroadleafRequestContext().getRequest();
        
        boolean secureRequest = true;
        if (request != null) {
            secureRequest = isRequestSecure(request);
        }
        
        String elementValue = element.getAttributeValue(attributeName);

        if (elementValue.startsWith("/")) {
            elementValue = "@{ " + elementValue + " }";
        }
        Expression expression = (Expression) StandardExpressions.getExpressionParser(arguments.getConfiguration())
                .parseExpression(arguments.getConfiguration(), arguments, elementValue);
        String assetPath = (String) expression.execute(arguments.getConfiguration(), arguments);
        
        // We are forcing an evaluation of @{} from Thymeleaf above which will automatically add a contextPath, no need to
        // add it twice
        assetPath = staticAssetPathService.convertAssetPath(assetPath, null, secureRequest);
        
        attrs.put("src", assetPath);
        
        return attrs;
    }

    @Override
    protected ModificationType getModificationType(Arguments arguments, Element element, String attributeName, String newAttributeName) {
        return ModificationType.SUBSTITUTION;
    }

    @Override
    protected boolean removeAttributeIfEmpty(Arguments arguments, Element element, String attributeName, String newAttributeName) {
        return true;
    }

    @Override
    protected boolean recomputeProcessorsAfterExecution(Arguments arguments, Element element, String attributeName) {
        return false;
    }
}