/*
    * Copyright 2008 Google Inc.
    * 
    * 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.vectomatic.dev.svg.impl.gen;
  
  import java.net.URL;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.vectomatic.dom.svg.impl.ExternalSVGResourcePrototype;
  import org.vectomatic.dom.svg.ui.SVGResource;
  import org.vectomatic.dom.svg.ui.ExternalSVGResource.Validated;
  
  import com.google.gwt.core.ext.Generator;
  import com.google.gwt.core.ext.TreeLogger;
  import com.google.gwt.core.ext.UnableToCompleteException;
  import com.google.gwt.core.ext.typeinfo.JClassType;
  import com.google.gwt.core.ext.typeinfo.JMethod;
  import com.google.gwt.core.ext.typeinfo.JType;
  import com.google.gwt.core.ext.typeinfo.TypeOracle;
  import com.google.gwt.dev.util.Util;
  import com.google.gwt.resources.ext.AbstractResourceGenerator;
  import com.google.gwt.resources.ext.ClientBundleFields;
  import com.google.gwt.resources.ext.ClientBundleRequirements;
  import com.google.gwt.resources.ext.ResourceContext;
  import com.google.gwt.resources.ext.ResourceGeneratorUtil;
  import com.google.gwt.user.rebind.SourceWriter;
  import com.google.gwt.user.rebind.StringSourceWriter;
  
  /**
   * Implementation of ExternalSVGResource derived from Google's original
   * ExternalTextResourceGenerator implementation
   * @author laaglu
   */
  public class ExternalSVGResourceGenerator extends AbstractResourceGenerator {
  	private StringBuffer data;
  	private boolean first;
  	private String urlExpression;
  	private Map<String, Integer> hashes;
  	private Map<String, Integer> offsets;
  	private int currentIndex;
  
  	private String externalSVGUrlIdent;
  
  	private String externalSVGCacheIdent;
  
  	@Override
  	public String createAssignment(TreeLogger logger, ResourceContext context,
  			JMethod method) throws UnableToCompleteException {
  		String name = method.getName();
  
  		SourceWriter sw = new StringSourceWriter();
  		sw
  				.println("new " + ExternalSVGResourcePrototype.class.getName()
  						+ "(");
  		sw.indent();
  		sw.println('"' + name + "\",");
  		// These are field names
  		sw.println(externalSVGUrlIdent + ", " + externalSVGCacheIdent + ", ");
  		sw.println(offsets.get(method.getName()).toString());
  		sw.outdent();
  		sw.print(")");
  
  		return sw.toString();
  	}
  
  	@Override
  	public void createFields(TreeLogger logger, ResourceContext context,
  			ClientBundleFields fields) throws UnableToCompleteException {
  		data.append(']');
  
  		urlExpression = context.deploy(context.getClientBundleType()
  				.getQualifiedSourceName().replace('.', '_')
  				+ "_jsonbundle.txt", "text/plain", data.toString().getBytes(),
  				true);
  
  		TypeOracle typeOracle = context.getGeneratorContext().getTypeOracle();
  		JClassType stringType = typeOracle.findType(String.class.getName());
  		assert stringType != null;
  
  		externalSVGUrlIdent = fields.define(stringType, "externalSVGUrl",
  				urlExpression, true, true);
  
  		JClassType textResourceType = typeOracle.findType(SVGResource.class
  				.getName());
  		assert textResourceType != null;
  		JType textResourceArrayType = typeOracle.getArrayType(textResourceType);
 
 		externalSVGCacheIdent = fields.define(textResourceArrayType,
 				"externalSVGCache", "new " + SVGResource.class.getName()
 						+ "[" + currentIndex + "]", true, true);
 	}
 
 	@Override
 	public void init(TreeLogger logger, ResourceContext context)
 			throws UnableToCompleteException {
 		data = new StringBuffer("[\n");
 		first = true;
 		urlExpression = null;
 		hashes = new HashMap<String, Integer>();
 		offsets = new HashMap<String, Integer>();
 		currentIndex = 0;
 	}
 
 	@Override
 	public void prepare(TreeLogger logger, ResourceContext context,
 			ClientBundleRequirements requirements, JMethod method)
 			throws UnableToCompleteException {
 
 		URL[] urls = ResourceGeneratorUtil.findResources(logger, context,
 				method);
 
 		if (urls.length != 1) {
 			logger.log(TreeLogger.ERROR,
 					"Exactly one resource must be specified", null);
 			throw new UnableToCompleteException();
 		}
 
 		URL resource = urls[0];
 
 		String toWrite = Util.readURLAsString(resource);
 		if (getValidated(method)) {
 			SVGValidator.validate(toWrite, resource.toExternalForm(), logger, null);
 		}
 
 		// This de-duplicates strings in the bundle.
 		if (!hashes.containsKey(toWrite)) {
 			hashes.put(toWrite, currentIndex++);
 
 			if (!first) {
 				data.append(",\n");
 			} else {
 				first = false;
 			}
 
 			data.append('"');
 			data.append(Generator.escape(toWrite));
 			data.append('"');
 		}
 
 		// Store the (possibly n:1) mapping of resource function to bundle
 		// index.
 		offsets.put(method.getName(), hashes.get(toWrite));
 	}
 
 	private boolean getValidated(JMethod method) {
 		Validated validated = method.getAnnotation(Validated.class);
 		if (validated == null) {
 			return true;
 		} else {
 			return validated.validated();
 		}
 	}
 }