enterprise/web.client.rest/src/org/netbeans/modules/web/client/rest/wizard/ModelGenerator.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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
 *
 *   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.netbeans.modules.web.client.rest.wizard;

import java.beans.Introspector;
import java.io.IOException;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

import javax.lang.model.element.Element;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.Modifier;
import javax.lang.model.element.PackageElement;
import javax.lang.model.element.TypeElement;
import javax.lang.model.element.VariableElement;
import javax.lang.model.type.TypeKind;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.util.ElementFilter;

import org.netbeans.api.java.source.CompilationController;
import org.netbeans.api.project.FileOwnerQuery;
import org.netbeans.api.project.Project;
import org.netbeans.modules.web.client.rest.wizard.JSClientGenerator.HttpRequests;
import org.netbeans.modules.web.client.rest.wizard.JSClientGenerator.MethodType;
import org.netbeans.modules.web.client.rest.wizard.RestPanel.JsUi;
import org.netbeans.modules.websvc.rest.model.api.RestServiceDescription;
import org.netbeans.modules.websvc.rest.spi.MiscUtilities;
import org.netbeans.modules.websvc.rest.spi.RestSupport;


/**
 * @author ads
 *
 */
class ModelGenerator {
    
    private static final String SLASH = "/";                        // NOI18N
    private static final String ID = "javax.persistence.Id";         // NOI18N
    
    ModelGenerator(RestServiceDescription description , 
            StringBuilder builder, Set<String> entities , JsUi ui)
    {
        myDescription = description;
        myCommonModels = builder;
        myEntities = entities;
        myUi = ui;
    }

    void generateModel(TypeElement entity, String path,
            String collectionPath, Map<HttpRequests, String> httpPaths ,
            Map<HttpRequests, Boolean> useIds,
            CompilationController controller ) throws IOException
    {
        String fqn = entity.getQualifiedName().toString();
        String name = entity.getSimpleName().toString();
        myModelName = suggestModelName(name );
        
        myCommonModels.append("\n// Model for ");                    // NOI18N
        if ( name.equals(myModelName)){
            myCommonModels.append( name );
        }
        else {
            myCommonModels.append( fqn );
        }
        myCommonModels.append(" entity\n");                          // NOI18N
        
        String url = getUrl( path );
        
        myCommonModels.append("models.");                            // NOI18N
        myCommonModels.append(myModelName);
        myCommonModels.append(" = Backbone.Model.extend({\n");       // NOI18N
        myCommonModels.append("urlRoot : \"");                       // NOI18N
        myCommonModels.append( url );
        myCommonModels.append("\"");                                 // NOI18N
        myAttributes = new HashSet<ModelAttribute>();
        String parsedData = parse(entity, controller);
        if ( parsedData != null ){
            myCommonModels.append(',');                              
            myCommonModels.append(parsedData);
        }
        if ( !myAttributes.isEmpty() ){
            // suggest what attribute could be used as displayName 
            
            ModelAttribute preffered  = ModelAttribute.getPreffered();
            if ( myAttributes.contains( preffered )){
                myDisplayNameAlias = preffered.getName();
            }
            else if ( myIdAttribute == null){
                myDisplayNameAlias = myAttributes.iterator().next().getName();
            }
            else {
                myDisplayNameAlias = myIdAttribute.getName();
            }
            myCommonModels.append(",\n toViewJson: function(){\n");      // NOI18N
            myCommonModels.append("var result = this.toJSON();");        // NOI18N
            myCommonModels.append(" // displayName property is used to render item in the list\n");// NOI18N
            myCommonModels.append("result.displayName = this.get('");    // NOI18N
            myCommonModels.append(myDisplayNameAlias);
            myCommonModels.append("');\n return result;\n},\n");         // NOI18N
            
            myCommonModels.append("isNew: function(){\n");           // NOI18N
            myCommonModels.append(" // default isNew() method imlementation is\n");// NOI18N
            myCommonModels.append(" // based on the 'id' initialization which\n" );// NOI18N
            myCommonModels.append(" // sometimes is required to be initialized.\n");// NOI18N
            myCommonModels.append(" // So isNew() is rediefined here\n");   // NOI18N
            myCommonModels.append("return this.notSynced;\n}");          // NOI18N
        }
        else if ( myIdAttribute != null){
            myDisplayNameAlias = myIdAttribute.getName();
        }
          
        String sync = overrideSync( url, httpPaths , useIds); 
        if ( sync != null && sync.length()>0 ){
            myCommonModels.append(",\n");                            // NOI18N
            myCommonModels.append(sync);
            myCommonModels.append("\n");                             // NOI18N
        }
        myCommonModels.append("\n});\n\n");                          // NOI18N
        
        if ( collectionPath == null){
            return;
        }
        myCommonModels.append("\n // Collection class for ");          // NOI18N
        if ( name.equals(myModelName)){
            myCommonModels.append( name );
        }
        else {
            myCommonModels.append( entity.getQualifiedName().toString() );
        }
        myCommonModels.append(" entities\n");                        // NOI18N
        myCommonModels.append("models.");
        
        StringBuilder builder = new StringBuilder(myModelName);
        builder.append("Collection");                                // NOI18N
        myCollectionModelName = builder.toString();
        myCommonModels.append(myCollectionModelName);
        
        myCommonModels.append(" = Backbone.Collection.extend({\n");  // NOI18N
        myCommonModels.append("model: models.");                     // NOI18N
        myCommonModels.append(myModelName);
        myCommonModels.append(",\nurl : \"");                        // NOI18N
        myCommonModels.append( getUrl( collectionPath ));
        myCommonModels.append("\",\n");                              // NOI18N
        myCommonModels.append( getModifierdSync(""));
        myCommonModels.append("});\n\n");                            // NOI18N
    }
    
    JsUi getUi(){
        return myUi;
    }
    
    boolean hasCollection(){
        return myCollectionModelName!= null;
    }
    
    Set<ModelAttribute> getAttributes(){
        return myAttributes;
    }
    
    String getDisplayNameAlias(){
        return myDisplayNameAlias;
    }
    
    String getModelName(){
        return myModelName;
    }
    
    String getCollectionModelName(){
        return myCollectionModelName;
    }
    
    ModelAttribute getIdAttribute(){
        return myIdAttribute;
    }
    
    private String overrideSync( String url,
            Map<HttpRequests, String> httpPaths,
            Map<HttpRequests, Boolean> useIds ) throws IOException 
    {
        StringBuilder builder = new StringBuilder();
        for( Entry<HttpRequests,String> entry : httpPaths.entrySet() ){
            overrideMethod(url, entry.getValue(), 
                    useIds.get(entry.getKey()), entry.getKey(), builder);
        }
        EnumSet<HttpRequests> set = EnumSet.allOf(HttpRequests.class);
        set.removeAll( httpPaths.keySet());
        for( HttpRequests request : set  ){
            overrideMethod(url, null, null, request, builder);
        }
        return getModifierdSync(builder.toString());
    }
    
    private String getModifierdSync( String body ){
        StringBuilder result = new StringBuilder();
        result.append( "sync: function(method, model, options){\n");            // NOI18N
        result.append("options || (options = {});\n");                          // NOI18N
        result.append("var errorHandler = {\n");                                // NOI18N
        result.append("error: function (jqXHR, textStatus, errorThrown){\n");   // NOI18N
        result.append(" // TODO: put your error handling code here\n");          // NOI18N
        result.append(" // If you use the JS client from the different domain\n");// NOI18N
        result.append(" // (f.e. locally) then Cross-origin resource sharing \n");// NOI18N
        result.append(" // headers has to be set on the REST server side.\n");   // NOI18N
        result.append(" // Otherwise the JS client has to be copied into the\n");// NOI18N
        result.append(" // some (f.e. the same) Web project on the same domain\n");// NOI18N
        result.append("alert('Unable to fulfil the request');\n}\n};\n\n");        // NOI18N
        result.append( body );
        result.append("var result = Backbone.sync(method, model, ");            // NOI18N
        result.append("_.extend(options,errorHandler));\n");                    // NOI18N
        result.append("return result;\n}\n");    
        return result.toString();
    }
    
    private String getUrl( String relativePath ) throws IOException {
        Project project = FileOwnerQuery.getOwner(myDescription.getFile());
        RestSupport restSupport = project.getLookup().lookup(RestSupport.class);
        String applicationPath = restSupport.getApplicationPath();
        String uri = myDescription.getUriTemplate();
        
        if (applicationPath == null) {
            applicationPath = uri;
        }
        else {
            applicationPath = addUrlPath(applicationPath, uri);
        }
        applicationPath = addUrlPath(applicationPath, relativePath);
        
        return addUrlPath(MiscUtilities.getContextRootURL(project),applicationPath);
    }
    
    private String suggestModelName( String name ) {
        if ( myEntities.contains(name)){
            String newName ;
            int index =1;
            while( true ){
                newName = name+index;
                if ( !myEntities.contains(newName)){
                    myEntities.add(newName);
                    return newName;
                }
                index++;
            }
        }
        else {
            myEntities.add(name);
        }
        return name;
    }
    
    private String parse( TypeElement entity, CompilationController controller ) 
    {
        /*
         *  parse entity and generate attributes:
         *  1) idAttribute
         *  2) primitive attributes if any
         *  3) do not include attributes with complex type  
         */
        Set<String> attributes = parseBeanMethods( entity , controller );
        
        List<VariableElement> fields = ElementFilter.fieldsIn(
                controller.getElements().getAllMembers(entity));
        VariableElement id = null;
        for (VariableElement field : fields) {
            if ( JSClientGenerator.getAnnotation(field, ID) != null ){
                boolean has = attributes.remove(field.getSimpleName().toString());
                if ( has ){
                    id = field;
                    break;
                }
            }
        }
        StringBuilder builder = new StringBuilder();
        if ( id != null ){
            String idAttr = id.getSimpleName().toString();
            builder.append("\nidAttribute : '");                        // NOI18N
            builder.append(idAttr);
            builder.append("'");                                        // NOI18N
            if ( attributes.size() >0 ){
                builder.append(',');                                  
            }
            myIdAttribute = new ModelAttribute(idAttr);
        }
        
        if (attributes.size() > 0) {
            builder.append("\ndefaults: {");                            // NOI18N
            for (String attribute : attributes) {
                myAttributes.add( new ModelAttribute(attribute));
                builder.append("\n");                                   // NOI18N
                builder.append(attribute);
                builder.append(": \"\",");                              // NOI18N
            }
            builder.deleteCharAt(builder.length()-1);
            builder.append("\n}");                                      // NOI18N
        }
        
        if ( builder.length() >0 ){
            return builder.toString();
        }
        else {
            return null;
        }
    }
    
    private Set<String> parseBeanMethods( TypeElement entity,
            CompilationController controller )
    {
        List<ExecutableElement> methods = ElementFilter.methodsIn(
                controller.getElements().getAllMembers(entity));
        Set<String> result = new HashSet<String>();
        Map<String,TypeMirror> getAttrs = new HashMap<String, TypeMirror>();
        Map<String,TypeMirror> setAttrs = new HashMap<String, TypeMirror>();
        for (ExecutableElement method : methods) {
            if ( !method.getModifiers().contains( Modifier.PUBLIC)){
                continue;
            }
            
            Object[] attribute = getAttrName( method , controller);
            if ( attribute == null ){
                continue;
            }
            String name = (String)attribute[1];
            TypeMirror type = (TypeMirror)attribute[2];
            if ( attribute[0] == MethodType.GET ){
                if ( findAccessor(name, type, getAttrs, setAttrs, controller)){
                    result.add(name);
                }
            }
            else {
                if ( findAccessor(name, type, setAttrs, getAttrs, controller)){
                    result.add(name);
                }
            }
        }
        return result;
    }
    
    private boolean findAccessor(String name, TypeMirror type, 
            Map<String,TypeMirror> map1, Map<String,TypeMirror> map2, 
            CompilationController controller)
    {
        TypeMirror typeMirror = map2.remove(name);
        if ( typeMirror!= null && 
                controller.getTypes().isSameType(typeMirror, type))
        {
            return true;
        }
        else {
            map1.put(name, type);
        }
        return false;
    }
    
    private Object[] getAttrName( ExecutableElement method,
            CompilationController controller )
    {
        String name = method.getSimpleName().toString();
        if ( name.startsWith("set") ){                               // NOI18N
            TypeMirror returnType = method.getReturnType();
            if ( returnType.getKind()!= TypeKind.VOID){
                return null;
            }
            List<? extends VariableElement> parameters = method.getParameters();
            if ( parameters.size() !=1 ){
                return null;
            }
            VariableElement param = parameters.get(0);
            TypeMirror type = param.asType();
            if ( isSimple(type, controller)){
                return new Object[] {
                    MethodType.SET,
                    Introspector.decapitalize(name.substring(3)),
                    type
                };
            }
            else {
                return null;
            }
        }
        int start =0;
        if ( name.startsWith("get")){                                   // NOI18N
            start =3;
        }
        else if ( name.startsWith( "is")){                              // NOI18N
            start =2;
        }
        if ( start > 0){
            List<? extends VariableElement> parameters = method.getParameters();
            if (!parameters.isEmpty()) {
                return null;
            }
            TypeMirror returnType = method.getReturnType();
            if ( isSimple(returnType, controller)){
                return new Object[] {
                    MethodType.GET,
                    Introspector.decapitalize(name.substring(start)),
                    returnType
                };
            }
            else {
                return null;
            }
        }
        return null;
    }
    
    /*
     * returns true if type is primitive or String
     */
    private boolean isSimple(TypeMirror typeMirror, CompilationController controller){
        if ( typeMirror.getKind().isPrimitive() ){
            return true;
        }
        Element fieldTypeElement = controller.getTypes().asElement(typeMirror);
        TypeElement stringElement = controller.getElements().
            getTypeElement(String.class.getName());
        if ( stringElement != null && stringElement.equals( fieldTypeElement)){
            return true;
        }
        
        if (fieldTypeElement != null) {
            PackageElement pack = controller.getElements().getPackageOf(
                    fieldTypeElement);
            if ( pack.getQualifiedName().contentEquals("java.lang")){      // NOI18N
                try {
                    if ( controller.getTypes().unboxedType(typeMirror) != null ){
                        return true;
                    }
                }
                catch(IllegalArgumentException e){
                    // just skip field
                }
            }
        }
        
        return false;
    }
    
    private void overrideMethod(String url, String path, Boolean useId, 
            HttpRequests request, StringBuilder builder ) throws IOException
    {
        if ( path == null ){
            builder.append("if(method==='");                              // NOI18N
            builder.append(request.toString());
            builder.append("'){\n");                                     // NOI18N
            builder.append("return false;\n}\n");                        // NOI18N
        }
        else {
            path = getUrl(path);
            StringBuilder newUrlSnippet = new StringBuilder();
            boolean isModified = false;
            if ( !url.equals(path) ){
                newUrlSnippet.append("options.url = '");                 // NOI18N
                newUrlSnippet.append(path);
                isModified = true;
            }
            if (useId!= null && useId){
                if ( isModified ){
                    if ( !path.endsWith("/")){
                        newUrlSnippet.append('/');
                    }
                    newUrlSnippet.append("'+model.id;\n");
                }
            }
            else{
                if ( isModified ){
                    newUrlSnippet.append("';\n");
                }
                else{
                    newUrlSnippet.append("options.url = '");             // NOI18N
                    newUrlSnippet.append(path);
                    newUrlSnippet.append("';\n");
                }
            }
            if ( newUrlSnippet.length() == 0 ){
                return;
            }
            builder.append("if(method==='");                         // NOI18N
            builder.append(request.toString());
            builder.append("'){\n");                                // NOI18N
            builder.append(newUrlSnippet);
            builder.append("}\n");                                  // NOI18N
        }
    }
    
    private String addUrlPath( String path, String uri ) {
        if (uri.startsWith(SLASH)) {
            if (path.endsWith(SLASH)) {
                path = path + uri.substring(1);
            }
            else {
                path = path + uri;
            }
        }
        else {
            if (path.endsWith(SLASH)) {
                path = path + uri;
            }
            else {
                path = path + SLASH + uri;
            }
        }
        return path;
    }
    
    private final StringBuilder myCommonModels;
    private final RestServiceDescription myDescription;
    private final Set<String> myEntities;
    private final JsUi myUi;
    private Set<ModelAttribute> myAttributes;
    private String myDisplayNameAlias;
    private String myModelName;
    private String myCollectionModelName;
    private ModelAttribute myIdAttribute;
}