/**

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  * Copyright 2013-2014 Oracle and/or its affiliates. All rights reserved.

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  * The contents of this file are subject to the terms of either the GNU

  * General Public License Version 2 only ("GPL") or the Common

  * Development and Distribution License("CDDL") (collectively, the

  * "License"). You may not use this file except in compliance with the

  * License. You can obtain a copy of the License at

  * http://www.netbeans.org/cddl-gplv2.html

  * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the

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  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the GPL Version 2 section of the License file that

  * accompanied this code. If applicable, add the following below the

  * License Header, with the fields enclosed by brackets [] replaced by

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  *

  * Contributor(s):

  *

  * The Original Software is NetBeans. The Initial Developer of the Original

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  * If you wish your version of this file to be governed by only the CDDL

  * or only the GPL Version 2, indicate your decision by adding

  * "[Contributor] elects to include this software in this distribution

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  * to extend the choice of license to its licensees as provided above.

  * However, if you add GPL Version 2 code and therefore, elected the GPL

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 package org.netbeans.html.geo.impl;

 import java.io.IOException;

 import java.io.Writer;

 import java.util.List;

 import java.util.Locale;

 import java.util.Set;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 import javax.annotation.processing.AbstractProcessor;

 import javax.annotation.processing.Processor;

 import javax.annotation.processing.RoundEnvironment;

 import javax.annotation.processing.SupportedAnnotationTypes;

 import javax.annotation.processing.SupportedSourceVersion;

 import javax.lang.model.SourceVersion;

 import javax.lang.model.element.Element;

 import javax.lang.model.element.ElementKind;

 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.TypeMirror;

 import javax.tools.Diagnostic;

 import javax.tools.JavaFileObject;

 import net.java.html.geo.OnLocation;

 import net.java.html.geo.Position;

 import net.java.html.geo.Position.Handle;

 import org.openide.util.lookup.ServiceProvider;

 /** Annotation processor to generate callbacks from {@link Handle} class.

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 @ServiceProvider(service=Processor.class)

 @SupportedSourceVersion(SourceVersion.RELEASE_6)

 @SupportedAnnotationTypes({

     "net.java.html.geo.OnLocation"

 })

 public final class GeoProcessor extends AbstractProcessor {

     private static final Logger LOG = Logger.getLogger(GeoProcessor.class.getName());

     @Override

     public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {

         boolean ok = true;

         for (Element e : roundEnv.getElementsAnnotatedWith(OnLocation.class)) {

             if (!processLocation(e)) {

                 ok = false;

             }

         }

         return ok;

     }

     private void error(String msg, Element e) {

         processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, msg, e);

     }

     private boolean processLocation(Element e) {

         if (e.getKind() != ElementKind.METHOD) {

             return false;

         }

         ExecutableElement me = (ExecutableElement) e;

         OnLocation ol = e.getAnnotation(OnLocation.class);

         if (ol == null) {

             return true;

         }

         if (me.getModifiers().contains(Modifier.PRIVATE)) {

             error("Method annotated by @OnLocation cannot be private", e);

             return false;

         }

         TypeMirror positionClass = processingEnv.getElementUtils().getTypeElement(Position.class.getName()).asType();

         final List<? extends VariableElement> params = me.getParameters();

         if (params.size() < 1 || !params.get(0).asType().equals(positionClass)) {

             error("Method annotated by @OnLocation first argument must be net.java.html.geo.Position!", e);

             return false;

         }

         String className = ol.className();

         if (className.isEmpty()) {

             String n = e.getSimpleName().toString();

             if (n.isEmpty()) {

                 error("Empty method name", e);

                 return false;

             }

             final String firstLetter = n.substring(0, 1).toUpperCase(Locale.ENGLISH);

             className = firstLetter + n.substring(1) + "Handle";

         }

         TypeElement te = (TypeElement)e.getEnclosingElement();

         PackageElement pe = (PackageElement) te.getEnclosingElement();

         final String pkg = pe.getQualifiedName().toString();

         final String fqn = pkg + "." + className;

         final boolean isStatic = me.getModifiers().contains(Modifier.STATIC);

         String sep;

         try {

             JavaFileObject fo = processingEnv.getFiler().createSourceFile(fqn, e);

             Writer w = fo.openWriter();

             w.append("package ").append(pkg).append(";\n");

             w.append("class ").append(className).append(" extends net.java.html.geo.Position.Handle {\n");

             if (!isStatic) {

                 w.append("  private final ").append(te.getSimpleName()).append(" $i;\n");

             }

             for (int i = 1; i < params.size(); i++) {

                 final VariableElement p = params.get(i);

                 w.append("  private final ").append(p.asType().toString()).append(" ").append(p.getSimpleName()).append(";\n");

             }

             w.append("  private ").append(className).append("(boolean oneTime");

             w.append(", ").append(te.getSimpleName()).append(" i");

             for (int i = 1; i < params.size(); i++) {

                 final VariableElement p = params.get(i);

                 w.append(", ").append(p.asType().toString()).append(" ").append(p.getSimpleName());

             }

             w.append(") {\n    super(oneTime);\n");

             if (!isStatic) {

                 w.append("    this.$i = i;\n");

             }

             for (int i = 1; i < params.size(); i++) {

                 final VariableElement p = params.get(i);

                 w.append("  this.").append(p.getSimpleName()).append(" = ").append(p.getSimpleName()).append(";\n");

             }

             w.append("}\n");

             w.append("  static net.java.html.geo.Position.Handle createQuery(");

             String inst;

             if (!isStatic) {

                 w.append(te.getSimpleName()).append(" instance");

                 inst = "instance";

                 sep = ", ";

             } else {

                 inst = "null";

                 sep = "";

             }

             for (int i = 1; i < params.size(); i++) {

                 final VariableElement p = params.get(i);

                 w.append(sep).append(p.asType().toString()).append(" ").append(p.getSimpleName());

                 sep = ", ";

             }

             w.append(") { return new ").append(className).append("(true, ").append(inst);

             for (int i = 1; i < params.size(); i++) {

                 final VariableElement p = params.get(i);

                 w.append(", ").append(p.getSimpleName());

             }

             w.append("); }\n");

             w.append("  static net.java.html.geo.Position.Handle createWatch(");

             if (!isStatic) {

                 w.append(te.getSimpleName()).append(" instance");

                 sep = ", ";

             } else {

                 sep = "";

             }

             for (int i = 1; i < params.size(); i++) {

                 final VariableElement p = params.get(i);

                 w.append(sep).append(p.asType().toString()).append(" ").append(p.getSimpleName());

             }

             w.append(") { return new ").append(className).append("(false, ").append(inst);

             for (int i = 1; i < params.size(); i++) {

                 final VariableElement p = params.get(i);

                 w.append(", ").append(p.getSimpleName());

             }

             w.append("); }\n");

             w.append("  @Override protected void onError(Exception t) throws Throwable {\n");

             if (ol.onError().isEmpty()) {

                 w.append("    t.printStackTrace();");

             } else {

                 if (!findOnError(me, te, ol.onError(), isStatic)) {

                     return false;

                 }

                 if (isStatic) {

                     w.append("    ").append(te.getSimpleName()).append(".");

                 } else {

                     w.append("    $i.");

                 }

                 w.append(ol.onError()).append("(t");

                 for (int i = 1; i < params.size(); i++) {

                     final VariableElement p = params.get(i);

                     w.append(", ").append(p.getSimpleName());

                 }

                 w.append(");\n");

             }

             w.append("  }\n");

             w.append("  @Override protected void onLocation(net.java.html.geo.Position p) throws Throwable {\n");

             if (isStatic) {

                 w.append("    ").append(te.getSimpleName()).append(".");

             } else {

                 w.append("    $i.");

             }

             w.append(me.getSimpleName()).append("(p");

             for (int i = 1; i < params.size(); i++) {

                 final VariableElement p = params.get(i);

                 w.append(", ").append(p.getSimpleName());

             }

             w.append(");\n");

             w.append("  }\n");

             w.append("}\n");

             w.close();

         } catch (IOException ex) {

             Logger.getLogger(GeoProcessor.class.getName()).log(Level.SEVERE, null, ex);

             error("Can't write handler class: " + ex.getMessage(), e);

             return false;

         }

         return true;

     }

     private boolean findOnError(ExecutableElement errElem, TypeElement te, String name, boolean onlyStatic) {

         String err = null;

         METHODS: for (Element e : te.getEnclosedElements()) {

             if (e.getKind() != ElementKind.METHOD) {

                 continue;

             }

             if (!e.getSimpleName().contentEquals(name)) {

                 continue;

             }

             if (onlyStatic && !e.getModifiers().contains(Modifier.STATIC)) {

                 errElem = (ExecutableElement) e;

                 err = "Would have to be static";

                 continue;

             }

             ExecutableElement ee = (ExecutableElement) e;

             TypeMirror excType = processingEnv.getElementUtils().getTypeElement(Exception.class.getName()).asType();

             final List<? extends VariableElement> params = ee.getParameters(); 

             if (params.size() < 1 || 

                 !processingEnv.getTypeUtils().isAssignable(excType, ee.getParameters().get(0).asType())

             ) {

                 errElem = (ExecutableElement) e;

                 err = "Error method first argument needs to be Exception";

                 continue;

             }

             final List<? extends Element> origParams = errElem.getParameters();

             if (params.size() != origParams.size()) {

                 errElem = (ExecutableElement) e;

                 err = "Error method must have the same parameters as @OnLocation one";

                 continue;

             }

             for (int i = 1; i < origParams.size(); i++) {

                 final TypeMirror t1 = params.get(i).asType();

                 final TypeMirror t2 = origParams.get(i).asType();

                 if (!processingEnv.getTypeUtils().isSameType(t1, t2)) {

                     errElem = (ExecutableElement) e;

                     err = "Error method must have the same parameters as @OnLocation one";

                     continue METHODS;

                 }

             }

             return true;

         }

         if (err == null) {

             err = "Cannot find " + name + "(Exception) method in this class";

         }

         error(err, errElem);

         return false;

     }

 }