/**

 * Back 2 Browser Bytecode Translator

 * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, version 2 of the License.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program. Look for COPYING file in the top folder.

 * If not, see http://opensource.org/licenses/GPL-2.0.

 */

package org.apidesign.bck2brwsr.core.impl;

import java.util.Collections;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

import javax.annotation.processing.AbstractProcessor;

import javax.annotation.processing.Completion;

import javax.annotation.processing.Completions;

import javax.annotation.processing.Messager;

import javax.annotation.processing.Processor;

import javax.annotation.processing.RoundEnvironment;

import javax.lang.model.element.AnnotationMirror;

import javax.lang.model.element.Element;

import javax.lang.model.element.ElementKind;

import javax.lang.model.element.ExecutableElement;

import javax.lang.model.element.TypeElement;

import javax.lang.model.element.VariableElement;

import javax.lang.model.type.TypeKind;

import javax.tools.Diagnostic;

import org.apidesign.bck2brwsr.core.JavaScriptBody;

import org.openide.util.lookup.ServiceProvider;

/**

 *

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

 */

@ServiceProvider(service = Processor.class)

public final class JavaScriptProcesor extends AbstractProcessor {

    @Override

    public Set<String> getSupportedAnnotationTypes() {

        Set<String> set = new HashSet<>();

        set.add(JavaScriptBody.class.getName());

        return set;

    }

    @Override

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

        final Messager msg = processingEnv.getMessager();

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

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

                continue;

            }

            ExecutableElement ee = (ExecutableElement)e;

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

            JavaScriptBody jsb = e.getAnnotation(JavaScriptBody.class);

            if (jsb == null) {

                continue;

            }

            String[] arr = jsb.args();

            if (params.size() != arr.length) {

                msg.printMessage(Diagnostic.Kind.ERROR, "Number of args arguments does not match real arguments!", e);

            }

            if (ee.getReturnType().getKind() == TypeKind.LONG) {

                msg.printMessage(Diagnostic.Kind.WARNING, "Don't return long. Return double and convert it to long in Java code.", e);

            }

        }

        return true;

    }

    @Override

    public Iterable<? extends Completion> getCompletions(Element e, 

        AnnotationMirror annotation, ExecutableElement member, String userText

    ) {

        StringBuilder sb = new StringBuilder();

        if (e.getKind() == ElementKind.METHOD && member.getSimpleName().contentEquals("args")) {

            ExecutableElement ee = (ExecutableElement) e;

            String sep = "";

            sb.append("{ ");

            for (VariableElement ve : ee.getParameters()) {

                sb.append(sep).append('"').append(ve.getSimpleName())

                    .append('"');

                sep = ", ";

            }

            sb.append(" }");

            return Collections.nCopies(1, Completions.of(sb.toString()));

        }

        return null;

    }

}