/**

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

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

 *

 * Oracle and Java are registered trademarks of Oracle and/or its affiliates.

 * Other names may be trademarks of their respective owners.

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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

 * specific language governing permissions and limitations under the

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 * Notice in each file and include the License file at

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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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 *

 * 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

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 * under the [CDDL or GPL Version 2] license." If you do not indicate a

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

 * Version 2 license, then the option applies only if the new code is

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 */

package org.netbeans.html.boot.impl;

import java.io.IOException;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.PrintWriter;

import java.io.Writer;

import java.util.Collections;

import java.util.HashMap;

import java.util.HashSet;

import java.util.List;

import java.util.Map;

import java.util.Set;

import java.util.TreeMap;

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.SourceVersion;

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.Modifier;

import javax.lang.model.element.Name;

import javax.lang.model.element.PackageElement;

import javax.lang.model.element.TypeElement;

import javax.lang.model.element.VariableElement;

import javax.lang.model.type.ArrayType;

import javax.lang.model.type.ExecutableType;

import javax.lang.model.type.TypeKind;

import javax.lang.model.type.TypeMirror;

import javax.tools.Diagnostic;

import javax.tools.FileObject;

import javax.tools.StandardLocation;

import net.java.html.js.JavaScriptBody;

import net.java.html.js.JavaScriptResource;

import org.openide.util.lookup.ServiceProvider;

/**

 *

 * @author Jaroslav Tulach

 */

@ServiceProvider(service = Processor.class)

public final class JavaScriptProcesor extends AbstractProcessor {

    private final Map<String,Map<String,ExecutableElement>> javacalls = 

        new HashMap<String,Map<String,ExecutableElement>>();

    private final Map<String,Set<TypeElement>> bodies = 

        new HashMap<String, Set<TypeElement>>();

    @Override

    public Set<String> getSupportedAnnotationTypes() {

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

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

        set.add(JavaScriptResource.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;

            } else {

                Set<TypeElement> classes = this.bodies.get(findPkg(e));

                if (classes == null) {

                    classes = new HashSet<TypeElement>();

                    bodies.put(findPkg(e), classes);

                }

                Element t = e.getEnclosingElement();

                while (!t.getKind().isClass() && !t.getKind().isInterface()) {

                    t = t.getEnclosingElement();

                }

                classes.add((TypeElement)t);

            }

            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 (!jsb.wait4js() && ee.getReturnType().getKind() != TypeKind.VOID) {

                msg.printMessage(Diagnostic.Kind.ERROR, "Methods that don't wait for JavaScript to finish must return void!", e);

            }

            if (!jsb.javacall() && jsb.body().contains(".@")) {

                msg.printMessage(Diagnostic.Kind.WARNING, "Usage of .@ usually requires javacall=true", e);

            }

            if (jsb.javacall()) {

                JsCallback verify = new VerifyCallback(e);

                try {

                    verify.parse(jsb.body());

                } catch (IllegalStateException ex) {

                    msg.printMessage(Diagnostic.Kind.ERROR, ex.getLocalizedMessage(), e);

                }

            }

        }

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

            JavaScriptResource r = e.getAnnotation(JavaScriptResource.class);

            if (r == null) {

                continue;

            }

            final String res;

            if (r.value().startsWith("/")) {

                res = r.value().substring(1);

            } else {

                res = findPkg(e).replace('.', '/') + "/" + r.value();

            }

            try {

                FileObject os = processingEnv.getFiler().getResource(StandardLocation.SOURCE_PATH, "", res);

                os.openInputStream().close();

            } catch (IOException ex1) {

                try {

                    FileObject os2 = processingEnv.getFiler().getResource(StandardLocation.CLASS_OUTPUT, "", res);

                    os2.openInputStream().close();

                } catch (IOException ex2) {

                    try {

                        FileObject os3 = processingEnv.getFiler().getResource(StandardLocation.CLASS_PATH, "", res);

                        os3.openInputStream().close();

                    } catch (IOException ex3) {

                        msg.printMessage(Diagnostic.Kind.ERROR, "Cannot find resource " + res, e);

                    }

                }

            }

            boolean found = false;

            for (Element mthod : e.getEnclosedElements()) {

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

                    continue;

                }

                if (mthod.getAnnotation(JavaScriptBody.class) != null) {

                    found = true;

                    break;

                }

            }

            if (!found) {

                msg.printMessage(Diagnostic.Kind.ERROR, "At least one method needs @JavaScriptBody annotation. "

                    + "Otherwise it is not guaranteed the resource will ever be loaded,", e

                );

            }

        }

        if (roundEnv.processingOver()) {

            generateCallbackClass(javacalls);

            generateJavaScriptBodyList(bodies);

            javacalls.clear();

        }

        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;

    }

    private class VerifyCallback extends JsCallback {

        private final Element e;

        public VerifyCallback(Element e) {

            this.e = e;

        }

        @Override

        protected CharSequence callMethod(String ident, String fqn, String method, String params) {

            final TypeElement type = processingEnv.getElementUtils().getTypeElement(fqn);

            if (type == null) {

                processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, 

                    "Callback to non-existing class " + fqn, e

                );

                return "";

            }

            ExecutableElement found = null;

            StringBuilder foundParams = new StringBuilder();

            for (Element m : type.getEnclosedElements()) {

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

                    continue;

                }

                if (m.getSimpleName().contentEquals(method)) {

                    String paramTypes = findParamTypes((ExecutableElement)m);

                    if (paramTypes.equals(params)) {

                        found = (ExecutableElement) m;

                        break;

                    }

                    foundParams.append(paramTypes).append("\n");

                }

            }

            if (found == null) {

                if (foundParams.length() == 0) {

                    processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, 

                        "Callback to class " + fqn + " with unknown method " + method, e

                    );

                } else {

                    processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, 

                        "Callback to " + fqn + "." + method + " with wrong parameters: " + 

                        params + ". Only known parameters are " + foundParams, e

                    );

                }

            } else {

                Map<String,ExecutableElement> mangledOnes = javacalls.get(findPkg(e));

                if (mangledOnes == null) {

                    mangledOnes = new TreeMap<String, ExecutableElement>();

                    javacalls.put(findPkg(e), mangledOnes);

                }

                String mangled = JsCallback.mangle(fqn, method, findParamTypes(found));

                mangledOnes.put(mangled, found);

            }

            return "";

        }

        private String findParamTypes(ExecutableElement method) {

            ExecutableType t = (ExecutableType) method.asType();

            StringBuilder sb = new StringBuilder();

            sb.append('(');

            for (TypeMirror tm : t.getParameterTypes()) {

                if (tm.getKind().isPrimitive()) {

                    switch (tm.getKind()) {

                        case INT: sb.append('I'); break;

                        case BOOLEAN: sb.append('Z'); break;

                        case BYTE: sb.append('B'); break;

                        case CHAR: sb.append('C'); break;

                        case SHORT: sb.append('S'); break;

                        case DOUBLE: sb.append('D'); break;

                        case FLOAT: sb.append('F'); break;

                        case LONG: sb.append('J'); break;

                        default:

                            throw new IllegalStateException("Uknown " + tm.getKind());

                    }

                } else {

                    while (tm.getKind() == TypeKind.ARRAY) {

                        sb.append('[');

                        tm = ((ArrayType)tm).getComponentType();

                    }

                    sb.append('L');

                    sb.append(tm.toString().replace('.', '/'));

                    sb.append(';');

                }

            }

            sb.append(')');

            return sb.toString();

        }

    }

    private void generateJavaScriptBodyList(Map<String,Set<TypeElement>> bodies) {

        if (bodies.isEmpty()) {

            return;

        }

        try {

            FileObject all = processingEnv.getFiler().createResource(

                StandardLocation.CLASS_OUTPUT, "", "META-INF/net.java.html.js.classes"                

            );

            PrintWriter wAll = new PrintWriter(new OutputStreamWriter(

                all.openOutputStream(), "UTF-8"

            ));

            for (Map.Entry<String, Set<TypeElement>> entry : bodies.entrySet()) {

                String pkg = entry.getKey();

                Set<TypeElement> classes = entry.getValue();

                FileObject out = processingEnv.getFiler().createResource(

                    StandardLocation.CLASS_OUTPUT, pkg, "net.java.html.js.classes",

                    classes.iterator().next()

                );

                OutputStream os = out.openOutputStream();

                try {

                    PrintWriter w = new PrintWriter(new OutputStreamWriter(os, "UTF-8"));

                    for (TypeElement type : classes) {

                        final Name bn = processingEnv.getElementUtils().getBinaryName(type);

                        w.println(bn);

                        wAll.println(bn);

                    }

                    w.flush();

                    w.close();

                } catch (IOException x) {

                    processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, "Failed to write to " + entry.getKey() + ": " + x.toString());

                } finally {

                    os.close();

                }

            }

            wAll.close();

        } catch (IOException x) {

            processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, "Failed to write to " + "META-INF/net.java.html.js.classes: " + x.toString());

        }

    }

    private void generateCallbackClass(Map<String,Map<String, ExecutableElement>> process) {

        for (Map.Entry<String, Map<String, ExecutableElement>> pkgEn : process.entrySet()) {

            String pkgName = pkgEn.getKey();

            Map<String, ExecutableElement> map = pkgEn.getValue();

            StringBuilder source = new StringBuilder();

            source.append("package ").append(pkgName).append(";\n");

            source.append("public final class $JsCallbacks$ {\n");

            source.append("  static final $JsCallbacks$ VM = new $JsCallbacks$(null);\n");

            source.append("  private final org.apidesign.html.boot.spi.Fn.Presenter p;\n");

            source.append("  private $JsCallbacks$ last;\n");

            source.append("  private $JsCallbacks$(org.apidesign.html.boot.spi.Fn.Presenter p) {\n");

            source.append("    this.p = p;\n");

            source.append("  }\n");

            source.append("  final $JsCallbacks$ current() {\n");

            source.append("    org.apidesign.html.boot.spi.Fn.Presenter now = org.apidesign.html.boot.spi.Fn.activePresenter();\n");

            source.append("    if (now == p) return this;\n");

            source.append("    if (last != null && now == last.p) return last;\n");

            source.append("    return last = new $JsCallbacks$(now);\n");

            source.append("  }\n");

            for (Map.Entry<String, ExecutableElement> entry : map.entrySet()) {

                final String mangled = entry.getKey();

                final ExecutableElement m = entry.getValue();

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

                source.append("\n  public java.lang.Object ")

                    .append(mangled)

                    .append("(");

                String sep = "";

                if (!isStatic) {

                    source.append(((TypeElement)m.getEnclosingElement()).getQualifiedName());

                    source.append(" self");

                    sep = ", ";

                }

                int cnt = 0;

                StringBuilder convert = new StringBuilder();

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

                    source.append(sep);

                    ++cnt;

                    final TypeMirror t = ve.asType();

                    if (!t.getKind().isPrimitive()) {

                        source.append("Object");

                        convert.append("    if (p instanceof org.apidesign.html.boot.spi.Fn.FromJavaScript) {\n");

                        convert.append("      arg").append(cnt).

                            append(" = ((org.apidesign.html.boot.spi.Fn.FromJavaScript)p).toJava(arg").append(cnt).

                            append(");\n");

                        convert.append("    }\n");

                    } else {

                        source.append(t);

                    }

                    source.append(" arg").append(cnt);

                    sep = ", ";

                }

                source.append(") throws Throwable {\n");

                source.append(convert);

                if (useTryResources()) {

                    source.append("    try (java.io.Closeable a = org.apidesign.html.boot.spi.Fn.activate(p)) { \n");

                } else {

                    source.append("    java.io.Closeable a = org.apidesign.html.boot.spi.Fn.activate(p); try {\n");

                }

                source.append("    ");

                if (m.getReturnType().getKind() != TypeKind.VOID) {

                    source.append("Object $ret = ");

                }

                if (isStatic) {

                    source.append(((TypeElement)m.getEnclosingElement()).getQualifiedName());

                    source.append('.');

                } else {

                    source.append("self.");

                }

                source.append(m.getSimpleName());

                source.append("(");

                cnt = 0;

                sep = "";

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

                    source.append(sep);

                    source.append("(").append(ve.asType());

                    source.append(")arg").append(++cnt);

                    sep = ", ";

                }

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

                if (m.getReturnType().getKind() == TypeKind.VOID) {

                    source.append("    return null;\n");

                } else {

                    source.append("    if (p instanceof org.apidesign.html.boot.spi.Fn.ToJavaScript) {\n");

                    source.append("      $ret = ((org.apidesign.html.boot.spi.Fn.ToJavaScript)p).toJavaScript($ret);\n");

                    source.append("    }\n");

                    source.append("    return $ret;\n");

                }

                if (useTryResources()) {

                    source.append("    }\n");

                } else {

                    source.append("    } finally {\n");

                    source.append("      a.close();\n");

                    source.append("    }\n");

                }

                source.append("  }\n");

            }

            source.append("}\n");

            final String srcName = pkgName + ".$JsCallbacks$";

            try {

                Writer w = processingEnv.getFiler().createSourceFile(srcName,

                    map.values().toArray(new Element[map.size()])

                ).openWriter();

                w.write(source.toString());

                w.close();

            } catch (IOException ex) {

                processingEnv.getMessager().printMessage(

                    Diagnostic.Kind.ERROR, "Can't write " + srcName + ": " + ex.getMessage()

                );

            }

        }

    }

    private boolean useTryResources() {

        try {

            return processingEnv.getSourceVersion().compareTo(SourceVersion.RELEASE_7) >= 0;

        } catch (LinkageError err) {

            // can happen when running on JDK6

            return false;

        }

    }

    private static String findPkg(Element e) {

        while (e.getKind() != ElementKind.PACKAGE) {

            e = e.getEnclosingElement();

        }

        return ((PackageElement)e).getQualifiedName().toString();

    }

}