/*
 * Copyright (c) 2005, 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.tools.javac.processing;

import javax.annotation.processing.*;
import javax.lang.model.*;
import javax.lang.model.element.*;
import static javax.lang.model.element.ElementKind.*;
import static javax.lang.model.element.NestingKind.*;
import static javax.lang.model.element.ModuleElement.*;
import javax.lang.model.type.*;
import javax.lang.model.util.*;

import java.io.PrintWriter;
import java.io.Writer;
import java.util.*;
import java.util.stream.Collectors;


import com.sun.tools.javac.util.DefinedBy;
import com.sun.tools.javac.util.DefinedBy.Api;
import com.sun.tools.javac.util.StringUtils;

A processor which prints out elements.  Used to implement the
-Xprint option; the included visitor class is used to implement
Elements.printElements.
This is NOT part of any supported API.
If you write code that depends on this, you do so at your own risk.
This code and its internal interfaces are subject to change or
deletion without notice.
/**
 * A processor which prints out elements.  Used to implement the
 * -Xprint option; the included visitor class is used to implement
 * Elements.printElements.
 *
 * <p><b>This is NOT part of any supported API.
 * If you write code that depends on this, you do so at your own risk.
 * This code and its internal interfaces are subject to change or
 * deletion without notice.</b>
 */
@SupportedAnnotationTypes("*")
@SupportedSourceVersion(SourceVersion.RELEASE_17)
public class PrintingProcessor extends AbstractProcessor {
    PrintWriter writer;

    public PrintingProcessor() {
        super();
        writer = new PrintWriter(System.out);
    }

    public void setWriter(Writer w) {
        writer = new PrintWriter(w);
    }

    @Override @DefinedBy(Api.ANNOTATION_PROCESSING)
    public boolean process(Set<? extends TypeElement> tes,
                           RoundEnvironment renv) {

        for(Element element : renv.getRootElements()) {
            print(element);
        }

        // Just print the elements, nothing more to do.
        return true;
    }

    void print(Element element) {
        new PrintingElementVisitor(writer, processingEnv.getElementUtils()).
            visit(element).flush();
    }

    
Used for the -Xprint option and called by Elements.printElements
/**
     * Used for the -Xprint option and called by Elements.printElements
     */
    @SuppressWarnings("preview")
    public static class PrintingElementVisitor
        extends SimpleElementVisitor14<PrintingElementVisitor, Boolean> {
        int indentation; // Indentation level;
        final PrintWriter writer;
        final Elements elementUtils;

        public PrintingElementVisitor(Writer w, Elements elementUtils) {
            super();
            this.writer = new PrintWriter(w);
            this.elementUtils = elementUtils;
            indentation = 0;
        }

        @Override @DefinedBy(Api.LANGUAGE_MODEL)
        protected PrintingElementVisitor defaultAction(Element e, Boolean newLine) {
            if (newLine != null && newLine)
                writer.println();
            printDocComment(e);
            printModifiers(e);
            return this;
        }

        @Override @DefinedBy(Api.LANGUAGE_MODEL)
        public PrintingElementVisitor visitRecordComponent(RecordComponentElement e, Boolean p) {
                // Do nothing; printing of component information done by
                // printing the record type itself
            return this;
        }

        @Override @DefinedBy(Api.LANGUAGE_MODEL)
        public PrintingElementVisitor visitExecutable(ExecutableElement e, Boolean p) {
            ElementKind kind = e.getKind();

            if (kind != STATIC_INIT &&
                kind != INSTANCE_INIT) {
                Element enclosing = e.getEnclosingElement();

                // Don't print out the constructor of an anonymous class
                if (kind == CONSTRUCTOR &&
                    enclosing != null &&
                    NestingKind.ANONYMOUS ==
                    // Use an anonymous class to determine anonymity!
                    (new SimpleElementVisitor14<NestingKind, Void>() {
                        @Override @DefinedBy(Api.LANGUAGE_MODEL)
                        public NestingKind visitType(TypeElement e, Void p) {
                            return e.getNestingKind();
                        }
                    }).visit(enclosing))
                    return this;

                defaultAction(e, true);
                printFormalTypeParameters(e, true);

                switch(kind) {
                    case CONSTRUCTOR:
                    // Print out simple name of the class
                    writer.print(e.getEnclosingElement().getSimpleName());
                    break;

                    case METHOD:
                    writer.print(e.getReturnType().toString());
                    writer.print(" ");
                    writer.print(e.getSimpleName().toString());
                    break;
                }

                writer.print("(");
                printParameters(e);
                writer.print(")");
                AnnotationValue defaultValue = e.getDefaultValue();
                if (defaultValue != null)
                    writer.print(" default " + defaultValue);

                printThrows(e);
                writer.println(";");
            }
            return this;
        }


        @Override @DefinedBy(Api.LANGUAGE_MODEL)
        public PrintingElementVisitor visitType(TypeElement e, Boolean p) {
            ElementKind kind = e.getKind();
            NestingKind nestingKind = e.getNestingKind();

            if (NestingKind.ANONYMOUS == nestingKind) {
                // Print out an anonymous class in the style of a
                // class instance creation expression rather than a
                // class declaration.
                writer.print("new ");

                // If the anonymous class implements an interface
                // print that name, otherwise print the superclass.
                List<? extends TypeMirror> interfaces = e.getInterfaces();
                if (!interfaces.isEmpty())
                    writer.print(interfaces.get(0));
                else
                    writer.print(e.getSuperclass());

                writer.print("(");
                // Anonymous classes that implement an interface can't
                // have any constructor arguments.
                if (interfaces.isEmpty()) {
                    // Print out the parameter list from the sole
                    // constructor.  For now, don't try to elide any
                    // synthetic parameters by determining if the
                    // anonymous class is in a static context, etc.
                    List<? extends ExecutableElement> constructors =
                        ElementFilter.constructorsIn(e.getEnclosedElements());

                    if (!constructors.isEmpty())
                        printParameters(constructors.get(0));
                }
                writer.print(")");
            } else {
                if (nestingKind == TOP_LEVEL) {
                    PackageElement pkg = elementUtils.getPackageOf(e);
                    if (!pkg.isUnnamed())
                        writer.print("package " + pkg.getQualifiedName() + ";\n");
                }

                defaultAction(e, true);

                switch(kind) {
                case ANNOTATION_TYPE:
                    writer.print("@interface");
                    break;
                default:
                    writer.print(StringUtils.toLowerCase(kind.toString()));
                }
                writer.print(" ");
                writer.print(e.getSimpleName());

                printFormalTypeParameters(e, false);

                if (kind == RECORD) {
                    // Print out record components
                    writer.print("(");
                    writer.print(e.getRecordComponents()
                                 .stream()
                                 .map(recordDes -> annotationsToString(recordDes) + recordDes.asType().toString() + " " + recordDes.getSimpleName())
                                 .collect(Collectors.joining(", ")));
                    writer.print(")");
                }

                // Print superclass information if informative
                if (kind == CLASS) {
                    TypeMirror supertype = e.getSuperclass();
                    if (supertype.getKind() != TypeKind.NONE) {
                        TypeElement e2 = (TypeElement)
                            ((DeclaredType) supertype).asElement();
                        if (e2.getSuperclass().getKind() != TypeKind.NONE)
                            writer.print(" extends " + supertype);
                    }
                }

                printInterfaces(e);
                printPermittedSubclasses(e);
            }
            writer.println(" {");
            indentation++;

            if (kind == ENUM) {
                List<Element> enclosedElements = new ArrayList<>(e.getEnclosedElements());
                // Handle any enum constants specially before other entities.
                List<Element> enumConstants = new ArrayList<>();
                for(Element element : enclosedElements) {
                    if (element.getKind() == ENUM_CONSTANT)
                        enumConstants.add(element);
                }
                if (!enumConstants.isEmpty()) {
                    int i;
                    for(i = 0; i < enumConstants.size()-1; i++) {
                        this.visit(enumConstants.get(i), true);
                        writer.print(",");
                    }
                    this.visit(enumConstants.get(i), true);
                    writer.println(";\n");

                    enclosedElements.removeAll(enumConstants);
                }

                for(Element element : enclosedElements)
                    this.visit(element);
            } else {
                for(Element element :
                        (kind != RECORD ?
                         e.getEnclosedElements() :
                         e.getEnclosedElements()
                         .stream()
                         .filter(elt -> elementUtils.getOrigin(elt) == Elements.Origin.EXPLICIT )
                         .collect(Collectors.toList()) ) )
                    this.visit(element);
            }

            indentation--;
            indent();
            writer.println("}");
            return this;
        }

        @Override @DefinedBy(Api.LANGUAGE_MODEL)
        public PrintingElementVisitor visitVariable(VariableElement e, Boolean newLine) {
            ElementKind kind = e.getKind();
            defaultAction(e, newLine);

            if (kind == ENUM_CONSTANT)
                writer.print(e.getSimpleName());
            else {
                writer.print(e.asType().toString() + " " + e.getSimpleName() );
                Object constantValue  = e.getConstantValue();
                if (constantValue != null) {
                    writer.print(" = ");
                    writer.print(elementUtils.getConstantExpression(constantValue));
                }
                writer.println(";");
            }
            return this;
        }

        @Override @DefinedBy(Api.LANGUAGE_MODEL)
        public PrintingElementVisitor visitTypeParameter(TypeParameterElement e, Boolean p) {
            writer.print(e.getSimpleName());
            return this;
        }

        // Should we do more here?
        @Override @DefinedBy(Api.LANGUAGE_MODEL)
        public PrintingElementVisitor visitPackage(PackageElement e, Boolean p) {
            defaultAction(e, false);
            if (!e.isUnnamed())
                writer.println("package " + e.getQualifiedName() + ";");
            else
                writer.println("// Unnamed package");
            return this;
        }

        @Override @DefinedBy(Api.LANGUAGE_MODEL)
        public PrintingElementVisitor visitModule(ModuleElement e, Boolean p) {
            defaultAction(e, false);

            if (!e.isUnnamed()) {
                if (e.isOpen()) {
                    writer.print("open ");
                }
                writer.println("module " + e.getQualifiedName() + " {");
                indentation++;
                for (ModuleElement.Directive directive : e.getDirectives()) {
                    printDirective(directive);
                }
                indentation--;
                writer.println("}");
            } else
                writer.println("// Unnamed module"); // Should we do more here?
            return this;
        }

        private void printDirective(ModuleElement.Directive directive) {
            indent();
            (new PrintDirective(writer)).visit(directive);
            writer.println(";");
        }

        private static class PrintDirective implements ModuleElement.DirectiveVisitor<Void, Void> {
            private final PrintWriter writer;

            PrintDirective(PrintWriter writer) {
                this.writer = writer;
            }

            @Override @DefinedBy(Api.LANGUAGE_MODEL)
            public Void visitExports(ExportsDirective d, Void p) {
                // "exports package-name [to module-name-list]"
                writer.print("exports ");
                writer.print(d.getPackage().getQualifiedName());
                printModuleList(d.getTargetModules());
                return null;
            }

            @Override @DefinedBy(Api.LANGUAGE_MODEL)
            public Void visitOpens(OpensDirective d, Void p) {
                // opens package-name [to module-name-list]
                writer.print("opens ");
                writer.print(d.getPackage().getQualifiedName());
                printModuleList(d.getTargetModules());
                return null;
            }

            @Override @DefinedBy(Api.LANGUAGE_MODEL)
            public Void visitProvides(ProvidesDirective d, Void p) {
                // provides service-name with implementation-name
                writer.print("provides ");
                writer.print(d.getService().getQualifiedName());
                writer.print(" with ");
                printNameableList(d.getImplementations());
                return null;
            }

            @Override @DefinedBy(Api.LANGUAGE_MODEL)
            public Void visitRequires(RequiresDirective d, Void p) {
                // requires (static|transitive)* module-name
                writer.print("requires ");
                if (d.isStatic())
                    writer.print("static ");
                if (d.isTransitive())
                    writer.print("transitive ");
                writer.print(d.getDependency().getQualifiedName());
                return null;
            }

            @Override @DefinedBy(Api.LANGUAGE_MODEL)
            public Void visitUses(UsesDirective d, Void p) {
                // uses service-name
                writer.print("uses ");
                writer.print(d.getService().getQualifiedName());
                return null;
            }

            private void printModuleList(List<? extends ModuleElement> modules) {
                if (modules != null) {
                    writer.print(" to ");
                    printNameableList(modules);
                }
            }

            private void printNameableList(List<? extends QualifiedNameable> nameables) {
                writer.print(nameables.stream().
                             map(QualifiedNameable::getQualifiedName).
                             collect(Collectors.joining(", ")));
            }
        }

        public void flush() {
            writer.flush();
        }

        private void printDocComment(Element e) {
            String docComment = elementUtils.getDocComment(e);

            if (docComment != null) {
                // Break comment into lines
                java.util.StringTokenizer st = new StringTokenizer(docComment,
                                                                  "\n\r");
                indent();
                writer.println("/**");

                while(st.hasMoreTokens()) {
                    indent();
                    writer.print(" *");
                    writer.println(st.nextToken());
                }

                indent();
                writer.println(" */");
            }
        }

        private void printModifiers(Element e) {
            ElementKind kind = e.getKind();
            if (kind == PARAMETER || kind == RECORD_COMPONENT) {
                // Print annotation inline
                writer.print(annotationsToString(e));
            } else {
                printAnnotations(e);
                indent();
            }

            if (kind == ENUM_CONSTANT || kind == RECORD_COMPONENT)
                return;

            Set<Modifier> modifiers = new LinkedHashSet<>();
            modifiers.addAll(e.getModifiers());

            switch (kind) {
            case ANNOTATION_TYPE:
            case INTERFACE:
                modifiers.remove(Modifier.ABSTRACT);
                break;

            case ENUM:
                modifiers.remove(Modifier.FINAL);
                modifiers.remove(Modifier.ABSTRACT);
                modifiers.remove(Modifier.SEALED);
                break;

            case RECORD:
                modifiers.remove(Modifier.FINAL);
                break;

            case METHOD:
            case FIELD:
                Element enclosingElement = e.getEnclosingElement();
                if (enclosingElement != null &&
                    enclosingElement.getKind().isInterface()) {
                    modifiers.remove(Modifier.PUBLIC);
                    modifiers.remove(Modifier.ABSTRACT); // only for methods
                    modifiers.remove(Modifier.STATIC);   // only for fields
                    modifiers.remove(Modifier.FINAL);    // only for fields
                }
                break;

            }
            if (!modifiers.isEmpty()) {
                writer.print(modifiers.stream()
                             .map(Modifier::toString)
                             .collect(Collectors.joining(" ", "", " ")));
            }
        }

        private void printFormalTypeParameters(Parameterizable e,
                                               boolean pad) {
            List<? extends TypeParameterElement> typeParams = e.getTypeParameters();
            if (!typeParams.isEmpty()) {
                writer.print(typeParams.stream()
                             .map(tpe -> annotationsToString(tpe) + tpe.toString())
                             .collect(Collectors.joining(", ", "<", ">")));
                if (pad)
                    writer.print(" ");
            }
        }

        private String annotationsToString(Element e) {
            List<? extends AnnotationMirror> annotations = e.getAnnotationMirrors();
            return annotations.isEmpty() ?
                "" :
                annotations.stream()
                .map(AnnotationMirror::toString)
                .collect(Collectors.joining(" ", "", " "));
        }

        private void printAnnotations(Element e) {
            List<? extends AnnotationMirror> annots = e.getAnnotationMirrors();
            for(AnnotationMirror annotationMirror : annots) {
                indent();
                writer.println(annotationMirror);
            }
        }

        // TODO: Refactor
        private void printParameters(ExecutableElement e) {
            List<? extends VariableElement> parameters = e.getParameters();
            int size = parameters.size();

            switch (size) {
            case 0:
                break;

            case 1:
                for(VariableElement parameter: parameters) {
                    printModifiers(parameter);

                    if (e.isVarArgs() ) {
                        TypeMirror tm = parameter.asType();
                        if (tm.getKind() != TypeKind.ARRAY)
                            throw new AssertionError("Var-args parameter is not an array type: " + tm);
                        writer.print((ArrayType.class.cast(tm)).getComponentType() );
                        writer.print("...");
                    } else
                        writer.print(parameter.asType());
                    writer.print(" " + parameter.getSimpleName());
                }
                break;

            default:
                {
                    int i = 1;
                    for(VariableElement parameter: parameters) {
                        if (i == 2)
                            indentation++;

                        if (i > 1)
                            indent();

                        printModifiers(parameter);

                        if (i == size && e.isVarArgs() ) {
                            TypeMirror tm = parameter.asType();
                            if (tm.getKind() != TypeKind.ARRAY)
                                throw new AssertionError("Var-args parameter is not an array type: " + tm);
                                    writer.print((ArrayType.class.cast(tm)).getComponentType() );

                            writer.print("...");
                        } else
                            writer.print(parameter.asType());
                        writer.print(" " + parameter.getSimpleName());

                        if (i < size)
                            writer.println(",");

                        i++;
                    }

                    if (parameters.size() >= 2)
                        indentation--;
                }
                break;
            }
        }

        private void printInterfaces(TypeElement e) {
            ElementKind kind = e.getKind();

            if(kind != ANNOTATION_TYPE) {
                List<? extends TypeMirror> interfaces = e.getInterfaces();
                if (!interfaces.isEmpty()) {
                    writer.print((kind.isClass() ? " implements " : " extends "));
                    writer.print(interfaces.stream()
                                 .map(TypeMirror::toString)
                                 .collect(Collectors.joining(", ")));
                }
            }
        }

        private void printPermittedSubclasses(TypeElement e) {
            List<? extends TypeMirror> subtypes = e.getPermittedSubclasses();
            if (!subtypes.isEmpty()) { // could remove this check with more complicated joining call
                writer.print(" permits ");
                writer.print(subtypes
                             .stream()
                             .map(subtype -> subtype.toString())
                             .collect(Collectors.joining(", ")));
            }
        }

        private void printThrows(ExecutableElement e) {
            List<? extends TypeMirror> thrownTypes = e.getThrownTypes();
            final int size = thrownTypes.size();
            if (size != 0) {
                writer.print(" throws");

                int i = 1;
                for(TypeMirror thrownType: thrownTypes) {
                    if (i == 1)
                        writer.print(" ");

                    if (i == 2)
                        indentation++;

                    if (i >= 2)
                        indent();

                    writer.print(thrownType);

                    if (i != size)
                        writer.println(", ");

                    i++;
                }

                if (size >= 2)
                    indentation--;
            }
        }

        private static final String [] spaces = {
            "",
            "  ",
            "    ",
            "      ",
            "        ",
            "          ",
            "            ",
            "              ",
            "                ",
            "                  ",
            "                    "
        };

        private void indent() {
            int indentation = this.indentation;
            if (indentation < 0)
                return;
            final int maxIndex = spaces.length - 1;

            while (indentation > maxIndex) {
                writer.print(spaces[maxIndex]);
                indentation -= maxIndex;
            }
            writer.print(spaces[indentation]);
        }

    }
}