/*
 * Copyright (c) 2001, 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 jdk.javadoc.internal.tool;

import java.nio.file.Files;
import java.nio.file.InvalidPathException;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import javax.tools.JavaFileObject;
import javax.tools.StandardJavaFileManager;

import com.sun.tools.javac.code.ClassFinder;
import com.sun.tools.javac.code.DeferredCompletionFailureHandler;
import com.sun.tools.javac.code.Symbol.Completer;
import com.sun.tools.javac.code.Symbol.CompletionFailure;
import com.sun.tools.javac.code.Symbol.PackageSymbol;
import com.sun.tools.javac.comp.Enter;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
import com.sun.tools.javac.util.Abort;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.ListBuffer;
import com.sun.tools.javac.util.Position;
import jdk.javadoc.doclet.DocletEnvironment;

import static jdk.javadoc.internal.tool.Main.Result.*;

 This class could be the main entry point for Javadoc when Javadoc is used as a
 component in a larger software system. It provides operations to
 construct a new javadoc processor, and to run it on a set of source
 files.
 
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.
/**
 *  This class could be the main entry point for Javadoc when Javadoc is used as a
 *  component in a larger software system. It provides operations to
 *  construct a new javadoc processor, and to run it on a set of source
 *  files.
 *
 *  <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>
 */
public class JavadocTool extends com.sun.tools.javac.main.JavaCompiler {
    ToolEnvironment toolEnv;

    final Messager messager;
    final ClassFinder javadocFinder;
    final DeferredCompletionFailureHandler dcfh;
    final Enter javadocEnter;
    final Set<JavaFileObject> uniquefiles;

    
Construct a new JavaCompiler processor, using appropriately
extended phases of the underlying compiler.
/**
     * Construct a new JavaCompiler processor, using appropriately
     * extended phases of the underlying compiler.
     */
    protected JavadocTool(Context context) {
        super(context);
        messager = Messager.instance0(context);
        javadocFinder = JavadocClassFinder.instance(context);
        dcfh = DeferredCompletionFailureHandler.instance(context);
        javadocEnter = JavadocEnter.instance(context);
        uniquefiles = new HashSet<>();
    }

    
For javadoc, the parser needs to keep comments. Overrides method from JavaCompiler.
/**
     * For javadoc, the parser needs to keep comments. Overrides method from JavaCompiler.
     */
    @Override
    protected boolean keepComments() {
        return true;
    }

    
 Construct a new javadoc tool.
/**
     *  Construct a new javadoc tool.
     */
    public static JavadocTool make0(Context context) {
        Messager messager = null;
        try {
            // force the use of Javadoc's class finder
            JavadocClassFinder.preRegister(context);

            // force the use of Javadoc's own enter phase
            JavadocEnter.preRegister(context);

            // force the use of Javadoc's own member enter phase
            JavadocMemberEnter.preRegister(context);

            // force the use of Javadoc's own todo phase
            JavadocTodo.preRegister(context);

            // force the use of Messager as a Log
            messager = Messager.instance0(context);

            return new JavadocTool(context);
        } catch (CompletionFailure ex) {
            assert messager != null;
            messager.error(Position.NOPOS, ex.getMessage());
            return null;
        }
    }

    public DocletEnvironment getEnvironment(ToolOptions toolOptions,
                                            List<String> javaNames,
                                            Iterable<? extends JavaFileObject> fileObjects)
            throws ToolException
    {
        toolEnv = ToolEnvironment.instance(context);
        toolEnv.initialize(toolOptions);
        ElementsTable etable = new ElementsTable(context, toolOptions);
        javadocFinder.sourceCompleter = etable.xclasses
                ? Completer.NULL_COMPLETER
                : sourceCompleter;

        if (etable.xclasses) {
            // If -Xclasses is set, the args should be a list of class names
            for (String arg: javaNames) {
                if (!isValidPackageName(arg)) { // checks
                    String text = messager.getText("main.illegal_class_name", arg);
                    throw new ToolException(CMDERR, text);
                }
            }
            if (messager.hasErrors()) {
                return null;
            }
            etable.setClassArgList(javaNames);
            // prepare, force the data structures to be analyzed
            etable.analyze();
            return new DocEnvImpl(toolEnv, etable);
        }

        ListBuffer<JCCompilationUnit> classTrees = new ListBuffer<>();

        try {
            StandardJavaFileManager fm = toolEnv.fileManager instanceof StandardJavaFileManager
                    ? (StandardJavaFileManager) toolEnv.fileManager
                    : null;
            Set<String> packageNames = new LinkedHashSet<>();
            // Normally, the args should be a series of package names or file names.
            // Parse the files and collect the package names.
            for (String arg: javaNames) {
                if (fm != null && arg.endsWith(".java") && isRegularFile(arg)) {
                    parse(fm.getJavaFileObjects(arg), classTrees, true);
                } else if (isValidPackageName(arg)) {
                    packageNames.add(arg);
                } else if (arg.endsWith(".java")) {
                    if (fm == null) {
                        String text = messager.getText("main.assertion.error", "fm == null");
                        throw new ToolException(ABNORMAL, text);
                    } else {
                        String text = messager.getText("main.file_not_found", arg);
                        throw new ToolException(ERROR, text);
                    }
                } else {
                    String text = messager.getText("main.illegal_package_name", arg);
                    throw new ToolException(CMDERR, text);
                }
            }

            // Parse file objects provide via the DocumentationTool API
            parse(fileObjects, classTrees, true);

            etable.packages(packageNames)
                    .classTrees(classTrees.toList())
                    .scanSpecifiedItems();

            // abort, if errors were encountered during modules initialization
            if (messager.hasErrors()) {
                return null;
            }

            // Parse the files in the packages and subpackages to be documented
            ListBuffer<JCCompilationUnit> allTrees = new ListBuffer<>();
            allTrees.addAll(classTrees);
            parse(etable.getFilesToParse(), allTrees, false);
            modules.newRound();
            modules.initModules(allTrees.toList());

            if (messager.hasErrors()) {
                return null;
            }

            // Enter symbols for all files
            toolEnv.notice("main.Building_tree");
            javadocEnter.main(allTrees.toList());

            if (messager.hasErrors()) {
                return null;
            }

            etable.setClassDeclList(listClasses(classTrees.toList()));

            dcfh.setHandler(dcfh.userCodeHandler);
            etable.analyze();

            // Ensure that package-info is read for all included packages
            for (Element e : etable.getIncludedElements()) {
                if (e.getKind() == ElementKind.PACKAGE) {
                    PackageSymbol p = (PackageSymbol) e;
                    if (p.package_info != null) {
                        p.package_info.complete();
                    }
                }
            }

        } catch (CompletionFailure cf) {
            throw new ToolException(ABNORMAL, cf.getMessage(), cf);
        } catch (Abort abort) {
            if (messager.hasErrors()) {
                // presumably a message has been emitted, keep silent
                throw new ToolException(ABNORMAL, "", abort);
            } else {
                String text = messager.getText("main.internal.error");
                Throwable t = abort.getCause() == null ? abort : abort.getCause();
                throw new ToolException(ABNORMAL, text, t);
            }
        }

        if (messager.hasErrors())
            return null;

        toolEnv.docEnv = new DocEnvImpl(toolEnv, etable);
        return toolEnv.docEnv;
    }

    private boolean isRegularFile(String s) {
        try {
            return Files.isRegularFile(Paths.get(s));
        } catch (InvalidPathException e) {
            return false;
        }
    }

    
Is the given string a valid package name? /** Is the given string a valid package name? */
    boolean isValidPackageName(String s) {
        if (s.contains("/")) {
            String[] a = s.split("/");
            if (a.length == 2) {
                 return isValidPackageName0(a[0]) && isValidPackageName0(a[1]);
            }
            return false;
        }
        return isValidPackageName0(s);
    }

    private boolean isValidPackageName0(String s) {
        for (int index = s.indexOf('.') ; index != -1; index = s.indexOf('.')) {
            if (!isValidClassName(s.substring(0, index))) {
                return false;
            }
            s = s.substring(index + 1);
        }
        return isValidClassName(s);
    }

    private void parse(Iterable<? extends JavaFileObject> files, ListBuffer<JCCompilationUnit> trees,
                       boolean trace) {
        for (JavaFileObject fo: files) {
            if (uniquefiles.add(fo)) { // ignore duplicates
                if (trace)
                    toolEnv.notice("main.Loading_source_file", fo.getName());
                trees.append(parse(fo));
            }
        }
    }

    
Are surrogates supported? /** Are surrogates supported? */
    static final boolean surrogatesSupported = surrogatesSupported();
    private static boolean surrogatesSupported() {
        try {
            boolean b = Character.isHighSurrogate('a');
            return true;
        } catch (NoSuchMethodError ex) {
            return false;
        }
    }

    
Return true if given file name is a valid class name
(including "package-info").
Params:
s – the name of the class to check.
Returns:
true if given class name is a valid class name
and false otherwise./**
     * Return true if given file name is a valid class name
     * (including "package-info").
     * @param s the name of the class to check.
     * @return true if given class name is a valid class name
     * and false otherwise.
     */
    public static boolean isValidClassName(String s) {
        if (s.length() < 1) return false;
        if (s.equals("package-info")) return true;
        if (surrogatesSupported) {
            int cp = s.codePointAt(0);
            if (!Character.isJavaIdentifierStart(cp))
                return false;
            for (int j = Character.charCount(cp); j < s.length(); j += Character.charCount(cp)) {
                cp = s.codePointAt(j);
                if (!Character.isJavaIdentifierPart(cp))
                    return false;
            }
        } else {
            if (!Character.isJavaIdentifierStart(s.charAt(0)))
                return false;
            for (int j = 1; j < s.length(); j++)
                if (!Character.isJavaIdentifierPart(s.charAt(j)))
                    return false;
        }
        return true;
    }

    
From a list of top level trees, return the list of contained class definitions
/**
     * From a list of top level trees, return the list of contained class definitions
     */
    List<JCClassDecl> listClasses(List<JCCompilationUnit> trees) {
        List<JCClassDecl> result = new ArrayList<>();
        for (JCCompilationUnit t : trees) {
            for (JCTree def : t.defs) {
                if (def.hasTag(JCTree.Tag.CLASSDEF))
                    result.add((JCClassDecl)def);
            }
        }
        return result;
    }
}