/*

 * Copyright (c) 1999, 2019, 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.tree;

import java.io.*;

import com.sun.source.tree.MemberReferenceTree.ReferenceMode;

import com.sun.source.tree.ModuleTree.ModuleKind;

import com.sun.tools.javac.code.*;

import com.sun.tools.javac.tree.JCTree.*;

import com.sun.tools.javac.util.*;

import com.sun.tools.javac.util.List;

import static com.sun.tools.javac.code.Flags.*;

import static com.sun.tools.javac.code.Flags.ANNOTATION;

import static com.sun.tools.javac.tree.JCTree.Tag.*;

/** Prints out a tree as an indented Java source program.

 *

 *  <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 Pretty extends JCTree.Visitor {

    public Pretty(Writer out, boolean sourceOutput) {

        this.out = out;

        this.sourceOutput = sourceOutput;

    }

    /** Set when we are producing source output.  If we're not

     *  producing source output, we can sometimes give more detail in

     *  the output even though that detail would not be valid java

     *  source.

     */

    private final boolean sourceOutput;

    /** The output stream on which trees are printed.

     */

    Writer out;

    /** Indentation width (can be reassigned from outside).

     */

    public int width = 4;

    /** The current left margin.

     */

    int lmargin = 0;

    /** The enclosing class name.

     */

    Name enclClassName;

    /** A table mapping trees to their documentation comments

     *  (can be null)

     */

    DocCommentTable docComments = null;

    /**

     * A string sequence to be used when Pretty output should be constrained

     * to fit into a given size

     */

    private final static String trimSequence = "[...]";

    /**

     * Max number of chars to be generated when output should fit into a single line

     */

    private final static int PREFERRED_LENGTH = 20;

    /** Align code to be indented to left margin.

     */

    void align() throws IOException {

        for (int i = 0; i < lmargin; i++) out.write(" ");

    }

    /** Increase left margin by indentation width.

     */

    void indent() {

        lmargin = lmargin + width;

    }

    /** Decrease left margin by indentation width.

     */

    void undent() {

        lmargin = lmargin - width;

    }

    /** Enter a new precedence level. Emit a `(' if new precedence level

     *  is less than precedence level so far.

     *  @param contextPrec    The precedence level in force so far.

     *  @param ownPrec        The new precedence level.

     */

    void open(int contextPrec, int ownPrec) throws IOException {

        if (ownPrec < contextPrec) out.write("(");

    }

    /** Leave precedence level. Emit a `(' if inner precedence level

     *  is less than precedence level we revert to.

     *  @param contextPrec    The precedence level we revert to.

     *  @param ownPrec        The inner precedence level.

     */

    void close(int contextPrec, int ownPrec) throws IOException {

        if (ownPrec < contextPrec) out.write(")");

    }

    /** Print string, replacing all non-ascii character with unicode escapes.

     */

    public void print(Object s) throws IOException {

        out.write(Convert.escapeUnicode(s.toString()));

    }

    /** Print new line.

     */

    public void println() throws IOException {

        out.write(lineSep);

    }

    public static String toSimpleString(JCTree tree) {

        return toSimpleString(tree, PREFERRED_LENGTH);

    }

    public static String toSimpleString(JCTree tree, int maxLength) {

        StringWriter s = new StringWriter();

        try {

            new Pretty(s, false).printExpr(tree);

        }

        catch (IOException e) {

            // should never happen, because StringWriter is defined

            // never to throw any IOExceptions

            throw new AssertionError(e);

        }

        //we need to (i) replace all line terminators with a space and (ii) remove

        //occurrences of 'missing' in the Pretty output (generated when types are missing)

        String res = s.toString().trim().replaceAll("\\s+", " ").replaceAll("/\\*missing\\*/", "");

        if (res.length() < maxLength) {

            return res;

        } else {

            int head = (maxLength - trimSequence.length()) * 2 / 3;

            int tail = maxLength - trimSequence.length() - head;

            return res.substring(0, head) + trimSequence + res.substring(res.length() - tail);

        }

    }

    String lineSep = System.getProperty("line.separator");

    /**************************************************************************

     * Traversal methods

     *************************************************************************/

    /** Exception to propogate IOException through visitXXX methods */

    private static class UncheckedIOException extends Error {

        static final long serialVersionUID = -4032692679158424751L;

        UncheckedIOException(IOException e) {

            super(e.getMessage(), e);

        }

    }

    /** Visitor argument: the current precedence level.

     */

    int prec;

    /** Visitor method: print expression tree.

     *  @param prec  The current precedence level.

     */

    public void printExpr(JCTree tree, int prec) throws IOException {

        int prevPrec = this.prec;

        try {

            this.prec = prec;

            if (tree == null) print("/*missing*/");

            else {

                tree.accept(this);

            }

        } catch (UncheckedIOException ex) {

            IOException e = new IOException(ex.getMessage());

            e.initCause(ex);

            throw e;

        } finally {

            this.prec = prevPrec;

        }

    }

    /** Derived visitor method: print expression tree at minimum precedence level

     *  for expression.

     */

    public void printExpr(JCTree tree) throws IOException {

        printExpr(tree, TreeInfo.noPrec);

    }

    /** Derived visitor method: print statement tree.

     */

    public void printStat(JCTree tree) throws IOException {

        printExpr(tree, TreeInfo.notExpression);

    }

    /** Derived visitor method: print list of expression trees, separated by given string.

     *  @param sep the separator string

     */

    public <T extends JCTree> void printExprs(List<T> trees, String sep) throws IOException {

        if (trees.nonEmpty()) {

            printExpr(trees.head);

            for (List<T> l = trees.tail; l.nonEmpty(); l = l.tail) {

                print(sep);

                printExpr(l.head);

            }

        }

    }

    /** Derived visitor method: print list of expression trees, separated by commas.

     */

    public <T extends JCTree> void printExprs(List<T> trees) throws IOException {

        printExprs(trees, ", ");

    }

    /** Derived visitor method: print list of statements, each on a separate line.

     */

    public void printStats(List<? extends JCTree> trees) throws IOException {

        for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail) {

            align();

            printStat(l.head);

            println();

        }

    }

    /** Print a set of modifiers.

     */

    public void printFlags(long flags) throws IOException {

        if ((flags & SYNTHETIC) != 0) print("/*synthetic*/ ");

        print(TreeInfo.flagNames(flags));

        if ((flags & ExtendedStandardFlags) != 0) print(" ");

        if ((flags & ANNOTATION) != 0) print("@");

    }

    public void printAnnotations(List<JCAnnotation> trees) throws IOException {

        for (List<JCAnnotation> l = trees; l.nonEmpty(); l = l.tail) {

            printStat(l.head);

            println();

            align();

        }

    }

    public void printTypeAnnotations(List<JCAnnotation> trees) throws IOException {

        for (List<JCAnnotation> l = trees; l.nonEmpty(); l = l.tail) {

            printExpr(l.head);

            print(" ");

        }

    }

    /** Print documentation comment, if it exists

     *  @param tree    The tree for which a documentation comment should be printed.

     */

    public void printDocComment(JCTree tree) throws IOException {

        if (docComments != null) {

            String dc = docComments.getCommentText(tree);

            if (dc != null) {

                print("/**"); println();

                int pos = 0;

                int endpos = lineEndPos(dc, pos);

                while (pos < dc.length()) {

                    align();

                    print(" *");

                    if (pos < dc.length() && dc.charAt(pos) > ' ') print(" ");

                    print(dc.substring(pos, endpos)); println();

                    pos = endpos + 1;

                    endpos = lineEndPos(dc, pos);

                }

                align(); print(" */"); println();

                align();

            }

        }

    }

//where

    static int lineEndPos(String s, int start) {

        int pos = s.indexOf('\n', start);

        if (pos < 0) pos = s.length();

        return pos;

    }

    /** If type parameter list is non-empty, print it enclosed in

     *  {@literal "<...>"} brackets.

     */

    public void printTypeParameters(List<JCTypeParameter> trees) throws IOException {

        if (trees.nonEmpty()) {

            print("<");

            printExprs(trees);

            print(">");

        }

    }

    /** Print a block.

     */

    public void printBlock(List<? extends JCTree> stats) throws IOException {

        print("{");

        println();

        indent();

        printStats(stats);

        undent();

        align();

        print("}");

    }

    /** Print a block.

     */

    public void printEnumBody(List<JCTree> stats) throws IOException {

        print("{");

        println();

        indent();

        boolean first = true;

        for (List<JCTree> l = stats; l.nonEmpty(); l = l.tail) {

            if (isEnumerator(l.head)) {

                if (!first) {

                    print(",");

                    println();

                }

                align();

                printStat(l.head);

                first = false;

            }

        }

        print(";");

        println();

        for (List<JCTree> l = stats; l.nonEmpty(); l = l.tail) {

            if (!isEnumerator(l.head)) {

                align();

                printStat(l.head);

                println();

            }

        }

        undent();

        align();

        print("}");

    }

    /** Is the given tree an enumerator definition? */

    boolean isEnumerator(JCTree t) {

        return t.hasTag(VARDEF) && (((JCVariableDecl) t).mods.flags & ENUM) != 0;

    }

    /** Print unit consisting of package clause and import statements in toplevel,

     *  followed by class definition. if class definition == null,

     *  print all definitions in toplevel.

     *  @param tree     The toplevel tree

     *  @param cdef     The class definition, which is assumed to be part of the

     *                  toplevel tree.

     */

    public void printUnit(JCCompilationUnit tree, JCClassDecl cdef) throws IOException {

        docComments = tree.docComments;

        printDocComment(tree);

        boolean firstImport = true;

        for (List<JCTree> l = tree.defs;

             l.nonEmpty() &&

                 (cdef == null ||

                  l.head.hasTag(IMPORT) || l.head.hasTag(PACKAGEDEF));

             l = l.tail) {

            if (l.head.hasTag(IMPORT)) {

                JCImport imp = (JCImport)l.head;

                Name name = TreeInfo.name(imp.qualid);

                if (name == name.table.names.asterisk ||

                        cdef == null ||

                        isUsed(TreeInfo.symbol(imp.qualid), cdef)) {

                    if (firstImport) {

                        firstImport = false;

                        println();

                    }

                    printStat(imp);

                }

            } else {

                printStat(l.head);

            }

        }

        if (cdef != null) {

            printStat(cdef);

            println();

        }

    }

    // where

    boolean isUsed(final Symbol t, JCTree cdef) {

        class UsedVisitor extends TreeScanner {

            public void scan(JCTree tree) {

                if (tree!=null && !result) tree.accept(this);

            }

            boolean result = false;

            public void visitIdent(JCIdent tree) {

                if (tree.sym == t) result = true;

            }

        }

        UsedVisitor v = new UsedVisitor();

        v.scan(cdef);

        return v.result;

    }

    /**************************************************************************

     * Visitor methods

     *************************************************************************/

    public void visitTopLevel(JCCompilationUnit tree) {

        try {

            printUnit(tree, null);

        } catch (IOException e) {

            throw new UncheckedIOException(e);

        }

    }

    public void visitPackageDef(JCPackageDecl tree) {

        try {

            printDocComment(tree);

            printAnnotations(tree.annotations);

            if (tree.pid != null) {

                print("package ");

                printExpr(tree.pid);

                print(";");

                println();

            }

        } catch (IOException e) {

            throw new UncheckedIOException(e);

        }

    }

    @Override

    public void visitModuleDef(JCModuleDecl tree) {

        try {

            printDocComment(tree);

            printAnnotations(tree.mods.annotations);

            if (tree.getModuleType() == ModuleKind.OPEN) {

                print("open ");

            }

            print("module ");

            printExpr(tree.qualId);

            if (tree.directives == null) {

                print(";");

            } else {

                printBlock(tree.directives);

            }

            println();

        } catch (IOException e) {

            throw new UncheckedIOException(e);

        }

    }

    @Override

    public void visitExports(JCExports tree) {

        try {

            print("exports ");

            printExpr(tree.qualid);

            if (tree.moduleNames != null) {

                print(" to ");

                printExprs(tree.moduleNames);

            }

            print(";");

        } catch (IOException e) {

            throw new UncheckedIOException(e);

        }

    }

    @Override

    public void visitOpens(JCOpens tree) {

        try {

            print("opens ");

            printExpr(tree.qualid);

            if (tree.moduleNames != null) {

                print(" to ");

                printExprs(tree.moduleNames);

            }

            print(";");

        } catch (IOException e) {

            throw new UncheckedIOException(e);

        }

    }

    @Override

    public void visitProvides(JCProvides tree) {

        try {

            print("provides ");

            printExpr(tree.serviceName);

            print(" with ");

            printExprs(tree.implNames);

            print(";");

        } catch (IOException e) {

            throw new UncheckedIOException(e);

        }

    }

    @Override

    public void visitRequires(JCRequires tree) {

        try {

            print("requires ");

            if (tree.isStaticPhase)

                print("static ");

            if (tree.isTransitive)

                print("transitive ");

            printExpr(tree.moduleName);