/*

 * Copyright (c) 1999, 2014, 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 com.sun.source.tree.Tree;

import com.sun.source.util.TreePath;

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

import com.sun.tools.javac.comp.AttrContext;

import com.sun.tools.javac.comp.Env;

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

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

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

import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;

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

import static com.sun.tools.javac.code.TypeTag.BOT;

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

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

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

/** Utility class containing inspector methods for trees.

 *

 *  <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 TreeInfo {

    protected static final Context.Key<TreeInfo> treeInfoKey = new Context.Key<>();

    public static TreeInfo instance(Context context) {

        TreeInfo instance = context.get(treeInfoKey);

        if (instance == null)

            instance = new TreeInfo(context);

        return instance;

    }

    /** The names of all operators.

     */

    private Name[] opname = new Name[Tag.getNumberOfOperators()];

    private void setOpname(Tag tag, String name, Names names) {

         setOpname(tag, names.fromString(name));

     }

     private void setOpname(Tag tag, Name name) {

         opname[tag.operatorIndex()] = name;

     }

    private TreeInfo(Context context) {

        context.put(treeInfoKey, this);

        Names names = Names.instance(context);

        /*  Internally we use +++, --- for unary +, - to reduce +, - operators

         *  overloading

         */

        setOpname(POS, "+++", names);

        setOpname(NEG, "---", names);

        setOpname(NOT, "!", names);

        setOpname(COMPL, "~", names);

        setOpname(PREINC, "++", names);

        setOpname(PREDEC, "--", names);

        setOpname(POSTINC, "++", names);

        setOpname(POSTDEC, "--", names);

        setOpname(NULLCHK, "<*nullchk*>", names);

        setOpname(OR, "||", names);

        setOpname(AND, "&&", names);

        setOpname(EQ, "==", names);

        setOpname(NE, "!=", names);

        setOpname(LT, "<", names);

        setOpname(GT, ">", names);

        setOpname(LE, "<=", names);

        setOpname(GE, ">=", names);

        setOpname(BITOR, "|", names);

        setOpname(BITXOR, "^", names);

        setOpname(BITAND, "&", names);

        setOpname(SL, "<<", names);

        setOpname(SR, ">>", names);

        setOpname(USR, ">>>", names);

        setOpname(PLUS, "+", names);

        setOpname(MINUS, names.hyphen);

        setOpname(MUL, names.asterisk);

        setOpname(DIV, names.slash);

        setOpname(MOD, "%", names);

    }

    public static List<JCExpression> args(JCTree t) {

        switch (t.getTag()) {

            case APPLY:

                return ((JCMethodInvocation)t).args;

            case NEWCLASS:

                return ((JCNewClass)t).args;

            default:

                return null;

        }

    }

    /** Return name of operator with given tree tag.

     */

    public Name operatorName(JCTree.Tag tag) {

        return opname[tag.operatorIndex()];

    }

    /** Is tree a constructor declaration?

     */

    public static boolean isConstructor(JCTree tree) {

        if (tree.hasTag(METHODDEF)) {

            Name name = ((JCMethodDecl) tree).name;

            return name == name.table.names.init;

        } else {

            return false;

        }

    }

    /** Is there a constructor declaration in the given list of trees?

     */

    public static boolean hasConstructors(List<JCTree> trees) {

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

            if (isConstructor(l.head)) return true;

        return false;

    }

    public static boolean isMultiCatch(JCCatch catchClause) {

        return catchClause.param.vartype.hasTag(TYPEUNION);

    }

    /** Is statement an initializer for a synthetic field?

     */

    public static boolean isSyntheticInit(JCTree stat) {

        if (stat.hasTag(EXEC)) {

            JCExpressionStatement exec = (JCExpressionStatement)stat;

            if (exec.expr.hasTag(ASSIGN)) {

                JCAssign assign = (JCAssign)exec.expr;

                if (assign.lhs.hasTag(SELECT)) {

                    JCFieldAccess select = (JCFieldAccess)assign.lhs;

                    if (select.sym != null &&

                        (select.sym.flags() & SYNTHETIC) != 0) {

                        Name selected = name(select.selected);

                        if (selected != null && selected == selected.table.names._this)

                            return true;

                    }

                }

            }

        }

        return false;

    }

    /** If the expression is a method call, return the method name, null

     *  otherwise. */

    public static Name calledMethodName(JCTree tree) {

        if (tree.hasTag(EXEC)) {

            JCExpressionStatement exec = (JCExpressionStatement)tree;

            if (exec.expr.hasTag(APPLY)) {

                Name mname = TreeInfo.name(((JCMethodInvocation) exec.expr).meth);

                return mname;

            }

        }

        return null;

    }

    /** Is this a call to this or super?

     */

    public static boolean isSelfCall(JCTree tree) {

        Name name = calledMethodName(tree);

        if (name != null) {

            Names names = name.table.names;

            return name==names._this || name==names._super;

        } else {

            return false;

        }

    }

    /** Is this a call to super?

     */

    public static boolean isSuperCall(JCTree tree) {

        Name name = calledMethodName(tree);

        if (name != null) {

            Names names = name.table.names;

            return name==names._super;

        } else {

            return false;

        }

    }

    /** Is this a constructor whose first (non-synthetic) statement is not

     *  of the form this(...)?

     */

    public static boolean isInitialConstructor(JCTree tree) {

        JCMethodInvocation app = firstConstructorCall(tree);

        if (app == null) return false;

        Name meth = name(app.meth);

        return meth == null || meth != meth.table.names._this;

    }

    /** Return the first call in a constructor definition. */

    public static JCMethodInvocation firstConstructorCall(JCTree tree) {

        if (!tree.hasTag(METHODDEF)) return null;

        JCMethodDecl md = (JCMethodDecl) tree;

        Names names = md.name.table.names;

        if (md.name != names.init) return null;

        if (md.body == null) return null;

        List<JCStatement> stats = md.body.stats;

        // Synthetic initializations can appear before the super call.

        while (stats.nonEmpty() && isSyntheticInit(stats.head))

            stats = stats.tail;

        if (stats.isEmpty()) return null;

        if (!stats.head.hasTag(EXEC)) return null;

        JCExpressionStatement exec = (JCExpressionStatement) stats.head;

        if (!exec.expr.hasTag(APPLY)) return null;

        return (JCMethodInvocation)exec.expr;

    }

    /** Return true if a tree represents a diamond new expr. */

    public static boolean isDiamond(JCTree tree) {

        switch(tree.getTag()) {

            case TYPEAPPLY: return ((JCTypeApply)tree).getTypeArguments().isEmpty();

            case NEWCLASS: return isDiamond(((JCNewClass)tree).clazz);

            case ANNOTATED_TYPE: return isDiamond(((JCAnnotatedType)tree).underlyingType);

            default: return false;

        }

    }

    public static boolean isEnumInit(JCTree tree) {

        switch (tree.getTag()) {

            case VARDEF:

                return (((JCVariableDecl)tree).mods.flags & ENUM) != 0;

            default:

                return false;

        }

    }

    /** set 'polyKind' on given tree */

    public static void setPolyKind(JCTree tree, PolyKind pkind) {

        switch (tree.getTag()) {

            case APPLY:

                ((JCMethodInvocation)tree).polyKind = pkind;

                break;

            case NEWCLASS:

                ((JCNewClass)tree).polyKind = pkind;

                break;

            case REFERENCE:

                ((JCMemberReference)tree).refPolyKind = pkind;

                break;

            default:

                throw new AssertionError("Unexpected tree: " + tree);

        }

    }

    /** set 'varargsElement' on given tree */

    public static void setVarargsElement(JCTree tree, Type varargsElement) {

        switch (tree.getTag()) {

            case APPLY:

                ((JCMethodInvocation)tree).varargsElement = varargsElement;

                break;

            case NEWCLASS:

                ((JCNewClass)tree).varargsElement = varargsElement;

                break;

            case REFERENCE:

                ((JCMemberReference)tree).varargsElement = varargsElement;

                break;

            default:

                throw new AssertionError("Unexpected tree: " + tree);

        }

    }

    /** Return true if the tree corresponds to an expression statement */

    public static boolean isExpressionStatement(JCExpression tree) {

        switch(tree.getTag()) {

            case PREINC: case PREDEC:

            case POSTINC: case POSTDEC:

            case ASSIGN:

            case BITOR_ASG: case BITXOR_ASG: case BITAND_ASG:

            case SL_ASG: case SR_ASG: case USR_ASG:

            case PLUS_ASG: case MINUS_ASG:

            case MUL_ASG: case DIV_ASG: case MOD_ASG:

            case APPLY: case NEWCLASS:

            case ERRONEOUS:

                return true;

            default:

                return false;

        }

    }

    /**

     * Return true if the AST corresponds to a static select of the kind A.B

     */

    public static boolean isStaticSelector(JCTree base, Names names) {

        if (base == null)

            return false;

        switch (base.getTag()) {

            case IDENT:

                JCIdent id = (JCIdent)base;

                return id.name != names._this &&

                        id.name != names._super &&

                        isStaticSym(base);

            case SELECT:

                return isStaticSym(base) &&

                    isStaticSelector(((JCFieldAccess)base).selected, names);

            case TYPEAPPLY:

            case TYPEARRAY:

                return true;

            case ANNOTATED_TYPE:

                return isStaticSelector(((JCAnnotatedType)base).underlyingType, names);

            default:

                return false;

        }

    }

    //where

        private static boolean isStaticSym(JCTree tree) {

            Symbol sym = symbol(tree);

            return (sym.kind == Kinds.TYP ||

                    sym.kind == Kinds.PCK);

        }

    /** Return true if a tree represents the null literal. */

    public static boolean isNull(JCTree tree) {

        if (!tree.hasTag(LITERAL))

            return false;

        JCLiteral lit = (JCLiteral) tree;

        return (lit.typetag == BOT);

    }

    /** Return true iff this tree is a child of some annotation. */

    public static boolean isInAnnotation(Env<?> env, JCTree tree) {

        TreePath tp = TreePath.getPath(env.toplevel, tree);

        if (tp != null) {

            for (Tree t : tp) {

                if (t.getKind() == Tree.Kind.ANNOTATION)

                    return true;

            }

        }

        return false;

    }

    public static String getCommentText(Env<?> env, JCTree tree) {

        DocCommentTable docComments = (tree.hasTag(JCTree.Tag.TOPLEVEL))

                ? ((JCCompilationUnit) tree).docComments

                : env.toplevel.docComments;

        return (docComments == null) ? null : docComments.getCommentText(tree);

    }

    public static DCTree.DCDocComment getCommentTree(Env<?> env, JCTree tree) {

        DocCommentTable docComments = (tree.hasTag(JCTree.Tag.TOPLEVEL))

                ? ((JCCompilationUnit) tree).docComments

                : env.toplevel.docComments;

        return (docComments == null) ? null : docComments.getCommentTree(tree);

    }

    /** The position of the first statement in a block, or the position of

     *  the block itself if it is empty.

     */

    public static int firstStatPos(JCTree tree) {

        if (tree.hasTag(BLOCK) && ((JCBlock) tree).stats.nonEmpty())

            return ((JCBlock) tree).stats.head.pos;

        else

            return tree.pos;

    }

    /** The end position of given tree, if it is a block with

     *  defined endpos.

     */

    public static int endPos(JCTree tree) {

        if (tree.hasTag(BLOCK) && ((JCBlock) tree).endpos != Position.NOPOS)

            return ((JCBlock) tree).endpos;

        else if (tree.hasTag(SYNCHRONIZED))

            return endPos(((JCSynchronized) tree).body);

        else if (tree.hasTag(TRY)) {

            JCTry t = (JCTry) tree;

            return endPos((t.finalizer != null) ? t.finalizer

                          : (t.catchers.nonEmpty() ? t.catchers.last().body : t.body));

        } else

            return tree.pos;

    }

    /** Get the start position for a tree node.  The start position is

     * defined to be the position of the first character of the first

     * token of the node's source text.

     * @param tree  The tree node

     */

    public static int getStartPos(JCTree tree) {

        if (tree == null)

            return Position.NOPOS;

        switch(tree.getTag()) {

            case APPLY:

                return getStartPos(((JCMethodInvocation) tree).meth);

            case ASSIGN:

                return getStartPos(((JCAssign) tree).lhs);

            case BITOR_ASG: case BITXOR_ASG: case BITAND_ASG:

            case SL_ASG: case SR_ASG: case USR_ASG:

            case PLUS_ASG: case MINUS_ASG: case MUL_ASG:

            case DIV_ASG: case MOD_ASG:

                return getStartPos(((JCAssignOp) tree).lhs);

            case OR: case AND: case BITOR:

            case BITXOR: case BITAND: case EQ:

            case NE: case LT: case GT:

            case LE: case GE: case SL:

            case SR: case USR: case PLUS:

            case MINUS: case MUL: case DIV:

            case MOD:

                return getStartPos(((JCBinary) tree).lhs);

            case CLASSDEF: {

                JCClassDecl node = (JCClassDecl)tree;

                if (node.mods.pos != Position.NOPOS)

                    return node.mods.pos;

                break;

            }

            case CONDEXPR:

                return getStartPos(((JCConditional) tree).cond);

            case EXEC:

                return getStartPos(((JCExpressionStatement) tree).expr);

            case INDEXED:

                return getStartPos(((JCArrayAccess) tree).indexed);

            case METHODDEF: {

                JCMethodDecl node = (JCMethodDecl)tree;

                if (node.mods.pos != Position.NOPOS)

                    return node.mods.pos;

                if (node.typarams.nonEmpty()) // List.nil() used for no typarams

                    return getStartPos(node.typarams.head);

                return node.restype == null ? node.pos : getStartPos(node.restype);

            }

            case SELECT:

                return getStartPos(((JCFieldAccess) tree).selected);

            case TYPEAPPLY:

                return getStartPos(((JCTypeApply) tree).clazz);

            case TYPEARRAY:

                return getStartPos(((JCArrayTypeTree) tree).elemtype);

            case TYPETEST:

                return getStartPos(((JCInstanceOf) tree).expr);

            case POSTINC:

            case POSTDEC:

                return getStartPos(((JCUnary) tree).arg);

            case ANNOTATED_TYPE: {

                JCAnnotatedType node = (JCAnnotatedType) tree;

                if (node.annotations.nonEmpty()) {

                    if (node.underlyingType.hasTag(TYPEARRAY) ||

                            node.underlyingType.hasTag(SELECT)) {

                        return getStartPos(node.underlyingType);

                    } else {

                        return getStartPos(node.annotations.head);

                    }

                } else {

                    return getStartPos(node.underlyingType);

                }

            }

            case NEWCLASS: {

                JCNewClass node = (JCNewClass)tree;

                if (node.encl != null)

                    return getStartPos(node.encl);

                break;

            }

            case VARDEF: {

                JCVariableDecl node = (JCVariableDecl)tree;

                if (node.mods.pos != Position.NOPOS) {

                    return node.mods.pos;

                } else if (node.vartype == null) {

                    //if there's no type (partially typed lambda parameter)

                    //simply return node position

                    return node.pos;

                } else {

                    return getStartPos(node.vartype);

                }

            }

            case ERRONEOUS: {

                JCErroneous node = (JCErroneous)tree;

                if (node.errs != null && node.errs.nonEmpty())

                    return getStartPos(node.errs.head);

            }

        }

        return tree.pos;

    }