/*

 * 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.api;

import java.io.IOException;

import java.util.HashSet;

import java.util.Set;

import javax.annotation.processing.ProcessingEnvironment;

import javax.lang.model.element.AnnotationMirror;

import javax.lang.model.element.AnnotationValue;

import javax.lang.model.element.Element;

import javax.lang.model.element.ElementKind;

import javax.lang.model.element.ExecutableElement;

import javax.lang.model.element.TypeElement;

import javax.lang.model.type.DeclaredType;

import javax.lang.model.type.TypeKind;

import javax.lang.model.type.TypeMirror;

import javax.tools.Diagnostic;

import javax.tools.JavaCompiler;

import javax.tools.JavaFileObject;

import com.sun.source.doctree.DocCommentTree;

import com.sun.source.doctree.DocTree;

import com.sun.source.tree.CatchTree;

import com.sun.source.tree.CompilationUnitTree;

import com.sun.source.tree.Scope;

import com.sun.source.tree.Tree;

import com.sun.source.util.DocSourcePositions;

import com.sun.source.util.DocTreePath;

import com.sun.source.util.DocTreeScanner;

import com.sun.source.util.DocTrees;

import com.sun.source.util.JavacTask;

import com.sun.source.util.TreePath;

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

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

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

import com.sun.tools.javac.code.Symbol.ClassSymbol;

import com.sun.tools.javac.code.Symbol.MethodSymbol;

import com.sun.tools.javac.code.Symbol.PackageSymbol;

import com.sun.tools.javac.code.Symbol.TypeSymbol;

import com.sun.tools.javac.code.Symbol.VarSymbol;

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

import com.sun.tools.javac.code.Type.ArrayType;

import com.sun.tools.javac.code.Type.ClassType;

import com.sun.tools.javac.code.Type.ErrorType;

import com.sun.tools.javac.code.Type.UnionClassType;

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

import com.sun.tools.javac.code.Types.TypeRelation;

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

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

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

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

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

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

import com.sun.tools.javac.model.JavacElements;

import com.sun.tools.javac.processing.JavacProcessingEnvironment;

import com.sun.tools.javac.tree.DCTree;

import com.sun.tools.javac.tree.DCTree.DCBlockTag;

import com.sun.tools.javac.tree.DCTree.DCDocComment;

import com.sun.tools.javac.tree.DCTree.DCEndPosTree;

import com.sun.tools.javac.tree.DCTree.DCErroneous;

import com.sun.tools.javac.tree.DCTree.DCIdentifier;

import com.sun.tools.javac.tree.DCTree.DCParam;

import com.sun.tools.javac.tree.DCTree.DCReference;

import com.sun.tools.javac.tree.DCTree.DCText;

import com.sun.tools.javac.tree.EndPosTable;

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

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

import com.sun.tools.javac.tree.TreeCopier;

import com.sun.tools.javac.tree.TreeInfo;

import com.sun.tools.javac.tree.TreeMaker;

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

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

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

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

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

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

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

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

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

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

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

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

/**

 * Provides an implementation of 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></p>

 *

 * @author Peter von der Ahé

 */

public class JavacTrees extends DocTrees {

    // in a world of a single context per compilation, these would all be final

    private Resolve resolve;

    private Enter enter;

    private Log log;

    private MemberEnter memberEnter;

    private Attr attr;

    private TreeMaker treeMaker;

    private JavacElements elements;

    private JavacTaskImpl javacTaskImpl;

    private Names names;

    private Types types;

    // called reflectively from Trees.instance(CompilationTask task)

    public static JavacTrees instance(JavaCompiler.CompilationTask task) {

        if (!(task instanceof BasicJavacTask))

            throw new IllegalArgumentException();

        return instance(((BasicJavacTask)task).getContext());

    }

    // called reflectively from Trees.instance(ProcessingEnvironment env)

    public static JavacTrees instance(ProcessingEnvironment env) {

        if (!(env instanceof JavacProcessingEnvironment))

            throw new IllegalArgumentException();

        return instance(((JavacProcessingEnvironment)env).getContext());

    }

    public static JavacTrees instance(Context context) {

        JavacTrees instance = context.get(JavacTrees.class);

        if (instance == null)

            instance = new JavacTrees(context);

        return instance;

    }

    protected JavacTrees(Context context) {

        context.put(JavacTrees.class, this);

        init(context);

    }

    public void updateContext(Context context) {

        init(context);

    }

    private void init(Context context) {

        attr = Attr.instance(context);

        enter = Enter.instance(context);

        elements = JavacElements.instance(context);

        log = Log.instance(context);

        resolve = Resolve.instance(context);

        treeMaker = TreeMaker.instance(context);

        memberEnter = MemberEnter.instance(context);

        names = Names.instance(context);

        types = Types.instance(context);

        JavacTask t = context.get(JavacTask.class);

        if (t instanceof JavacTaskImpl)

            javacTaskImpl = (JavacTaskImpl) t;

    }

    public DocSourcePositions getSourcePositions() {

        return new DocSourcePositions() {

                public long getStartPosition(CompilationUnitTree file, Tree tree) {

                    return TreeInfo.getStartPos((JCTree) tree);

                }

                public long getEndPosition(CompilationUnitTree file, Tree tree) {

                    EndPosTable endPosTable = ((JCCompilationUnit) file).endPositions;

                    return TreeInfo.getEndPos((JCTree) tree, endPosTable);

                }

                public long getStartPosition(CompilationUnitTree file, DocCommentTree comment, DocTree tree) {

                    return ((DCTree) tree).getSourcePosition((DCDocComment) comment);

                }

                @SuppressWarnings("fallthrough")

                public long getEndPosition(CompilationUnitTree file, DocCommentTree comment, DocTree tree) {

                    DCDocComment dcComment = (DCDocComment) comment;

                    if (tree instanceof DCEndPosTree) {

                        int endPos = ((DCEndPosTree) tree).getEndPos(dcComment);

                        if (endPos != Position.NOPOS) {

                            return endPos;

                        }

                    }

                    int correction = 0;

                    switch (tree.getKind()) {

                        case TEXT:

                            DCText text = (DCText) tree;

                            return dcComment.comment.getSourcePos(text.pos + text.text.length());

                        case ERRONEOUS:

                            DCErroneous err = (DCErroneous) tree;

                            return dcComment.comment.getSourcePos(err.pos + err.body.length());

                        case IDENTIFIER:

                            DCIdentifier ident = (DCIdentifier) tree;

                            return dcComment.comment.getSourcePos(ident.pos + (ident.name != names.error ? ident.name.length() : 0));

                        case PARAM:

                            DCParam param = (DCParam) tree;

                            if (param.isTypeParameter && param.getDescription().isEmpty()) {

                                correction = 1;

                            }

                        case AUTHOR: case DEPRECATED: case RETURN: case SEE:

                        case SERIAL: case SERIAL_DATA: case SERIAL_FIELD: case SINCE:

                        case THROWS: case UNKNOWN_BLOCK_TAG: case VERSION: {

                            DocTree last = getLastChild(tree);

                            if (last != null) {

                                return getEndPosition(file, comment, last) + correction;

                            }

                            DCBlockTag block = (DCBlockTag) tree;

                            return dcComment.comment.getSourcePos(block.pos + block.getTagName().length() + 1);

                        }

                        default:

                            DocTree last = getLastChild(tree);

                            if (last != null) {

                                return getEndPosition(file, comment, last);

                            }

                            break;

                    }

                    return Position.NOPOS;

                }

            };

    }

    private DocTree getLastChild(DocTree tree) {

        final DocTree[] last = new DocTree[] {null};

        tree.accept(new DocTreeScanner<Void, Void>() {

            @Override public Void scan(DocTree node, Void p) {

                if (node != null) last[0] = node;

                return null;

            }

        }, null);

        return last[0];

    }

    public JCClassDecl getTree(TypeElement element) {

        return (JCClassDecl) getTree((Element) element);

    }

    public JCMethodDecl getTree(ExecutableElement method) {

        return (JCMethodDecl) getTree((Element) method);

    }

    public JCTree getTree(Element element) {

    }

    public JCTree getTree(Element e, AnnotationMirror a) {

        return getTree(e, a, null);

    }

    public JCTree getTree(Element e, AnnotationMirror a, AnnotationValue v) {

        Pair<JCTree, JCCompilationUnit> treeTopLevel = elements.getTreeAndTopLevel(e, a, v);

        if (treeTopLevel == null)

            return null;

        return treeTopLevel.fst;

    }

    public TreePath getPath(CompilationUnitTree unit, Tree node) {

        return TreePath.getPath(unit, node);

    }

    public TreePath getPath(Element e) {

        return getPath(e, null, null);

    }

    public TreePath getPath(Element e, AnnotationMirror a) {

        return getPath(e, a, null);

    }

    public TreePath getPath(Element e, AnnotationMirror a, AnnotationValue v) {

        final Pair<JCTree, JCCompilationUnit> treeTopLevel = elements.getTreeAndTopLevel(e, a, v);

        if (treeTopLevel == null)

            return null;

        return TreePath.getPath(treeTopLevel.snd, treeTopLevel.fst);

    }

    public Symbol getElement(TreePath path) {

        JCTree tree = (JCTree) path.getLeaf();

        Symbol sym = TreeInfo.symbolFor(tree);

        if (sym == null) {

            if (TreeInfo.isDeclaration(tree)) {

                for (TreePath p = path; p != null; p = p.getParentPath()) {

                    JCTree t = (JCTree) p.getLeaf();

                    if (t.hasTag(JCTree.Tag.CLASSDEF)) {

                        JCClassDecl ct = (JCClassDecl) t;

                        if (ct.sym != null) {

                            if ((ct.sym.flags_field & Flags.UNATTRIBUTED) != 0) {

                                attr.attribClass(ct.pos(), ct.sym);

                                sym = TreeInfo.symbolFor(tree);

                            }

                            break;

                        }

                    }

                }

            }

        }

        return sym;

    }

    @Override

    public Element getElement(DocTreePath path) {

        DocTree forTree = path.getLeaf();

        if (forTree instanceof DCReference)

            return attributeDocReference(path.getTreePath(), ((DCReference) forTree));

        if (forTree instanceof DCIdentifier) {

            if (path.getParentPath().getLeaf() instanceof DCParam) {

                return attributeParamIdentifier(path.getTreePath(), (DCParam) path.getParentPath().getLeaf());

            }

        }

        return null;

    }

    private Symbol attributeDocReference(TreePath path, DCReference ref) {

        Env<AttrContext> env = getAttrContext(path);

        Log.DeferredDiagnosticHandler deferredDiagnosticHandler =

                new Log.DeferredDiagnosticHandler(log);

        try {

            final TypeSymbol tsym;

            final Name memberName;

            if (ref.qualifierExpression == null) {

                tsym = env.enclClass.sym;

                memberName = ref.memberName;

            } else {

                // See if the qualifierExpression is a type or package name.

                // javac does not provide the exact method required, so

                // we first check if qualifierExpression identifies a type,

                // and if not, then we check to see if it identifies a package.

                Type t = attr.attribType(ref.qualifierExpression, env);

                if (t.isErroneous()) {

                    if (ref.memberName == null) {

                        // Attr/Resolve assume packages exist and create symbols as needed

                        // so use getPackageElement to restrict search to existing packages

                        PackageSymbol pck = elements.getPackageElement(ref.qualifierExpression.toString());

                        if (pck != null) {

                            return pck;

                        } else if (ref.qualifierExpression.hasTag(JCTree.Tag.IDENT)) {

                            // fixup:  allow "identifier" instead of "#identifier"

                            // for compatibility with javadoc

                            tsym = env.enclClass.sym;

                            memberName = ((JCIdent) ref.qualifierExpression).name;

                        } else

                            return null;

                    } else {

                        return null;

                    }

                } else {

                    tsym = t.tsym;

                    memberName = ref.memberName;

                }

            }

            if (memberName == null)

                return tsym;

            final List<Type> paramTypes;

            if (ref.paramTypes == null)

                paramTypes = null;

            else {

                ListBuffer<Type> lb = new ListBuffer<>();

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

                    JCTree tree = l.head;

                    Type t = attr.attribType(tree, env);

                    lb.add(t);

                }

                paramTypes = lb.toList();

            }

            ClassSymbol sym = (ClassSymbol) types.upperBound(tsym.type).tsym;

            Symbol msym = (memberName == sym.name)

                    ? findConstructor(sym, paramTypes)

                    : findMethod(sym, memberName, paramTypes);

            if (paramTypes != null) {

                // explicit (possibly empty) arg list given, so cannot be a field

                return msym;

            }

            VarSymbol vsym = (ref.paramTypes != null) ? null : findField(sym, memberName);

            // prefer a field over a method with no parameters

            if (vsym != null &&

                    (msym == null ||

                        types.isSubtypeUnchecked(vsym.enclClass().asType(), msym.enclClass().asType()))) {

                return vsym;

            } else {

                return msym;

            }

        } catch (Abort e) { // may be thrown by Check.completionError in case of bad class file

            return null;

        } finally {

            log.popDiagnosticHandler(deferredDiagnosticHandler);

        }

    }

    private Symbol attributeParamIdentifier(TreePath path, DCParam ptag) {

        Symbol javadocSymbol = getElement(path);

        if (javadocSymbol == null)

            return null;

        ElementKind kind = javadocSymbol.getKind();

        List<? extends Symbol> params = List.nil();

        if (kind == ElementKind.METHOD || kind == ElementKind.CONSTRUCTOR) {

            MethodSymbol ee = (MethodSymbol) javadocSymbol;

            params = ptag.isTypeParameter()

                    ? ee.getTypeParameters()

                    : ee.getParameters();

        } else if (kind.isClass() || kind.isInterface()) {

            ClassSymbol te = (ClassSymbol) javadocSymbol;

            params = te.getTypeParameters();

        }

        for (Symbol param : params) {

            if (param.getSimpleName() == ptag.getName().getName()) {

                return param;

            }

        }

        return null;

    }

    /** @see com.sun.tools.javadoc.ClassDocImpl#findField */

    private VarSymbol findField(ClassSymbol tsym, Name fieldName) {

        return searchField(tsym, fieldName, new HashSet<ClassSymbol>());

    }

    /** @see com.sun.tools.javadoc.ClassDocImpl#searchField */

    private VarSymbol searchField(ClassSymbol tsym, Name fieldName, Set<ClassSymbol> searched) {

        if (searched.contains(tsym)) {

            return null;

        }

        searched.add(tsym);

        for (com.sun.tools.javac.code.Scope.Entry e = tsym.members().lookup(fieldName);

                e.scope != null; e = e.next()) {

            if (e.sym.kind == Kinds.VAR) {

                return (VarSymbol)e.sym;

            }

        }

        //### If we found a VarSymbol above, but which did not pass

        //### the modifier filter, we should return failure here!

        ClassSymbol encl = tsym.owner.enclClass();

        if (encl != null) {

            VarSymbol vsym = searchField(encl, fieldName, searched);

            if (vsym != null) {

                return vsym;

            }

        }

        // search superclass

        Type superclass = tsym.getSuperclass();

        if (superclass.tsym != null) {

            VarSymbol vsym = searchField((ClassSymbol) superclass.tsym, fieldName, searched);

            if (vsym != null) {

                return vsym;

            }

        }

        // search interfaces

        List<Type> intfs = tsym.getInterfaces();

        for (List<Type> l = intfs; l.nonEmpty(); l = l.tail) {

            Type intf = l.head;

            if (intf.isErroneous()) continue;

            VarSymbol vsym = searchField((ClassSymbol) intf.tsym, fieldName, searched);

            if (vsym != null) {

                return vsym;

            }

        }

        return null;