/*
 * Copyright (c) 2011, 2015, 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
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package com.sun.tools.sjavac.comp;

import static javax.lang.model.element.Modifier.PRIVATE;

import java.util.List;
import java.util.stream.Collectors;

import javax.lang.model.element.Element;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.TypeElement;
import javax.lang.model.element.TypeParameterElement;
import javax.lang.model.element.VariableElement;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.util.ElementScanner9;

import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.util.DefinedBy;
import com.sun.tools.javac.util.DefinedBy.Api;
import com.sun.tools.sjavac.pubapi.PubApi;
import com.sun.tools.sjavac.pubapi.PubApiTypeParam;
import com.sun.tools.sjavac.pubapi.PubMethod;
import com.sun.tools.sjavac.pubapi.PubType;
import com.sun.tools.sjavac.pubapi.PubVar;
import com.sun.tools.sjavac.pubapi.TypeDesc;

Utility class that constructs a textual representation
of the public api of a class.
 
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.
/** Utility class that constructs a textual representation
 * of the public api of a class.
 *
 *  <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 PubapiVisitor extends ElementScanner9<Void, Void> {

    private PubApi collectedApi = new PubApi();

    private boolean isNonPrivate(Element e) {
        return !e.getModifiers().contains(PRIVATE);
    }

    @Override @DefinedBy(Api.LANGUAGE_MODEL)
    public Void visitType(TypeElement e, Void p) {
        if (isNonPrivate(e)) {
            PubApi prevApi = collectedApi;
            collectedApi = new PubApi();
            super.visitType(e, p);
            if (!isAnonymous(e)) {
                String name = ((ClassSymbol) e).flatname.toString();
                PubType t = new PubType(e.getModifiers(),
                                        name,
                                        //e.getQualifiedName().toString(),
                                        collectedApi);
                prevApi.types.put(t.fqName, t);
            }
            collectedApi = prevApi;
        }
        return null;
    }

    private boolean isAnonymous(TypeElement e) {
        return e.getQualifiedName().length() == 0;
    }

    private static String encodeChar(int c) {
        return String.format("\\u%04x", c);
    }

    @Override @DefinedBy(Api.LANGUAGE_MODEL)
    public Void visitVariable(VariableElement e, Void p) {
        if (isNonPrivate(e)) {
            Object constVal = e.getConstantValue();
            String constValStr = null;
            // TODO: This doesn't seem to be entirely accurate. What if I change
            // from, say, 0 to 0L? (And the field is public final static so that
            // it could get inlined.)
            if (constVal != null) {
                if (e.asType().toString().equals("char")) {
                    // What type is 'value'? Is it already a char?
                    char c = constVal.toString().charAt(0);
                    constValStr = "'" + encodeChar(c) + "'";
                } else {
                    constValStr = constVal.toString()
                                          .chars()
                                          .mapToObj(PubapiVisitor::encodeChar)
                                          .collect(Collectors.joining("", "\"", "\""));
                }
            }

            PubVar v = new PubVar(e.getModifiers(),
                                  TypeDesc.fromType(e.asType()),
                                  e.toString(),
                                  constValStr);
            collectedApi.variables.put(v.identifier, v);
        }

        // Safe to not recurse here, because the only thing
        // to visit here is the constructor of a variable declaration.
        // If it happens to contain an anonymous inner class (which it might)
        // then this class is never visible outside of the package anyway, so
        // we are allowed to ignore it here.
        return null;
    }

    @Override @DefinedBy(Api.LANGUAGE_MODEL)
    public Void visitExecutable(ExecutableElement e, Void p) {
        if (isNonPrivate(e)) {
            PubMethod m = new PubMethod(e.getModifiers(),
                                        getTypeParameters(e.getTypeParameters()),
                                        TypeDesc.fromType(e.getReturnType()),
                                        e.getSimpleName().toString(),
                                        getTypeDescs(getParamTypes(e)),
                                        getTypeDescs(e.getThrownTypes()));
            collectedApi.methods.put(m.asSignatureString(), m);
        }
        return null;
    }

    private List<PubApiTypeParam> getTypeParameters(List<? extends TypeParameterElement> elements) {
        return elements.stream()
                       .map(e -> new PubApiTypeParam(e.getSimpleName().toString(), getTypeDescs(e.getBounds())))
                       .collect(Collectors.toList());
    }

    private List<TypeMirror> getParamTypes(ExecutableElement e) {
        return e.getParameters()
                .stream()
                .map(VariableElement::asType)
                .collect(Collectors.toList());
    }

    private List<TypeDesc> getTypeDescs(List<? extends TypeMirror> list) {
        return list.stream()
                   .map(TypeDesc::fromType)
                   .collect(Collectors.toList());
    }

    public PubApi getCollectedPubApi() {
        return collectedApi;
    }
}