/*

 * Copyright (c) 2008, 2011, 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.classfile;

import java.util.Arrays;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

/*

 *  Family of classes used to represent the parsed form of a {@link Descriptor}

 *  or {@link Signature}.

 *

 *  <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 abstract class Type {

    protected Type() { }

    public boolean isObject() {

        return false;

    }

    public abstract <R,D> R accept(Visitor<R,D> visitor, D data);

    protected static void append(StringBuilder sb, String prefix, List<? extends Type> types, String suffix) {

        sb.append(prefix);

        String sep = "";

        for (Type t: types) {

            sb.append(sep);

            sb.append(t);

            sep = ", ";

        }

        sb.append(suffix);

    }

    protected static void appendIfNotEmpty(StringBuilder sb, String prefix, List<? extends Type> types, String suffix) {

        if (types != null && types.size() > 0)

            append(sb, prefix, types, suffix);

    }

    public interface Visitor<R,P> {

        R visitSimpleType(SimpleType type, P p);

        R visitArrayType(ArrayType type, P p);

        R visitMethodType(MethodType type, P p);

        R visitClassSigType(ClassSigType type, P p);

        R visitClassType(ClassType type, P p);

        R visitTypeParamType(TypeParamType type, P p);

        R visitWildcardType(WildcardType type, P p);

    }

    /**

     * Represents a type signature with a simple name. The name may be that of a

     * primitive type, such "{@code int}, {@code float}, etc

     * or that of a type argument, such as {@code T}, {@code K}, {@code V}, etc.

     *

     * See:

     * JVMS 4.3.2

     *      BaseType:

     *          {@code B}, {@code C}, {@code D}, {@code F}, {@code I},

     *          {@code J}, {@code S}, {@code Z};

     *      VoidDescriptor:

     *          {@code V};

     * JVMS 4.3.4

     *      TypeVariableSignature:

     *          {@code T} Identifier {@code ;}

     */

    public static class SimpleType extends Type {

        public SimpleType(String name) {

            this.name = name;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visitSimpleType(this, data);

        }

        public boolean isPrimitiveType() {

            return primitiveTypes.contains(name);

        }

        // where

        private static final Set<String> primitiveTypes = new HashSet<>(Arrays.asList(

            "boolean", "byte", "char", "double", "float", "int", "long", "short", "void"));

        @Override

        public String toString() {

            return name;

        }

        public final String name;

    }

    /**

     * Represents an array type signature.

     *

     * See:

     * JVMS 4.3.4

     *      ArrayTypeSignature:

     *          {@code [} TypeSignature {@code ]}

     */

    public static class ArrayType extends Type {

        public ArrayType(Type elemType) {

            this.elemType = elemType;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visitArrayType(this, data);

        }

        @Override

        public String toString() {

            return elemType + "[]";

        }

        public final Type elemType;

    }

    /**

     * Represents a method type signature.

     *

     * See;

     * JVMS 4.3.4

     *      MethodTypeSignature:

     *          FormalTypeParameters_opt {@code (} TypeSignature* {@code)} ReturnType

     *              ThrowsSignature*

     */

    public static class MethodType extends Type {

        public MethodType(List<? extends Type> paramTypes, Type resultType) {

            this(null, paramTypes, resultType, null);

        }

        public MethodType(List<? extends TypeParamType> typeParamTypes,

                List<? extends Type> paramTypes,

                Type returnType,

                List<? extends Type> throwsTypes) {

            this.typeParamTypes = typeParamTypes;

            this.paramTypes = paramTypes;

            this.returnType = returnType;

            this.throwsTypes = throwsTypes;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visitMethodType(this, data);

        }

        @Override

        public String toString() {

            StringBuilder sb = new StringBuilder();

            appendIfNotEmpty(sb, "<", typeParamTypes, "> ");

            sb.append(returnType);

            append(sb, " (", paramTypes, ")");

            appendIfNotEmpty(sb, " throws ", throwsTypes, "");

            return sb.toString();

        }

        public final List<? extends TypeParamType> typeParamTypes;

        public final List<? extends Type> paramTypes;

        public final Type returnType;

        public final List<? extends Type> throwsTypes;

    }

    /**

     * Represents a class signature. These describe the signature of

     * a class that has type arguments.

     *

     * See:

     * JVMS 4.3.4

     *      ClassSignature:

     *          FormalTypeParameters_opt SuperclassSignature SuperinterfaceSignature*

     */

    public static class ClassSigType extends Type {

        public ClassSigType(List<TypeParamType> typeParamTypes, Type superclassType,

                List<Type> superinterfaceTypes) {

            this.typeParamTypes = typeParamTypes;

            this.superclassType = superclassType;

            this.superinterfaceTypes = superinterfaceTypes;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visitClassSigType(this, data);

        }

        @Override

        public String toString() {

            StringBuilder sb = new StringBuilder();

            appendIfNotEmpty(sb, "<", typeParamTypes, ">");

            if (superclassType != null) {

                sb.append(" extends ");

                sb.append(superclassType);

            }

            appendIfNotEmpty(sb, " implements ", superinterfaceTypes, "");

            return sb.toString();

        }

        public final List<TypeParamType> typeParamTypes;

        public final Type superclassType;

        public final List<Type> superinterfaceTypes;

    }

    /**

     * Represents a class type signature. This is used to represent a

     * reference to a class, such as in a field, parameter, return type, etc.

     *

     * See:

     * JVMS 4.3.4

     *      ClassTypeSignature:

     *          {@code L} PackageSpecifier_opt SimpleClassTypeSignature

     *                  ClassTypeSignatureSuffix* {@code ;}

     *      PackageSpecifier:

     *          Identifier {@code /} PackageSpecifier*

     *      SimpleClassTypeSignature:

     *          Identifier TypeArguments_opt }

     *      ClassTypeSignatureSuffix:

     *          {@code .} SimpleClassTypeSignature

     */

    public static class ClassType extends Type {

        public ClassType(ClassType outerType, String name, List<Type> typeArgs) {

            this.outerType = outerType;

            this.name = name;

            this.typeArgs = typeArgs;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visitClassType(this, data);

        }

        public String getBinaryName() {

            if (outerType == null)

                return name;

            else

                return (outerType.getBinaryName() + "$" + name);

        }

        @Override

        public String toString() {

            StringBuilder sb = new StringBuilder();

            if (outerType != null) {

                sb.append(outerType);

                sb.append(".");

            }

            sb.append(name);

            appendIfNotEmpty(sb, "<", typeArgs, ">");

            return sb.toString();

        }

        @Override

        public boolean isObject() {

            return (outerType == null)

                    && name.equals("java/lang/Object")

                    && (typeArgs == null || typeArgs.isEmpty());

        }

        public final ClassType outerType;

        public final String name;

        public final List<Type> typeArgs;

    }

    /**

     * Represents a FormalTypeParameter. These are used to declare the type

     * parameters for generic classes and methods.

     *

     * See:

     * JVMS 4.3.4

     *     FormalTypeParameters:

     *          {@code <} FormalTypeParameter+ {@code >}

     *     FormalTypeParameter:

     *          Identifier ClassBound InterfaceBound*

     *     ClassBound:

     *          {@code :} FieldTypeSignature_opt

     *     InterfaceBound:

     *          {@code :} FieldTypeSignature

     */

    public static class TypeParamType extends Type {

        public TypeParamType(String name, Type classBound, List<Type> interfaceBounds) {

            this.name = name;

            this.classBound = classBound;

            this.interfaceBounds = interfaceBounds;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visitTypeParamType(this, data);

        }

        @Override

        public String toString() {

            StringBuilder sb = new StringBuilder();

            sb.append(name);

            String sep = " extends ";

            if (classBound != null) {

                sb.append(sep);

                sb.append(classBound);

                sep = " & ";

            }

            if (interfaceBounds != null) {

                for (Type bound: interfaceBounds) {

                    sb.append(sep);

                    sb.append(bound);

                    sep = " & ";

                }

            }

            return sb.toString();

        }

        public final String name;

        public final Type classBound;

        public final List<Type> interfaceBounds;

    }

    /**

     * Represents a wildcard type argument.  A type argument that is not a

     * wildcard type argument will be represented by a ClassType, ArrayType, etc.

     *

     * See:

     * JVMS 4.3.4

     *      TypeArgument:

     *          WildcardIndicator_opt FieldTypeSignature

     *          {@code *}

     *      WildcardIndicator:

     *          {@code +}

     *          {@code -}

     */

    public static class WildcardType extends Type {

        public enum Kind { UNBOUNDED, EXTENDS, SUPER }

        public WildcardType() {

            this(Kind.UNBOUNDED, null);

        }

        public WildcardType(Kind kind, Type boundType) {

            this.kind = kind;

            this.boundType = boundType;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visitWildcardType(this, data);

        }

        @Override

        public String toString() {

            switch (kind) {

                case UNBOUNDED:

                    return "?";

                case EXTENDS:

                    return "? extends " + boundType;

                case SUPER:

                    return "? super " + boundType;

                default:

                    throw new AssertionError();

            }

        }

        public final Kind kind;

        public final Type boundType;

    }

}