/*

 * Copyright (c) 2010, 2013, 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.

 */

/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file, and Oracle licenses the original version of this file under the BSD

 * license:

 */

/*

   Copyright 2009-2013 Attila Szegedi

*/

package jdk.dynalink.beans;

import java.lang.invoke.MethodType;

import java.util.LinkedList;

import java.util.List;

import jdk.dynalink.linker.support.TypeUtilities;

/**

 * Represents overloaded methods applicable to a specific call site signature.

 */

class ApplicableOverloadedMethods {

    private final List<SingleDynamicMethod> methods;

    private final boolean varArgs;

    /**

     * Creates a new ApplicableOverloadedMethods instance

     *

     * @param methods a list of all overloaded methods with the same name for a class.

     * @param callSiteType the type of the call site

     * @param test applicability test. One of {@link #APPLICABLE_BY_SUBTYPING},

     * {@link #APPLICABLE_BY_METHOD_INVOCATION_CONVERSION}, or {@link #APPLICABLE_BY_VARIABLE_ARITY}.

     */

    ApplicableOverloadedMethods(final List<SingleDynamicMethod> methods, final MethodType callSiteType,

            final ApplicabilityTest test) {

        this.methods = new LinkedList<>();

        for(final SingleDynamicMethod m: methods) {

            if(test.isApplicable(callSiteType, m)) {

                this.methods.add(m);

            }

        }

        varArgs = test == APPLICABLE_BY_VARIABLE_ARITY;

    }

    /**

     * Retrieves all the methods this object holds.

     *

     * @return list of all methods.

     */

    List<SingleDynamicMethod> getMethods() {

        return methods;

    }

    /**

     * Returns a list of all methods in this objects that are maximally specific.

     *

     * @return a list of maximally specific methods.

     */

    List<SingleDynamicMethod> findMaximallySpecificMethods() {

        return MaximallySpecific.getMaximallySpecificMethods(methods, varArgs);

    }

    abstract static class ApplicabilityTest {

        abstract boolean isApplicable(MethodType callSiteType, SingleDynamicMethod method);

    }

    /**

     * Implements the applicability-by-subtyping test from JLS 15.12.2.2.

     */

    static final ApplicabilityTest APPLICABLE_BY_SUBTYPING = new ApplicabilityTest() {

        @Override

        boolean isApplicable(final MethodType callSiteType, final SingleDynamicMethod method) {

            final MethodType methodType = method.getMethodType();

            final int methodArity = methodType.parameterCount();

            if(methodArity != callSiteType.parameterCount()) {

                return false;

            }

            // 0th arg is receiver; it doesn't matter for overload

            // resolution.

            for(int i = 1; i < methodArity; ++i) {

                if(!TypeUtilities.isSubtype(callSiteType.parameterType(i), methodType.parameterType(i))) {

                    return false;

                }

            }

            return true;

        }

    };

    /**

     * Implements the applicability-by-method-invocation-conversion test from JLS 15.12.2.3.

     */

    static final ApplicabilityTest APPLICABLE_BY_METHOD_INVOCATION_CONVERSION = new ApplicabilityTest() {

        @Override

        boolean isApplicable(final MethodType callSiteType, final SingleDynamicMethod method) {

            final MethodType methodType = method.getMethodType();

            final int methodArity = methodType.parameterCount();

            if(methodArity != callSiteType.parameterCount()) {

                return false;

            }

            // 0th arg is receiver; it doesn't matter for overload

            // resolution.

            for(int i = 1; i < methodArity; ++i) {

                if(!TypeUtilities.isMethodInvocationConvertible(callSiteType.parameterType(i),

                        methodType.parameterType(i))) {

                    return false;

                }

            }

            return true;

        }

    };

    /**

     * Implements the applicability-by-variable-arity test from JLS 15.12.2.4.

     */

    static final ApplicabilityTest APPLICABLE_BY_VARIABLE_ARITY = new ApplicabilityTest() {

        @Override

        boolean isApplicable(final MethodType callSiteType, final SingleDynamicMethod method) {

            if(!method.isVarArgs()) {

                return false;

            }

            final MethodType methodType = method.getMethodType();

            final int methodArity = methodType.parameterCount();

            final int fixArity = methodArity - 1;

            final int callSiteArity = callSiteType.parameterCount();

            if(fixArity > callSiteArity) {

                return false;

            }

            // 0th arg is receiver; it doesn't matter for overload

            // resolution.

            for(int i = 1; i < fixArity; ++i) {

                if(!TypeUtilities.isMethodInvocationConvertible(callSiteType.parameterType(i),

                        methodType.parameterType(i))) {

                    return false;

                }

            }

            final Class<?> varArgType = methodType.parameterType(fixArity).getComponentType();

            for(int i = fixArity; i < callSiteArity; ++i) {

                if(!TypeUtilities.isMethodInvocationConvertible(callSiteType.parameterType(i), varArgType)) {

                    return false;

                }

            }

            return true;

        }

    };

}