/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.commons.weaver.model;

import java.lang.reflect.Member;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.apache.commons.weaver.utils.Args;

/**
 * Represents a {@link Weavable} "executable".
 *
 * @param <SELF> own type
 * @param <TARGET> target executable type
 * @param <T> owning type
 * @param <P> parameter type
 */
public abstract class WeavableExecutable
    <SELF extends WeavableExecutable<SELF, TARGET, T, P>,
    TARGET extends Member,
    T,
    P extends WeavableParameter<P, SELF, TARGET, T>>
    extends NestedWeavable<SELF, TARGET, WeavableClass<T>, Class<T>> {

    private final List<P> parameters;

    /**
     * Create a new {@link WeavableExecutable} instance.
     * @param target executable
     * @param parent enclosing {@link WeavableClass}
     */
    protected WeavableExecutable(final TARGET target, final WeavableClass<T> parent) {
        super(target, parent);
        final List<P> params = new ArrayList<>();
        final int paramCount = getParameterTypes().length;
        for (int i = 0; i < paramCount; i++) {
            params.add(createParameter(i));
        }
        parameters = Collections.unmodifiableList(params);
    }

    /**
     * Create an appropriate {@link WeavableParameter} object.
     * @param index of parameter
     * @return {@code P}
     */
    protected abstract P createParameter(int index);

    /**
     * Gets the parameter types of {@link #getTarget()}.
     * @return {@link Class}[]
     */
    protected abstract Class<?>[] getParameterTypes();

    /**
     * {@inheritDoc}
     */
    @Override
    protected int localCompareTo(final SELF obj) {
        return Args.compare(getParameterTypes(), obj.getParameterTypes());
    }

    /**
     * Gets the parameter at the specified index.
     * @param index {@code int}
     * @return {@code P}
     */
    public P getWeavableParameter(final int index) {
        return parameters.get(index);
    }

    /**
     * Gets the parameters declared by this {@link WeavableExecutable}.
     * @return {@link Iterable} of {@code P}
     */
    public Iterable<P> getParameters() {
        return parameters;
    }
}