/*
 * 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.logging.log4j.message;

import org.apache.logging.log4j.util.PerformanceSensitive;

/**
 * Mutable Message wrapper around a String message.
 * @since 2.6
 */
@PerformanceSensitive("allocation")
public class ReusableSimpleMessage implements ReusableMessage, CharSequence, ParameterVisitable {
    private static final Object[] EMPTY_PARAMS = new Object[0];
    private CharSequence charSequence;

    public void set(final String message) {
        this.charSequence = message;
    }

    public void set(final CharSequence charSequence) {
        this.charSequence = charSequence;
    }

    @Override
    public String getFormattedMessage() {
        return String.valueOf(charSequence);
    }

    @Override
    public String getFormat() {
        return charSequence instanceof String ? (String) charSequence : null;
    }

    @Override
    public Object[] getParameters() {
        return EMPTY_PARAMS;
    }

    @Override
    public Throwable getThrowable() {
        return null;
    }

    @Override
    public void formatTo(final StringBuilder buffer) {
        buffer.append(charSequence);
    }

    /**
     * This message does not have any parameters, so this method returns the specified array.
     * @param emptyReplacement the parameter array to return
     * @return the specified array
     */
    @Override
    public Object[] swapParameters(final Object[] emptyReplacement) {
        return emptyReplacement;
    }

    /**
     * This message does not have any parameters so this method always returns zero.
     * @return 0 (zero)
     */
    @Override
    public short getParameterCount() {
        return 0;
    }

    @Override
    public <S> void forEachParameter(final ParameterConsumer<S> action, final S state) {
    }

    @Override
    public Message memento() {
        return new SimpleMessage(charSequence);
    }

    // CharSequence impl

    @Override
    public int length() {
        return charSequence == null ? 0 : charSequence.length();
    }

    @Override
    public char charAt(final int index) {
        return charSequence.charAt(index);
    }

    @Override
    public CharSequence subSequence(final int start, final int end) {
        return charSequence.subSequence(start, end);
    }

    @Override
    public void clear() {
        charSequence = null;
    }
}
