/*
 *  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
 *
 *      https://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.tools.ant.filters;

import java.io.IOException;
import java.io.Reader;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.PropertyHelper;
import org.apache.tools.ant.property.GetProperty;
import org.apache.tools.ant.property.ParseProperties;
import org.apache.tools.ant.types.PropertySet;

Expands Ant properties, if any, in the data.
Example:
<expandproperties/>
Or:
<filterreader
   classname="org.apache.tools.ant.filters.ExpandProperties"/>
/**
 * Expands Ant properties, if any, in the data.
 * <p>Example:</p>
 * <pre>&lt;expandproperties/&gt;</pre>
 * Or:
 * <pre>&lt;filterreader
 *    classname=&quot;org.apache.tools.ant.filters.ExpandProperties&quot;/&gt;</pre>
 *
 */
public final class ExpandProperties
    extends BaseFilterReader
    implements ChainableReader {

    private static final int EOF = -1;

    private char[] buffer;
    private int index;
    private PropertySet propertySet;

    
Constructor for "dummy" instances.
See Also:
BaseFilterReader.BaseFilterReader()/**
     * Constructor for "dummy" instances.
     *
     * @see BaseFilterReader#BaseFilterReader()
     */
    public ExpandProperties() {
        super();
    }

    
Creates a new filtered reader.
Params:
in – A Reader object providing the underlying stream.
          Must not be null./**
     * Creates a new filtered reader.
     *
     * @param in A Reader object providing the underlying stream.
     *           Must not be <code>null</code>.
     */
    public ExpandProperties(final Reader in) {
        super(in);
    }

    
Restrict the expanded properties using a PropertySet.
Params:
propertySet – replacement lookup/**
     * Restrict the expanded properties using a PropertySet.
     * @param propertySet replacement lookup
     */
    public void add(PropertySet propertySet) {
        if (this.propertySet != null) {
            throw new BuildException("expandproperties filter accepts only one propertyset");
        }
        this.propertySet = propertySet;
    }

    
Returns the next character in the filtered stream. The original
stream is first read in fully, and the Ant properties are expanded.
The results of this expansion are then queued so they can be read
character-by-character.
Throws:
IOException – if the underlying stream throws an IOException
during reading
Returns:
the next character in the resulting stream, or -1
if the end of the resulting stream has been reached/**
     * Returns the next character in the filtered stream. The original
     * stream is first read in fully, and the Ant properties are expanded.
     * The results of this expansion are then queued so they can be read
     * character-by-character.
     *
     * @return the next character in the resulting stream, or -1
     * if the end of the resulting stream has been reached
     *
     * @exception IOException if the underlying stream throws an IOException
     * during reading
     */
    public int read() throws IOException {
        if (index > EOF) {
            if (buffer == null) {
                String data = readFully();
                Project project = getProject();
                GetProperty getProperty;
                if (propertySet == null) {
                    getProperty = PropertyHelper.getPropertyHelper(project);
                } else {
                    getProperty = propertySet.getProperties()::getProperty;
                }
                Object expanded = new ParseProperties(project, PropertyHelper
                                                      .getPropertyHelper(project)
                                                      .getExpanders(),
                                                      getProperty)
                    .parseProperties(data);
                buffer = expanded == null ? new char[0]
                    : expanded.toString().toCharArray();
            }
            if (index < buffer.length) {
                return buffer[index++];
            }
            index = EOF;
        }
        return EOF;
    }

    
Creates a new ExpandProperties filter using the passed in
Reader for instantiation.
Params:
rdr – A Reader object providing the underlying stream.
           Must not be null.
Returns:
a new filter based on this configuration, but filtering
        the specified reader/**
     * Creates a new ExpandProperties filter using the passed in
     * Reader for instantiation.
     *
     * @param rdr A Reader object providing the underlying stream.
     *            Must not be <code>null</code>.
     *
     * @return a new filter based on this configuration, but filtering
     *         the specified reader
     */
    public Reader chain(final Reader rdr) {
        ExpandProperties newFilter = new ExpandProperties(rdr);
        newFilter.setProject(getProject());
        newFilter.add(propertySet);
        return newFilter;
    }
}