/*
 *  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.property;

import java.text.ParsePosition;
import java.util.Collection;
import java.util.Objects;

import org.apache.tools.ant.Project;

Parse properties using a collection of expanders.
Since:
Ant 1.8.0/**
 * Parse properties using a collection of expanders.
 *
 * @since Ant 1.8.0
 */
public class ParseProperties implements ParseNextProperty {

    private final Project project;
    private final GetProperty getProperty;
    private final Collection<PropertyExpander> expanders;

    
Constructor with a getProperty.
Params:
project – the current Ant project.
expanders – a sequence of expanders
getProperty – property resolver./**
     * Constructor with a getProperty.
     * @param project the current Ant project.
     * @param expanders a sequence of expanders
     * @param getProperty property resolver.
     */
    public ParseProperties(Project project, Collection<PropertyExpander> expanders, GetProperty getProperty) {
        this.project = project;
        this.expanders = expanders;
        this.getProperty = getProperty;
    }

    
Get the project.
Returns:
the current Ant project./**
     * Get the project.
     * @return the current Ant project.
     */
    @Override
    public Project getProject() {
        return project;
    }

    
Decode properties from a String representation.

 
This implementation starts parsing the value parameter (unsurprisingly) at the beginning and asks each PropertyExpander whether there is a property reference at that point. PropertyExpanders return the name of a property they may find and may advance the parse position.
 
If the PropertyExpander returns null the method continues with the next PropertyExpander, otherwise it tries to look up the property's value using the configured GetProperty instance.
 
Once all PropertyExpanders have been consulted, the parse
 position is advanced by one character and the process repeated
 until value is exhausted.

If the entire contents of value resolves to a
single property, the looked up property value is returned.
Otherwise a String is returned that concatenates the
non-property parts of value and the expanded
values of the properties that have been found.
Params:
value – The string to be scanned for property references.
             May be null, in which case this
             method returns immediately with no effect.
Returns:
the original string with the properties replaced, or
        null if the original string is null./**
     * Decode properties from a String representation.
     *
     * <ul>
     *
     *  <li>This implementation starts parsing the <code>value</code>
     *  parameter (unsurprisingly) at the beginning and asks each
     *  {@link PropertyExpander PropertyExpander} whether there is a
     *  property reference at that point.  PropertyExpanders return
     *  the name of a property they may find and may advance the parse
     *  position.</li>
     *
     *  <li>If the PropertyExpander returns <code>null</code> the
     *  method continues with the next PropertyExpander, otherwise it
     *  tries to look up the property's value using the configured
     *  {@link GetProperty GetProperty} instance.</li>
     *
     *  <li>Once all PropertyExpanders have been consulted, the parse
     *  position is advanced by one character and the process repeated
     *  until <code>value</code> is exhausted.</li>
     *
     * </ul>
     *
     * <p>If the entire contents of <code>value</code> resolves to a
     * single property, the looked up property value is returned.
     * Otherwise a String is returned that concatenates the
     * non-property parts of <code>value</code> and the expanded
     * values of the properties that have been found.</p>
     *
     * @param value The string to be scanned for property references.
     *              May be <code>null</code>, in which case this
     *              method returns immediately with no effect.
     *
     * @return the original string with the properties replaced, or
     *         <code>null</code> if the original string is <code>null</code>.
     */
    public Object parseProperties(String value) {
        if (value == null || value.isEmpty()) {
            return value;
        }
        final int len = value.length();
        ParsePosition pos = new ParsePosition(0);
        Object o = parseNextProperty(value, pos);
        if (o != null && pos.getIndex() >= len) {
            return o;
        }
        StringBuilder sb = new StringBuilder(len * 2);
        if (o == null) {
            sb.append(value.charAt(pos.getIndex()));
            pos.setIndex(pos.getIndex() + 1);
        } else {
            sb.append(o);
        }
        while (pos.getIndex() < len) {
            o = parseNextProperty(value, pos);
            if (o == null) {
                sb.append(value.charAt(pos.getIndex()));
                pos.setIndex(pos.getIndex() + 1);
            } else {
                sb.append(o);
            }
        }
        return sb.toString();
    }

    
Learn whether a String contains replaceable properties.
Uses the configured 
 PropertyExpanders and scans through the string. Returns true as soon as any expander finds a property.
Params:
value – the String to check.
Returns:
true if value contains property notation./**
     * Learn whether a String contains replaceable properties.
     *
     * <p>Uses the configured {@link PropertyExpander
     *  PropertyExpanders} and scans through the string.  Returns true
     *  as soon as any expander finds a property.</p>
     *
     * @param value the String to check.
     * @return <code>true</code> if <code>value</code> contains property notation.
     */
    public boolean containsProperties(String value) {
        if (value == null) {
            return false;
        }
        final int len = value.length();
        for (ParsePosition pos = new ParsePosition(0); pos.getIndex() < len;) {
            if (parsePropertyName(value, pos) != null) {
                return true;
            }
            pos.setIndex(pos.getIndex() + 1);
        }
        return false;
    }

    
Return any property that can be parsed from the specified position
in the specified String.
Uses the configured 
 PropertyExpanders and GetProperty instance .
Params:
value – String to parse
pos – ParsePosition
Returns:
Object or null if no property is at the current
location.  If a property reference has been found but the
property doesn't expand to a value, the property's name is
returned./**
     * Return any property that can be parsed from the specified position
     * in the specified String.
     *
     * <p>Uses the configured {@link PropertyExpander
     *  PropertyExpanders} and {@link GetProperty GetProperty}
     *  instance .</p>
     *
     * @param value String to parse
     * @param pos ParsePosition
     * @return Object or null if no property is at the current
     * location.  If a property reference has been found but the
     * property doesn't expand to a value, the property's name is
     * returned.
     */
    @Override
    public Object parseNextProperty(String value, ParsePosition pos) {
        final int start = pos.getIndex();

        if (start > value.length()) {
            // early exit, can't find any property here, no need to
            // consult all the delegates.
            return null;
        }

        String propertyName = parsePropertyName(value, pos);
        if (propertyName != null) {
            Object result = getProperty(propertyName);
            if (result != null) {
                return result;
            }
            if (project != null) {
                project.log(
                    "Property \"" + propertyName
                    + "\" has not been set", Project.MSG_VERBOSE);
            }
            return value.substring(start, pos.getIndex());
        }
        return null;
    }

    private String parsePropertyName(String value, ParsePosition pos) {
        return expanders.stream()
            .map(xp -> xp.parsePropertyName(value, pos, this))
            .filter(Objects::nonNull).findFirst().orElse(null);
    }

    private Object getProperty(String propertyName) {
        return getProperty.getProperty(propertyName);
    }
}