/*
 *  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.grails.web.xml;

import java.io.IOException;
import java.io.Writer;

import groovy.xml.streamingmarkupsupport.StreamingMarkupWriter;

/**
 * A XMLStreamWriter dedicated to create indented/pretty printed output.
 *
 * @author Siegfried Puchbauer
 * @since 1.1
 */
public class PrettyPrintXMLStreamWriter extends XMLStreamWriter {

    public static final String DEFAULT_INDENT_STR = "  ";

    public static final String NEWLINE;

    static {
        String nl = System.getProperty("line.separator");
        NEWLINE = nl != null ? nl : "\n";
    }

    private final String indent;

    private int level = 0;

    private boolean doIndent = false;

    public PrettyPrintXMLStreamWriter(StreamingMarkupWriter writer) {
        this(writer, DEFAULT_INDENT_STR);
    }

    public PrettyPrintXMLStreamWriter(StreamingMarkupWriter writer, String indent) {
        super(writer);
        this.indent = indent;
    }

    private void newline() throws IOException {
        writer.unescaped().write(NEWLINE);
    }

    private void indent() throws IOException {
        Writer ue = writer.unescaped();
        for (int i = 0; i < level; i++) {
            ue.write(indent);
        }
    }

    @Override
    protected void endStartTag() throws IOException {
        super.endStartTag();
        newline();
        if (doIndent)
            indent();
    }

    @Override
    protected void startTag() throws IOException {
        indent();
        super.startTag();
    }

    @Override
    public XMLStreamWriter startNode(String tag) throws IOException {
        doIndent = false;
        super.startNode(tag);
        level++;
        return this;
    }

    @Override
    public XMLStreamWriter end() throws IOException {
        level--;
        if (mode != Mode.TAG) {
            indent();
        }
        super.end();
        newline();
        // indent();
        return this;
    }

    @Override
    public XMLStreamWriter characters(String data) throws IOException {
        doIndent = true;
        super.characters(data);
        newline();
        return this;
    }

    @Override
    public XMLStreamWriter startDocument(String encoding, String version) throws IOException {
        super.startDocument(encoding, version);
        newline();
        return this;
    }
}
