/*
 * 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.
 *
 *   SPDX-License-Identifier: Apache-2.0
 */

package org.apache.jena.sparql.resultset;

import java.io.OutputStream;
import java.io.PrintWriter;

import org.apache.jena.query.QuerySolution;
import org.apache.jena.query.ResultSet;
import org.apache.jena.rdf.model.RDFNode;
import org.apache.jena.sparql.core.Prologue;
import org.apache.jena.sparql.serializer.SerializationContext;
import org.apache.jena.sparql.util.FmtUtils;
import org.apache.jena.util.FileUtils;

public class PlainFormat implements ResultSetProcessor {
    private PrintWriter out;
    private int count = 0;
    private boolean lineNumbers = true;
    private boolean first = true;
    private SerializationContext context;

    public PlainFormat(OutputStream outStream, SerializationContext context) {
        this.out = FileUtils.asPrintWriterUTF8(outStream);
        this.context = context;
    }

    public PlainFormat(OutputStream outStream, Prologue prologue) {
        this(outStream, new SerializationContext(prologue));
    }

    @Override
    public void start(ResultSet rs) {}

    @Override
    public void finish(ResultSet rs) {
        out.flush();
    }

    @Override
    public void start(QuerySolution qs) {
        count++;
        // insertLineNumber() ;
        first = true;
    }

    @Override
    public void finish(QuerySolution qs) {
        out.println();
    }

    @Override
    public void binding(String varName, RDFNode value) {
        if ( value == null )
            return; // Unbound
        if ( !first )
            out.print(" ");
        // Would like to share code Binding here.
        String s = FmtUtils.stringForRDFNode(value, context);
        out.print("( ?" + varName + " = " + s + " )");
        first = false;
    }

    void insertLineNumber() {
        if ( !lineNumbers )
            return;
        String s = Integer.toString(count);
        for ( int i = 0 ; i < 3 - s.length() ; i++ )
            out.print(' ');
        out.print(s);
        out.print(' ');
    }
}
