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/*   __    __         _
 *   \ \  / /__ _ __ (_) ___ ___
 *    \ \/ / _ \ '_ \| |/ __/ _ \
 *     \  /  __/ | | | | (_|  __/
 *      \/ \___|_| |_|_|\___\___|
 *
 *
 * Copyright 2017-2024 Venice
 *
 * Licensed 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 com.github.jlangch.venice.impl.util.csv;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.nio.charset.Charset;

import com.github.jlangch.venice.impl.util.io.CharsetUtil;


public class CharacterReader {

    public CharacterReader(final String s) {
        this(new StringReader(s == null ? "" : s));
    }

    public CharacterReader(final InputStream is, final Charset charset) {
        this(new InputStreamReader(is, CharsetUtil.charset(charset)));
    }

    public CharacterReader(final Reader r) {
        rd = r;
        chNext = next();
    }

    public int peek() {
        return chNext;
    }

    public void consume() {
        if (chNext != EOF) {
            if (chNext == LF) {
                lineNr++;
                columnNr = 1;
            }
            else if (chNext == CR) {
                // pass over regarding line/column nr
            }
            else {
                columnNr++;
            }

            chNext = next();
        }
    }

    public void skipAllOfChar(final char ch) {
        while(peek() == ch) consume();
    }

    public boolean isEof() {
        return chNext == EOF;
    }

    public boolean isLf() {
        return chNext == LF;
    }

    public boolean isCr() {
        return chNext == CR;
    }

    public int getLineNr() {
        return lineNr;
    }

    public int getColNr() {
        return columnNr;
    }


    private int next() {
        try {
            return rd.read();
        }
        catch(IOException ex) {
            throw new RuntimeException(
                    String.format(
                        "Failed to read next char from CSV reader at line %d, col %d.",
                        lineNr,
                        columnNr),
                    ex);
        }
    }


    private static final int EOF = -1;
    private static final int LF  = '\n';
    private static final int CR  = '\r';

    private final Reader rd;
    private int chNext;

    private int lineNr = 1;
    private int columnNr = 1;
}