/*******************************************************************************
 * Copyright 2010 Simon Mieth
 * 
 * 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 org.kabeja.tools;

import java.io.BufferedReader;
import java.io.IOException;

import org.kabeja.util.Constants;


/**
 * @author <a href="mailto:simon.mieth@gmx.de">Simon Mieth</a>
 *
 */
public class CodePageParser {
    public static final String CODEPAGE_CODE = "$DWGCODEPAGE";
    public static final String GROUPCODE = "3";
    private static final String[] prefix = { "ansi_", "dos" };
    private static final String javaPrefix = "Cp";

    public String parseEncoding(BufferedReader reader) {
        String encoding = "";

        try {
            String line = null;
            String code;
            String value;
            boolean next = true;
            boolean codepage = false;
            boolean key = true;
            String currentKey = null;

            while (((line = reader.readLine()) != null) && next) {
                line = line.trim();

                if (key) {
                    currentKey = line;
                    key = false;
                } else {
                    key = true;

                    // we read the first section
                    if (Constants.SECTION_END.equals(line)) {
                        return encoding;
                    } else if (CODEPAGE_CODE.equals(line)) {
                        codepage = true;
                    } else if (codepage && currentKey.equals("3")) {
                        // the encoding
                        return translateCodePage(line);
                    } else if (Constants.SECTION_CLASSES.equals(line) ||
                            Constants.SECTION_BLOCKS.equals(line) ||
                            Constants.SECTION_ENTITIES.equals(line)) {
                        return encoding;
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

        return encoding;
    }

    public String translateCodePage(String cp) {
        String c = cp.toLowerCase();

        for (int i = 0; i < prefix.length; i++) {
            if (c.startsWith(prefix[i])) {
                return javaPrefix + cp.substring(prefix[i].length());
            }
        }

        return cp;
    }
}