/*
 * Copyright (C) 2007, 2009 Martin Kempf, Reto Kleeb, Michael Klenk
 *
 * IFS Institute for Software, HSR Rapperswil, Switzerland
 * http://ifs.hsr.ch/
 *
 * 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.codehaus.groovy.eclipse.refactoring.core.utils;

import groovy.lang.IntRange;

import java.io.FileReader;
import java.io.IOException;
import java.util.List;

import org.codehaus.groovy.antlr.LineColumn;
import org.codehaus.groovy.runtime.DefaultGroovyMethods;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;

/**
 * Reads parts of a file *
 *
 * @author reto kleeb
 * @author Andrew Eisenberg
 */
public class FilePartReader {

    private static List<String> getWords(String line, IntRange range) {
        String relevantPieceOfLine = DefaultGroovyMethods.getAt(line, range);
        relevantPieceOfLine = relevantPieceOfLine.replaceAll("\\(", " ( ");
        relevantPieceOfLine = relevantPieceOfLine.replaceAll("\\)", " ) ");
        return DefaultGroovyMethods.tokenize(relevantPieceOfLine);
    }

    public static String readBackwardsFromCoordinate(IDocument doc, LineColumn coord) throws BadLocationException {
        //make sure that no one reads from a file with impossible coordinates
        if(doc != null && coord.getLine() > 0 && coord.getColumn() > 0) {
            int lineLength = doc.getLineLength(coord.getLine()-1);
            int offset = doc.getLineOffset(coord.getLine()-1);
            String line = doc.get(offset, lineLength);
            List<String> words = getWords(line, new IntRange(0, coord.getColumn()-2));
            return words.get(words.size()-1);
        } else {
            return " ";
        }
    }

    public static String readForwardFromCoordinate(IDocument doc, LineColumn coord) throws BadLocationException {
        //make sure that no one reads from a file with impossible coordinates
        if(doc != null && coord.getLine() > 0 && coord.getColumn() > 0) {
            int lineLength = doc.getLineLength(coord.getLine()-1);
            int offset = doc.getLineOffset(coord.getLine()-1);
            String line = doc.get(offset, lineLength);
            List<String> words = getWords(line, new IntRange(coord.getColumn()-1, line.length()));
            return words.get(0);
        } else {
            return " ";
        }

    }

    public static final String DEFAULT_LINE_DELIMITER = System.getProperty("line.separator");

    public static String getLineDelimiter(FileReader file) throws IOException {
        char[] content = DefaultGroovyMethods.getText(file).toCharArray();
        String lineDelimiter = DEFAULT_LINE_DELIMITER;
        int index = 0;
        for (char currentChar : content) {
            if(currentChar == '\r') {
                if(content[index+1] == '\n') {
                    lineDelimiter = "\r\n";
                    break;
                }
                lineDelimiter = "\r"; // mac os 9
                break;
            }
            else if(currentChar == '\n'){
                lineDelimiter = "\n";
                break;
            }
            index++;
        }
        return lineDelimiter;
    }
}