/*******************************************************************************
 * Copyright Technophobia Ltd 2012
 * 
 * This file is part of the Substeps Eclipse Plugin.
 * 
 * The Substeps Eclipse Plugin is free software: you can redistribute it and/or modify
 * it under the terms of the Eclipse Public License v1.0.
 * 
 * The Substeps Eclipse Plugin is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * Eclipse Public License for more details.
 * 
 * You should have received a copy of the Eclipse Public License
 * along with the Substeps Eclipse Plugin.  If not, see <http://www.eclipse.org/legal/epl-v10.html>.
 ******************************************************************************/
package com.technophobia.substeps.document.text.rule;

import java.util.Arrays;
import java.util.Comparator;

import org.eclipse.jface.text.rules.ICharacterScanner;
import org.eclipse.jface.text.rules.IToken;
import org.eclipse.jface.text.rules.MultiLineRule;

public class UntilOtherContentTypeSequenceRule extends MultiLineRule {

    private final Comparator<char[]> lineDelimiterComparator = new DecreasingCharArrayLengthComparator();

    private char[][] lineDelimiters;
    private char[][] sortedLineDelimiters;

    private final String[] otherContentTypes;


    public UntilOtherContentTypeSequenceRule(final String startSequence, final IToken token, final boolean breaksOnEOF,
            final String... otherContentTypes) {
        super(startSequence, "Not applicable", token, (char) 0, breaksOnEOF);
        this.otherContentTypes = otherContentTypes;
    }


    /**
     * Returns whether the end sequence was detected. As the pattern can be
     * considered ended by a line delimiter, the result of this method is
     * <code>true</code> if the rule breaks on the end of the line, or if the
     * EOF character is read.
     * 
     * @param scanner
     *            the character scanner to be used
     * @return <code>true</code> if the end sequence has been detected
     */
    @Override
    protected boolean endSequenceDetected(final ICharacterScanner scanner) {

        final char[][] originalDelimiters = scanner.getLegalLineDelimiters();
        int count = originalDelimiters.length;
        if (this.lineDelimiters == null || this.lineDelimiters.length != count) {
            sortedLineDelimiters = new char[count][];
        } else {
            while (count > 0 && Arrays.equals(lineDelimiters[count - 1], originalDelimiters[count - 1]))
                count--;
        }
        if (count != 0) {
            lineDelimiters = originalDelimiters;
            System.arraycopy(lineDelimiters, 0, sortedLineDelimiters, 0, lineDelimiters.length);
            Arrays.sort(sortedLineDelimiters, lineDelimiterComparator);
        }

        int readCount = 1;
        int c;
        while ((c = scanner.read()) != ICharacterScanner.EOF) {
            if (c == fEscapeCharacter) {
                // Skip escaped character(s)
                if (fEscapeContinuesLine) {
                    c = scanner.read();
                    for (int i = 0; i < sortedLineDelimiters.length; i++) {
                        if (c == sortedLineDelimiters[i][0]
                                && sequenceDetected(scanner, sortedLineDelimiters[i], fBreaksOnEOF))
                            break;
                    }
                } else
                    scanner.read();

            } else if (isOtherContentTypeFound(scanner, c)) {
                return true;
            } else if (fBreaksOnEOL) {
                // Check for end of line since it can be used to terminate the
                // pattern.
                for (int i = 0; i < sortedLineDelimiters.length; i++) {
                    if (c == sortedLineDelimiters[i][0]
                            && sequenceDetected(scanner, sortedLineDelimiters[i], fBreaksOnEOF))
                        return true;
                }
            }
            readCount++;
        }

        if (fBreaksOnEOF)
            return true;

        for (; readCount > 0; readCount--)
            scanner.unread();

        return false;
    }


    private boolean isOtherContentTypeFound(final ICharacterScanner scanner, final int c) {
        for (final String otherContentType : otherContentTypes) {
            final char[] charArr = otherContentType.toCharArray();
            if (otherContentType != null && c == charArr[0]) {

                // Check if the specified end sequence has been found.
                if (sequenceDetected(scanner, charArr, fBreaksOnEOF)) {
                    // we've found a match, now unread the other content type
                    for (int i = 0; i < charArr.length; i++) {
                        scanner.unread();
                    }
                    return true;
                }
            }
        }
        return false;
    }

    private static final class DecreasingCharArrayLengthComparator implements Comparator<char[]> {
        @Override
        public int compare(final char[] o1, final char[] o2) {
            return o2.length - o1.length;
        }
    }
}