/*******************************************************************************
 *
 * Copyright (c) 2004-2009 Oracle Corporation.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * 
 *    Kohsuke Kawaguchi
 *
 *
 *******************************************************************************/ 

package hudson;

import hudson.MarkupText.SubText;

import java.util.List;
import java.util.ArrayList;
import java.util.regex.Pattern;
import java.util.regex.Matcher;

/**
 * Common part between {@link MarkupText} and {@link MarkupText.SubText}.
 *
 * <p> See {@link MarkupText} for more discussion about what this class
 * represents.
 *
 * @author Kohsuke Kawaguchi
 * @since 1.250
 */
public abstract class AbstractMarkupText {
    /*package*/ AbstractMarkupText() {
    } // limit who can subclass this type.

    /**
     * Returns the plain text portion of this {@link MarkupText} without any
     * markup, nor any escape.
     */
    public abstract String getText();

    public char charAt(int idx) {
        return getText().charAt(idx);
    }

    /**
     * Length of the plain text.
     */
    public final int length() {
        return getText().length();
    }

    /**
     * Returns a subtext.
     *
     * @param end If negative, -N means "trim the last N-1 chars". That is,
     * (s,-1) is the same as (s,length)
     */
    public abstract MarkupText.SubText subText(int start, int end);

    /**
     * Adds a start tag and end tag at the specified position.
     *
     * <p> For example, if the text was "abc", then
     * <tt>addMarkup(1,2,"<b>","</b>")</tt> would generate
     * <tt>"a<b>b</b>c"</tt>
     */
    public abstract void addMarkup(int startPos, int endPos, String startTag, String endTag);

    /**
     * Inserts an A tag that surrounds the given position.
     *
     * @since 1.349
     */
    public void addHyperlink(int startPos, int endPos, String url) {
        addMarkup(startPos, endPos, "<a href='" + url + "'>", "</a>");
    }

    /**
     * Inserts an A tag that surrounds the given position. But this hyperlink is
     * less visible.
     *
     * @since 1.395
     */
    public void addHyperlinkLowKey(int startPos, int endPos, String url) {
        addMarkup(startPos, endPos, "<a class='lowkey' href='" + url + "'>", "</a>");
    }

    /**
     * Hides the given text.
     */
    public void hide(int startPos, int endPos) {
        addMarkup(startPos, endPos, "<span style='display:none'>", "</span>");
    }

    /**
     * Adds a start tag and end tag around the entire text
     */
    public final void wrapBy(String startTag, String endTag) {
        addMarkup(0, length(), startTag, endTag);
    }

    /**
     * Find the first occurrence of the given pattern in this text, or null.
     *
     * @since 1.349
     */
    public MarkupText.SubText findToken(Pattern pattern) {
        String text = getText();
        Matcher m = pattern.matcher(text);

        if (m.find()) {
            return createSubText(m);
        }

        return null;
    }

    /**
     * Find all "tokens" that match the given pattern in this text.
     *
     * <p> A token is like a substring, except that it's aware of word
     * boundaries. For example, while "bc" is a string of "abc", calling
     * {@code findTokens} with "bc" as a pattern on string "abc" won't match
     * anything.
     *
     * <p> This method is convenient for finding keywords that follow a certain
     * syntax from natural text. You can then use
     * {@link MarkupText.SubText#surroundWith(String,String)} to put mark up
     * around such text.
     */
    public List<MarkupText.SubText> findTokens(Pattern pattern) {
        String text = getText();
        Matcher m = pattern.matcher(text);
        List<SubText> r = new ArrayList<SubText>();

        while (m.find()) {
            int idx = m.start();
            if (idx > 0) {
                char ch = text.charAt(idx - 1);
                if (Character.isLetter(ch) || Character.isDigit(ch)) {
                    continue;   // not at a word boundary
                }
            }
            idx = m.end();
            if (idx < text.length()) {
                char ch = text.charAt(idx);
                if (Character.isLetter(ch) || Character.isDigit(ch)) {
                    continue;   // not at a word boundary
                }
            }
            r.add(createSubText(m));
        }

        return r;
    }

    protected abstract SubText createSubText(Matcher m);
}