/*******************************************************************************
 *
 * Copyright (c) 2004-2010 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 java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Mutable representation of string with HTML mark up.
 *
 * <p> This class is used to put mark up on plain text. See <a
 * href="https://github.com/hudson/hudson/blob/master/hudson-core/src/test/java/hudson/MarkupTextTest.java">
 * the test code</a> for a typical usage and its result.
 *
 * @author Kohsuke Kawaguchi
 * @since 1.70
 */
public class MarkupText extends AbstractMarkupText {

    private final String text;
    /**
     * Added mark up tags.
     */
    private final List<Tag> tags = new ArrayList<Tag>();

    /**
     * Represents one mark up inserted into text.
     */
    private static final class Tag implements Comparable<Tag> {

        /**
         * Char position of this tag in {@link MarkupText#text}. This tag is
         * placed in front of the character of this index.
         */
        private final int pos;
        private final String markup;

        public Tag(int pos, String markup) {
            this.pos = pos;
            this.markup = markup;
        }

        public int compareTo(Tag that) {
            return this.pos - that.pos;
        }
    }

    /**
     * Represents a substring of a {@link MarkupText}.
     */
    public final class SubText extends AbstractMarkupText {

        private final int start, end;
        private final int[] groups;

        public SubText(Matcher m, int textOffset) {
            start = m.start() + textOffset;
            end = m.end() + textOffset;

            int cnt = m.groupCount();
            groups = new int[cnt * 2];
            for (int i = 0; i < cnt; i++) {
                groups[i * 2] = m.start(i + 1) + textOffset;
                groups[i * 2 + 1] = m.end(i + 1) + textOffset;
            }
        }

        public SubText(int start, int end) {
            this.start = start;
            this.end = end;
            groups = new int[0];
        }

        @Override
        public SubText subText(int start, int end) {
            return MarkupText.this.subText(this.start + start,
                    end < 0 ? this.end + 1 + end : this.start + end);
        }

        @Override
        public String getText() {
            return text.substring(start, end);
        }

        @Override
        public void addMarkup(int startPos, int endPos, String startTag, String endTag) {
            MarkupText.this.addMarkup(startPos + start, endPos + start, startTag, endTag);
        }

        /**
         * Surrounds this subtext with the specified start tag and the end tag.
         *
         * <p> Start/end tag text can contain special tokens "$0", "$1", ... and
         * they will be replaced by their {@link #group(int) group match}. "\$"
         * can be used to escape characters.
         */
        public void surroundWith(String startTag, String endTag) {
            addMarkup(0, length(), replace(startTag), replace(endTag));
        }

        /**
         * Works like {@link #surroundWith(String, String)} except that the
         * token replacement is not performed on parameters.
         */
        public void surroundWithLiteral(String startTag, String endTag) {
            addMarkup(0, length(), startTag, endTag);
        }

        /**
         * Surrounds this subtext with &lt;a>...&lt;/a>.
         */
        public void href(String url) {
            addHyperlink(0, length(), url);
        }

        /**
         * Gets the start index of the captured group within
         * {@link MarkupText#getText()}.
         *
         * @param groupIndex 0 means the start of the whole subtext. 1, 2, ...
         * are groups captured by '(...)' in the regexp.
         */
        public int start(int groupIndex) {
            if (groupIndex == 0) {
                return start;
            }
            return groups[groupIndex * 2 - 2];
        }

        /**
         * Gets the start index of this subtext within
         * {@link MarkupText#getText()}.
         */
        public int start() {
            return start;
        }

        /**
         * Gets the end index of the captured group within
         * {@link MarkupText#getText()}.
         */
        public int end(int groupIndex) {
            if (groupIndex == 0) {
                return end;
            }
            return groups[groupIndex * 2 - 1];
        }

        /**
         * Gets the end index of this subtext within
         * {@link MarkupText#getText()}.
         */
        public int end() {
            return end;
        }

        /**
         * Gets the text that represents the captured group.
         */
        public String group(int groupIndex) {
            if (start(groupIndex) == -1) {
                return null;
            }
            return text.substring(start(groupIndex), end(groupIndex));
        }

        /**
         * How many captured groups are in this subtext.
         *
         * @since 1.357
         */
        public int groupCount() {
            return groups.length / 2;
        }

        /**
         * Replaces the group tokens like "$0", "$1", and etc with their actual
         * matches.
         */
        public String replace(String s) {
            StringBuffer buf = new StringBuffer();

            for (int i = 0; i < s.length(); i++) {
                char ch = s.charAt(i);
                if (ch == '\\') {// escape char
                    i++;
                    buf.append(s.charAt(i));
                } else if (ch == '$') {// replace by group
                    i++;

                    ch = s.charAt(i);
                    // get the group number
                    int groupId = ch - '0';
                    if (groupId < 0 || groupId > 9) {
                        buf.append('$').append(ch);
                    } else {
                        // add the group text
                        String group = group(groupId);
                        if (group != null) {
                            buf.append(group);
                        }
                    }

                } else {
                    // other chars
                    buf.append(ch);
                }
            }

            return buf.toString();
        }

        @Override
        protected SubText createSubText(Matcher m) {
            return new SubText(m, start);
        }
    }

    /**
     *
     * @param text Plain text. This shouldn't include any markup nor escape.
     * Those are done later in {@link #toString(boolean)}.
     */
    public MarkupText(String text) {
        this.text = text;
    }

    @Override
    public String getText() {
        return text;
    }

    /**
     * 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 SubText subText(int start, int end) {
        return new SubText(start, end < 0 ? text.length() + 1 + end : end);
    }

    @Override
    public void addMarkup(int startPos, int endPos, String startTag, String endTag) {
        rangeCheck(startPos);
        rangeCheck(endPos);
        if (startPos > endPos) {
            throw new IndexOutOfBoundsException();
        }

        // when multiple tags are added to the same range, we want them to show up like
        // <b><i>abc</i></b>, not <b><i>abc</b></i>. Also, we'd like <b>abc</b><i>def</i>,
        // not <b>abc<i></b>def</i>. Do this by inserting them to different places.
        tags.add(new Tag(startPos, startTag));
        tags.add(0, new Tag(endPos, endTag));
    }

    public void addMarkup(int pos, String tag) {
        rangeCheck(pos);
        tags.add(new Tag(pos, tag));
    }

    private void rangeCheck(int pos) {
        if (pos < 0 || pos > text.length()) {
            throw new IndexOutOfBoundsException();
        }
    }

    /**
     * Returns the fully marked-up text.
     *
     * @deprecated as of 1.350. Use {@link #toString(boolean)} to be explicit
     * about the escape mode.
     */
    @Override
    public String toString() {
        return toString(false);
    }

    /**
     * Returns the fully marked-up text.
     *
     * @param preEscape If true, the escaping is for the &lt;PRE> context. This
     * leave SP and CR/LF intact. If false, the escape is for the normal HTML,
     * thus SP becomes &amp;nbsp; and CR/LF becomes &lt;BR>
     */
    public String toString(boolean preEscape) {
        if (tags.isEmpty()) {
            return preEscape ? Util.xmlEscape(text) : Util.escape(text);  // the most common case
        }
        Collections.sort(tags);

        StringBuilder buf = new StringBuilder();
        int copied = 0; // # of chars already copied from text to buf

        for (Tag tag : tags) {
            if (copied < tag.pos) {
                String portion = text.substring(copied, tag.pos);
                buf.append(preEscape ? Util.xmlEscape(portion) : Util.escape(portion));
                copied = tag.pos;
            }
            buf.append(tag.markup);
        }
        if (copied < text.length()) {
            String portion = text.substring(copied, text.length());
            buf.append(preEscape ? Util.xmlEscape(portion) : Util.escape(portion));
        }

        return buf.toString();
    }

    // perhaps this method doesn't need to be here to remain binary compatible with past versions,
    // but having this seems to be safer.
    @Override
    public List<SubText> findTokens(Pattern pattern) {
        return super.findTokens(pattern);
    }

    @Override
    protected SubText createSubText(Matcher m) {
        return new SubText(m, 0);
    }
}
