/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code 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 GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.swing.text;

import java.util.Vector;

import javax.swing.event.*;

/**

 * A plain document that maintains no character attributes.  The

 * default element structure for this document is a map of the lines in

 * the text.  The Element returned by getDefaultRootElement is

 * a map of the lines, and each child element represents a line.

 * This model does not maintain any character level attributes,

 * but each line can be tagged with an arbitrary set of attributes.

 * Line to offset, and offset to line translations can be quickly

 * performed using the default root element.  The structure information

 * of the DocumentEvent's fired by edits will indicate the line

 * structure changes.

 * <p>

 * The default content storage management is performed by a

 * gapped buffer implementation (GapContent).  It supports

 * editing reasonably large documents with good efficiency when

 * the edits are contiguous or clustered, as is typical.

 * <p>

 * <strong>Warning:</strong>

 * Serialized objects of this class will not be compatible with

 * future Swing releases. The current serialization support is

 * appropriate for short term storage or RMI between applications running

 * the same version of Swing.  As of 1.4, support for long term storage

 * of all JavaBeans<sup><font size="-2">TM</font></sup>

 * has been added to the <code>java.beans</code> package.

 * Please see {@link java.beans.XMLEncoder}.

 *

 * @author  Timothy Prinzing

 * @see     Document

 * @see     AbstractDocument

 */

public class PlainDocument extends AbstractDocument {

    /**

     * Name of the attribute that specifies the tab

     * size for tabs contained in the content.  The

     * type for the value is Integer.

     */

    public static final String tabSizeAttribute = "tabSize";

    /**

     * Name of the attribute that specifies the maximum

     * length of a line, if there is a maximum length.

     * The type for the value is Integer.

     */

    public static final String lineLimitAttribute = "lineLimit";

    /**

     * Constructs a plain text document.  A default model using

     * <code>GapContent</code> is constructed and set.

     */

    public PlainDocument() {

        this(new GapContent());

    }

    /**

     * Constructs a plain text document.  A default root element is created,

     * and the tab size set to 8.

     *

     * @param c  the container for the content

     */

    public PlainDocument(Content c) {

        super(c);

        putProperty(tabSizeAttribute, Integer.valueOf(8));

        defaultRoot = createDefaultRoot();

    }

    /**

     * Inserts some content into the document.

     * Inserting content causes a write lock to be held while the

     * actual changes are taking place, followed by notification

     * to the observers on the thread that grabbed the write lock.

     * <p>

     * This method is thread safe, although most Swing methods

     * are not. Please see

     * <A HREF="http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html">How

     * to Use Threads</A> for more information.

     *

     * @param offs the starting offset >= 0

     * @param str the string to insert; does nothing with null/empty strings

     * @param a the attributes for the inserted content

     * @exception BadLocationException  the given insert position is not a valid

     *   position within the document

     * @see Document#insertString

     */

    public void insertString(int offs, String str, AttributeSet a) throws BadLocationException {

        // fields don't want to have multiple lines.  We may provide a field-specific

        // model in the future in which case the filtering logic here will no longer

        // be needed.

        Object filterNewlines = getProperty("filterNewlines");

        if ((filterNewlines instanceof Boolean) && filterNewlines.equals(Boolean.TRUE)) {

            if ((str != null) && (str.indexOf('\n') >= 0)) {

                StringBuffer filtered = new StringBuffer(str);

                int n = filtered.length();

                for (int i = 0; i < n; i++) {

                    if (filtered.charAt(i) == '\n') {

                        filtered.setCharAt(i, ' ');

                    }

                }

                str = filtered.toString();

            }

        }

        super.insertString(offs, str, a);

    }

    /**

     * Gets the default root element for the document model.

     *

     * @return the root

     * @see Document#getDefaultRootElement

     */

    public Element getDefaultRootElement() {

        return defaultRoot;

    }

    /**

     * Creates the root element to be used to represent the

     * default document structure.

     *

     * @return the element base

     */

    protected AbstractElement createDefaultRoot() {

        BranchElement map = (BranchElement) createBranchElement(null, null);

        Element line = createLeafElement(map, null, 0, 1);

        Element[] lines = new Element[1];

        lines[0] = line;

        map.replace(0, 0, lines);

        return map;

    }

    /**

     * Get the paragraph element containing the given position.  Since this

     * document only models lines, it returns the line instead.

     */

    public Element getParagraphElement(int pos){

        Element lineMap = getDefaultRootElement();

        return lineMap.getElement( lineMap.getElementIndex( pos ) );

    }

    /**

     * Updates document structure as a result of text insertion.  This

     * will happen within a write lock.  Since this document simply

     * maps out lines, we refresh the line map.

     *

     * @param chng the change event describing the dit

     * @param attr the set of attributes for the inserted text

     */

    protected void insertUpdate(DefaultDocumentEvent chng, AttributeSet attr) {

        removed.removeAllElements();

        added.removeAllElements();

        BranchElement lineMap = (BranchElement) getDefaultRootElement();

        int offset = chng.getOffset();

        int length = chng.getLength();

        if (offset > 0) {

          offset -= 1;

          length += 1;

        }

        int index = lineMap.getElementIndex(offset);

        Element rmCandidate = lineMap.getElement(index);

        int rmOffs0 = rmCandidate.getStartOffset();

        int rmOffs1 = rmCandidate.getEndOffset();

        int lastOffset = rmOffs0;

        try {

            if (s == null) {

                s = new Segment();

            }

            getContent().getChars(offset, length, s);

            boolean hasBreaks = false;

            for (int i = 0; i < length; i++) {

                char c = s.array[s.offset + i];

                if (c == '\n') {

                    int breakOffset = offset + i + 1;

                    added.addElement(createLeafElement(lineMap, null, lastOffset, breakOffset));

                    lastOffset = breakOffset;

                    hasBreaks = true;

                }

            }

            if (hasBreaks) {

                int rmCount = 1;

                removed.addElement(rmCandidate);

                if ((offset + length == rmOffs1) && (lastOffset != rmOffs1) &&

                    ((index+1) < lineMap.getElementCount())) {

                    rmCount += 1;

                    Element e = lineMap.getElement(index+1);

                    removed.addElement(e);

                    rmOffs1 = e.getEndOffset();

                }

                if (lastOffset < rmOffs1) {

                    added.addElement(createLeafElement(lineMap, null, lastOffset, rmOffs1));

                }

                Element[] aelems = new Element[added.size()];

                added.copyInto(aelems);

                Element[] relems = new Element[removed.size()];

                removed.copyInto(relems);

                ElementEdit ee = new ElementEdit(lineMap, index, relems, aelems);

                chng.addEdit(ee);

                lineMap.replace(index, relems.length, aelems);

            }

            if (Utilities.isComposedTextAttributeDefined(attr)) {

                insertComposedTextUpdate(chng, attr);

            }

        } catch (BadLocationException e) {

            throw new Error("Internal error: " + e.toString());

        }

        super.insertUpdate(chng, attr);

    }

    /**

     * Updates any document structure as a result of text removal.

     * This will happen within a write lock. Since the structure

     * represents a line map, this just checks to see if the

     * removal spans lines.  If it does, the two lines outside

     * of the removal area are joined together.

     *

     * @param chng the change event describing the edit

     */

    protected void removeUpdate(DefaultDocumentEvent chng) {

        removed.removeAllElements();

        BranchElement map = (BranchElement) getDefaultRootElement();

        int offset = chng.getOffset();

        int length = chng.getLength();

        int line0 = map.getElementIndex(offset);

        int line1 = map.getElementIndex(offset + length);

        if (line0 != line1) {

            // a line was removed

            for (int i = line0; i <= line1; i++) {

                removed.addElement(map.getElement(i));

            }

            int p0 = map.getElement(line0).getStartOffset();

            int p1 = map.getElement(line1).getEndOffset();

            Element[] aelems = new Element[1];

            aelems[0] = createLeafElement(map, null, p0, p1);

            Element[] relems = new Element[removed.size()];

            removed.copyInto(relems);

            ElementEdit ee = new ElementEdit(map, line0, relems, aelems);

            chng.addEdit(ee);

            map.replace(line0, relems.length, aelems);

        } else {

            //Check for the composed text element

            Element line = map.getElement(line0);

            if (!line.isLeaf()) {

                Element leaf = line.getElement(line.getElementIndex(offset));

                if (Utilities.isComposedTextElement(leaf)) {

                    Element[] aelem = new Element[1];

                    aelem[0] = createLeafElement(map, null,

                        line.getStartOffset(), line.getEndOffset());

                    Element[] relem = new Element[1];

                    relem[0] = line;

                    ElementEdit ee = new ElementEdit(map, line0, relem, aelem);

                    chng.addEdit(ee);

                    map.replace(line0, 1, aelem);

                }

            }

        }

        super.removeUpdate(chng);

    }

    //

    // Inserts the composed text of an input method. The line element

    // where the composed text is inserted into becomes an branch element

    // which contains leaf elements of the composed text and the text

    // backing store.

    //

    private void insertComposedTextUpdate(DefaultDocumentEvent chng, AttributeSet attr) {

        added.removeAllElements();

        BranchElement lineMap = (BranchElement) getDefaultRootElement();

        int offset = chng.getOffset();

        int length = chng.getLength();

        int index = lineMap.getElementIndex(offset);

        Element elem = lineMap.getElement(index);

        int elemStart = elem.getStartOffset();

        int elemEnd = elem.getEndOffset();

        BranchElement[] abelem = new BranchElement[1];

        abelem[0] = (BranchElement) createBranchElement(lineMap, null);

        Element[] relem = new Element[1];

        relem[0] = elem;

        if (elemStart != offset)

            added.addElement(createLeafElement(abelem[0], null, elemStart, offset));

        added.addElement(createLeafElement(abelem[0], attr, offset, offset+length));

        if (elemEnd != offset+length)

            added.addElement(createLeafElement(abelem[0], null, offset+length, elemEnd));

        Element[] alelem = new Element[added.size()];

        added.copyInto(alelem);

        ElementEdit ee = new ElementEdit(lineMap, index, relem, abelem);

        chng.addEdit(ee);

        abelem[0].replace(0, 0, alelem);

        lineMap.replace(index, 1, abelem);

    }

    private AbstractElement defaultRoot;

    private Vector added = new Vector();     // Vector<Element>

    private Vector removed = new Vector();   // Vector<Element>

    private transient Segment s;

}