/*******************************************************************************
 * Copyright (c) 2000, 2007 IBM Corporation and others.
 * 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:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwtx.jface.text.DefaultDocumentAdapter;

import dwt.dwthelper.utils;


import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import dwt.DWT;
import dwt.custom.TextChangeListener;
import dwt.custom.TextChangedEvent;
import dwt.custom.TextChangingEvent;
import dwtx.core.runtime.Assert;


/**
 * Default implementation of {@link dwtx.jface.text.IDocumentAdapter}.
 * <p>
 * <strong>Note:</strong> This adapter does not work if the widget auto-wraps the text.
 * </p>
 */
class DefaultDocumentAdapter : IDocumentAdapter, IDocumentListener, IDocumentAdapterExtension {

    /** The adapted document. */
    private IDocument fDocument;
    /** The document clone for the non-forwarding case. */
    private IDocument fDocumentClone;
    /** The original content */
    private String fOriginalContent;
    /** The original line delimiters */
    private String[] fOriginalLineDelimiters;
    /** The registered text change listeners */
    private List fTextChangeListeners= new ArrayList(1);
    /**
     * The remembered document event
     * @since 2.0
     */
    private DocumentEvent fEvent;
    /** The line delimiter */
    private String fLineDelimiter= null;
    /**
     * Indicates whether this adapter is forwarding document changes
     * @since 2.0
     */
    private bool fIsForwarding= true;
    /**
     * Length of document at receipt of <code>documentAboutToBeChanged</code>
     * @since 2.1
     */
    private int fRememberedLengthOfDocument;
    /**
     * Length of first document line at receipt of <code>documentAboutToBeChanged</code>
     * @since 2.1
     */
    private int fRememberedLengthOfFirstLine;
    /**
     * The data of the event at receipt of <code>documentAboutToBeChanged</code>
     * @since 2.1
     */
    private  DocumentEvent fOriginalEvent= new DocumentEvent();


    /**
     * Creates a new document adapter which is initially not connected to
     * any document.
     */
    public DefaultDocumentAdapter() {
    }

    /**
     * Sets the given document as the document to be adapted.
     *
     * @param document the document to be adapted or <code>null</code> if there is no document
     */
    public void setDocument(IDocument document) {

        if (fDocument !is null)
            fDocument.removePrenotifiedDocumentListener(this);

        fDocument= document;
        fLineDelimiter= null;

        if (!fIsForwarding) {
            fDocumentClone= null;
            if (fDocument !is null) {
                fOriginalContent= fDocument.get();
                fOriginalLineDelimiters= fDocument.getLegalLineDelimiters();
            } else {
                fOriginalContent= null;
                fOriginalLineDelimiters= null;
            }
        }

        if (fDocument !is null)
            fDocument.addPrenotifiedDocumentListener(this);
    }

    /*
     * @see StyledTextContent#addTextChangeListener(TextChangeListener)
     */
    public void addTextChangeListener(TextChangeListener listener) {
        Assert.isNotNull(listener);
        if (!fTextChangeListeners.contains(listener))
            fTextChangeListeners.add(listener);
    }

    /*
     * @see StyledTextContent#removeTextChangeListener(TextChangeListener)
     */
    public void removeTextChangeListener(TextChangeListener listener) {
        Assert.isNotNull(listener);
        fTextChangeListeners.remove(listener);
    }

    /**
     * Tries to repair the line information.
     *
     * @param document the document
     * @see IRepairableDocument#repairLineInformation()
     * @since 3.0
     */
    private void repairLineInformation(IDocument document) {
        if (document instanceof IRepairableDocument) {
            IRepairableDocument repairable= (IRepairableDocument) document;
            repairable.repairLineInformation();
        }
    }

    /**
     * Returns the line for the given line number.
     *
     * @param document the document
     * @param line the line number
     * @return the content of the line of the given number in the given document
     * @throws BadLocationException if the line number is invalid for the adapted document
     * @since 3.0
     */
    private String doGetLine(IDocument document, int line) throws BadLocationException {
        IRegion r= document.getLineInformation(line);
        return document.get(r.getOffset(), r.getLength());
    }

    private IDocument getDocumentForRead() {
        if (!fIsForwarding) {
            if (fDocumentClone is null) {
                String content= fOriginalContent is null ? "" : fOriginalContent; //$NON-NLS-1$
                String[] delims= fOriginalLineDelimiters is null ? DefaultLineTracker.DELIMITERS : fOriginalLineDelimiters;
                fDocumentClone= new DocumentClone(content, delims);
            }
            return fDocumentClone;
        }

        return fDocument;
    }

    /*
     * @see StyledTextContent#getLine(int)
     */
    public String getLine(int line) {

        IDocument document= getDocumentForRead();
        try {
            return doGetLine(document, line);
        } catch (BadLocationException x) {
            repairLineInformation(document);
            try {
                return doGetLine(document, line);
            } catch (BadLocationException x2) {
            }
        }

        DWT.error(DWT.ERROR_INVALID_ARGUMENT);
        return null;
    }

    /*
     * @see StyledTextContent#getLineAtOffset(int)
     */
    public int getLineAtOffset(int offset) {
        IDocument document= getDocumentForRead();
        try {
            return document.getLineOfOffset(offset);
        } catch (BadLocationException x) {
            repairLineInformation(document);
            try {
                return document.getLineOfOffset(offset);
            } catch (BadLocationException x2) {
            }
        }

        DWT.error(DWT.ERROR_INVALID_ARGUMENT);
        return -1;
    }

    /*
     * @see StyledTextContent#getLineCount()
     */
    public int getLineCount() {
        return getDocumentForRead().getNumberOfLines();
    }

    /*
     * @see StyledTextContent#getOffsetAtLine(int)
     */
    public int getOffsetAtLine(int line) {
        IDocument document= getDocumentForRead();
        try {
            return document.getLineOffset(line);
        } catch (BadLocationException x) {
            repairLineInformation(document);
            try {
                return document.getLineOffset(line);
            } catch (BadLocationException x2) {
            }
        }

        DWT.error(DWT.ERROR_INVALID_ARGUMENT);
        return -1;
    }

    /*
     * @see StyledTextContent#getTextRange(int, int)
     */
    public String getTextRange(int offset, int length) {
        try {
            return getDocumentForRead().get(offset, length);
        } catch (BadLocationException x) {
            DWT.error(DWT.ERROR_INVALID_ARGUMENT);
            return null;
        }
    }

    /*
     * @see StyledTextContent#replaceTextRange(int, int, String)
     */
    public void replaceTextRange(int pos, int length, String text) {
        try {
            fDocument.replace(pos, length, text);
        } catch (BadLocationException x) {
            DWT.error(DWT.ERROR_INVALID_ARGUMENT);
        }
    }

    /*
     * @see StyledTextContent#setText(String)
     */
    public void setText(String text) {
        fDocument.set(text);
    }

    /*
     * @see StyledTextContent#getCharCount()
     */
    public int getCharCount() {
        return getDocumentForRead().getLength();
    }

    /*
     * @see StyledTextContent#getLineDelimiter()
     */
    public String getLineDelimiter() {
        if (fLineDelimiter is null)
            fLineDelimiter= TextUtilities.getDefaultLineDelimiter(fDocument);
        return fLineDelimiter;
    }

    /*
     * @see IDocumentListener#documentChanged(DocumentEvent)
     */
    public void documentChanged(DocumentEvent event) {
        // check whether the given event is the one which was remembered
        if (fEvent is null || event !is fEvent)
            return;

        if (isPatchedEvent(event) || (event.getOffset() is 0 && event.getLength() is fRememberedLengthOfDocument)) {
            fLineDelimiter= null;
            fireTextSet();
        } else {
            if (event.getOffset() < fRememberedLengthOfFirstLine)
                fLineDelimiter= null;
            fireTextChanged();
        }
    }

    /*
     * @see IDocumentListener#documentAboutToBeChanged(DocumentEvent)
     */
    public void documentAboutToBeChanged(DocumentEvent event) {

        fRememberedLengthOfDocument= fDocument.getLength();
        try {
            fRememberedLengthOfFirstLine= fDocument.getLineLength(0);
        } catch (BadLocationException e) {
            fRememberedLengthOfFirstLine= -1;
        }

        fEvent= event;
        rememberEventData(fEvent);
        fireTextChanging();
    }

    /**
     * Checks whether this event has been changed between <code>documentAboutToBeChanged</code> and
     * <code>documentChanged</code>.
     *
     * @param event the event to be checked
     * @return <code>true</code> if the event has been changed, <code>false</code> otherwise
     */
    private bool isPatchedEvent(DocumentEvent event) {
        return fOriginalEvent.fOffset !is event.fOffset || fOriginalEvent.fLength !is event.fLength || fOriginalEvent.fText !is event.fText;
    }

    /**
     * Makes a copy of the given event and remembers it.
     *
     * @param event the event to be copied
     */
    private void rememberEventData(DocumentEvent event) {
        fOriginalEvent.fOffset= event.fOffset;
        fOriginalEvent.fLength= event.fLength;
        fOriginalEvent.fText= event.fText;
    }

    /**
     * Sends a text changed event to all registered listeners.
     */
    private void fireTextChanged() {

        if (!fIsForwarding)
            return;

        TextChangedEvent event= new TextChangedEvent(this);

        if (fTextChangeListeners !is null && fTextChangeListeners.size() > 0) {
            Iterator e= new ArrayList(fTextChangeListeners).iterator();
            while (e.hasNext())
                ((TextChangeListener) e.next()).textChanged(event);
        }
    }

    /**
     * Sends a text set event to all registered listeners.
     */
    private void fireTextSet() {

        if (!fIsForwarding)
            return;

        TextChangedEvent event = new TextChangedEvent(this);

        if (fTextChangeListeners !is null && fTextChangeListeners.size() > 0) {
            Iterator e= new ArrayList(fTextChangeListeners).iterator();
            while (e.hasNext())
                ((TextChangeListener) e.next()).textSet(event);
        }
    }

    /**
     * Sends the text changing event to all registered listeners.
     */
    private void fireTextChanging() {

        if (!fIsForwarding)
            return;

        try {
            IDocument document= fEvent.getDocument();
            if (document is null)
                return;

            TextChangingEvent event= new TextChangingEvent(this);
            event.start= fEvent.fOffset;
            event.replaceCharCount= fEvent.fLength;
            event.replaceLineCount= document.getNumberOfLines(fEvent.fOffset, fEvent.fLength) - 1;
            event.newText= fEvent.fText;
            event.newCharCount= (fEvent.fText is null ? 0 : fEvent.fText.length());
            event.newLineCount= (fEvent.fText is null ? 0 : document.computeNumberOfLines(fEvent.fText));

            if (fTextChangeListeners !is null && fTextChangeListeners.size() > 0) {
                Iterator e= new ArrayList(fTextChangeListeners).iterator();
                while (e.hasNext())
                     ((TextChangeListener) e.next()).textChanging(event);
            }

        } catch (BadLocationException e) {
        }
    }

    /*
     * @see IDocumentAdapterExtension#resumeForwardingDocumentChanges()
     * @since 2.0
     */
    public void resumeForwardingDocumentChanges() {
        fIsForwarding= true;
        fDocumentClone= null;
        fOriginalContent= null;
        fOriginalLineDelimiters= null;
        fireTextSet();
    }

    /*
     * @see IDocumentAdapterExtension#stopForwardingDocumentChanges()
     * @since 2.0
     */
    public void stopForwardingDocumentChanges() {
        fDocumentClone= null;
        fOriginalContent= fDocument.get();
        fOriginalLineDelimiters= fDocument.getLegalLineDelimiters();
        fIsForwarding= false;
    }
}