source: java/FramclipsePlugin/src/main/java/com/framsticks/framclipse/editors/hover/FramscriptTextHover.java @ 13

package com.framsticks.framclipse.editors.hover;

import java.util.List;

import org.eclipse.jface.internal.text.html.BrowserInformationControl;
import org.eclipse.jface.internal.text.html.HTMLTextPresenter;
import org.eclipse.jface.text.AbstractReusableInformationControlCreator;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DefaultInformationControl;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IInformationControl;
import org.eclipse.jface.text.IInformationControlCreator;
import org.eclipse.jface.text.IInformationControlExtension4;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextHover;
import org.eclipse.jface.text.ITextHoverExtension;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.information.IInformationProviderExtension2;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.editors.text.EditorsUI;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.xpath.XPath;

import com.framsticks.framclipse.Framclipse;
import com.framsticks.framclipse.editors.codeCompletion.SyntaxUtils;


public class FramscriptTextHover implements ITextHover, ITextHoverExtension, IInformationProviderExtension2 {
        
        private static final class PresenterControlCreator extends AbstractReusableInformationControlCreator {

                public IInformationControl doCreateInformationControl(Shell parent) {
                        int shellStyle= SWT.RESIZE | SWT.TOOL;
                        int style= SWT.V_SCROLL | SWT.H_SCROLL;
                        if (BrowserInformationControl.isAvailable(parent))
                                return new BrowserInformationControl(parent, shellStyle, style);
                        else
                                return new DefaultInformationControl(parent, shellStyle, style, new HTMLTextPresenter(false));
                }
        }

        private static final class HoverControlCreator extends AbstractReusableInformationControlCreator {
                
                public IInformationControl doCreateInformationControl(Shell parent) {
                        if (BrowserInformationControl.isAvailable(parent))
                                return new BrowserInformationControl(parent, SWT.TOOL | SWT.NO_TRIM, SWT.NONE, EditorsUI.getTooltipAffordanceString());
                        else
                                return new DefaultInformationControl(parent, SWT.NONE, new HTMLTextPresenter(true), EditorsUI.getTooltipAffordanceString());
                }

                /*
                 * @see org.eclipse.jdt.internal.ui.text.java.hover.AbstractReusableInformationControlCreator#canReuse(org.eclipse.jface.text.IInformationControl)
                 */
                public boolean canReuse(IInformationControl control) {
                        if (!super.canReuse(control))
                                return false;
                        
                        if (control instanceof IInformationControlExtension4)
                                ((IInformationControlExtension4)control).setStatusText(EditorsUI.getTooltipAffordanceString());
                        
                        return true;
                }
        }



        private static final int DESCRIPTION_LENGTH = 60;
        
        private IInformationControlCreator fHoverControlCreator;
        
        private IInformationControlCreator fPresenterControlCreator;
        
        public IInformationControlCreator getInformationPresenterControlCreator() {
                if (fPresenterControlCreator == null)
                        fPresenterControlCreator= new PresenterControlCreator();
                return fPresenterControlCreator;
        }

        public IInformationControlCreator getHoverControlCreator() {
                if (fHoverControlCreator == null)
                        fHoverControlCreator= new HoverControlCreator();
                return fHoverControlCreator;
        }

        public String getHoverInfo(ITextViewer textViewer, IRegion hoverRegion) {
                int offset = hoverRegion.getOffset() + hoverRegion.getLength();
                IDocument document = textViewer.getDocument();

                List<String> elements = SyntaxUtils.getElementsAt(document, offset);

                if (elements.size() == 0) {
                        return null;
                }

                String name = elements.remove(elements.size() - 1);
                String elementFormat = "%s[@" + SyntaxUtils.NAME_ATTRIBUTE + "='%s']/";
                String query = SyntaxUtils.ROOT + "/";

                if (elements.size() == 0) {
                        query += String.format(elementFormat, SyntaxUtils.TYPE_ELEMENT, name);
                } else { // elements.size() > 1
                        String parent;
                        try {
                                parent = SyntaxUtils.getLastElementType(elements);
                        } catch (JDOMException e) {
                                e.printStackTrace();
                                return null;
                        }
                        query += String.format(elementFormat, SyntaxUtils.TYPE_ELEMENT, parent)
                                        + String.format(elementFormat, SyntaxUtils.ELEMENT_ELEMENT, name);
                }
                query += SyntaxUtils.DESCRIPTION_ELEMENT;

                Document syntax = Framclipse.getDefault().getFramscriptSyntax();
                try {
                        XPath xpath = XPath.newInstance(query);
                        Element element = (Element) xpath.selectSingleNode(syntax);
                        if (element == null) {
                                return null;
                        }

                        return formatDescription(element.getValue());
                } catch (Exception e) {
                        e.printStackTrace();
                }

                return null;
        }

        public IRegion getHoverRegion(ITextViewer textViewer, int offset) {
                IDocument document = textViewer.getDocument();
                String after = SyntaxUtils.getElementAfter(document, offset);

                int line = 0;
                try {
                        line = document.getLineOfOffset(offset);
                } catch (BadLocationException e) {
                        e.printStackTrace();
                }

                int lineStart = offset;
                try {
                        lineStart = document.getLineInformation(line).getOffset();
                } catch (BadLocationException e) {
                        e.printStackTrace();
                }
                IRegion region = new Region(lineStart, offset + after.length() - lineStart);

                return region;
        }

        private static String formatDescription(String description) {
                String result = "";
                int offset = 0;
                while (offset < description.length()) {
                        int length = DESCRIPTION_LENGTH;
                        if (offset + length > description.length()) {
                                result += description.substring(offset);
                                return result;
                        }

                        for (int i = length; i > 0; i--) {
                                if (Character.isWhitespace(description.charAt(offset + i))) {
                                        length = i;
                                        i = 0;
                                }
                        }

                        result += description.substring(offset, offset + length) + "\n";
                        offset += length + 1;
                }
                return result;
        }
}