/*******************************************************************************
 * Copyright (c) 2011 Manumitting Technologies, Inc.
 * 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:
 *     Brian de Alwis (MT) - initial API and implementation
 *******************************************************************************/
package org.eclipse.e4.tools.css.spy;

import java.io.IOException;
import java.util.LinkedList;
import java.util.List;

import org.eclipse.e4.ui.css.core.dom.CSSStylableElement;
import org.eclipse.e4.ui.css.core.engine.CSSEngine;
import org.eclipse.e4.ui.css.swt.dom.WidgetElement;
import org.eclipse.e4.ui.css.swt.engine.CSSSWTEngineImpl;
import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.layout.TableColumnLayout;
import org.eclipse.jface.layout.TreeColumnLayout;
import org.eclipse.jface.viewers.CellEditor;
import org.eclipse.jface.viewers.ColumnLabelProvider;
import org.eclipse.jface.viewers.ColumnViewerEditor;
import org.eclipse.jface.viewers.ColumnViewerEditorActivationStrategy;
import org.eclipse.jface.viewers.ColumnViewerToolTipSupport;
import org.eclipse.jface.viewers.ColumnWeightData;
import org.eclipse.jface.viewers.EditingSupport;
import org.eclipse.jface.viewers.FocusCellOwnerDrawHighlighter;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.TableViewerColumn;
import org.eclipse.jface.viewers.TableViewerEditor;
import org.eclipse.jface.viewers.TableViewerFocusCellManager;
import org.eclipse.jface.viewers.TextCellEditor;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.TreeViewerColumn;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerComparator;
import org.eclipse.jface.viewers.ViewerFilter;
import org.eclipse.jface.window.Window;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.SashForm;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.FocusAdapter;
import org.eclipse.swt.events.FocusEvent;
import org.eclipse.swt.events.KeyAdapter;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.MouseMoveListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Region;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import org.eclipse.swt.widgets.ToolItem;
import org.eclipse.swt.widgets.Widget;
import org.w3c.css.sac.SelectorList;
import org.w3c.dom.NodeList;
import org.w3c.dom.css.CSSStyleDeclaration;

public class CssSpyDialog extends Dialog {
	/** @return the CSS element corresponding to the argument, or null if none */
	public static CSSStylableElement getCSSElement(Object o) {
		if (o instanceof CSSStylableElement) {
			return (CSSStylableElement) o;
        } else {
            CSSEngine engine = getCSSEngine(o);
            if (engine != null) {
                return (CSSStylableElement) engine.getElement(o);
            }
		}
		return null;
	}

	/** @return the CSS engine governing the argument, or null if none */
	public static CSSEngine getCSSEngine(Object o) {
        CSSEngine engine = null;
		if (o instanceof CSSStylableElement) {
			CSSStylableElement element = (CSSStylableElement) o;
            engine = WidgetElement.getEngine((Widget) element.getNativeWidget());
        }
        if (engine == null && o instanceof Widget) {
            engine = WidgetElement.getEngine((Widget) o);
        }
        if (engine == null && Display.getCurrent() != null) {
            engine = new CSSSWTEngineImpl(Display.getCurrent());
		}
        return engine;
	}

	private Display display;
	private Widget specimen;
	private Widget shown;

	private TableViewer cssPropertiesViewer;
	private TreeViewer widgetTreeViewer;
	private Text cssRules;

	private List<Shell> highlights = new LinkedList<Shell>();
	private List<Region> highlightRegions = new LinkedList<Region>();
	private Text cssSearchBox;
	private Button showUnsetProperties;

	protected ViewerFilter unsetPropertyFilter = new ViewerFilter() {

		@Override
		public boolean select(Viewer viewer, Object parentElement,
				Object element) {
			if (element instanceof CSSPropertyProvider) {
				try {
					return ((CSSPropertyProvider) element).getValue() != null;
				} catch (Exception e) {
					return false;
				}
			}
			return false;
		}
	};

	/**
	 * Create the dialog.
	 * 
	 * @param parentShell
	 */
	public CssSpyDialog(Shell parentShell) {
		super(parentShell);
		display = parentShell.getDisplay();
		setShellStyle(SWT.DIALOG_TRIM | SWT.RESIZE/* | SWT.PRIMARY_MODAL */);
	}

	public Widget getSpecimen() {
		return specimen;
	}

	private boolean isLive() {
		return specimen == null;
	}

	public void setSpecimen(Widget specimen) {
		this.specimen = specimen;
		update();
	}

	private Widget getActiveSpecimen() {
		if (specimen != null) {
			return specimen;
		}
		return display.getCursorControl();
	}

	protected boolean shouldDismissOnLostFocus() {
		return false;
	}

	protected void update() {
		if (getShell() == null) {
			return;
		}
		Widget current = getActiveSpecimen();
		if (shown == current) {
			return;
		}
		shown = current;

        CSSEngine engine = getCSSEngine(shown);
		CSSStylableElement element = (CSSStylableElement) engine
				.getElement(shown);
		if (element == null) {
			return;
		}

		widgetTreeViewer
				.setInput(new Object[] { shown instanceof Control ? ((Control) shown)
						.getShell() : shown });
		widgetTreeViewer.reveal(shown);
		widgetTreeViewer.setSelection(new StructuredSelection(shown));

		populate(shown);
	}

	protected void populate(Widget selected) {
		CSSStylableElement element = getCSSElement(selected);
		if (element == null) {
			return;
		}

		cssPropertiesViewer.setInput(selected);

		StringBuilder sb = new StringBuilder();
		CSSEngine engine = getCSSEngine(element);
		CSSStyleDeclaration decl = engine.getViewCSS().getComputedStyle(
				element, null);

		if (element.getCSSStyle() != null) {
			sb.append("\nCSS Inline Style(s):\n  ");
			Activator.join(sb, element.getCSSStyle().split(";"), ";\n  ");
		}

		if (decl != null) {
			sb.append("\n\nCSS Properties:\n");
			try {
				if (decl != null) {
					sb.append(decl.getCssText());
				}
			} catch (Throwable e) {
				sb.append(e);
			}
		}
		if (element.getStaticPseudoInstances().length > 0) {
			sb.append("\nStatic Pseudoinstances:\n  ");
			Activator.join(sb, element.getStaticPseudoInstances(), "\n  ");
		}

		if (element.getCSSClass() != null) {
			sb.append("\n\nCSS Classes:\n  ");
			Activator.join(sb, element.getCSSClass().split(" +"), "\n  ");
		}

		// FIXME: shouldn't this be getCSSStyle?
		if (element.getAttribute("style") != null) {
			sb.append("\n\nSWT Style Bits:\n  ");
			Activator.join(sb, element.getAttribute("style").split(" +"),
					"\n  ");
		}

		sb.append("\n\nCSS Class Element:\n  ").append(
				element.getClass().getName());

		// this is useful for diagnosing issues
		if (element.getNativeWidget() instanceof Composite) {
			sb.append("\n\nSWT Layout:\n  ").append(
					((Composite) element.getNativeWidget()).getLayout());
		}

		cssRules.setText(sb.toString().trim());

		disposeHighlights();
		highlightWidget(selected);
	}

	private void highlightWidget(Widget selected) {
		widgetTreeViewer.reveal(selected);

		Rectangle bounds = getBounds(selected); // relative to absolute display,
												// not the widget
		if (bounds == null /* || bounds.height == 0 || bounds.width == 0 */) {
			return;
		}
		// emulate a transparent background as per SWT Snippet180
		Shell selectedShell = getShell(selected);
		if (selectedShell != null) {
			// bounds = slectedShell.getDisplay().map(null, selectedShell,
			// bounds);
		}
		Shell highlight = new Shell(selectedShell, SWT.NO_TRIM | SWT.MODELESS); // appears
																				// on
																				// top
		highlight.setBackground(display.getSystemColor(SWT.COLOR_RED));
		Region highlightRegion = new Region();
		highlightRegion.add(0, 0, 1, bounds.height + 2);
		highlightRegion.add(0, 0, bounds.width + 2, 1);
		highlightRegion.add(bounds.width + 1, 0, 1, bounds.height + 2);
		highlightRegion.add(0, bounds.height + 1, bounds.width + 2, 1);
		highlight.setRegion(highlightRegion);
		highlight.setBounds(bounds.x - 1, bounds.y - 1, bounds.width + 2,
				bounds.height + 2);
		highlight.setEnabled(false);
		highlight.setVisible(true); // not open(): setVisible() prevents taking
									// focus

		highlights.add(highlight);
		highlightRegions.add(highlightRegion);
	}

	private Shell getShell(Widget widget) {
		if (widget instanceof Control) {
			return ((Control) widget).getShell();
		}
		return null;
	}

	private void disposeHighlights() {
		for (Shell highlight : highlights) {
			highlight.dispose();
		}
		highlights.clear();
		for (Region region : highlightRegions) {
			region.dispose();
		}
		highlightRegions.clear();
	}

	private Rectangle getBounds(Widget widget) {
		if (widget instanceof Shell) {
			// Shell bounds are already in display coordinates
			return ((Shell) widget).getBounds();
		} else if (widget instanceof Control) {
			Control control = (Control) widget;
			Rectangle bounds = control.getBounds();
			return control.getDisplay().map(control.getParent(), null, bounds);
		} else if (widget instanceof ToolItem) {
			ToolItem item = (ToolItem) widget;
			Rectangle bounds = item.getBounds();
			return item.getDisplay().map(item.getParent(), null, bounds);
		}
		// FIXME: figure out how to map items to a position
		return null;
	}

	/**
	 * Create contents of the dialog.
	 * 
	 * @param parent
	 */
	@Override
	protected Control createDialogArea(Composite parent) {
		Composite outer = (Composite) super.createDialogArea(parent);

		cssSearchBox = new Text(outer, SWT.BORDER | SWT.SEARCH
				| SWT.ICON_SEARCH | SWT.ICON_CANCEL);
		cssSearchBox.setMessage("CSS Selector");
		cssSearchBox.setToolTipText("Highlight matching widgets");
		cssSearchBox.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true,
				false, 1, 1));

		SashForm sashForm = new SashForm(outer, SWT.VERTICAL);
		sashForm.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true, 1,
				1));

		// / THE WIDGET TREE
		Composite widgetsComposite = new Composite(sashForm, SWT.NONE);

		widgetTreeViewer = new TreeViewer(widgetsComposite, SWT.BORDER);
		widgetTreeViewer.setContentProvider(new WidgetTreeProvider());
		widgetTreeViewer.setAutoExpandLevel(0);
		widgetTreeViewer.getTree().setLinesVisible(true);
		widgetTreeViewer.getTree().setHeaderVisible(true);
		ColumnViewerToolTipSupport.enableFor(widgetTreeViewer);

		TreeViewerColumn widgetTypeColumn = new TreeViewerColumn(
				widgetTreeViewer, SWT.NONE);
		widgetTypeColumn.getColumn().setWidth(100);
		widgetTypeColumn.getColumn().setText("Widget");
		widgetTypeColumn.setLabelProvider(new ColumnLabelProvider() {
			@Override
			public String getText(Object item) {
				CSSStylableElement element = CssSpyDialog.getCSSElement(item);
				return element.getLocalName() + " ("
						+ element.getNamespaceURI() + ")";
			}
		});

		TreeViewerColumn widgetClassColumn = new TreeViewerColumn(
				widgetTreeViewer, SWT.NONE);
		widgetClassColumn.getColumn().setText("CSS Class");
		widgetClassColumn.getColumn().setWidth(100);
		widgetClassColumn.setLabelProvider(new ColumnLabelProvider() {
			@Override
			public String getText(Object item) {
				CSSStylableElement element = CssSpyDialog.getCSSElement(item);
				if (element.getCSSClass() == null) {
					return null;
				}
				String classes[] = element.getCSSClass().split(" +");
				return classes.length <= 1 ? classes[0] : classes[0] + " (+"
						+ (classes.length - 1) + " others)";
			}

			@Override
			public String getToolTipText(Object item) {
				CSSStylableElement element = CssSpyDialog.getCSSElement(item);
				if (element == null) {
					return null;
				}
				StringBuilder sb = new StringBuilder();
				sb.append(element.getLocalName()).append(" (")
						.append(element.getNamespaceURI()).append(")");
				if (element.getCSSClass() != null) {
					sb.append("\nClasses:\n  ");
					Activator.join(sb, element.getCSSClass().split(" +"),
							"\n  ");
				}
				return sb.toString();
			}
		});

		TreeViewerColumn widgetIdColumn = new TreeViewerColumn(
				widgetTreeViewer, SWT.NONE);
		widgetIdColumn.getColumn().setWidth(100);
		widgetIdColumn.getColumn().setText("CSS Id");
		widgetIdColumn.setLabelProvider(new ColumnLabelProvider() {
			@Override
			public String getText(Object item) {
				CSSStylableElement element = CssSpyDialog.getCSSElement(item);
				return element.getCSSId();
			}
		});

		TreeColumnLayout widgetsTableLayout = new TreeColumnLayout();
		widgetsTableLayout.setColumnData(widgetTypeColumn.getColumn(),
				new ColumnWeightData(50));
		widgetsTableLayout.setColumnData(widgetIdColumn.getColumn(),
				new ColumnWeightData(40));
		widgetsTableLayout.setColumnData(widgetClassColumn.getColumn(),
				new ColumnWeightData(40));
		widgetsComposite.setLayout(widgetsTableLayout);

		// / HEADERS
		Composite container = new Composite(sashForm, SWT.NONE);
		container.setLayout(new GridLayout(2, true));

		Label lblCssProperties = new Label(container, SWT.NONE);
		lblCssProperties.setLayoutData(new GridData(SWT.CENTER, SWT.CENTER,
				false, false, 1, 1));
		lblCssProperties.setText("CSS Properties");

		Label lblCssRules = new Label(container, SWT.NONE);
		lblCssRules.setLayoutData(new GridData(SWT.CENTER, SWT.CENTER, false,
				false, 1, 1));
		lblCssRules.setText("CSS Rules");

		// // THE CSS PROPERTIES TABLE
		Composite propsComposite = new Composite(container, SWT.BORDER
				| SWT.H_SCROLL | SWT.V_SCROLL);
		GridData gridData = new GridData(SWT.FILL, SWT.FILL, true, true, 1, 1);
		gridData.minimumHeight = 50;
		propsComposite.setLayoutData(gridData);

		cssPropertiesViewer = new TableViewer(propsComposite, SWT.BORDER
				| SWT.V_SCROLL | SWT.FULL_SELECTION);
		cssPropertiesViewer
				.setContentProvider(new CSSPropertiesContentProvider());
		cssPropertiesViewer.getTable().setLinesVisible(true);
		cssPropertiesViewer.getTable().setHeaderVisible(true);
		cssPropertiesViewer.setComparator(new ViewerComparator());

		final TextCellEditor textCellEditor = new TextCellEditor(
				cssPropertiesViewer.getTable());
		TableViewerEditor
				.create(cssPropertiesViewer,
						new TableViewerFocusCellManager(cssPropertiesViewer,
								new FocusCellOwnerDrawHighlighter(
										cssPropertiesViewer)),
						new ColumnViewerEditorActivationStrategy(
								cssPropertiesViewer),
						ColumnViewerEditor.TABBING_HORIZONTAL
								| ColumnViewerEditor.TABBING_MOVE_TO_ROW_NEIGHBOR
								| ColumnViewerEditor.TABBING_VERTICAL
								| ColumnViewerEditor.KEYBOARD_ACTIVATION);


		TableViewerColumn propName = new TableViewerColumn(cssPropertiesViewer,
				SWT.NONE);
		propName.getColumn().setWidth(100);
		propName.getColumn().setText("Property");
		propName.setLabelProvider(new ColumnLabelProvider() {
			@Override
			public String getText(Object element) {
				return ((CSSPropertyProvider) element).getPropertyName();
			}
		});

		TableViewerColumn propValue = new TableViewerColumn(
				cssPropertiesViewer, SWT.NONE);
		propValue.getColumn().setWidth(100);
		propValue.getColumn().setText("Value");
		propValue.setLabelProvider(new ColumnLabelProvider() {
			@Override
			public String getText(Object element) {
				try {
					return ((CSSPropertyProvider) element).getValue();
				} catch (Exception e) {
					System.err.println("Error fetching property: " + element
							+ ": " + e);
					return null;
				}
			}
		});
		propValue.setEditingSupport(new EditingSupport(cssPropertiesViewer) {
			@Override
			protected CellEditor getCellEditor(Object element) {
				// do the fancy footwork here to return an appropriate editor to
				// the value-type
				return textCellEditor;
			}

			@Override
			protected boolean canEdit(Object element) {
				return true;
			}

			@Override
			protected Object getValue(Object element) {
				try {
					String value = ((CSSPropertyProvider) element).getValue();
					return value == null ? "" : value;
				} catch (Exception e) {
					return "";
				}
			}

			@Override
			protected void setValue(Object element, Object value) {
				try {
					if (value == null || ((String) value).trim().length() == 0) {
						return;
					}
					CSSPropertyProvider provider = (CSSPropertyProvider) element;
					provider.setValue((String) value);
				} catch (Throwable e) {
					MessageDialog.openError(getShell(), "Error",
							"Unable to set property:\n\n"
									+ e.getMessage());
				}
				cssPropertiesViewer.update(element, null);
			}
		});

		TableColumnLayout propsTableLayout = new TableColumnLayout();
		propsTableLayout.setColumnData(propName.getColumn(),
				new ColumnWeightData(50));
		propsTableLayout.setColumnData(propValue.getColumn(),
				new ColumnWeightData(50));
		propsComposite.setLayout(propsTableLayout);

		// / THE CSS RULES
		cssRules = new Text(container, SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL
				| SWT.MULTI);
		cssRules.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true, 1,
				1));

		// / THE CSS PROPERTIES TABLE (again)
		showUnsetProperties = new Button(container, SWT.CHECK);
		showUnsetProperties.setText("Show unset properties");

		// and for balance
		new Label(container, SWT.NONE);

		// / The listeners

		cssSearchBox.addModifyListener(new ModifyListener() {
			private Runnable updater;

			public void modifyText(ModifyEvent e) {
				display.timerExec(200, updater = new Runnable() {
					public void run() {
						if (updater == this) {
							performCSSSearch(cssSearchBox.getText());
						}
					}
				});
			}
		});
		cssSearchBox.addKeyListener(new KeyAdapter() {
			@Override
			public void keyPressed(KeyEvent e) {
				if (e.keyCode == SWT.ARROW_DOWN
						&& (e.stateMask & SWT.MODIFIER_MASK) == 0) {
					widgetTreeViewer.getControl().setFocus();
				}
			}
		});

		widgetTreeViewer
				.addSelectionChangedListener(new ISelectionChangedListener() {
					public void selectionChanged(SelectionChangedEvent event) {
						if (!event.getSelection().isEmpty()) {
							populate((Widget) ((StructuredSelection) event
									.getSelection()).getFirstElement());
						}
					}
				});
		if (isLive()) {
			container.addMouseMoveListener(new MouseMoveListener() {
				public void mouseMove(MouseEvent e) {
					update();
				}
			});
		}

		if (shouldDismissOnLostFocus()) {
			container.addFocusListener(new FocusAdapter() {
				@Override
				public void focusLost(FocusEvent e) {
					setReturnCode(Window.OK);
					close();
				}
			});
		}
		container.addKeyListener(new KeyAdapter() {
			public void keyPressed(KeyEvent e) {
				if (e.character == SWT.ESC) {
					cancelPressed();
				} else if (e.character == SWT.CR | e.character == SWT.LF) {
					okPressed();
				}
			}
		});

		outer.addDisposeListener(new DisposeListener() {
			public void widgetDisposed(DisposeEvent e) {
				dispose();
			}
		});

		showUnsetProperties.setSelection(true);
		showUnsetProperties.addSelectionListener(new SelectionAdapter() {
			@Override
			public void widgetSelected(SelectionEvent e) {
				if (showUnsetProperties.getSelection()) {
					cssPropertiesViewer.removeFilter(unsetPropertyFilter);
				} else {
					cssPropertiesViewer.addFilter(unsetPropertyFilter);
				}
			}
		});

		update();
		sashForm.setWeights(new int[] { 50, 50 });
		widgetTreeViewer.getControl().setFocus();
		return outer;
	}

	private String searchInProgress;

	private void performCSSSearch(String text) {
		disposeHighlights();
		widgetTreeViewer.collapseAll();
		if (text.trim().length() == 0) {
			return;
		}
		searchInProgress = text;
		CSSStylableElement element = getCSSElement(getShell(shown));
		if (element == null) {
			return;
		}

        CSSEngine engine = getCSSEngine(shown);
		try {
			SelectorList selectors = engine.parseSelectors(text);
			processCSSSearch(text, null, engine, selectors, element);
		} catch (IOException e) {
			e.printStackTrace();
		}

	}

	private void processCSSSearch(String text, String pseudo, CSSEngine engine,
			SelectorList selectors, CSSStylableElement element) {
		if (text != searchInProgress) {
			return;
		}
		boolean matched = false;
		for (int i = 0; i < selectors.getLength(); i++) {
			if (matched = engine.matches(selectors.item(i), element, pseudo)) {
				break;
			}
		}
		if (matched) {
			highlightWidget((Widget) element.getNativeWidget());
		}
		NodeList children = element.getChildNodes();
		for (int i = 0; i < children.getLength(); i++) {
			if (text != searchInProgress) {
				return;
			}
			processCSSSearch(text, pseudo, engine, selectors,
					(CSSStylableElement) children.item(i));
		}
	}

	protected void dispose() {
		disposeHighlights();
	}

	/**
	 * Create contents of the button bar.
	 * 
	 * @param parent
	 */
	@Override
	protected void createButtonsForButtonBar(Composite parent) {
		createButton(parent, IDialogConstants.OK_ID, IDialogConstants.OK_LABEL,
				true);
		createButton(parent, IDialogConstants.CANCEL_ID,
				IDialogConstants.CANCEL_LABEL, false);
	}

	/**
	 * Return the initial size of the dialog.
	 */
	@Override
	protected Point getInitialSize() {
		return new Point(600, 500);
	}
}