/**
 * Copyright winterwell Mathematics Ltd.
 * @author Daniel Winterstein
 * 11 Jan 2007
 */
package winterwell.markdown.editors;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;

import org.eclipse.jface.action.Action;
import org.eclipse.jface.action.IAction;
import org.eclipse.jface.action.IToolBarManager;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DocumentEvent;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IDocumentListener;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.events.KeyListener;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.ui.IActionBars;
import org.eclipse.ui.part.IPageSite;
import org.eclipse.ui.texteditor.IDocumentProvider;
import org.eclipse.ui.views.contentoutline.ContentOutlinePage;

import winterwell.markdown.pagemodel.MarkdownPage;
import winterwell.markdown.pagemodel.MarkdownPage.Header;
import winterwell.markdown.pagemodel.MarkdownPage.KLineType;
import winterwell.utils.StrUtils;
import winterwell.utils.Utils;
import winterwell.utils.web.WebUtils;

/**
 *
 *
 * @author Daniel Winterstein
 */
public final class MarkdownContentOutlinePage extends ContentOutlinePage {

	/**
	 *
	 *
	 * @author Daniel Winterstein
	 */
	public final class ContentProvider implements ITreeContentProvider,
			IDocumentListener {

		// protected final static String SEGMENTS= "__md_segments";
		// //$NON-NLS-1$
		// protected IPositionUpdater fPositionUpdater= new
		// DefaultPositionUpdater(SEGMENTS);
		private MarkdownPage fContent;
		// protected List fContent= new ArrayList(10);
		private MarkdownEditor fTextEditor;

		private void parse() {
			fContent = fTextEditor.getMarkdownPage();
		}

		/*
		 * @see IContentProvider#inputChanged(Viewer, Object, Object)
		 */
		public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
			// Detach from old
			if (oldInput != null) {
				IDocument document = fDocumentProvider.getDocument(oldInput);
				if (document != null) {
					document.removeDocumentListener(this);
				}
			}
			fContent = null;
			// Attach to new
			if (newInput == null)
				return;
			IDocument document = fDocumentProvider.getDocument(newInput);
			if (document == null)
				return;
			fTextEditor = MarkdownEditor.getEditor(document);
			document.addDocumentListener(this);
			parse();
		}

		/*
		 * @see IContentProvider#dispose
		 */
		public void dispose() {
			fContent = null;
		}

		/*
		 * @see IContentProvider#isDeleted(Object)
		 */
		public boolean isDeleted(Object element) {
			return false;
		}

		/*
		 * @see IStructuredContentProvider#getElements(Object)
		 */
		public Object[] getElements(Object element) {
			return fContent.getHeadings(null).toArray();
		}

		/*
		 * @see ITreeContentProvider#hasChildren(Object)
		 */
		public boolean hasChildren(Object element) {
			if (element == fInput) {
				return true;
			}
			if (element instanceof MarkdownPage.Header) {
				MarkdownPage.Header header = (MarkdownPage.Header) element;
				return header.getSubHeaders().size() > 0;
			}
			;
			return false;
		}

		/*
		 * @see ITreeContentProvider#getParent(Object)
		 */
		public Object getParent(Object element) {
			if (!(element instanceof MarkdownPage.Header))
				return null;
			return ((MarkdownPage.Header) element).getParent();
		}

		/*
		 * @see ITreeContentProvider#getChildren(Object)
		 */
		public Object[] getChildren(Object element) {
			if (element == fInput) {
				return fContent.getHeadings(null).toArray();
			}
			if (!(element instanceof MarkdownPage.Header))
				return null;
			return ((MarkdownPage.Header) element).getSubHeaders().toArray();
		}

		public void documentAboutToBeChanged(DocumentEvent event) {
			// nothing
		}

		public void documentChanged(DocumentEvent event) {
			parse();
			update();
		}
	}

	private Object fInput = null;
	private final IDocumentProvider fDocumentProvider;
	private final MarkdownEditor fTextEditor;
	protected boolean showWordCounts;
	private List<Header> selectedHeaders;

	/**
	 * @param documentProvider
	 * @param mdEditor
	 */
	public MarkdownContentOutlinePage(IDocumentProvider documentProvider,
			MarkdownEditor mdEditor) {
		fDocumentProvider = documentProvider;
		fTextEditor = mdEditor;
	}

	/*
	 * (non-Javadoc) Method declared on ContentOutlinePage
	 */
	@Override
	public void createControl(Composite parent) {
		super.createControl(parent);
		TreeViewer viewer = getTreeViewer();
		viewer.setContentProvider(new ContentProvider());
		// Add word count annotations
		viewer.setLabelProvider(new LabelProvider() {
			@Override
			public String getText(Object element) {
				if (!(element instanceof MarkdownPage.Header))
					return super.getText(element);
				Header header = ((MarkdownPage.Header) element);
				String hText = header.toString();
				if (!showWordCounts)
					return hText;
				IRegion region = getRegion(header);
				String text;
				try {
					text = fTextEditor.getDocument().get(region.getOffset(),
							region.getLength());
					text = WebUtils.stripTags(text);
					text = text.replaceAll("#", "").trim();
					assert text.startsWith(hText);
					text = text.substring(hText.length());
					int wc = StrUtils.wordCount(text);
					return hText + " (" + wc + ":" + text.length() + ")";
				} catch (BadLocationException e) {
					return hText;
				}
			}
		});
		viewer.addSelectionChangedListener(this);

		if (fInput != null)
			viewer.setInput(fInput);

		// Buttons
		IPageSite site = getSite();
		IActionBars bars = site.getActionBars();
		IToolBarManager toolbar = bars.getToolBarManager();
		// Word count action
		Action action = new Action("123", IAction.AS_CHECK_BOX) {
			@Override
			public void run() {
				showWordCounts = isChecked();
				update();
			}
		};
		action.setToolTipText("Show/hide section word:character counts");
		toolbar.add(action);
		// +/- actions
		action = new Action("<") {
			@Override
			public void run() {
				doPromoteDemote(-1);
			}
		};
		action.setToolTipText("Promote the selected section\n -- move it up a level.");
		toolbar.add(action);
		//
		action = new Action(">") {
			@Override
			public void run() {
				doPromoteDemote(1);
			}
		};
		action.setToolTipText("Demote the selected section\n -- move it down a level.");
		toolbar.add(action);
		// up/down actions
		action = new Action("/\\") {
			@Override
			public void run() {
				try {
					doMove(-1);
				} catch (BadLocationException e) {
					throw Utils.runtime(e);
				}
			}
		};
		action.setToolTipText("Move the selected section earlier");
		toolbar.add(action);
		//
		action = new Action("\\/") {
			@Override
			public void run() {
				try {
					doMove(1);
				} catch (BadLocationException e) {
					throw Utils.runtime(e);
				}
			}
		};
		action.setToolTipText("Move the selected section later");
		toolbar.add(action);
		// Collapse
		ImageDescriptor id = ImageDescriptor.createFromFile(getClass(), "collapseall.gif");
		action = new Action("collapse", id) {
			@Override
			public void run() {
				doCollapseAll();
			}
		};
		action.setImageDescriptor(id);
		action.setToolTipText("Collapse outline tree");
		toolbar.add(action);
		// Sync
		id = ImageDescriptor.createFromFile(getClass(), "synced.gif");
		action = new Action("sync") {
			@Override
			public void run() {
				try {
					doSyncToEditor();
				} catch (BadLocationException e) {
					throw Utils.runtime(e);
				}
			}
		};
		action.setImageDescriptor(id);
		action.setToolTipText("Link with editor");
		toolbar.add(action);
		// Add edit ability
		viewer.getControl().addKeyListener(new KeyListener() {
			public void keyPressed(KeyEvent e) {
				if (e.keyCode==SWT.F2) {
					doEditHeader();
				}
			}
			public void keyReleased(KeyEvent e) {
				//
			}
		});
	}

	/**
	 * @throws BadLocationException
	 *
	 */
	protected void doSyncToEditor() throws BadLocationException {
		TreeViewer viewer = getTreeViewer();
		if (viewer == null) return;
		// Get header
		MarkdownPage page = fTextEditor.getMarkdownPage();
		int caretOffset = fTextEditor.getViewer().getTextWidget().getCaretOffset();
		IDocument doc = fTextEditor.getDocument();
		int line = doc.getLineOfOffset(caretOffset);
		List<KLineType> lineTypes = page.getLineTypes();
		for(; line>-1; line--) {
			KLineType lt = lineTypes.get(line);
			if (lt.toString().startsWith("H")) break;
		}
		if (line<0) return;
		Header header = (Header) page.getPageObject(line);
		// Set
		IStructuredSelection selection = new StructuredSelection(header);
		viewer.setSelection(selection , true);
	}

	void doEditHeader() {
		TreeViewer viewer = getTreeViewer();
		viewer.editElement(selectedHeaders.get(0), 0);
	}

	protected void doCollapseAll() {
		TreeViewer viewer = getTreeViewer();
		if (viewer == null) return;
//		Control control = viewer.getControl();
//		if (control != null && !control.isDisposed()) {
//			control.setRedraw(false);
		viewer.collapseAll();
//			control.setRedraw(true);
//		}
	}

	/**
	 * Move the selected sections up/down
	 * @param i 1 or -1. 1==move later, -1=earlier
	 * @throws BadLocationException
	 */
	protected void doMove(int i) throws BadLocationException {
		assert i==1 || i==-1;
		if (selectedHeaders == null || selectedHeaders.size() == 0)
			return;
		// Get text region to move
		MarkdownPage.Header first = selectedHeaders.get(0);
		MarkdownPage.Header last = selectedHeaders.get(selectedHeaders.size()-1);
		int start = fTextEditor.getDocument().getLineOffset(
				first.getLineNumber());
		IRegion r = getRegion(last);
		int end = r.getOffset() + r.getLength();
		int length = end - start;
		// Get new insertion point
		int insert;
		if (i==1) {
			Header nextSection = last.getNext();
			if (nextSection==null) return;
			IRegion nr = getRegion(nextSection);
			insert = nr.getOffset()+nr.getLength();
		} else {
			Header prevSection = first.getPrevious();
			if (prevSection==null) return;
			IRegion nr = getRegion(prevSection);
			insert = nr.getOffset();
		}
		// Get text
		String text = fTextEditor.getDocument().get();
		// Move text
		String section = text.substring(start, end);
		String pre, post;
		if (i==1) {
			pre = text.substring(0, start) + text.substring(end, insert);
			post = text.substring(insert);
		} else {
			pre = text.substring(0, insert);
			post = text.substring(insert,start)+text.substring(end);
		}
		text =  pre + section + post;
		assert text.length() == fTextEditor.getDocument().get().length() :
			text.length()-fTextEditor.getDocument().get().length()+" chars gained/lost";
		// Update doc
		fTextEditor.getDocument().set(text);
	}

	/**
	 * Does not support -------- / ========= underlining, only # headers
	 * @param upDown 1 for demote (e.g. h2 -> h3), -1 for promote (e.g. h2 -> h1)
	 */
	protected void doPromoteDemote(int upDown) {
		assert upDown==1 || upDown==-1;
		if (selectedHeaders == null || selectedHeaders.size() == 0)
			return;
		HashSet<Header> toAdjust = new HashSet<Header>(selectedHeaders);
		HashSet<Header> adjusted = new HashSet<Header>();
		// Adjust
		MarkdownPage mdPage = fTextEditor.getMarkdownPage();
		List<String> lines = new ArrayList<String>(mdPage.getText());
		while(toAdjust.size() != 0) {
			Header h = toAdjust.iterator().next();
			toAdjust.remove(h);
			adjusted.add(h);
			String line = lines.get(h.getLineNumber());
			if (upDown==-1) {
				if (h.getLevel() == 1) return; // Level 1; can't promote
				if (line.startsWith("##")) line = line.substring(1);
				else {
					return; // TODO support for ------ / ========
				}
			} else line = "#" + line;
			int ln = h.getLineNumber();
			lines.set(ln, line);
			// kids
			ArrayList<Header> kids = new ArrayList<Header>(h.getSubHeaders());
			for (Header header : kids) {
				if ( ! adjusted.contains(header)) toAdjust.add(header);
			}
		}
		// Set
		StringBuilder sb = new StringBuilder();
		for (String line : lines) {
			sb.append(line);
		}
		fTextEditor.getDocument().set(sb.toString());
	}

	/**
	 * The region of text for this header. This includes the header itself.
	 * @param header
	 * @return
	 * @throws BadLocationException
	 */
	protected IRegion getRegion(Header header) {
		try {
			IDocument doc = fTextEditor.getDocument();
			// Line numbers
			int start = header.getLineNumber();
			Header next = header.getNext();
			int end;
			if (next != null) {
				end = next.getLineNumber() - 1;
			} else {
				end = doc.getNumberOfLines() - 1;
			}
			int offset = doc.getLineOffset(start);
			IRegion ei = doc.getLineInformation(end);
			int length = ei.getOffset() + ei.getLength() - offset;
			return new Region(offset, length);
		} catch (BadLocationException ex) {
			throw Utils.runtime(ex);
		}
	}

	/*
	 * (non-Javadoc) Method declared on ContentOutlinePage
	 */
	@Override
	public void selectionChanged(SelectionChangedEvent event) {
		super.selectionChanged(event);
		selectedHeaders = null;
		ISelection selection = event.getSelection();
		if (selection.isEmpty())
			return;
		if (!(selection instanceof IStructuredSelection))
			return;
		try {
			IStructuredSelection strucSel = (IStructuredSelection) selection;
			Object[] sections = strucSel.toArray();
			selectedHeaders = (List) Arrays.asList(sections);
			MarkdownPage.Header first = (Header) sections[0];
			MarkdownPage.Header last = (Header) sections[sections.length - 1];
			int start = fTextEditor.getDocument().getLineOffset(
					first.getLineNumber());
			int length;
			if (first == last) {
				length = fTextEditor.getDocument().getLineLength(
						first.getLineNumber());
			} else {
				IRegion r = getRegion(last);
				int end = r.getOffset() + r.getLength();
				length = end - start;
			}
			fTextEditor.setHighlightRange(start, length, true);
		} catch (Exception x) {
			System.out.println(x.getStackTrace());
			fTextEditor.resetHighlightRange();
		}
	}

	/**
	 * Sets the input of the outline page
	 *
	 * @param input
	 *            the input of this outline page
	 */
	public void setInput(Object input) {
		fInput = input;
		update();
	}

	/**
	 * Updates the outline page.
	 */
	public void update() {
		TreeViewer viewer = getTreeViewer();

		if (viewer != null) {
			Control control = viewer.getControl();
			if (control != null && !control.isDisposed()) {
				control.setRedraw(false);
				viewer.setInput(fInput);
				viewer.expandAll();
				control.setRedraw(true);
			}
		}
	}

}