/*******************************************************************************
 * Copyright (c) 2015-2021 MINRES Technologies GmbH 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:
 *     MINRES Technologies GmbH - initial API and implementation
 *******************************************************************************/
package com.minres.scviewer.database.ui.swt.internal;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map.Entry;
import java.util.Optional;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ControlAdapter;
import org.eclipse.swt.events.ControlEvent;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.ScrollBar;

import com.google.common.collect.Lists;
import com.minres.scviewer.database.EventEntry;
import com.minres.scviewer.database.IEvent;
import com.minres.scviewer.database.IWaveform;
import com.minres.scviewer.database.RelationType;
import com.minres.scviewer.database.tx.ITx;
import com.minres.scviewer.database.tx.ITxEvent;
import com.minres.scviewer.database.ui.IWaveformStyleProvider;
import com.minres.scviewer.database.ui.IWaveformView;
import com.minres.scviewer.database.ui.IWaveformZoom;
import com.minres.scviewer.database.ui.TrackEntry;
import com.minres.scviewer.database.ui.ZoomKind;
import com.minres.scviewer.database.ui.swt.Constants;
import com.minres.scviewer.database.ui.swt.internal.slider.ZoomBar;

public class WaveformCanvas extends Canvas implements IWaveformZoom{

	public static final long ZOOM_FIT = -2;

	public static final long ZOOM_FULL = -1;

	private static final int INITIAL_ZOOM_BAR_MAX = 1000;
	
	private boolean doubleBuffering = true;

	IWaveformStyleProvider styleProvider;

	private int scaleMagnitude = 6;

	private long scaleFactor = Constants.POWERS_OF_TEN[scaleMagnitude];

	private long maxTime;

	protected Point origin; /* original size */

	protected int rulerHeight=40;

	protected List<IPainter> painterList;

	ITx currentSelection;

	private List<SelectionAdapter> selectionListeners;

	private RulerPainter rulerPainter;

	private TrackAreaPainter trackAreaPainter;

	private ArrowPainter arrowPainter;

	private List<CursorPainter> cursorPainters;

	private ZoomBar horizontal;

	private int[] lastHorSelection;
	
	private long sliderScaleFactor = 1;
	
	private ScrollBar vertical;

	HashMap<IWaveform, IWaveformPainter> wave2painterMap;

	public WaveformCanvas(final Composite parent, int style, IWaveformStyleProvider styleProvider, ZoomBar.IProvider scrollbarProvider) {
		super(parent, (style & ~SWT.H_SCROLL) | SWT.DOUBLE_BUFFERED | SWT.NO_BACKGROUND | SWT.V_SCROLL );
		this.styleProvider=styleProvider;
		addControlListener(new ControlAdapter() { /* resize listener. */
			@Override
			public void controlResized(ControlEvent event) {
				syncSb();
			}
		});
		addPaintListener((final PaintEvent event) -> paint(event.gc));
		painterList = new LinkedList<>();
		origin = new Point(0, 0);
		selectionListeners = new LinkedList<>();
		cursorPainters= new ArrayList<>();
		wave2painterMap=new HashMap<>();

		horizontal = scrollbarProvider.getScrollBar();
		vertical = getVerticalBar();
		initScrollBars();
		// order is important: it is bottom to top
		trackAreaPainter=new TrackAreaPainter(this);
		painterList.add(trackAreaPainter);
		arrowPainter=new ArrowPainter(this, IWaveformView.NEXT_PREV_IN_STREAM);
		painterList.add(arrowPainter);
		rulerPainter=new RulerPainter(this);
		painterList.add(rulerPainter);
		CursorPainter cp = new CursorPainter(this, getScale() * 10, cursorPainters.size()-1);
		painterList.add(cp);
		cursorPainters.add(cp);
		CursorPainter marker = new CursorPainter(this, getScale() * 100, cursorPainters.size()-1);
		painterList.add(marker);
		cursorPainters.add(marker);
		wave2painterMap=new HashMap<>();
	}

	public void addCursoPainter(CursorPainter cursorPainter){
		painterList.add(cursorPainter);
		cursorPainters.add(cursorPainter);
	}

	public void setHighliteRelation(RelationType relationType){
		if(arrowPainter!=null){
			boolean redraw = arrowPainter.getHighlightType()!=relationType; 
			arrowPainter.setHighlightType(relationType);
			if(redraw) redraw();
		}
	}

	public Point getOrigin() {
		return origin;
	}

	public int getWidth() {
		return getClientArea().width; 
	}
	public void setOrigin(Point origin) {
		setOrigin(origin.x, origin.y);
	}

	public void setOrigin(int x, int y) {
		checkWidget();
		origin.x = x;
		origin.y = y;
		syncSb();
	}

	@Override
	public long getMaxTime() {
		return maxTime;
	}

	public void setMaxTime(long maxTime) {
		this.maxTime = maxTime;
		if(maxTime>INITIAL_ZOOM_BAR_MAX) {
			long maxBarTime = maxTime;
			while(maxBarTime>Integer.MAX_VALUE)	maxBarTime/=1000;
			horizontal.setMaximum((int) maxBarTime);
		}
		sliderScaleFactor = maxTime/horizontal.getMaximum();
		syncSb();
	}

	@Override
	public long getScale() {
		return scaleFactor;
	}

	@Override
	public void setScale(long factor) {
		setScalingFactor(factor, (getMaxVisibleTime()+getMinVisibleTime())/2);
	}

	@Override
	public void setVisibleRange(long startTime, long endTime) {
		assert(startTime<endTime);
		long time_diff = endTime-startTime;
		long factor = (time_diff*11/10)/getClientArea().width;
		setScalingFactor(factor, startTime+time_diff/2);
	}

	//@Override
	public void setScalingFactor(long factor, long centerTime) {
		Rectangle clientArea = getClientArea();
		long clientAreaWidth = clientArea.width;
		long maxFactor=maxTime/clientAreaWidth;
		if(factor<0) {
			if(factor== ZOOM_FIT) {
				long cTime = getCursorPainters().get(0).getTime();
				long time_diff = centerTime>cTime?centerTime-cTime:cTime-centerTime;
				centerTime = (centerTime>cTime?cTime:centerTime)+time_diff/2;
				factor = (time_diff*11/10)/clientAreaWidth;
			} else if(factor== ZOOM_FULL)
				factor = maxFactor;
		} 
		if(factor==0)
			factor=1;
		else if(factor>maxFactor)
			factor=maxFactor;
		if(factor!=getScale() || (getMaxVisibleTime()+getMinVisibleTime()/2) != centerTime) {
			updateScaleFactor(factor);
			ITx tx = arrowPainter.getTx();
			arrowPainter.setTx(null);
			/*
			 * xc = tc/oldScaleFactor
			 * xoffs = xc+origin.x
			 * xcn = tc/newScaleFactor
			 * t0n = (xcn-xoffs)*getScale()
			 */
			long xoffs = clientAreaWidth/2;
			long xcn=centerTime/getScale(); // new total x-offset
			long originX=xcn-xoffs;
			if(originX>0) {
				origin.x=(int) -originX; // new cursor time offset relative to left border
			}else {
				origin.x=0;
			}
			syncSb();
			arrowPainter.setTx(tx);    		
			redraw();
		}
	}

	private void updateScaleFactor(long factor) {
		scaleFactor = factor;
		scaleMagnitude = 0;
		for(int i=Constants.POWERS_OF_TEN.length-1; i>0; i--) {
			if(scaleFactor>=Constants.POWERS_OF_TEN[i]) {
				scaleMagnitude = i;
				break;
			}
		}
	}

	@Override
	public String timeToString(long time) {
		int idx = scaleMagnitude/3;
		double fTime = (double)time/Constants.UNIT_MULTIPLIER[idx];
		return Constants.getTimeFormatForLevel(idx).format(fTime)+Constants.UNIT_STRING[idx];
	}

	public long getTimeForOffset(int xOffset){
		return (xOffset-origin.x) * getScale();
	}

	public void addPainter(IPainter painter) {
		painterList.add(painter);
		redraw();
	}

	public void removePainter(IPainter painter) {
		painterList.remove(painter);
		redraw();
	}

	public void clearAllWaveformPainter() {
		clearAllWaveformPainter(true);
	}

	void clearAllWaveformPainter(boolean update) {
		trackAreaPainter.trackVerticalOffset.clear();
		wave2painterMap.clear();
		if(update) syncSb();
	}

	public void addWaveformPainter(IWaveformPainter painter) {
		addWaveformPainter(painter, true);
	}

	void addWaveformPainter(IWaveformPainter painter, boolean update) {
		trackAreaPainter.addTrackPainter(painter);
		wave2painterMap.put(painter.getTrackEntry().waveform, painter);
		if(update) syncSb();
	}

	public List<CursorPainter> getCursorPainters() {
		return cursorPainters;
	}

	/* Initialize the scrollbar and register listeners. */
	private void initScrollBars() {
		horizontal.setEnabled(false);
		horizontal.setVisible(true);
		horizontal.addSelectionListener(new SelectionAdapter() {
			@Override
			public void widgetSelected(SelectionEvent event) {
				if (!painterList.isEmpty()) {
					int[] sel = horizontal.getSelection();
					long lowerTime = sel[0]*sliderScaleFactor;
					long upperTime = sel[1]*sliderScaleFactor;
					if(sel[1]-sel[0] != lastHorSelection[1]-lastHorSelection[0]) {
						long time_diff = upperTime-lowerTime;
						long factor = time_diff/getClientArea().width;
						setScalingFactor(factor, lowerTime+time_diff/2);
					} else {
						origin.x = -(int) (lowerTime/getScale());
						WaveformCanvas.this.getDisplay().asyncExec(() -> {redraw();});
					}
					lastHorSelection=sel;
				}
			}
		});
		horizontal.setMinimum(0);
		horizontal.setMaximum(INITIAL_ZOOM_BAR_MAX);
		lastHorSelection = horizontal.getSelection();
		
		vertical.setEnabled(false);
		vertical.setVisible(true);
		vertical.addSelectionListener(new SelectionAdapter() {
			@Override
			public void widgetSelected(SelectionEvent event) {
				if (!painterList.isEmpty()) {
					origin.y=-vertical.getSelection();
					fireSelectionEvent();
					WaveformCanvas.this.getDisplay().asyncExec(() -> {redraw();});
				}
			}
		});
	}

	/**
	 * Synchronize the scrollbar with the image. If the transform is out of
	 * range, it will correct it. This function considers only following factors
	 * :<b> transform, image size, client area</b>.
	 */
	public void syncSb() {
		if (!painterList.isEmpty()) {
			syncHSb();
			syncVSb();
			fireSelectionEvent();
		}
		redraw();
	}

	private void syncVSb() {
		Rectangle clientArea=getClientArea();
		int height = trackAreaPainter.getHeight(); // incl. Ruler
		int clientHeight = clientArea.height;
		vertical.setIncrement(clientHeight / 100);
		vertical.setPageIncrement(clientHeight/2);
		if (height > clientHeight) { /* image is higher than client area */
			vertical.setMinimum(0);
			vertical.setMaximum(height);
			vertical.setEnabled(true);
			if ( -origin.y > vertical.getMaximum() - clientHeight) {
				origin.y = -vertical.getMaximum() + clientHeight;
			}
		} else { /* image is less higher than client area */
			vertical.setMaximum(clientHeight);
			vertical.setEnabled(false);
			if ( -origin.y > vertical.getMaximum() - height) {
				origin.y = -vertical.getMaximum() + height;
			}
		}
		vertical.setThumb(clientHeight);
		vertical.setSelection(-origin.y);
	}

	private void syncHSb() {
		horizontal.setEnabled(wave2painterMap.size()>0);
		Rectangle clientArea=getClientArea();
		int clientWidth = clientArea.width;
		if(sliderScaleFactor>0) {
			int lower = (int) ( (           -origin.x  * getScale()) / sliderScaleFactor);
			int upper = (int) (((clientWidth-origin.x) * getScale()) / sliderScaleFactor);
			lastHorSelection = new int[] {Math.max(lower,0), Math.min(upper, horizontal.getMaximum())};
			horizontal.setSelection(lastHorSelection);
		}
		long width = maxTime / getScale();
		horizontal.setButtonsEnabled(width > clientWidth);
	}

	/* Paint function */
	private void paint(GC gc) {
		Point pt = getSize();
		if(pt.x==0  || pt.y==0) return;
		Rectangle clientRect = getClientArea(); /* Canvas' painting area */
		GC thisGc = gc;
		Image dBackingImg = null;
		if(doubleBuffering) {
			dBackingImg = new Image(getDisplay(), pt.x, pt.y);
			thisGc = new GC(dBackingImg);
			thisGc.setBackground(gc.getBackground());
			thisGc.setForeground(gc.getForeground());
			thisGc.setFont(gc.getFont());

		}
		Projection p = new Projection(thisGc);
		p.setTranslation(origin);
		if (!painterList.isEmpty() ) {
			for (IPainter painter : painterList)
				painter.paintArea(p, clientRect);
		} else {
			gc.fillRectangle(clientRect);
			initScrollBars();
		}
		if(doubleBuffering) {
			gc.drawImage(dBackingImg, 0, 0);
			if(dBackingImg!=null) dBackingImg.dispose();
			thisGc.dispose();
		}
	}

	public List<Object> getElementsAt(Point point) {
		LinkedList<Object> result=new LinkedList<>();
		for (IPainter p : Lists.reverse(painterList)) {
			if (p instanceof TrackAreaPainter) {
				int y = point.y - origin.y;
				int x = point.x - origin.x;
				Entry<Integer, IWaveformPainter> entry = trackAreaPainter.trackVerticalOffset.floorEntry(y);
				if (entry != null) {
					if (entry.getValue() instanceof StreamPainter) {
						ITx tx = ((StreamPainter) entry.getValue()).getClicked(new Point(x, y - entry.getKey()));
						if(tx!=null)
							result.add(tx);
					} 
					result.add(entry.getValue().getTrackEntry());
				}
			} else if (p instanceof CursorPainter) {
				if (Math.abs(point.x - origin.x - ((CursorPainter) p).getTime()/getScale()) < 2) {
					result.add(p);
				}
			}
		}
		return result;
	}

	public List<Object> getEntriesAtPosition(IWaveform iWaveform, int i) {
		LinkedList<Object> result=new LinkedList<>();
		int x = i - origin.x;
		for(IWaveformPainter p: wave2painterMap.values()){
			if (p instanceof StreamPainter && ((StreamPainter)p).getStream()==iWaveform) {
				result.add(((StreamPainter) p).getClicked(new Point(x, styleProvider.getTrackHeight()/2)));
			}
		}
		return result;
	}

	public void setSelected(ITx currentSelection) {
		this.currentSelection = currentSelection;
		if (currentSelection != null)
			reveal(currentSelection);
		arrowPainter.setTx(currentSelection);
		redraw();
	}

	public void reveal(ITx tx) {
		int lower = (int) (tx.getBeginTime() / getScale());
		int higher = (int) (tx.getEndTime() / getScale());
		Point size = getSize();
		size.x -= vertical.getSize().x + 2;
		size.y -= horizontal.getSize().y;
		if (lower < -origin.x) {
			setOrigin(-lower, origin.y);
		} else if (higher > (size.x - origin.x)) {
			setOrigin(size.x - higher, origin.y);
		}
		for (IWaveformPainter painter : wave2painterMap.values()) {
			if (painter instanceof StreamPainter && ((StreamPainter) painter).getStream() == tx.getStream()) {
				EventEntry entry = tx.getStream().getEvents().floorEntry(tx.getBeginTime());
				Optional<IEvent> res = Arrays.stream(entry.events).filter(e -> ((ITxEvent)e).getTransaction().equals(tx)).findFirst();
				if(res.isPresent()) {
					int top = painter.getVerticalOffset() + styleProvider.getTrackHeight() * ((ITxEvent)res.get()).getRowIndex();
					int bottom = top + styleProvider.getTrackHeight();
					if (top < -origin.y) {
						setOrigin(origin.x, -(top-styleProvider.getTrackHeight()));
					} else if (bottom > (size.y - origin.y)) {
						setOrigin(origin.x, size.y - bottom);
					}
				}
			}
		}
	}

	public void reveal(IWaveform waveform) {
		for (IWaveformPainter painter : wave2painterMap.values()) {
			TrackEntry te = painter.getTrackEntry();
			if(te.waveform == waveform) {
				Point size = getSize();
				size.y -=+rulerHeight;
				if((horizontal.getStyle()&SWT.SCROLLBAR_OVERLAY)!=0 && horizontal.isVisible())
					size.y-=  horizontal.getSize().y;
				int top = te.vOffset;
				int bottom = top + styleProvider.getTrackHeight();
				if (top < -origin.y) {
					setOrigin(origin.x, -(top-styleProvider.getTrackHeight()));
				} else if (bottom > (size.y - origin.y)) {
					setOrigin(origin.x, size.y - bottom);
				}
			}
		}
	}

	public void reveal(long time) {
		int scaledTime = (int) (time / getScale());
		Point size = getSize();
		size.x -= vertical.getSize().x + 2;
		size.y -= horizontal.getSize().y;
		if (scaledTime < -origin.x) {
			setOrigin(-scaledTime+10, origin.y);
		} else if (scaledTime > (size.x - origin.x)) {
			setOrigin(size.x - scaledTime-30, origin.y);
		}
	}

	@Override
	public void centerAt(long time) {
		int scaledTime = (int) (time / getScale());
		int newX = -scaledTime+getWidth()/2;
		setOrigin(newX>0?0:newX, origin.y);
	}

	public int getRulerHeight() {
		return rulerHeight;
	}

	public void setRulerHeight(int rulerHeight) {
		this.rulerHeight = rulerHeight;
	}

	public void addSelectionListener(SelectionAdapter selectionAdapter) {
		selectionListeners.add(selectionAdapter);
	}

	public void removeSelectionListener(SelectionAdapter selectionAdapter) {
		selectionListeners.remove(selectionAdapter);
	}

	/**
	 * 
	 */
	protected void fireSelectionEvent() {
		Event e = new Event();
		e.widget = this;
		e.detail=SWT.SELECTED;
		e.type=SWT.Selection;
		SelectionEvent ev = new SelectionEvent(e);
		ev.x = origin.x;
		ev.y = origin.y;
		for (SelectionAdapter a : selectionListeners) {
			a.widgetSelected(ev);
		}
	}


	@Override
	public long getMaxVisibleTime() {
		return (getClientArea().width-origin.x)*getScale();
	}

	@Override
	public long getMinVisibleTime() {
		return -origin.x * getScale();
	}

	@Override
	public void setMinVisibleTime(long time) {
		long duration = getMaxVisibleTime()-getMinVisibleTime();
		if(time>0) {
			if((time+duration)<getMaxTime()) {
				int scaledTime = (int) (time / getScale());
				setOrigin(-scaledTime, origin.y);
			}
		} else {
			setOrigin(0, origin.y);
		}
	}

	@Override
	public void zoom(ZoomKind kind) {
		switch(kind) {
		case IN:
			setScale(getScale()/2);
			break;
		case OUT:
			setScale(getScale()*2);			
			break;
		case FIT:
			setScalingFactor(WaveformCanvas.ZOOM_FIT, cursorPainters.get(1).getTime());
			break;
		case FULL:
			setScale(WaveformCanvas.ZOOM_FULL);
			break;
		}
	}

	public void setStyleProvider(IWaveformStyleProvider styleProvider) {
		this.styleProvider=styleProvider;
		redraw();
	}

	public int getScaleMagnitude() {
		return scaleMagnitude;
	}

}