/*
 * Copyright (C) 2008, 2014 Shawn O. Pearce <spearce@spearce.org>
 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * - Neither the name of the Eclipse Foundation, Inc. nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 */

package org.eclipse.jgit.revplot;

import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.revwalk.RevFlag;

Basic commit graph renderer for graphical user interfaces.

Lanes are drawn as columns left-to-right in the graph, and the commit short
message is drawn to the right of the lane lines for this cell. It is assumed
that the commits are being drawn as rows of some sort of table.

Client applications can subclass this implementation to provide the necessary
drawing primitives required to display a commit graph. Most of the graph
layout is handled by this class, allowing applications to implement only a
handful of primitive stubs.

This class is suitable for us within an AWT TableCellRenderer or within a SWT
PaintListener registered on a Table instance. It is meant to rubber stamp the
graphics necessary for one row of a plotted commit list.
 Subclasses should call paintCommit(PlotCommit, int) after they have otherwise configured their instance to draw one commit into the current location. 

All drawing methods assume the coordinate space for the current commit's cell
starts at (upper left corner is) 0,0. If this is not true (like say in SWT)
the implementation must perform the cell offset computations within the
various draw methods.
Type parameters:
<TLane> – 
           type of lane being used by the application.
<TColor> – 
           type of color object used by the graphics library./**
 * Basic commit graph renderer for graphical user interfaces.
 * <p>
 * Lanes are drawn as columns left-to-right in the graph, and the commit short
 * message is drawn to the right of the lane lines for this cell. It is assumed
 * that the commits are being drawn as rows of some sort of table.
 * <p>
 * Client applications can subclass this implementation to provide the necessary
 * drawing primitives required to display a commit graph. Most of the graph
 * layout is handled by this class, allowing applications to implement only a
 * handful of primitive stubs.
 * <p>
 * This class is suitable for us within an AWT TableCellRenderer or within a SWT
 * PaintListener registered on a Table instance. It is meant to rubber stamp the
 * graphics necessary for one row of a plotted commit list.
 * <p>
 * Subclasses should call {@link #paintCommit(PlotCommit, int)} after they have
 * otherwise configured their instance to draw one commit into the current
 * location.
 * <p>
 * All drawing methods assume the coordinate space for the current commit's cell
 * starts at (upper left corner is) 0,0. If this is not true (like say in SWT)
 * the implementation must perform the cell offset computations within the
 * various draw methods.
 *
 * @param <TLane>
 *            type of lane being used by the application.
 * @param <TColor>
 *            type of color object used by the graphics library.
 */
public abstract class AbstractPlotRenderer<TLane extends PlotLane, TColor> {
	private static final int LANE_WIDTH = 14;

	private static final int LINE_WIDTH = 2;

	private static final int LEFT_PAD = 2;

	
Paint one commit using the underlying graphics library.
Params:
commit – 
           the commit to render in this cell. Must not be null.
h – 
           total height (in pixels) of this cell./**
	 * Paint one commit using the underlying graphics library.
	 *
	 * @param commit
	 *            the commit to render in this cell. Must not be null.
	 * @param h
	 *            total height (in pixels) of this cell.
	 */
	@SuppressWarnings("unchecked")
	protected void paintCommit(PlotCommit<TLane> commit, int h) {
		final int dotSize = computeDotSize(h);
		final TLane myLane = commit.getLane();
		final int myLaneX = laneC(myLane);
		final TColor myColor = laneColor(myLane);

		int maxCenter = myLaneX;
		for (TLane passingLane : (TLane[]) commit.passingLanes) {
			final int cx = laneC(passingLane);
			final TColor c = laneColor(passingLane);
			drawLine(c, cx, 0, cx, h, LINE_WIDTH);
			maxCenter = Math.max(maxCenter, cx);
		}

		final int dotX = myLaneX - dotSize / 2 - 1;
		final int dotY = (h - dotSize) / 2;

		final int nParent = commit.getParentCount();
		if (nParent > 0) {
			drawLine(myColor, myLaneX, h, myLaneX, (h + dotSize) / 2,
					LINE_WIDTH);

			for (PlotLane mergingLane : commit.mergingLanes) {
				final TLane pLane = (TLane) mergingLane;
				final TColor pColor = laneColor(pLane);
				final int cx = laneC(pLane);
				if (Math.abs(myLaneX - cx) > LANE_WIDTH) {
					final int ix;
					if (myLaneX < cx) {
						ix = cx - LANE_WIDTH / 2;
					} else {
						ix = cx + LANE_WIDTH / 2;
					}

					drawLine(pColor, myLaneX, h / 2, ix, h / 2, LINE_WIDTH);
					drawLine(pColor, ix, h / 2, cx, h, LINE_WIDTH);
				} else
					drawLine(pColor, myLaneX, h / 2, cx, h, LINE_WIDTH);
				maxCenter = Math.max(maxCenter, cx);
			}
		}


		if (commit.getChildCount() > 0) {
			for (PlotLane forkingOffLane : commit.forkingOffLanes) {
				final TLane childLane = (TLane) forkingOffLane;
				final TColor cColor = laneColor(childLane);
				final int cx = laneC(childLane);
				if (Math.abs(myLaneX - cx) > LANE_WIDTH) {
					final int ix;
					if (myLaneX < cx) {
						ix = cx - LANE_WIDTH / 2;
					} else {
						ix = cx + LANE_WIDTH / 2;
					}

					drawLine(cColor, myLaneX, h / 2, ix, h / 2, LINE_WIDTH);
					drawLine(cColor, ix, h / 2, cx, 0, LINE_WIDTH);
				} else {
					drawLine(cColor, myLaneX, h / 2, cx, 0, LINE_WIDTH);
				}
				maxCenter = Math.max(maxCenter, cx);
			}

			int nonForkingChildren = commit.getChildCount()
					- commit.forkingOffLanes.length;
			if (nonForkingChildren > 0)
						drawLine(myColor, myLaneX, 0, myLaneX, dotY, LINE_WIDTH);
		}

		if (commit.has(RevFlag.UNINTERESTING))
			drawBoundaryDot(dotX, dotY, dotSize, dotSize);
		else
			drawCommitDot(dotX, dotY, dotSize, dotSize);

		int textx = Math.max(maxCenter + LANE_WIDTH / 2, dotX + dotSize) + 8;
		int n = commit.refs.length;
		for (int i = 0; i < n; ++i) {
			textx += drawLabel(textx + dotSize, h/2, commit.refs[i]);
		}

		final String msg = commit.getShortMessage();
		drawText(msg, textx + dotSize, h);
	}

	
Draw a decoration for the Ref ref at x,y
Params:
x – 
           left
y – 
           top
ref – 
           A peeled ref
Returns:
width of label in pixels/**
	 * Draw a decoration for the Ref ref at x,y
	 *
	 * @param x
	 *            left
	 * @param y
	 *            top
	 * @param ref
	 *            A peeled ref
	 * @return width of label in pixels
	 */
	protected abstract int drawLabel(int x, int y, Ref ref);

	private static int computeDotSize(int h) {
		int d = (int) (Math.min(h, LANE_WIDTH) * 0.50f);
		d += (d & 1);
		return d;
	}

	
Obtain the color reference used to paint this lane.

Colors returned by this method will be passed to the other drawing
primitives, so the color returned should be application specific.

If a null lane is supplied the return value must still be acceptable to a
drawing method. Usually this means the implementation should return a
default color.
Params:
myLane – 
           the current lane. May be null.
Returns:
graphics specific color reference. Must be a valid color./**
	 * Obtain the color reference used to paint this lane.
	 * <p>
	 * Colors returned by this method will be passed to the other drawing
	 * primitives, so the color returned should be application specific.
	 * <p>
	 * If a null lane is supplied the return value must still be acceptable to a
	 * drawing method. Usually this means the implementation should return a
	 * default color.
	 *
	 * @param myLane
	 *            the current lane. May be null.
	 * @return graphics specific color reference. Must be a valid color.
	 */
	protected abstract TColor laneColor(TLane myLane);

	
Draw a single line within this cell.
Params:
color – 
           the color to use while drawing the line.
x1 – 
           starting X coordinate, 0 based.
y1 – 
           starting Y coordinate, 0 based.
x2 – 
           ending X coordinate, 0 based.
y2 – 
           ending Y coordinate, 0 based.
width – 
           number of pixels wide for the line. Always at least 1./**
	 * Draw a single line within this cell.
	 *
	 * @param color
	 *            the color to use while drawing the line.
	 * @param x1
	 *            starting X coordinate, 0 based.
	 * @param y1
	 *            starting Y coordinate, 0 based.
	 * @param x2
	 *            ending X coordinate, 0 based.
	 * @param y2
	 *            ending Y coordinate, 0 based.
	 * @param width
	 *            number of pixels wide for the line. Always at least 1.
	 */
	protected abstract void drawLine(TColor color, int x1, int y1, int x2,
			int y2, int width);

	
Draw a single commit dot.

Usually the commit dot is a filled oval in blue, then a drawn oval in
black, using the same coordinates for both operations.
Params:
x – 
           upper left of the oval's bounding box.
y – 
           upper left of the oval's bounding box.
w – 
           width of the oval's bounding box.
h – 
           height of the oval's bounding box./**
	 * Draw a single commit dot.
	 * <p>
	 * Usually the commit dot is a filled oval in blue, then a drawn oval in
	 * black, using the same coordinates for both operations.
	 *
	 * @param x
	 *            upper left of the oval's bounding box.
	 * @param y
	 *            upper left of the oval's bounding box.
	 * @param w
	 *            width of the oval's bounding box.
	 * @param h
	 *            height of the oval's bounding box.
	 */
	protected abstract void drawCommitDot(int x, int y, int w, int h);

	
Draw a single boundary commit (aka uninteresting commit) dot.

Usually a boundary commit dot is a light gray oval with a white center.
Params:
x – 
           upper left of the oval's bounding box.
y – 
           upper left of the oval's bounding box.
w – 
           width of the oval's bounding box.
h – 
           height of the oval's bounding box./**
	 * Draw a single boundary commit (aka uninteresting commit) dot.
	 * <p>
	 * Usually a boundary commit dot is a light gray oval with a white center.
	 *
	 * @param x
	 *            upper left of the oval's bounding box.
	 * @param y
	 *            upper left of the oval's bounding box.
	 * @param w
	 *            width of the oval's bounding box.
	 * @param h
	 *            height of the oval's bounding box.
	 */
	protected abstract void drawBoundaryDot(int x, int y, int w, int h);

	
Draw a single line of text.

The font and colors used to render the text are left up to the
implementation.
Params:
msg – 
           the text to draw. Does not contain LFs.
x – 
           first pixel from the left that the text can be drawn at.
           Character data must not appear before this position.
y – 
           pixel coordinate of the baseline of the text. Implementations
           must adjust this coordinate to account for the way their
           implementation handles font rendering./**
	 * Draw a single line of text.
	 * <p>
	 * The font and colors used to render the text are left up to the
	 * implementation.
	 *
	 * @param msg
	 *            the text to draw. Does not contain LFs.
	 * @param x
	 *            first pixel from the left that the text can be drawn at.
	 *            Character data must not appear before this position.
	 * @param y
	 *            pixel coordinate of the baseline of the text. Implementations
	 *            must adjust this coordinate to account for the way their
	 *            implementation handles font rendering.
	 */
	protected abstract void drawText(String msg, int x, int y);

	private static int laneX(PlotLane myLane) {
		final int p = myLane != null ? myLane.getPosition() : 0;
		return LEFT_PAD + LANE_WIDTH * p;
	}

	private static int laneC(PlotLane myLane) {
		return laneX(myLane) + LANE_WIDTH / 2;
	}
}