package org.simantics.diagram.svg.export;

import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.io.StringWriter;
import java.util.UUID;

import org.apache.batik.dom.GenericDOMImplementation;
import org.apache.batik.svggen.SVGGraphics2D;
import org.simantics.g2d.canvas.ICanvasContext;
import org.simantics.g2d.diagram.DiagramHints;
import org.simantics.g2d.diagram.DiagramUtils;
import org.simantics.g2d.diagram.IDiagram;
import org.simantics.g2d.participant.TransformUtil;
import org.simantics.scenegraph.g2d.G2DRenderingHints;
import org.simantics.scenegraph.utils.QualityHints;
import org.simantics.utils.page.MarginUtils;
import org.simantics.utils.page.MarginUtils.Margin;
import org.simantics.utils.page.MarginUtils.Margins;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.Element;


/**
 * org.simantics.diagram.export.ImageBuilder with SVG support 
 * 
 * @author Marko Luukkainen <marko.luukkainen@vtt.fi>
 *
 */
public class SVGBuilder {
	Double dpi;
	Point size;
	double margin;
	Margins margins;
	
	/**
	 * 
	 * @param file File to write the image (optional)
	 * @param dpi Dots Per Inch
	 * @param size Image size in pixels
	 * @param margin percentage of image width for margins. 0.05 is 5%.
	 */
	public SVGBuilder(Double dpi, Point size, double margin) {
		this.dpi = dpi;
		this.size = size;
		this.margin = Math.max(margin,0.0);
		this.margins = null;
	}

	/**
	 * 
	 * @param file File to write the image (optional)
	 * @param dpi Dots Per Inch
	 * @param size Image size in pixels
	 * @param margins Margins
	 */
	public SVGBuilder(Double dpi, Point size, Margins margins) {
		this.dpi = dpi;
		this.size = size;
		this.margin = 0.0;
		this.margins = margins;
	}
	
	public static SVGGraphics2D defaultSVGGenerator() {
		DOMImplementation domImpl =  GenericDOMImplementation.getDOMImplementation();
		
		// Create an instance of org.w3c.dom.Document.
	    String svgNS = "http://www.w3.org/2000/svg";
	    Document document = domImpl.createDocument(svgNS, "svg", null);
	
	    // Create an instance of the SVG Generator.
	    SVGGraphics2D svgGenerator = new SVGGraphics2D(document);
	    svgGenerator.getGeneratorContext().setIDGenerator(new UniqueIDGenerator(UUID.randomUUID().toString()));
	    return svgGenerator;
	}

	/**
	 * @param canvasContext
	 *            the canvas context to paint
	 * @param writeResults
	 *            <code>true</code> to actually write the resulting Image to the file.
	 */
	public String paint(ICanvasContext canvasContext) throws Exception {
		return paint(canvasContext, defaultSVGGenerator());
	}
	
	/**
	 * @param canvasContext
	 *            the canvas context to paint
	 *        svgGenerator 
	 *            the svg generator to use
	 * @param writeResults
	 *            <code>true</code> to actually write the resulting Image to the file.
	 */
	public String paint(ICanvasContext canvasContext, SVGGraphics2D svgGenerator) throws Exception {
		
		Graphics2D g2 = svgGenerator;
		
		IDiagram diagram = canvasContext.getDefaultHintContext().getHint(DiagramHints.KEY_DIAGRAM);
		Rectangle2D diagramRect = DiagramUtils.getContentRect(diagram);

		if (diagramRect == null)
			diagramRect = new Rectangle2D.Double(0, 0, 100, 100);

		// add margins to content.
		double off = Math.max(diagramRect.getWidth(), diagramRect.getHeight()) * margin*0.5;
		diagramRect = new Rectangle2D.Double(diagramRect.getX() - off, diagramRect.getY() - off, diagramRect.getWidth() + off * 2.0, diagramRect.getHeight() + off * 2.0);

		if (margins != null) {
			diagramRect = org.simantics.scenegraph.utils.GeometryUtils.expandRectangle(diagramRect,
					margins.top.diagramAbsolute,
					margins.bottom.diagramAbsolute,
					margins.left.diagramAbsolute,
					margins.right.diagramAbsolute
					);
		}
		
		// Make sure the transformation is reset.
		AffineTransform tr = new AffineTransform();

		Rectangle2D controlArea;
		if (dpi != null) {
			double mmToInch = 1.0 / 25.4;
			controlArea = new Rectangle2D.Double(0, 0, diagramRect.getWidth() * mmToInch * dpi, diagramRect.getHeight() * mmToInch * dpi);

			if (margins != null) {
				double w = controlArea.getWidth();
				double h = controlArea.getHeight();
				controlArea = org.simantics.scenegraph.utils.GeometryUtils.expandRectangle(controlArea,
						margins.top.controlAbsolute + margins.top.controlRelative * h,
						margins.bottom.controlAbsolute + margins.bottom.controlRelative * h,
						margins.left.controlAbsolute + margins.left.controlRelative * w,
						margins.right.controlAbsolute + margins.right.controlRelative * w
						);
			}
		} else {
			controlArea = new Rectangle2D.Double(0, 0, size.getX(), size.getY());
			if (margins != null) {
				double w = controlArea.getWidth();
				double h = controlArea.getHeight();
				controlArea = org.simantics.scenegraph.utils.GeometryUtils.expandRectangle(controlArea,
						-(margins.top.controlAbsolute + margins.top.controlRelative * h),
						-(margins.bottom.controlAbsolute + margins.bottom.controlRelative * h),
						-(margins.left.controlAbsolute + margins.left.controlRelative * w),
						-(margins.right.controlAbsolute + margins.right.controlRelative * w)
						);
			}
		}

		canvasContext.getSingleItem(TransformUtil.class).fitArea(controlArea, diagramRect, MarginUtils.NO_MARGINS);
		
		float width = (float)controlArea.getWidth();
		float height = (float)controlArea.getHeight();
		

		QualityHints.HIGH_QUALITY_HINTS.setQuality(g2);
		g2.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);


		g2.setTransform(tr);
		g2.setClip(new Rectangle2D.Double(0, 0, controlArea.getWidth(), controlArea.getHeight()));

		g2.setRenderingHint(G2DRenderingHints.KEY_CONTROL_BOUNDS, new Rectangle2D.Double(0, 0, controlArea.getWidth(), controlArea.getHeight()));

		if (canvasContext.isLocked())
			throw new IllegalStateException("cannot render image, canvas context is locked: " + canvasContext);

		canvasContext.getSceneGraph().render(g2);
			

		
		Element root = svgGenerator.getRoot();
		root.setAttributeNS(null, "viewBox", "0 0 " + width + " " + height); 
		root.setAttributeNS(null, "height", Float.toString(height));
		root.setAttributeNS(null, "width", Float.toString(width));
		
		// Finally, stream out SVG to the standard output using
	    // UTF-8 encoding.
	    boolean useCSS = false; // we want to use CSS style attributes
	    StringWriter writer = new StringWriter();
	    //svgGenerator.stream(writer, useCSS);
	    svgGenerator.stream(root,writer, useCSS, false);
	    return writer.toString();
	}
}