import java.nio.Buffer;
import java.nio.FloatBuffer;

public class OpenExrReaderMain {
	
	static {
		
		System.loadLibrary("OpenExrReader");
	}
	
	private OpenExrReader openExrReader;
	private int imgHeight;
	private int imgWidth;
	
	private Texture redTexture;
	private Texture greenTexture;
	private Texture blueTexture;
	private Texture rgbTexture;
	
	private FloatBuffer redPixelBuffer;
	private FloatBuffer greenPixelBuffer;
	private FloatBuffer bluePixelBuffer;
	private FloatBuffer rgbPixelBuffer;
	
	public static final int RGB_CHANNEL = 0;
	public static final int R_CHANNEL = 1;
	public static final int G_CHANNEL = 2;
	public static final int B_CHANNEL = 3;
	
	
	public OpenExrReaderMain() {
		
		openExrReader = new OpenExrReader();
		imgHeight = 0;
		imgWidth = 0;
	}
	
	public void readExrFile(String filePath) {
		
		openExrReader.readExrFile(filePath);
		imgHeight = openExrReader.getHeight();
		imgWidth = openExrReader.getWidth();
	}
	
	public int getWidth() {
		
		return imgWidth;
	}
	
	public int getHeight() {
		
		return imgHeight;
	}
	
	private void fillBuffer(int startX, int startY, int height, int width, boolean storeAlphaChannel) {
		
		int valuesPerPixel = 0;
		
		if(storeAlphaChannel) {
			
			valuesPerPixel = 4;
		}
		else {
			
			valuesPerPixel = 3;
		}
		
		redPixelBuffer = FloatBuffer.allocate(height * width * valuesPerPixel);
		greenPixelBuffer = FloatBuffer.allocate(height * width * valuesPerPixel);
		bluePixelBuffer = FloatBuffer.allocate(height * width * valuesPerPixel);
		rgbPixelBuffer = FloatBuffer.allocate(height * width * valuesPerPixel);
		
		if(startX + width <= imgWidth && startY + height <= imgHeight) {
			
			for(int i = startY; i < height; i++) {
				
				for (int j = startX; j < width; j++) {
					
					Rgba pixelData = openExrReader.getScruct(i, j);
					
					redPixelBuffer.put(pixelData.getR());
					redPixelBuffer.put(0.0f);
					redPixelBuffer.put(0.0f);
					
					greenPixelBuffer.put(0.0f);
					greenPixelBuffer.put(pixelData.getG());
					greenPixelBuffer.put(0.0f);
					
					bluePixelBuffer.put(0,0f);
					bluePixelBuffer.put(0.0f);
					bluePixelBuffer.put(pixelData.getB());
					
					rgbPixelBuffer.put(pixelData.getR());
					rgbPixelBuffer.put(pixelData.getG());
					rgbPixelBuffer.put(pixelData.getB());					
				
					if(storeAlphaChannel) {
					
						redPixelBuffer.put(pixelData.getA());
						greenPixelBuffer.put(pixelData.getA());
						bluePixelBuffer.put(pixelData.getA());
						rgbPixelBuffer.put(pixelData.getA());
					}
				}
			}
		}
	}
	
	public void createOpenExrTextures(int startX, int startY, int height, int width, boolean storeAlphaChannel) {
		
		this.fillBuffer(startX, startY, height, width, storeAlphaChannel);
		
		if(redPixelBuffer.capacity() > 0) {
			
			redTexture = new Texture(redPixelBuffer, width, height);
		}
		if(greenPixelBuffer.capacity() > 0) {
			
			greenTexture = new Texture(greenPixelBuffer, width, height);
		}
		if(bluePixelBuffer.capacity() > 0) {
			
			blueTexture = new Texture(bluePixelBuffer, width, height);
		}
		if(rgbPixelBuffer.capacity() > 0) {
			
			rgbTexture = new Texture(rgbPixelBuffer, width, height);
		}
	}
	
	public Texture getRedTexture() {
		
		return redTexture;
	}
	
	public Texture getGreenTexture() {
		
		return greenTexture;
	}
	
	public Texture getBlueTexture() {
		
		return blueTexture;
	}
	
	public Texture getRgbTexture() {
		
		return rgbTexture;
	}
	
	private FloatBuffer getImageTile(int startX, int startY, int height, int width, boolean storeAlphaChannel, int channel) {
		
		int valuesPerPixel = 0;
		
		if(storeAlphaChannel) {
			
			valuesPerPixel = 4;
		}
		else {
			
			valuesPerPixel = 3;
		}
		
		FloatBuffer pixelBuffer = FloatBuffer.allocate(height * width * valuesPerPixel);
		
		if(startX + width <= imgWidth && startY + height <= imgHeight) {
			
			for(int i = startY; i < height; i++) {
				
				for (int j = startX; j < width; j++) {
					
					Rgba pixelData = openExrReader.getScruct(i, j);
					
					switch(channel) {
					
						case RGB_CHANNEL:	pixelBuffer.put(pixelData.getR());
											pixelBuffer.put(pixelData.getG());
											pixelBuffer.put(pixelData.getB());
											break;
						case R_CHANNEL:		pixelBuffer.put(pixelData.getR());
											pixelBuffer.put(0.0f);
											pixelBuffer.put(0.0f);
											break;
						case G_CHANNEL:		pixelBuffer.put(0.0f);
											pixelBuffer.put(pixelData.getG());
											pixelBuffer.put(0.0f);
											break;
						case B_CHANNEL:		pixelBuffer.put(0.0f);
											pixelBuffer.put(0.0f);
											pixelBuffer.put(pixelData.getB());
											break;
					}					
					if(storeAlphaChannel) {
						
						pixelBuffer.put(pixelData.getA());
					}
				}
			}
		}
		
		return pixelBuffer;		
	}
	
	public OpenExrReaderMain.Texture getOpenExrTexture(int startX, int startY, int height, int width, boolean storeAlphaChannel, int channel) {
		
		FloatBuffer pixelBuffer = this.getImageTile(startX, startY, height, width, storeAlphaChannel, channel);
		
		if(pixelBuffer.capacity() > 0) {
		
			return new Texture(pixelBuffer, width, height);
		}
		else {
			
			return null;
		}
	}

    public static class Texture {
        
    	private Buffer pixels;
        private int width;
        private int height;

        public Texture(Buffer pixels, int width, int height) {
            
        	this.height = height;
            this.pixels = pixels;
            this.width = width;
        }

        public int getHeight() {
            
        	return height;
        }

        public Buffer getPixels() {
            
        	return pixels;
        }
        
        public int getWidth() {
            
        	return width;
        }
    }
}