package util;

import com.google.zxing.LuminanceSource;

import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.awt.image.WritableRaster;

/**
 * This LuminanceSource implementation is meant for J2SE clients and our blackbox unit tests.
 *
 * @author [email protected] (Daniel Switkin)
 * @author Sean Owen
 * @author [email protected] (Wolfgang Jung)
 */
public final class BufferedImageLuminanceSource extends LuminanceSource {

    // Math.toRadians(-45.0)
    private static final double MINUS_45_IN_RADIANS = -0.7853981633974483;

    private final BufferedImage image;
    private final int           left;
    private final int           top;

    public BufferedImageLuminanceSource(BufferedImage image) {
        this(image, 0, 0, image.getWidth(), image.getHeight());
    }

    public BufferedImageLuminanceSource(BufferedImage image, int left, int top, int width, int height) {
        super(width, height);

        if (image.getType() == BufferedImage.TYPE_BYTE_GRAY) {
            this.image = image;
        } else {
            int sourceWidth  = image.getWidth();
            int sourceHeight = image.getHeight();
            if (left + width > sourceWidth || top + height > sourceHeight) {
                throw new IllegalArgumentException("Crop rectangle does not fit within image data.");
            }

            this.image = new BufferedImage(sourceWidth, sourceHeight, BufferedImage.TYPE_BYTE_GRAY);

            WritableRaster raster = this.image.getRaster();
            int[]          buffer = new int[width];
            for (int y = top; y < top + height; y++) {
                image.getRGB(left, y, width, 1, buffer, 0, sourceWidth);
                for (int x = 0; x < width; x++) {
                    int pixel = buffer[x];

                    // The color of fully-transparent pixels is irrelevant. They are often, technically, fully-transparent
                    // black (0 alpha, and then 0 RGB). They are often used, of course as the "white" area in a
                    // barcode image. Force any such pixel to be white:
                    if ((pixel & 0xFF000000) == 0) {
                        pixel = 0xFFFFFFFF;
                    }

                    // .299R + 0.587G + 0.114B (YUV/YIQ for PAL and NTSC),
                    // (306*R) >> 10 is approximately equal to R*0.299, and so on.
                    // 0x200 >> 10 is 0.5, it implements rounding.
                    buffer[x] =
                            (306 * ((pixel >> 16) & 0xFF) +
                                    601 * ((pixel >> 8) & 0xFF) +
                                    117 * (pixel & 0xFF) +
                                    0x200) >> 10;
                }
                raster.setPixels(left, y, width, 1, buffer);
            }

        }
        this.left = left;
        this.top = top;
    }

    @Override
    public byte[] getRow(int y, byte[] row) {
        if (y < 0 || y >= getHeight()) {
            throw new IllegalArgumentException("Requested row is outside the image: " + y);
        }
        int width = getWidth();
        if (row == null || row.length < width) {
            row = new byte[width];
        }
        // The underlying raster of image consists of bytes with the luminance values
        image.getRaster().getDataElements(left, top + y, width, 1, row);
        return row;
    }

    @Override
    public byte[] getMatrix() {
        int    width  = getWidth();
        int    height = getHeight();
        int    area   = width * height;
        byte[] matrix = new byte[area];
        // The underlying raster of image consists of area bytes with the luminance values
        image.getRaster().getDataElements(left, top, width, height, matrix);
        return matrix;
    }

    @Override
    public boolean isCropSupported() {
        return true;
    }

    @Override
    public LuminanceSource crop(int left, int top, int width, int height) {
        return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height);
    }

    /**
     * This is always true, since the image is a gray-scale image.
     *
     * @return true
     */
    @Override
    public boolean isRotateSupported() {
        return true;
    }

    @Override
    public LuminanceSource rotateCounterClockwise() {
        int sourceWidth  = image.getWidth();
        int sourceHeight = image.getHeight();

        // Rotate 90 degrees counterclockwise.
        AffineTransform transform = new AffineTransform(0.0, -1.0, 1.0, 0.0, 0.0, sourceWidth);

        // Note width/height are flipped since we are rotating 90 degrees.
        BufferedImage rotatedImage = new BufferedImage(sourceHeight, sourceWidth, BufferedImage.TYPE_BYTE_GRAY);

        // Draw the original image into rotated, via transformation
        Graphics2D g = rotatedImage.createGraphics();
        g.drawImage(image, transform, null);
        g.dispose();

        // Maintain the cropped region, but rotate it too.
        int width = getWidth();
        return new BufferedImageLuminanceSource(rotatedImage, top, sourceWidth - (left + width), getHeight(), width);
    }

    @Override
    public LuminanceSource rotateCounterClockwise45() {
        int width  = getWidth();
        int height = getHeight();

        int oldCenterX = left + width / 2;
        int oldCenterY = top + height / 2;

        // Rotate 45 degrees counterclockwise.
        AffineTransform transform = AffineTransform.getRotateInstance(MINUS_45_IN_RADIANS, oldCenterX, oldCenterY);

        int           sourceDimension = Math.max(image.getWidth(), image.getHeight());
        BufferedImage rotatedImage    = new BufferedImage(sourceDimension, sourceDimension, BufferedImage.TYPE_BYTE_GRAY);

        // Draw the original image into rotated, via transformation
        Graphics2D g = rotatedImage.createGraphics();
        g.drawImage(image, transform, null);
        g.dispose();

        int halfDimension = Math.max(width, height) / 2;
        int newLeft       = Math.max(0, oldCenterX - halfDimension);
        int newTop        = Math.max(0, oldCenterY - halfDimension);
        int newRight      = Math.min(sourceDimension - 1, oldCenterX + halfDimension);
        int newBottom     = Math.min(sourceDimension - 1, oldCenterY + halfDimension);

        return new BufferedImageLuminanceSource(rotatedImage, newLeft, newTop, newRight - newLeft, newBottom - newTop);
    }

}