package gecaoji;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.geom.AffineTransform;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Point2D;

import javax.swing.ImageIcon;

/** Mower rendering helper. */
public class Gecaoji {
    private static final double ICON_PIXEL_SIZE = 48.0;
    private static final double ICON_SCALE_FACTOR = 0.8;
    private static final double MIN_SCALE = 1e-6;
    private static final Color FALLBACK_FILL = new Color(0, 150, 0);

    private final Image mowerIcon;
    private final Ellipse2D.Double fallbackShape = new Ellipse2D.Double();
    private Point2D.Double position = new Point2D.Double();
    private boolean positionValid;
    private double headingDegrees;

    public Gecaoji() {
        mowerIcon = loadIcon();
        refreshFromDevice();
    }

    private Image loadIcon() {
        try {
            ImageIcon icon = new ImageIcon("image/gecaoji.png");
            if (icon.getIconWidth() <= 0 || icon.getIconHeight() <= 0) {
                return null;
            }
            return icon.getImage();
        } catch (Exception ex) {
            System.err.println("Unable to load mower icon: " + ex.getMessage());
            return null;
        }
    }

    public void refreshFromDevice() {
        Device device = Device.getGecaoji();
        if (device == null) {
            positionValid = false;
            return;
        }

        double x = parseCoordinate(device.getRealtimeX());
        double y = parseCoordinate(device.getRealtimeY());
        double heading = parseHeading(device.getHeading());
        if (Double.isNaN(x) || Double.isNaN(y)) {
            positionValid = false;
            return;
        }

        ensurePosition();
        position.x = x;
        position.y = y;
        positionValid = true;
        headingDegrees = heading;
    }

    private void ensurePosition() {
        if (position == null) {
            position = new Point2D.Double();
        }
    }

    private double parseCoordinate(String value) {
        if (value == null) {
            return Double.NaN;
        }
        String trimmed = value.trim();
        if (trimmed.isEmpty() || "-1".equals(trimmed)) {
            return Double.NaN;
        }
        try {
            return Double.parseDouble(trimmed);
        } catch (NumberFormatException ex) {
            return Double.NaN;
        }
    }

    private double parseHeading(String value) {
        if (value == null) {
            return 0.0;
        }
        String trimmed = value.trim();
        if (trimmed.isEmpty() || "-1".equals(trimmed)) {
            return 0.0;
        }
        try {
            double parsed = Double.parseDouble(trimmed);
            if (!Double.isFinite(parsed)) {
                return 0.0;
            }
            double normalized = parsed % 360.0;
            return normalized < 0 ? normalized + 360.0 : normalized;
        } catch (NumberFormatException ex) {
            return 0.0;
        }
    }

    public void draw(Graphics2D g2d, double scale) {
        if (!positionValid) {
            return;
        }

    double worldSize = (ICON_PIXEL_SIZE * ICON_SCALE_FACTOR) / Math.max(scale, MIN_SCALE);
        if (mowerIcon != null && mowerIcon.getWidth(null) > 0 && mowerIcon.getHeight(null) > 0) {
            drawIcon(g2d, worldSize);
        } else {
            drawFallback(g2d, worldSize);
        }
    }

    private void drawIcon(Graphics2D g2d, double worldSize) {
        double iconWidth = mowerIcon.getWidth(null);
        double iconHeight = mowerIcon.getHeight(null);
        double maxSide = Math.max(iconWidth, iconHeight);
        double scaleFactor = worldSize / Math.max(maxSide, MIN_SCALE);
        double rotationRadians = Math.toRadians(-headingDegrees);

        AffineTransform original = g2d.getTransform();
        AffineTransform transformed = new AffineTransform(original);
        transformed.translate(position.x, position.y);
        if (rotationRadians != 0.0) {
            transformed.rotate(rotationRadians);
        }
        transformed.scale(scaleFactor, scaleFactor);
        transformed.translate(-iconWidth / 2.0, -iconHeight / 2.0);
        g2d.setTransform(transformed);
        g2d.drawImage(mowerIcon, 0, 0, null);
        g2d.setTransform(original);
    }

    private void drawFallback(Graphics2D g2d, double worldSize) {
        double radius = worldSize / 2.0;
        ensurePosition();
        fallbackShape.setFrame(position.x - radius, position.y - radius, worldSize, worldSize);

        Color original = g2d.getColor();
        g2d.setColor(FALLBACK_FILL);
        g2d.fill(fallbackShape);
        g2d.setColor(Color.WHITE);
        g2d.draw(fallbackShape);
    double rotationRadians = Math.toRadians(-headingDegrees);
    double lineLength = radius;
    double dx = lineLength * Math.sin(rotationRadians);
    double dy = lineLength * Math.cos(rotationRadians);
    g2d.drawLine(
        (int) Math.round(position.x),
        (int) Math.round(position.y),
        (int) Math.round(position.x + dx),
        (int) Math.round(position.y + dy));
        g2d.setColor(original);
    }

    public boolean hasValidPosition() {
        return positionValid;
    }

    public Point2D.Double getPosition() {
        if (!positionValid) {
            return null;
        }
        ensurePosition();
        return new Point2D.Double(position.x, position.y);
    }

    public double getWorldRadius(double scale) {
        if (!positionValid) {
            return Double.NaN;
        }
        double worldSize = (ICON_PIXEL_SIZE * ICON_SCALE_FACTOR) / Math.max(scale, MIN_SCALE);
        return worldSize / 2.0;
    }
}