package tz.signaturecapture;

import java.io.OutputStream;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;

public class SignatureWidget extends View
{
    private static final float STROKE_WIDTH = 5f;
    private static final float HALF_STROKE_WIDTH = STROKE_WIDTH / 2;
    private Paint paint = new Paint();
    private Path path = new Path();

    private float lastTouchX;
    private float lastTouchY;
    private final RectF dirtyRect = new RectF();

    public SignatureWidget(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        paint.setAntiAlias(true);
        paint.setColor(Color.BLACK);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeJoin(Paint.Join.ROUND);
        paint.setStrokeWidth(STROKE_WIDTH);
    }

    public void save(View parent, OutputStream os)
    {
        Log.v("log_tag", "Width: " + parent.getWidth());
        Log.v("log_tag", "Height: " + parent.getHeight());
        Bitmap bm =  Bitmap.createBitmap(parent.getWidth(), parent.getHeight(), Bitmap.Config.RGB_565);;
        Canvas canvas = new Canvas(bm);
        parent.draw(canvas);
        bm.compress(Bitmap.CompressFormat.PNG, 90, os);
    }

    public void clear()
    {
        path.reset();
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas)
    {
        canvas.drawPath(path, paint);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event)
    {
        float eventX = event.getX();
        float eventY = event.getY();

        switch (event.getAction())
        {
        case MotionEvent.ACTION_DOWN:
            path.moveTo(eventX, eventY);
            lastTouchX = eventX;
            lastTouchY = eventY;
            return true;

        case MotionEvent.ACTION_MOVE:

        case MotionEvent.ACTION_UP:

            resetDirtyRect(eventX, eventY);
            int historySize = event.getHistorySize();
            for (int i = 0; i < historySize; i++)
            {
                float historicalX = event.getHistoricalX(i);
                float historicalY = event.getHistoricalY(i);
                expandDirtyRect(historicalX, historicalY);
                path.lineTo(historicalX, historicalY);
            }
            path.lineTo(eventX, eventY);
            break;

        default:
            debug("Ignored touch event: " + event.toString());
            return false;
        }

        invalidate((int) (dirtyRect.left - HALF_STROKE_WIDTH),
                (int) (dirtyRect.top - HALF_STROKE_WIDTH),
                (int) (dirtyRect.right + HALF_STROKE_WIDTH),
                (int) (dirtyRect.bottom + HALF_STROKE_WIDTH));

        lastTouchX = eventX;
        lastTouchY = eventY;

        return true;
    }

    private void debug(String string){
    }

    private void expandDirtyRect(float historicalX, float historicalY)
    {
        if (historicalX < dirtyRect.left)
        {
            dirtyRect.left = historicalX;
        }
        else if (historicalX > dirtyRect.right)
        {
            dirtyRect.right = historicalX;
        }

        if (historicalY < dirtyRect.top)
        {
            dirtyRect.top = historicalY;
        }
        else if (historicalY > dirtyRect.bottom)
        {
            dirtyRect.bottom = historicalY;
        }
    }

    private void resetDirtyRect(float eventX, float eventY)
    {
        dirtyRect.left = Math.min(lastTouchX, eventX);
        dirtyRect.right = Math.max(lastTouchX, eventX);
        dirtyRect.top = Math.min(lastTouchY, eventY);
        dirtyRect.bottom = Math.max(lastTouchY, eventY);
    }
}