// ClassicalSharp copyright 2014-2016 UnknownShadow200 | Licensed under MIT
using System;
using System.Drawing;
using ClassicalSharp;

namespace Launcher.Drawing {
	public unsafe static class BitmapDrawer {
		
		public static void DrawIndexed( byte[] indices, FastColour[] palette,
		                               int size, int x, int y, FastBitmap dst ) {
			int* argb = stackalloc int[palette.Length];
			for( int i = 0; i < palette.Length; i++ )
				argb[i] = palette[i].ToArgb();

			for( int i = 0, yy = 0; yy < size; yy++ ) {
				if( (y + yy) < 0 ) { i += size; continue; }
				if( (y + yy) >= dst.Height ) break;
				int* row = dst.GetRowPtr( y + yy );
				
				for( int xx = 0; xx < size; xx++ ) {
					int col = argb[indices[i]]; i++;
					if( col == 0 ) continue; // transparent pixel
					if( (x + xx) < 0 || (x + xx) >= dst.Width ) continue;
					row[x + xx] = col;
				}
			}
		}
		
		public static void DrawScaled( FastBitmap src, FastBitmap dst, Size scale,
		                              Rectangle srcRect, Rectangle dstRect, byte scaleA, byte scaleB ) {
			int srcWidth = srcRect.Width, dstWidth = dstRect.Width;
			int srcHeight = srcRect.Height, dstHeight = dstRect.Height;
			int srcX = srcRect.X, dstX = dstRect.X;
			int srcY = srcRect.Y, dstY = dstRect.Y;
			int scaleWidth = scale.Width, scaleHeight = scale.Height;
			
			for( int yy = 0; yy < dstHeight; yy++ ) {
				int scaledY = (yy + dstY) * srcHeight / scaleHeight;
				int* srcRow = src.GetRowPtr( srcY + (scaledY % srcHeight) );
				int* dstRow = dst.GetRowPtr( dstY + yy );
				byte rgbScale = (byte)Utils.Lerp( scaleA, scaleB, (float)yy / dstHeight );
				
				for( int xx = 0; xx < dstWidth; xx++ ) {
					int scaledX = (xx + dstX) * srcWidth / scaleWidth;
					int pixel = srcRow[srcX + (scaledX % srcWidth)];
					
					int col = pixel & ~0xFFFFFF; // keep a, but clear rgb
					col |= ((pixel & 0xFF) * rgbScale / 255);
					col |= (((pixel >> 8) & 0xFF) * rgbScale / 255) << 8;
					col |= (((pixel >> 16) & 0xFF) * rgbScale / 255) << 16;
					dstRow[dstX + xx] = col;
				}
			}
		}
		
		public static void DrawTiled( FastBitmap src, FastBitmap dst,
		                             Rectangle srcRect, Rectangle dstRect ) {
			int srcX = srcRect.X, srcWidth = srcRect.Width, srcHeight = srcRect.Height;
			int x, y, width, height;
			if( !Drawer2DExt.ClampCoords( dst, dstRect, out x, out y, out width, out height ) )
				return;
			
			for( int yy = 0; yy < height; yy++ ) {
				// srcY is always 0 so we don't need to add
				int* srcRow = src.GetRowPtr( ((yy + y) % srcHeight) );
				int* dstRow = dst.GetRowPtr( y + yy );
				
				for( int xx = 0; xx < width; xx++ )
					dstRow[x + xx] = srcRow[srcX + ((xx + x) % srcWidth)];
			}
		}
	}
}