namespace RemoteFrameBuffer.Common
{
    public class RgbFrameBuffer
    {
        private RgbPixel[][] _frame;

        public UInt16 Width
        {
            get
            {
                return (UInt16)this._frame[0].Length;
            }
        }
        public UInt16 Height
        {
            get
            {
                return (UInt16)this._frame.Length;
            }
        }

        private static RgbPixel[][] MakeFrameBuffer(UInt16 width, UInt16 height)
        {
            RgbPixel[][] buf = new RgbPixel[height][];
            for (Int32 i = 0; i < height; i++)
            {
                buf[i] = new RgbPixel[width];
            }
            return buf;
        }

        public RgbFrameBuffer(UInt16 width, UInt16 height)
        {
            this._frame = MakeFrameBuffer(width, height);
        }

        public void SetRegion(RgbPixel[][] source, UInt16 source_x, UInt16 source_y, UInt16 width, UInt16 height, UInt16 target_x, UInt16 target_y)
        {
            for (Int32 y = 0; y < height; y++)
            {
                Array.Copy(source[y + source_y], source_x, this._frame[y + target_y], target_x, width);
            }
        }

        public void CopyRegion(UInt16 source_x, UInt16 source_y, UInt16 width, UInt16 height, UInt16 target_x, UInt16 target_y) => this.SetRegion(this._frame, source_x, source_y, width, height, target_x, target_y);

        public void SaveBitmap(String filename)
        {
#warning Endianness is straight up ignored
            Int32 rowBytes = (this.Width * 3) + 3;
            rowBytes -= rowBytes % 4;
            Int32 bytes = 54 + (this.Height * rowBytes);
            Byte[] buf = new Byte[bytes];
            buf[0] = 0x42;
            buf[1] = 0x4D;
            Array.Copy(BitConverter.GetBytes(bytes), 0, buf, 2, 4);
            buf[10] = 54;
            buf[14] = 40;
            Array.Copy(BitConverter.GetBytes((UInt32)this.Width), 0, buf, 18, 4);
            Array.Copy(BitConverter.GetBytes((UInt32)this.Height), 0, buf, 22, 4);
            buf[26] = 1;
            buf[28] = 24;
            Array.Copy(BitConverter.GetBytes(this.Height * rowBytes), 0, buf, 34, 4);
            for (Int32 j = 0; j < this.Height; j++)
            {
                Int32 off = 54 + (j * rowBytes);
                for (Int32 i = 0; i < this.Width; i++)
                {
                    Int32 pos = off + (i * 3);
                    buf[pos] = this._frame[this.Height - j - 1][i].Blue;
                    buf[pos + 1] = this._frame[this.Height - j - 1][i].Green;
                    buf[pos + 2] = this._frame[this.Height - j - 1][i].Red;
                }
            }
            File.WriteAllBytes(filename, buf);
        }
    }
}