package ocelot.desktop.graphics_v2

import ocelot.desktop.color.Color

import java.nio.ByteBuffer

trait Graphics {

  /** Type of [[Image.Static]] used by this graphics backend.
    *
    * Created with [[createStaticImage()]] and must be destroyed with [[destroyStaticImage()]]
    */
  type StaticImage <: Image.Static

  /** Type of [[Image.Surface]] used by this graphics backend.
    *
    * This is used for off-screen rendering and for rendering to the window. Though the latter requires you to obtain
    * a window-bound surface using implementation-specific methods defined outside of this trait.
    *
    * Created with [[createSurface()]] and must be destroyed with [[destroySurface()]]
    */
  type Surface <: Image.Surface

  /** Defines various passes that happen during the rendering process in sequence. */
  sealed class Pass

  object Pass {

    /** Clears the surface with a solid color. */
    case class Clear(surface: Surface, color: Color) extends Pass

    /** Draws 2D geometry to a surface using the callback to populate it. */
    case class Draw2D(surface: Surface, callback: Encoder2D => Unit) extends Pass

    /** Downloads the surface contents, invoking the callback on completion. */
    case class Download(surface: Surface, callback: ByteBuffer => Unit) extends Pass
  }

  /** Creates a static image with given dimensions, format, and data (row-major, packed without alignment or padding).
    *
    * @throws IllegalArgumentException if width or height is zero or negative,
    *                                  if data is too short or too long for given format and dimensions
    */
  def createStaticImage(width: Int, height: Int, format: Image.Format, packedData: ByteBuffer): StaticImage

  /** Destroys a static image.
    * @throws IllegalArgumentException if the image does not belong to this [[Graphics]] instance or is already destroyed.
    */
  def destroyStaticImage(image: StaticImage): Unit

  /** Creates a drawable off-screen surface with given dimensions. */
  def createSurface(width: Int, height: Int, format: Image.Format): Surface

  /** Destroys a surface.
    * @throws IllegalArgumentException if the surface does not belong to this [[Graphics]] instance or is already destroyed.
    */
  def destroySurface(surface: Surface): Unit

  /** Performs all rendering passes from the specified array in sequence. */
  def process(passes: Array[Pass]): Unit
}