Main.scala

package demo

import pdapi.all._
import pdapi.enumerations.PDButtons.kButtonA
import pdapi.enumerations.PDSystemEvent
import pdapi.enumerations.PDSystemEvent.kEventInit
import scalanative.unsafe._

import scala.scalanative.unsigned.UInt

object Main {

  var x = 50
  var y = 50

  val VelocityX = 5
  val VelocityY = 2

  enum DirectionX {
    case Left, Right
  }

  enum DirectionY {
    case Up, Down
  }

  var dirX = DirectionX.Left
  var dirY = DirectionY.Down

  val LCD_COLUMNS = 400
  val LCD_ROWS = 240

  var w = 100.0f
  val h = 100.0f

  var state = false

  extension [A](
    inline ptr: Ptr[A]
  ) {

    inline def !(
      using inline tag: Tag[A]
    ): A = !ptr

  }

  @exported("sn_event")
  def event(
    pd: Ptr[PlaydateAPI],
    event: PDSystemEvent,
    arg: UInt,
  ): Int = {

    val f: CFuncPtr1[Ptr[Byte], CInt] = update

    val ptr: Ptr[PDCallbackFunction] = CFuncPtr.toPtr(f).asInstanceOf[Ptr[PDCallbackFunction]]

    if (event == kEventInit)
      pd.!.system.!.setUpdateCallback(ptr, pd.asInstanceOf[Ptr[Byte]])

    0
  }

  def update(
    arg: Ptr[Byte]
  ): Int = {
    val pd = arg.asInstanceOf[Ptr[PlaydateAPI]]

    val current = stackalloc[PDButtons](1)
    val pressed = stackalloc[PDButtons](1)
    val released = stackalloc[PDButtons](1)

    pd.!.system.!.getButtonState(current, pressed, released)

    if (pressed.!.is(kButtonA)) {
      pd.!.system.!.logToConsole(c"Button A is pressed")
      state = !state
    }

    if (dirX == DirectionX.Left) {
      x -= VelocityX
      if (x < 0) {
        dirX = DirectionX.Right
      }
    } else {
      x += VelocityX
      if (x > LCD_COLUMNS - w) {
        dirX = DirectionX.Left
      }
    }
    x = 0 max ((LCD_COLUMNS - w.toInt) min x.toInt)

    if (dirY == DirectionY.Up) {
      y -= VelocityY
      if (y < 0) {
        dirY = DirectionY.Down
      }
    } else {
      y += VelocityY
      if (y > (LCD_ROWS - h)) {
        dirY = DirectionY.Up
      }
    }
    y = 0 max ((LCD_ROWS - h.toInt) min y.toInt)

    val crankDelta = pd.!.system.!.getCrankChange()

    if (crankDelta != 0) {
      w += crankDelta.toInt
    }

    pd.!
      .graphics
      .!
      .clear(
        LCDColor(uintptr_t(LCDSolidColor.kColorWhite.value))
      )

    if (state)
      pd.!
        .graphics
        .!
        .fillRect(
          x,
          y,
          w.toInt,
          h.toInt,
          LCDColor(uintptr_t(LCDSolidColor.kColorBlack.value)),
        )
    else
      pd.!
        .graphics
        .!
        .drawRect(
          x,
          y,
          w.toInt,
          h.toInt,
          LCDColor(uintptr_t(LCDSolidColor.kColorBlack.value)),
        )

    1
  }

}