package snake

/** A thing to draw. The picture is plain data; drawing it is somebody else's job (m07). */
enum Shape:
  case Rect(x: Int, y: Int, w: Int, h: Int, color: String)
  case Text(x: Int, y: Int, text: String, color: String, size: Int, align: String)

/** A picture: shapes drawn in order. */
type Scene = List[Shape]

/** m06 view: the picture is plain data (a list of shapes); drawing it is somebody else's job (m07). */
object View:

  val CELL: Int = 20

  private def rect(x: Int, y: Int, w: Int, h: Int, color: String): Shape = Shape.Rect(x, y, w, h, color)

  private def text(x: Int, y: Int, str: String, size: Int, align: String): Shape =
    Shape.Text(x, y, str, "#ffffff", size, align)

  // One cell, inset by 1px so neighbouring segments show a gap.
  private def cell(p: Point, color: String): Shape = rect(p.x * CELL + 1, p.y * CELL + 1, CELL - 2, CELL - 2, color)

  private def overlay(state: GameState): Scene =
    val cx = state.width * CELL / 2
    val cy = state.height * CELL / 2
    def banner(title: String, hint: String): Scene =
      List(text(cx, cy, title, 32, "center"), text(cx, cy + 30, hint, 16, "center"))
    state.status match
      case Status.Paused   => banner("Paused", "Press Space to resume")
      case Status.GameOver => banner("Game Over", "Press R to restart")
      case Status.Won      => banner("You Win!", "Press R to restart")
      case Status.Playing  => Nil

  def view(state: GameState): Scene =
    List(rect(0, 0, state.width * CELL, state.height * CELL, "#111111")) ++
      state.apple.map(cell(_, "#e53935")).toList ++
      state.snake.zipWithIndex.map((p, i) => cell(p, if i == 0 then "#7cb342" else "#43a047")) ++
      List(text(6, 18, s"Score: ${state.score}", 16, "left")) ++
      overlay(state)