local scrn = view.newscreen(0, 2)
local player = {
  x = 40,
  y = 22,
  dx = 1,
  dy = 0,
  len = 8,
  tail = {}
}

function _init()
  image.pointer(image.new())
  gfx.cls()
  local w,h = view.size(scrn)
  gfx.palette(1, 15, 15, 15)
  gfx.palette(2, 15, 0, 0)
  gfx.fgcolor(1)
  gfx.line(0,0, w-1,0)
  gfx.line(w-1,0, w-1,h-1)
  gfx.line(w-1,h-1, 0, h-1)
  gfx.line(0, h-1, 0,0)
  gfx.fgcolor(2)
  gfx.plot(math.random(w-4), math.random(h-4))
  player.x = math.floor(w/2)
  player.y = math.floor(h/2)
  player.len = 1
  sys.stepinterval(1000/(w/8))
end

function _step(t)
  local btn = input.gamepad()
  if btn & 1 > 0 and player.dx == 0 then
    player.dx = 1
    player.dy = 0
  end
  if btn & 2 > 0 and player.dx == 0 then
    player.dx = -1
    player.dy = 0
  end
  if btn & 4 > 0 and player.dy == 0 then
    player.dx = 0
    player.dy = -1
  end
  if btn & 8 > 0 and player.dy == 0 then
    player.dx = 0
    player.dy = 1
  end
  player.x = player.x + player.dx
  player.y = player.y + player.dy
  if gfx.pixel(player.x, player.y) == 1 then
    _init()
  end
  if gfx.pixel(player.x, player.y) == 2 then
    player.len = player.len + 2
    local w,h = view.size(scrn)
    gfx.fgcolor(2)
    gfx.plot(math.random(w-4), math.random(h-4))
  end
  table.insert(player.tail, { x=player.x, y=player.y })
  gfx.fgcolor(1)
  gfx.plot(player.x, player.y)
  while #player.tail > player.len do
    local tailend = table.remove(player.tail, 1)
    if gfx.pixel(tailend.x, tailend.y) == 1 then
      gfx.fgcolor(0)
      gfx.plot(tailend.x, tailend.y)
    end
  end
  if input.hotkey() == "\x1b" then
    sys.exit()
  end
end