AUTOTILE_LOOKUP = [
    46, 46, 42, 42, 46, 46, 42, 42, 43, 43, 35, 34, 43, 43, 35, 34, 45, 45,
    37, 37, 45, 45, 36, 36, 33, 33, 23, 22, 33, 33, 21, 20, 46, 46, 42, 42,
    46, 46, 42, 42, 43, 43, 35, 34, 43, 43, 35, 34, 45, 45, 37, 37, 45, 45,
    36, 36, 33, 33, 23, 22, 33, 33, 21, 20, 44, 44, 32, 32, 44, 44, 32, 32,
    41, 41, 19, 17, 41, 41, 19, 17, 39, 39, 27, 27, 39, 39, 26, 26, 31, 31,
    15, 11, 31, 31, 7, 3, 44, 44, 32, 32, 44, 44, 32, 32, 40, 40, 18, 16,
    40, 40, 18, 16, 39, 39, 27, 27, 39, 39, 26, 26, 29, 29, 13, 9, 29, 29,
    5, 1, 46, 46, 42, 42, 46, 46, 42, 42, 43, 43, 35, 34, 43, 43, 35, 34,
    45, 45, 37, 37, 45, 45, 36, 36, 33, 33, 23, 22, 33, 33, 21, 20, 46, 46,
    42, 42, 46, 46, 42, 42, 43, 43, 35, 34, 43, 43, 35, 34, 45, 45, 37, 37,
    45, 45, 36, 36, 33, 33, 23, 22, 33, 33, 21, 20, 44, 44, 32, 32, 44, 44,
    32, 32, 41, 41, 19, 17, 41, 41, 19, 17, 38, 38, 25, 25, 38, 38, 24, 24,
    30, 30, 14, 10, 30, 30, 6, 2, 44, 44, 32, 32, 44, 44, 32, 32, 40, 40,
    18, 16, 40, 40, 18, 16, 38, 38, 25, 25, 38, 38, 24, 24, 28, 28, 12, 8,
    28, 28, 4,  0
  ]

  def autotile_flag(nb, id)
    nb.inject(0) { |r, nb_id| r << 1 | (nb_id == id ? 1 : 0) }
  end

  def put_autotile(x, y, tile_id)
    @map.data[x, y, 0] = (tile_id * 48 + 2048)
    @map.data[x, y, 1] = 0
    @map.data[x, y, 2] = 0
    update_autotile(x, y, 0)
    neighbors(x, y).each do |x2, y2|
      3.times { |z| update_autotile(x2, y2, z) }
    end
  end

  def update_autotile(x, y, z)
    id = autotile_type(x, y, z)
    return unless id.between?(0, 47)

    nb = neighbors(x, y).map do |x2, y2|
      autotile_type(x2, y2, z)
    end

    flag = autotile_flag(nb, id)

    @map.data[x, y, z] = (id * 48 + 2048) + AUTOTILE_LOOKUP[flag]
  end

  def neighbors(x, y)
    [*-1..1].product([*-1..1]).map do |iy, ix|
      next nil if iy.zero? && ix.zero?

      x2 = x + ix
      y2 = y + iy
      next [x, y] if !loop_horizontal? && (x2 < 0 || x2 > width)
      next [x, y] if !loop_vertical? && (y2 < 0 || y2 > height)

      [round_x(x2), round_y(y2)]
    end.compact
  end