tetris/lib/brick.ex

defmodule Tetris.Brick  do
  alias Tetris.Points

  @x_centre 40

  defstruct [
    name: :i,
    location: {40,0},
    rotation: 0,
    reflection: false
  ]

  def new(attributes \\ []), do: __struct__(attributes)

  def new_random() do
    %__MODULE__{
      name: random_name(),
      location: {40,0},
      rotation: random_rotation(),
      reflection: random_reflection()
    }
  end

  def random_name() do
    ~w(i l z o t)a
    |> Enum.random()
  end

  def random_rotation() do
    [0, 90, 180, 270]
    |> Enum.random()
  end


  def random_reflection() do
    [true, false]
    |> Enum.random
  end

  def left(brick) do
    %{brick| location: point_left(brick.location)}
  end

  def right(brick) do
    %{brick| location: point_right(brick.location)}
  end

  def down(brick) do
    %{brick| location: point_down(brick.location)}
  end

  def point_down({x,y}) do
    {x,y+1}
  end
  def point_left({x,y}) do
    {x-1,y}
  end
  def point_right({x,y}) do
    {x+1,y}
  end

  def spin_90(brick) do
    %{brick| rotation: rotate(brick.rotation)}
  end
  def rotate(270), do: 0
  def rotate(degrees), do: degrees + 90


  def shape(%{name: :l}) do
    [
     {2,1},
     {2,2},
     {2,3}, {3,3}
    ]
  end
  def shape(%{name: :i}) do
    [
     {2,1},
     {2,2},
     {2,3},
     {2,4}
    ]
  end
  def shape(%{name: :o}) do
    [
     {2,2}, {3,2},
     {2,3}, {3,3}
    ]
  end
  def shape(%{name: :z}) do
    [
      {2,2},
      {2,3}, {3,3},
             {3,4}
     ]
  end
  def shape(%{name: :t}) do
    [
     {2,1},
     {2,2}, {3,2} ,
     {2,3}
    ]
  end

  def prepare(brick) do
    brick
    |> shape
    |> Points.rotate(brick.rotation)
    |> Points.mirror(brick.reflection)
  end

  def to_string(brick) do
    brick
    |> prepare
    |> Points.to_string
  end

  def print(brick) do
    brick
    |> prepare
    |> Points.print

    brick
  end

  def colour(%{name: :i}), do: :blue
  def colour(%{name: :l}), do: :green
  def colour(%{name: :z}), do: :orange
  def colour(%{name: :o}), do: :red
  def colour(%{name: :t}), do: :yellow



  def x_centre(), do: @x_centre

  defimpl Inspect do
    import Inspect.Algebra
    def inspect(brick, _opts) do
      concat([
        "\n",
        Tetris.Brick.to_string(brick),
        "\n",
        "location  : #{inspect(brick.location)}",
        "\n",
        "reflection: #{inspect(brick.reflection)}",
        "\n",
        "rotation  : #{inspect(brick.rotation)}"
        ])
    end
  end

end