tetris/lib/points.ex

defmodule Tetris.Points do

  def move_to_location(points, {x,y}) do
    Enum.map(points,fn {dx, dy} -> {dx + x, dy + y} end )
  end

  def transpose(points) do
    points
    |> Enum.map( fn {x,y} -> {y,x} end )
  end
  def mirror(points) do
    points
    |> Enum.map( fn{x,y} -> {5-x,y} end )
  end
  def mirror(points, false), do: points
  def mirror(points, true), do: mirror points

  def flip(points) do
    points
    |> Enum.map( fn{x,y} -> {x,5-y} end )
  end

  def rotate_90(points) do
    #by 90 degrees clockwise
    points
    |> transpose
    |> mirror
  end

  def rotate(points, 0),  do: points
  def rotate(points, degrees) do
     rotate(
       rotate_90(points),
       degrees - 90
     )
  end

  def with_colour(points, colour) do
    Enum.map(points,fn point -> add_colour(point, colour) end)
  end

  defp add_colour({_x, _y, _c} = point, _colour), do: point
  defp add_colour({x,y}, colour), do: {x,y,colour}



  #🔴
  #⬜
  #🟥
  def to_string(points) do
    map =
      points
      |> Enum.map(fn key -> {key, "🟥"} end)
      |> Map.new()

   for y <- (1 .. 4), x <- (1 .. 4) do
     Map.get(map,{x,y},"⬜")
   end
   |> Enum.chunk_every(4)
   |> Enum.map(&Enum.join/1)
   |> Enum.join("\n")
  end

  def print(points) do
    IO.puts __MODULE__.to_string(points)
    points
  end
end