defmodule MarsExplorer.HighlandGrid do
  @moduledoc """
  Module responsible for managing a highland grid
  """
  defstruct [:north_limit, :east_limit]

  @type t :: %__MODULE__{
          north_limit: integer(),
          east_limit: integer()
        }

  @doc """
  Generates the highland grid

  ## Examples

      iex> alias MarsExplorer.HighlandGrid
      MarsExplorer.HighlandGrid
      iex> HighlandGrid.build(%{north: 5, east: 5})
      %HighlandGrid{north_limit: 5, east_limit: 5}
  """
  @spec build(%{north: integer(), east: integer()}) :: t()
  def build(%{north: north, east: east}), do: %__MODULE__{north_limit: north, east_limit: east}

  @doc """
  Determines if a position would be within the highland grid's limits

  ## Examples

      iex> alias MarsExplorer.HighlandGrid
      MarsExplorer.HighlandGrid
      iex> grid = %HighlandGrid{north_limit: 5, east_limit: 5}
      %HighlandGrid{north_limit: 5, east_limit: 5}
      iex> grid |> HighlandGrid.valid_position?(%{north: 0, east: 0})
      true
      iex> grid |> HighlandGrid.valid_position?(%{north: 5, east: 5})
      true
      iex> grid |> HighlandGrid.valid_position?(%{north: 0, east: 6})
      false
      iex> grid |> HighlandGrid.valid_position?(%{north: 6, east: 0})
      false
  """
  @spec valid_position?(t(), %{north: integer(), east: integer()}) :: boolean()
  def valid_position?(
        %__MODULE__{north_limit: north_limit, east_limit: east_limit},
        %{north: north, east: east}
      ) do
    north >= 0 && north <= north_limit &&
      east >= 0 && east <= east_limit
  end
end