scottwillson/racing_on_rails

# frozen_string_literal: true

require File.expand_path("../test_case", __dir__)
require File.expand_path("../../lib/array/each_row", __dir__)
require File.expand_path("../../lib/enumerable/stable_sort", __dir__)

# :stopdoc:
class EnumerableTest < Ruby::TestCase
  def test_each_row
    assert_equal([nil, nil], [].each_row { |row| })
    assert_equal([[1]], [1].each_row { |row| })
    assert_equal([[1, 2]], [1, 2].each_row { |row| })
    assert_equal([[1, 3], [2]], [1, 2, 3].each_row { |row| })
    assert_equal([[1, 3], [2, 4]], [1, 2, 3, 4].each_row { |row| })
    assert_equal([[1, 4], [2, 5], [3, 6]], [1, 2, 3, 4, 5, 6].each_row { |row| })
  end

  def test_merge_sort
    assert_equal([], [].merge_sort, "[].merge_sort")
    assert_equal([9], [9].merge_sort, "[9].merge_sort")
    assert_equal([1, 2], [1, 2].merge_sort, "[1, 2].merge_sort")
    assert_equal([1, 2, 7], [7, 1, 2].merge_sort, "[7, 1, 2].merge_sort")
    assert_equal([-20, 0, 0, 0, 1, 2, 7], [0, 0, 7, 1, 2, 0, -20].merge_sort, "[0, 0, 7, 1, 2, 0, -20].merge_sort")

    assert_equal_enumerables([-20, 0, 0, 0, 1, 2, 7],
                             [0, 0, 7, 1, 2, 0, -20].merge_sort { |x, y| x > y },
                             "[0, 0, 7, 1, 2, 0, -20].merge_sort { |x, y| x > y }")

    assert_equal_enumerables([7, 2, 1, 0, 0, 0, -20],
                             [0, 0, 7, 1, 2, 0, -20].merge_sort { |x, y| x < y },
                             "[0, 0, 7, 1, 2, 0, -20].merge_sort { |x, y| x < y }")
  end

  def test_merge_sort_preserves_order
    king_hearts   = Card.new("king", "hearts")
    king_diamonds = Card.new("king", "diamonds")
    king_spades   = Card.new("king", "spades")
    king_clubs    = Card.new("king", "clubs")

    assert_equal_enumerables(
      [king_hearts, king_diamonds, king_spades, king_clubs],
      [king_hearts, king_diamonds, king_spades, king_clubs].merge_sort,
      "merge_sort of equal elements should preserve order"
    )

    assert_equal_enumerables(
      [king_hearts, king_diamonds, king_spades, king_clubs],
      [king_hearts, king_diamonds, king_spades, king_clubs].merge_sort { |x, y| x.value > y.value },
      "merge_sort of equal elements should preserve order"
    )

    assert_equal_enumerables(
      [king_hearts, king_diamonds, king_spades, king_clubs],
      [king_hearts, king_diamonds, king_spades, king_clubs].merge_sort { |x, y| x.value < y.value },
      "merge_sort of equal elements should preserve order"
    )

    assert_equal_enumerables(
      [king_clubs, king_diamonds, king_hearts, king_spades],
      [king_hearts, king_diamonds, king_spades, king_clubs].merge_sort { |x, y| x.suit > y.suit },
      "merge_sort of equal elements should preserve order"
    )

    assert_equal_enumerables(
      [king_spades, king_hearts, king_diamonds, king_clubs],
      [king_hearts, king_diamonds, king_spades, king_clubs].merge_sort { |x, y| x.suit < y.suit },
      "merge_sort of equal elements should preserve order"
    )
  end

  def test_multiple_sorts_preserve_order
    king_hearts   = Card.new(14, "hearts")
    diamonds_10   = Card.new(10, "diamonds")
    diamonds_8    = Card.new(8, "diamonds")
    hearts_queen  = Card.new(13, "hearts")

    list = [king_hearts, diamonds_10, diamonds_8, hearts_queen]
    list = list.merge_sort { |x, y| x.suit >= y.suit }
    assert_equal_enumerables([diamonds_10, diamonds_8, king_hearts, hearts_queen], list, "Sorted by suit")

    list = list.merge_sort { |x, y| x.value >= y.value }
    assert_equal_enumerables([diamonds_8, diamonds_10, hearts_queen, king_hearts], list, "Sorted by value")

    list = list.merge_sort { |x, y| x.suit >= y.suit }
    list = list.merge_sort { |x, y| x.value >= y.value }
    list = list.merge_sort { |x, y| x.suit >= y.suit }
    list = list.merge_sort { |x, y| x.value >= y.value }
    list = list.merge_sort { |x, y| x.suit >= y.suit }
    list = list.merge_sort { |x, y| x.value >= y.value }
    list = list.merge_sort { |x, y| x.suit >= y.suit }
    list = list.merge_sort { |x, y| x.value >= y.value }
    assert_equal_enumerables([diamonds_8, diamonds_10, hearts_queen, king_hearts], list, "Sorted by value")
  end

  def test_stable_sort_by
    king_hearts   = Card.new(14, "hearts")
    diamonds_10   = Card.new(10, "diamonds")
    diamonds_8    = Card.new(8, "diamonds")
    hearts_queen  = Card.new(13, "hearts")

    list = [king_hearts, diamonds_10, diamonds_8, hearts_queen]
    list = list.stable_sort_by(:suit)
    assert_equal_enumerables([diamonds_10, diamonds_8, king_hearts, hearts_queen], list, "Sorted by suit")

    list = list.stable_sort_by(:value)
    assert_equal_enumerables([diamonds_8, diamonds_10, hearts_queen, king_hearts], list, "Sorted by value")

    list = list.stable_sort_by(:suit)
    list = list.stable_sort_by(:value)
    list = list.stable_sort_by(:suit)
    list = list.stable_sort_by(:value)
    list = list.stable_sort_by(:suit)
    list = list.stable_sort_by(:value)
    list = list.stable_sort_by(:suit)
    list = list.stable_sort_by(:value)
    assert_equal_enumerables([diamonds_8, diamonds_10, hearts_queen, king_hearts], list, "Sorted by value")

    list = list.stable_sort_by(:value, :desc)
    assert_equal_enumerables([king_hearts, hearts_queen, diamonds_10, diamonds_8], list, "Sorted by value desc")
  end

  def test_stable_sort_nil
    diamonds_10   = Card.new(10, "diamonds")
    diamonds_nil  = Card.new(nil, "diamonds")
    hearts_queen  = Card.new(13, "hearts")

    list = [diamonds_10, diamonds_nil, hearts_queen]
    list = list.stable_sort_by(:value)
    assert_equal_enumerables([diamonds_10, hearts_queen, diamonds_nil], list, "Sorted by value")
  end
end

class Card
  attr_accessor :value, :suit

  include Comparable

  def initialize(value, suit)
    @value = value
    @suit = suit
  end

  def <=>(other)
    return -1 unless other

    value <=> other.value
  end

  def to_s
    "#{value} #{suit}"
  end
end