require 'games_dice'

describe GamesDice::Die do

  before do
    # Set state of default PRNG
    srand(4567)
  end

  describe "#new" do
    it "should return an object that represents e.g. a six-sided die" do
      die = GamesDice::Die.new(6)
      die.min.should == 1
      die.max.should == 6
      die.sides.should == 6
    end

    it "should accept any object with a rand(Integer) method as the second param" do
      prng = TestPRNG.new()
      die = GamesDice::Die.new(20,prng)
      [16,7,3,11,16,18,20,7].each do |expected|
        die.roll.should == expected
        die.result.should == expected
      end
    end
  end

  describe "#roll and #result" do
    it "should return results based on Ruby's internal rand() by default" do
    die = GamesDice::Die.new(10)
      [5,4,10,4,7,8,1,9].each do |expected|
        die.roll.should == expected
        die.result.should == expected
      end
    end
  end

  describe "#min and #max" do
    it "should calculate correct min, max" do
      die = GamesDice::Die.new(20)
      die.min.should == 1
      die.max.should == 20
    end
  end

  describe "#probabilities" do
    it "should return the die's probability distribution as a GamesDice::Probabilities object" do
      die = GamesDice::Die.new(6)
      die.probabilities.is_a?( GamesDice::Probabilities ).should be_true
      probs = die.probabilities

      probs.p_eql(1).should be_within(1e-10).of 1/6.0
      probs.p_eql(2).should be_within(1e-10).of 1/6.0
      probs.p_eql(3).should be_within(1e-10).of 1/6.0
      probs.p_eql(4).should be_within(1e-10).of 1/6.0
      probs.p_eql(5).should be_within(1e-10).of 1/6.0
      probs.p_eql(6).should be_within(1e-10).of 1/6.0
      probs.to_h.values.inject(:+).should be_within(1e-9).of 1.0

      probs.p_gt(6).should == 0.0
      probs.p_gt(-20).should == 1.0
      probs.p_gt(4).should be_within(1e-10).of 2/6.0

      probs.p_ge(20).should == 0.0
      probs.p_ge(1).should == 1.0
      probs.p_ge(4).should be_within(1e-10).of 0.5

      probs.p_le(6).should == 1.0
      probs.p_le(-3).should == 0.0
      probs.p_le(5).should be_within(1e-10).of 5/6.0

      probs.p_lt(7).should == 1.0
      probs.p_lt(1).should == 0.0
      probs.p_lt(3).should be_within(1e-10).of 2/6.0

      probs.expected.should be_within(1e-10).of 3.5
    end
  end

end