# frozen_string_literal: true

require 'helpers'
# This spec demonstrates that documentation from the README.md works as intended

describe GamesDice do
  describe '#create' do
    it "converts a string such as '3d6+6' into a GamesDice::Dice object" do
      d = GamesDice.create '3d6+6'
      expect(d).to be_a GamesDice::Dice
    end

    it "takes a parameter 'dice_description', which is a string such as '3d6' or '2d4-1'" do
      d = GamesDice.create '3d6'
      expect(d).to be_a GamesDice::Dice
      d = GamesDice.create '2d4-1'
      expect(d).to be_a GamesDice::Dice
    end

    it "takes an optional parameter 'prng', which should be an object that has a method 'rand( integer )'" do
      prng = TestPRNG.new

      d = GamesDice.create '3d6', prng
      expect(d).to be_a GamesDice::Dice

      (0..5).each do |dresult|
        allow(prng).to receive(:rand).and_return(dresult)
        expect(prng).to receive(:rand).with(6)
        expect(d.roll).to eql (dresult + 1) * 3
      end
    end
  end
end

describe GamesDice::Dice do
  before :each do
    srand(67_809)
  end

  let(:dice) { GamesDice.create '3d6' }

  describe '#roll' do
    it 'simulates rolling the dice as they were described in the constructor' do
      expected_results = [11, 15, 11, 12, 12, 9]
      expected_results.each do |expected|
        expect(dice.roll).to eql expected
      end
    end
  end

  describe '#result' do
    it 'returns the value from the last call to roll' do
      expected_results = [11, 15, 11, 12, 12, 9]
      expected_results.each do |expected|
        dice.roll
        expect(dice.result).to eql expected
      end
    end

    it 'will be nil if no roll has been made yet' do
      expect(dice.result).to be_nil
    end
  end

  describe '#explain_result' do
    it 'attempts to show how the result from the last call to roll was composed' do
      expected_results = [
        '3d6: 3 + 6 + 2 = 11',
        '3d6: 4 + 5 + 6 = 15',
        '3d6: 3 + 6 + 2 = 11',
        '3d6: 5 + 6 + 1 = 12'
      ]
      expected_results.each do |expected|
        dice.roll
        expect(dice.explain_result).to eql expected
      end
    end

    it 'will be nil if no roll has been made yet' do
      expect(dice.explain_result).to be_nil
    end
  end

  describe '#max' do
    it 'returns the maximum possible value from a roll of the dice' do
      expect(dice.max).to eql 18
    end
  end

  describe '#min' do
    it 'returns the minimum possible value from a roll of the dice' do
      expect(dice.min).to eql 3
    end
  end

  describe '#minmax' do
    it 'returns an array [ dice.min, dice.max ]' do
      expect(dice.minmax).to eql [3, 18]
    end
  end

  describe '#probabilities' do
    it 'calculates probability distribution for the dice' do
      pd = dice.probabilities
      expect(pd).to be_a GamesDice::Probabilities
      expect(pd.p_eql(3)).to be_within(1e-10).of 1.0 / 216
      expect(pd.p_eql(11)).to be_within(1e-10).of 27.0 / 216
    end
  end
end

describe GamesDice::Probabilities do
  let(:probs) { GamesDice.create('3d6').probabilities }

  describe '#to_h' do
    it 'returns a hash representation of the probability distribution' do
      h = probs.to_h
      expect(h).to be_valid_distribution
      expect(h[3]).to be_within(1e-10).of 1.0 / 216
      expect(h[11]).to be_within(1e-10).of 27.0 / 216
    end
  end

  describe '#max' do
    it 'returns maximum result in the probability distribution' do
      expect(probs.max).to eql 18
    end
  end

  describe '#min' do
    it 'returns minimum result in the probability distribution' do
      expect(probs.min).to eql 3
    end
  end

  describe '#p_eql( n )' do
    it 'returns the probability of a result equal to the integer n' do
      expect(probs.p_eql(3)).to be_within(1e-10).of 1.0 / 216
      expect(probs.p_eql(2)).to eql 0.0
    end
  end

  describe '#p_gt( n )' do
    it 'returns the probability of a result greater than the integer n' do
      expect(probs.p_gt(17)).to be_within(1e-10).of 1.0 / 216
      expect(probs.p_gt(2)).to eql 1.0
    end
  end

  describe '#p_ge( n )' do
    it 'returns the probability of a result greater than the integer n' do
      expect(probs.p_ge(17)).to be_within(1e-10).of 4.0 / 216
      expect(probs.p_ge(3)).to eql 1.0
    end
  end

  describe '#p_le( n )' do
    it 'returns the probability of a result less than or equal to the integer n' do
      expect(probs.p_le(17)).to be_within(1e-10).of 215.0 / 216
      expect(probs.p_le(3)).to be_within(1e-10).of 1.0 / 216
    end
  end

  describe '#p_lt( n )' do
    it 'returns the probability of a result less than the integer n' do
      expect(probs.p_lt(17)).to be_within(1e-10).of 212.0 / 216
      expect(probs.p_lt(3)).to eql 0.0
    end
  end
end

describe 'String Dice Description' do
  before :each do
    srand(35_241)
  end

  describe "'1d6'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '1d6'
      expect((1..20).map { |_n| d.roll }).to eql [6, 3, 2, 3, 4, 6, 4, 2, 6, 3, 3, 5, 6, 6, 3, 6, 5, 2, 1, 4]
    end
  end

  describe "'2d6 + 1d4'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '2d6 + 1d4'
      expect((1..5).map { |_n| d.roll }).to eql [11, 10, 12, 12, 14]
    end
  end

  describe "'1d100 + 1d20 - 5'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '1d100 + 1d20 - 5'
      expect((1..5).map { |_n| d.roll }).to eql [75, 78, 24, 102, 32]
    end
  end

  describe "'1d10x'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '1d10x'
      expect((1..20).map { |_n| d.roll }).to eql [2, 3, 4, 7, 6, 7, 4, 2, 6, 3, 7, 5, 6, 7, 6, 6, 5, 19, 4, 19]
    end
  end

  describe "'1d6r1'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '1d6r1'
      expect((1..20).map { |_n| d.roll }).to eql [6, 3, 2, 3, 4, 6, 4, 2, 6, 3, 3, 5, 6, 6, 3, 6, 5, 2, 4, 2]
    end
  end

  describe "'5d10r:10,add.k2'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '5d10r:10,add.k2'
      expect((1..5).map { |_n| d.roll }).to eql [13, 13, 14, 38, 15]
    end
  end

  describe "'3d10m6'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '3d10m6'
      expect((1..6).map { |_n| d.roll }).to eql [0, 3, 1, 1, 3, 2]
    end
  end

  describe "'5d10k2'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '5d10k2'
      expect((1..5).map { |_n| d.roll }).to eql [13, 13, 14, 19, 19]
    end
  end

  describe "'5d10x'" do
    it "is the same as '5d10r:10,add.'" do
      srand(235_241)
      d = GamesDice.create '5d10x'
      results1 = (1..50).map { d.roll }

      srand(235_241)
      d = GamesDice.create '5d10r:10,add.'
      results2 = (1..50).map { d.roll }

      expect(results1).to eql results2
    end
  end

  describe "'1d6r:1.'" do
    it "should return same as '1d6r1'" do
      srand(235_241)
      d = GamesDice.create '1d6r:1.'
      results1 = (1..50).map { d.roll }

      srand(235_241)
      d = GamesDice.create '1d6r1'
      results2 = (1..50).map { d.roll }

      expect(results1).to eql results2
    end
  end

  describe "'1d10r:10,replace,1.'" do
    it 'should roll a 10-sided die, re-roll a result of 10 and take the value of the second roll' do
      d = GamesDice.create '1d10r:10,replace,1.'
      expect((1..27).map do
               d.roll
             end).to eql [2, 3, 4, 7, 6, 7, 4, 2, 6, 3, 7, 5, 6, 7, 6, 6, 5, 9, 4, 9, 8, 3, 1, 6, 7, 1, 1]
    end
  end

  describe "'1d20r:<=10,use_best,1.'" do
    it 'should roll a 20-sided die, re-roll a result if 10 or lower, and use best result' do
      d = GamesDice.create '1d20r:<=10,use_best,1.'
      expect((1..20).map do
               d.roll
             end).to eql [18, 19, 20, 20, 3, 11, 7, 20, 15, 19, 6, 16, 17, 16, 15, 11, 9, 15, 20, 16]
    end
  end

  describe "'5d10r:10,add.k2', '5d10xk2' and '5d10x.k2'" do
    it 'should all be equivalent' do
      srand(135_241)
      d = GamesDice.create '5d10r:10,add.k2'
      results1 = (1..50).map { d.roll }

      srand(135_241)
      d = GamesDice.create '5d10xk2'
      results2 = (1..50).map { d.roll }

      srand(135_241)
      d = GamesDice.create '5d10x.k2'
      results3 = (1..50).map { d.roll }

      expect(results1).to eql results2
      expect(results1).to eql results3
    end
  end

  describe "'5d10r:>8,add.'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '5d10r:>8,add.'
      expect((1..5).map { |_n| d.roll }).to eql [22, 22, 31, 64, 26]
    end
  end

  describe "'9d6x.m:10.'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '9d6x.m:10.'
      expect((1..5).map { |_n| d.roll }).to eql [1, 2, 1, 1, 1]
    end
    it 'can be explained as number of exploding dice scoring 10+' do
      d = GamesDice.create '9d6x.m:10.'
      expect((1..5).map do |_n|
               d.roll
               d.explain_result
             end).to eql [
               '9d6: [6+3] 9, 2, 3, 4, [6+4] 10, 2, [6+3] 9, 3, 5. Successes: 1',
               '9d6: [6+6+3] 15, [6+5] 11, 2, 1, 4, 2, 1, 3, 5. Successes: 2',
               '9d6: 1, [6+6+1] 13, 2, 1, 1, 3, [6+1] 7, 5, 4. Successes: 1',
               '9d6: [6+4] 10, 3, 4, 5, 5, 1, [6+3] 9, 3, 5. Successes: 1',
               '9d6: [6+3] 9, 3, [6+5] 11, 4, 2, 2, 1, 4, 5. Successes: 1'
             ]
    end
  end

  describe "'9d6x.m:10,1,S.'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '9d6x.m:10,1,S.'
      expect((1..5).map { |_n| d.roll }).to eql [1, 2, 1, 1, 1]
    end
    it "includes the string 'S' next to each success" do
      d = GamesDice.create '9d6x.m:10,1,S.'
      expect((1..5).map do |_n|
               d.roll
               d.explain_result
             end).to eql [
               '9d6: [6+3] 9, 2, 3, 4, [6+4] 10 S, 2, [6+3] 9, 3, 5. Successes: 1',
               '9d6: [6+6+3] 15 S, [6+5] 11 S, 2, 1, 4, 2, 1, 3, 5. Successes: 2',
               '9d6: 1, [6+6+1] 13 S, 2, 1, 1, 3, [6+1] 7, 5, 4. Successes: 1',
               '9d6: [6+4] 10 S, 3, 4, 5, 5, 1, [6+3] 9, 3, 5. Successes: 1',
               '9d6: [6+3] 9, 3, [6+5] 11 S, 4, 2, 2, 1, 4, 5. Successes: 1'
             ]
    end
  end

  describe "'5d10m:>=6,1,S.m:==1,-1,F.'" do
    it 'returns expected results from rolling' do
      d = GamesDice.create '5d10m:>=6,1,S.m:==1,-1,F.'
      expect((1..10).map { |_n| d.roll }).to eql [2, 2, 4, 3, 2, 1, 1, 3, 3, 0]
    end
    it "includes the string 'S' next to each success, and 'F' next to each 'fumble'" do
      d = GamesDice.create '5d10m:>=6,1,S.m:==1,-1,F.'
      expect((1..5).map do |_n|
               d.roll
               d.explain_result
             end).to eql [
               '5d10: 2, 3, 4, 7 S, 6 S. Successes: 2',
               '5d10: 7 S, 4, 2, 6 S, 3. Successes: 2',
               '5d10: 7 S, 5, 6 S, 7 S, 6 S. Successes: 4',
               '5d10: 6 S, 5, 10 S, 9 S, 4. Successes: 3',
               '5d10: 10 S, 9 S, 8 S, 3, 1 F. Successes: 2'
             ]
    end
  end

  describe "'4d6k:3.r:1,replace,1.'" do
    it 'represents roll 4 six-sided dice, re-roll any 1s, and keep best 3.' do
      d = GamesDice.create '4d6k:3.r:1,replace,1.'
      expect((1..10).map { |_n| d.roll }).to eql [12, 14, 14, 18, 11, 17, 11, 15, 14, 14]
    end
    it 'includes re-rolls and keeper choice in explanations' do
      d = GamesDice.create '4d6k:3.r:1,replace,1.'
      expect((1..5).map do |_n|
               d.roll
               d.explain_result
             end).to eql [
               '4d6: 6, 3, 2, 3. Keep: 3 + 3 + 6 = 12',
               '4d6: 4, 6, 4, 2. Keep: 4 + 4 + 6 = 14',
               '4d6: 6, 3, 3, 5. Keep: 3 + 5 + 6 = 14',
               '4d6: 6, 6, 3, 6. Keep: 6 + 6 + 6 = 18',
               '4d6: 5, 2, [1|4] 4, 2. Keep: 2 + 4 + 5 = 11'
             ]
    end
  end

  describe "'2d20k:1,worst.'" do
    it 'represents roll 2 twenty-sided dice, return lowest of the two results' do
      d = GamesDice.create '2d20k:1,worst.'
      expect((1..10).map { |_n| d.roll }).to eql [18, 6, 2, 3, 5, 10, 15, 1, 7, 10]
    end
    it 'includes keeper choice in explanations' do
      d = GamesDice.create '2d20k:1,worst.'
      expect((1..5).map do |_n|
               d.roll
               d.explain_result
             end).to eql [
               '2d20: 18, 19. Keep: 18',
               '2d20: 20, 6. Keep: 6',
               '2d20: 20, 2. Keep: 2',
               '2d20: 3, 11. Keep: 3',
               '2d20: 5, 7. Keep: 5'
             ]
    end
  end
end