space_game_server/game/spec/universe_spec.rb

# frozen_string_literal: true

require './universe'
require './planet'
require './position'
require './universe_array'

require './spec/stdout_helper'

RSpec.describe Universe do

  let(:name)          { 'Test Universe' }
  let(:universe_size) { 3 }
  let(:seed)          { 12345 }

  subject(:universe) do
    Universe.new(
      name,
      universe_size: universe_size,
      seed:          seed,
      create_chances: { planet: 1 }   # force a planet at every valid spot
    )
  end

  describe '#initialize' do
    it 'stores all expected instance variables' do
      expect(universe.name).to eq name
      expect(universe.instance_variable_get(:@universe_size)).to eq universe_size
      expect(universe.instance_variable_get(:@seed)).to eq seed
    end

    it 'creates a deterministic Random object when a seed is given' do
      rng = universe.instance_variable_get(:@random)
      expect(rng).to be_a(Random)
      expect(rng.rand(100)).to eq Random.new(seed).rand(100)
    end

    it 'initializes the random if no seed is passed in' do
      uni = Universe.new(name)
      rng = uni.instance_variable_get(:@random)
      expect(rng).to be_a(Random)
    end
  end

  describe '#create_universe' do

  end

  describe '#distance' do
    it 'is symmetric' do
      a = Position.new(0, 0)
      b = Position.new(4, 2)
      expect(universe.distance(a, b)).to eq universe.distance(b, a)
    end

    it 'returns 0 when both points are identical' do
      p = Position.new(1, 1)
      expect(universe.distance(p, p)).to eq 0
    end

    it 'correctly computes known hex distances' do
      p0 = Position.new(0, 0)
      p1 = Position.new(2, 0)
      p2 = Position.new(4, 2)
      p3 = Position.new(2, 2)
      # (0,0) to (2,0)  → 1
      expect(universe.distance(p0, p1)).to eq 1
      # (0,0) to (4,2)  → 3
      expect(universe.distance(p0, p2)).to eq 3
      # (0,0) to (2,2)  → 2
      expect(universe.distance(p0, p3)).to eq 2
    end
  end # describe '#distance'

  describe '#map generation' do
    it 'creates the expected dimensions' do
      universe.create_universe
      map = universe.instance_variable_get(:@universe_map)
      # Each valid (x,y) pair inside the radius contains a Planet
      # (our stub) and every other entry is nil.
      expect(map).to be_a(UniverseArray)
      # Check how may nodes were created:
      expect(map.flatten.compact.length).to eq 19 # 1 + 1*6 + 2*6
    end

    it 'contains a planet at every valid point when create_chances is 1' do
      universe.create_universe
      map = universe.instance_variable_get(:@universe_map)
      map.each do |row|
        row.each do |idx|
          # The indexes are allowed to be nil
          if idx.nil?
            next # Is allowed to be nil
          end
          if idx.is_a? Star
            next # Is allowed to be star
          end
          expect(idx).to be_a(Planet)
        end
      end
    end # describe '#map generation'

    it 'is deterministic when the same seed is used' do
      first_universe = Universe.new(
        name,
        universe_size: universe_size,
        seed:          seed,
        create_chances: { planet: 0.1 }
      )
      first_map = first_universe.instance_variable_get(:@universe_map)

      second_universe = Universe.new(
        name,
        universe_size: universe_size,
        seed:          seed,
        create_chances: { planet: 0.1 }
      )
      second_map = second_universe.instance_variable_get(:@universe_map)

      expect(first_map).to eq second_map
    end
  end

  describe '#print_universe' do
    it 'prints the center point as “O”' do
      out = capture_stdout do
        universe.create_universe
        universe.print_universe
      end
      expect(out).to include('O')
    end

    it 'can print blank spaces for nothing' do
      out = capture_stdout do
        uni = Universe.new(name, create_chances: {planet: 0.0})
        uni.create_universe
        uni.print_universe
      end
      expect(out).to include('O')
      expect(out).to include('- -')
    end
  end

  describe '#planets' do
    it 'lists all of the generated planets' do
      universe.create_universe
      expect(universe.planets.length).to eq 18
    end
  end

  describe '#tick' do
    it 'runs a tick of the game' do
      universe.create_universe
      player_1 = Player.new('test player 01')
      universe.add_player(player_1)
      universe.add_ship(player_1, Position.new(3, 5))
      ships = universe.get_player_ships(player_1)
      universe.move_ship(player_1, ships[0], Position.new(2, 4))
      # Now we tick the universe and the ship should move a little and the player should gain resources.
      expect{universe.tick}.to_not raise_error()
    end
  end
end