require "ruby_algebra"

RSpec.configure do |config|
  config.expect_with :rspec do |expectations|
    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
  end
end

RSpec.describe RubyAlgebra::Parser do
  describe "#parse" do
    it "returns nil for an empty string" do
      expect(RubyAlgebra::Parser.parse("")).to eq nil
    end

    it "returns Constant(a) for a" do
      [10, 100, 343843, 180.1, 777, 0.52242].each do |a|
        expect(RubyAlgebra::Parser.parse(a.to_s)).to eq RubyAlgebra::Constant.new(a)
      end
    end

    it "returns Variable(x) for x" do
      ["x", "y", "z", "coolVariable"].each do |x|
        expect(RubyAlgebra::Parser.parse(x)).to eq RubyAlgebra::Variable.new(x)
      end
    end

    it "returns Addition(Constant(5), Variable(x)) for 5 + x" do
      expect(RubyAlgebra::Parser.parse("5 + x")).to eq RubyAlgebra::Addition.new(RubyAlgebra::Constant.new(5), RubyAlgebra::Variable.new("x"))
    end

    it "returns Subtraction(Variable(z), Variable(h)) for z - h" do
      expect(RubyAlgebra::Parser.parse("z - h")).to eq RubyAlgebra::Subtraction.new(RubyAlgebra::Variable.new("z"), RubyAlgebra::Variable.new("h"))
    end

    it "returns Multiplication(Constant(5), Constant(8)) for 60 * 8" do
      expect(RubyAlgebra::Parser.parse("60 * 8")).to eq RubyAlgebra::Multiplication.new(RubyAlgebra::Constant.new(60), RubyAlgebra::Constant.new(8))
    end

    it "returns Division(Constant(3), Variable(j)) for 3/j" do
      expect(RubyAlgebra::Parser.parse("3/j")).to eq RubyAlgebra::Division.new(RubyAlgebra::Constant.new(3), RubyAlgebra::Variable.new("j"))
    end

    it "returns Division(Constant(3), Variable(j)) for 3/j" do
      expect(RubyAlgebra::Parser.parse("3/j")).to eq RubyAlgebra::Division.new(RubyAlgebra::Constant.new(3), RubyAlgebra::Variable.new("j"))
    end

    it "returns Power(Constant(2), Constant(24)) for 2^24" do
      expect(RubyAlgebra::Parser.parse("2^24")).to eq RubyAlgebra::Power.new(RubyAlgebra::Constant.new(2), RubyAlgebra::Constant.new(24))
    end

    it "returns Multiplication(Constant(-1), Variable(x)) for -x" do
      expect(RubyAlgebra::Parser.parse("-x")).to eq RubyAlgebra::Multiplication.new(RubyAlgebra::Constant.new(-1), RubyAlgebra::Variable.new("x"))
    end

    it "returns Variable(x) for +x" do
      expect(RubyAlgebra::Parser.parse("x")).to eq RubyAlgebra::Variable.new("x")
    end

    it "returns Addition(Addition(Constant(3), Constant(30)), Constant(300)) for 3 + 30 + 300" do
      expect(RubyAlgebra::Parser.parse("3 + 30 + 300")).to eq RubyAlgebra::Addition.new(RubyAlgebra::Addition.new(RubyAlgebra::Constant.new(3), RubyAlgebra::Constant.new(30)), RubyAlgebra::Constant.new(300))
    end

    it "returns Power(Constant(10), Power(Constant(10), Constant(10))) for 10 ^ 10 ^ 10" do
      expect(RubyAlgebra::Parser.parse("10 ^ 10 ^ 10")).to eq RubyAlgebra::Power.new(RubyAlgebra::Constant.new(10), RubyAlgebra::Power.new(RubyAlgebra::Constant.new(10), RubyAlgebra::Constant.new(10)))
    end
  end
end