# frozen_string_literal: true

RSpec.describe Fear::Right do
  it_behaves_like Fear::RightBiased::Right do
    let(:right) { Fear.right("value") }
  end

  let(:right) { Fear.right("value") }

  describe "#right?" do
    subject { right }
    it { is_expected.to be_right }
  end

  describe "#left?" do
    subject { right }
    it { is_expected.not_to be_left }
  end

  describe "#select_or_else" do
    subject { right.select_or_else(default, &predicate) }

    context "predicate evaluates to true" do
      let(:predicate) { ->(v) { v == "value" } }
      let(:default) { -1 }
      it { is_expected.to eq(right) }
    end

    context "predicate evaluates to false and default is a proc" do
      let(:predicate) { ->(v) { v != "value" } }
      let(:default) { -> { -1 } }
      it { is_expected.to eq(Fear.left(-1)) }
    end

    context "predicate evaluates to false and default is not a proc" do
      let(:predicate) { ->(v) { v != "value" } }
      let(:default) { -1 }
      it { is_expected.to eq(Fear.left(-1)) }
    end
  end

  describe "#select" do
    subject { right.select(&predicate) }

    context "predicate evaluates to true" do
      let(:predicate) { ->(v) { v == "value" } }
      it { is_expected.to eq(right) }
    end

    context "predicate evaluates to false" do
      let(:predicate) { ->(v) { v != "value" } }
      it { is_expected.to eq(Fear.left("value")) }
    end
  end

  describe "#reject" do
    subject { right.reject(&predicate) }

    context "predicate evaluates to true" do
      let(:predicate) { ->(v) { v == "value" } }
      it { is_expected.to eq(Fear.left("value")) }
    end

    context "predicate evaluates to false" do
      let(:predicate) { ->(v) { v != "value" } }
      it { is_expected.to eq(right) }
    end
  end

  describe "#swap" do
    subject { right.swap }
    it { is_expected.to eq(Fear.left("value")) }
  end

  describe "#reduce" do
    subject do
      right.reduce(
        ->(left) { "Left: #{left}" },
        ->(right) { "Right: #{right}" },
      )
    end

    it { is_expected.to eq("Right: value") }
  end

  describe "#join_right" do
    context "value is Either" do
      subject { described_class.new(value).join_right }
      let(:value) { Fear.left("error") }

      it "returns value" do
        is_expected.to eq(value)
      end
    end

    context "value is not Either" do
      subject { proc { described_class.new("35").join_right } }

      it "fails with type error" do
        is_expected.to raise_error(TypeError)
      end
    end
  end

  describe "#join_left" do
    context "value is Either" do
      subject { either.join_left }
      let(:either) { described_class.new(Fear.left("error")) }

      it { is_expected.to eq(either) }
    end

    context "value is not Either" do
      subject { either.join_left }
      let(:either) { described_class.new("result") }
      it { is_expected.to eq(either) }
    end
  end

  describe "#match" do
    context "matched" do
      subject do
        right.match do |m|
          m.right(->(x) { x.length < 2 }) { |x| "Right: #{x}" }
          m.right(->(x) { x.length > 2 }) { |x| "Right: #{x}" }
          m.left(->(x) { x.length > 2 }) { |x| "Left: #{x}" }
        end
      end

      it { is_expected.to eq("Right: value") }
    end

    context "nothing matched and no else given" do
      subject do
        proc do
          right.match do |m|
            m.right(->(x) { x.length < 2 }) { |x| "Right: #{x}" }
            m.left { |_| "noop" }
          end
        end
      end

      it { is_expected.to raise_error(Fear::MatchError) }
    end

    context "nothing matched and else given" do
      subject do
        right.match do |m|
          m.right(->(x) { x.length < 2 }) { |x| "Right: #{x}" }
          m.else { :default }
        end
      end

      it { is_expected.to eq(:default) }
    end
  end

  describe "#to_s" do
    subject { right.to_s }

    it { is_expected.to eq('#<Fear::Right value="value">') }
  end
end