TheCorrespondingSquares/chess-app

require 'rails_helper'

RSpec.describe Pawn, type: :model do
  let(:user) { FactoryGirl.create(:user) }
  let(:user2) { FactoryGirl.create(:user) }
  let(:game) { FactoryGirl.create(:game, white_player_id: user.id, black_player_id: user2.id) }
  before(:each) { game.pieces.destroy_all }
  
  describe "#can_enpassant?" do
    subject(:enpassant) {pawn.can_enpassant?(to_x, to_y)}
    
    let!(:pawn) {FactoryGirl.create(:pawn, color: "Black", x_pos: 3, y_pos: 3, game_id: game.id)}
    let(:to_x) { 2 }
    let(:to_y) { 2 }

    context 'when there is an adjacent opponent pawn that has moved once' do
      let!(:pawn2) {FactoryGirl.create(:pawn, color: "White", x_pos: 2, y_pos: 3, game_id: game.id, turn: 1)}

      it { is_expected.to eq(true) }
    end
    
    context 'when there is not an adjacent opponent pawn' do
      let!(:pawn2) {FactoryGirl.create(:pawn, color: "White", x_pos: 1, y_pos: 3, game_id: game.id, turn: 1)}

      it { is_expected.to eq(false) }
    end
    
    context 'when there is an adjacent opponent pawn but is not first move' do
      let!(:pawn2) {FactoryGirl.create(:pawn, color: "White", x_pos: 2, y_pos: 3, game_id: game.id, turn: 2)}

      it { is_expected.to eq(false) }
    end
    
    context 'when adjacent pawn is NOT opponent pawn' do
      let!(:pawn2) {FactoryGirl.create(:pawn, color: "Black", x_pos: 2, y_pos: 3, game_id: game.id, turn: 1)}

      it { is_expected.to eq(false) }
    end
    
    context 'when your pawn and adjacent opponent pawn are in the middle of board' do
      let!(:pawn) {FactoryGirl.create(:pawn, color: "Black", x_pos: 3, y_pos: 4, game_id: game.id)}
      let!(:pawn2) {FactoryGirl.create(:pawn, color: "White", x_pos: 2, y_pos: 4, game_id: game.id, turn: 2)}
      let(:to_x) { 2 }
      let(:to_y) { 3 }

      it { is_expected.to eq(false) }
    end
  end

  describe "#move_to!" do
    context "for a valid enpassant move" do
      it "white pawn should successfully capture black pawn on adjacent square" do
        white_pawn = FactoryGirl.create(:pawn, color: "White", x_pos: 3, y_pos: 4, game_id: game.id)
        black_pawn = FactoryGirl.create(:pawn, color: "Black", x_pos: 4, y_pos: 4, game_id: game.id, turn: 1)

        white_pawn.move_to!(4, 5)
        white_pawn.reload
        black_pawn.reload

        expect(white_pawn.x_pos).to eq(4)
        expect(white_pawn.y_pos).to eq(5)
        expect(black_pawn.captured).to eq(true)
      end

      it "black pawn should successfully capture white pawn on adjacent square" do
        black_pawn = FactoryGirl.create(:pawn, color: "Black", x_pos: 3, y_pos: 3, game_id: game.id)
        white_pawn = FactoryGirl.create(:pawn, color: "White", x_pos: 2, y_pos: 3, game_id: game.id, turn: 1)

        black_pawn.move_to!(2, 2)
        black_pawn.reload
        white_pawn.reload

        expect(black_pawn.x_pos).to eq(2)
        expect(black_pawn.y_pos).to eq(2)
        expect(white_pawn.captured).to eq(true)
      end
    end

    context "for an invalid enpassant move" do
      context "when moving diagonally with no opponent pawn adjacent to destination" do
        it "should leave game unchanged" do
          white_pawn = FactoryGirl.create(:pawn, color: "White", x_pos: 3, y_pos: 4, game_id: game.id)
          black_pawn = FactoryGirl.create(:pawn, color: "Black", x_pos: 4, y_pos: 4, game_id: game.id, turn: 1)

          white_pawn.move_to!(2, 5)
          white_pawn.reload
          black_pawn.reload

          expect(white_pawn.x_pos).to eq(3)
          expect(white_pawn.y_pos).to eq(4)
          expect(black_pawn.captured).to eq(false)        
        end
      end

      context "when opponent pawn has moved more than once" do
        it "should leave game unchanged" do
          black_pawn = FactoryGirl.create(:pawn, color: "Black", x_pos: 3, y_pos: 3, game_id: game.id)
          white_pawn = FactoryGirl.create(:pawn, color: "White", x_pos: 2, y_pos: 3, game_id: game.id, turn: 2)

          black_pawn.move_to!(2, 2)
          black_pawn.reload
          white_pawn.reload

          expect(black_pawn.x_pos).to eq(3)
          expect(black_pawn.y_pos).to eq(3)
          expect(white_pawn.captured).to eq(false)
        end   
      end
    end
  end

  describe "#valid_move?" do
    subject(:valid_move?) { pawn.valid_move?(to_x, to_y) }

    let!(:pawn) { FactoryGirl.create(:pawn, color: "White", x_pos: 3, y_pos: 1, game_id: game.id) }

    context 'for valid move' do
      context 'there is another piece (same color) on destination square' do
        let!(:pawn2) { FactoryGirl.create(:pawn, color: "White", x_pos: 3, y_pos: 3, game_id: game.id) }
        let(:to_x) { 3 }
        let(:to_y) { 3 }

        it { is_expected.to eq(false) }
      end

      context 'there is another piece (opposite color) on destination square' do
        let!(:pawn2) { FactoryGirl.create(:pawn, color: "Black", x_pos: 3, y_pos: 3, game_id: game.id) }
        let(:to_x) { 3 }
        let(:to_y) { 3 }

        it { is_expected.to eq(false) }
      end

      context 'vertical first move' do
        let(:to_x) { pawn.x_pos }
        let(:to_y) { 3 }

        it { is_expected.to eq(true) }
      end

      context 'vertical move of the opponent' do
        let(:pawn) { FactoryGirl.create(:pawn, color: "Black", x_pos: 3, y_pos: 5, game_id: game.id) }
        let(:to_x) { pawn.x_pos }
        let(:to_y) { 4 }

        it { is_expected.to eq(true) }
      end

      context 'diagonal move with capture' do
        let!(:pawn2) { FactoryGirl.create(:pawn, color: "Black", x_pos: 4, y_pos: 2, game_id: game.id) }
        let(:to_x) { 4 }
        let(:to_y) { 2 }

        it { is_expected.to eq(true) }
      end

      context 'valid enpassant move' do
        let!(:pawn) { FactoryGirl.create(:pawn, color: "White", x_pos: 3, y_pos: 4, game_id: game.id) }
        let!(:pawn2) { FactoryGirl.create(:pawn, color: "Black", x_pos: 4, y_pos: 4, game_id: game.id, turn: 1) }
        let(:to_x) { 4 }
        let(:to_y) { 5 }

        it { is_expected.to eq(true) }
      end
    end

    context 'not valid move' do
      context '2 squares other than first move' do
        let(:pawn) { FactoryGirl.create(:pawn, color: "White", x_pos: 3, y_pos: 2, game_id: game.id) }
        let(:to_x) { pawn.x_pos }
        let(:to_y) { 4 }

        it { is_expected.to eq(false) }
      end

      context 'diagonal without capture' do
        let(:pawn) { FactoryGirl.create(:pawn, color: "White", x_pos: 3, y_pos: 1, game_id: game.id) }
        let(:to_x) { 4 }
        let(:to_y) { 2 }

        it { is_expected.to eq(false) }
      end

      context 'backward vertical move' do
        let(:to_x) { 3 }
        let(:to_y) { 0 }

        it { is_expected.to eq(false) }
      end

      context 'horizontal move' do
        let(:to_x) { 4 }
        let(:to_y) { 1 }

        it { is_expected.to eq(false) }
      end

      context 'invalid enpassant move' do
        let!(:pawn) { FactoryGirl.create(:pawn, color: "White", x_pos: 3, y_pos: 4, game_id: game.id) }
        let!(:pawn2) { FactoryGirl.create(:pawn, color: "Black", x_pos: 4, y_pos: 4, game_id: game.id, turn: 1) }
        let(:to_x) { 2 }
        let(:to_y) { 5 }

        it { is_expected.to eq(false) }        
      end
    end
  end
end