Chess

This project is part of the The Odin Project's Ruby curriculum.

Table Of Contents

1. Description
2. Demo
3. Built With
4. Try Yourself
5. How To Play
6. Workflow
7. Features
8. Implementation Details
9. Possible Enhancements
10. What I Learned
11. Acknowledgements

Description

What is Chess?

Chess is a board game played between 2 players. More on Chess details here.

Why did I create this?

It's the capstone project of The Odin Project's Ruby Programming course to practice and utilize what I learned throughout the course.

My experience

It's definitely a big project. I thought chess is a complicated game because I don't have much experience with chess before starting to work on this project. But after doing some research it clicked, it felt simple. Planning and Refactoring helped me stay in the right direction. I spent more time refactoring my code than writing the code. Honestly I enjoyed it. And here comes the important part, Tests. Without tests I can't imagine how I might approached this project. So overall I gained more experience in Planning, Refactoring, Writing Unit Tests, Serialization, OOP concepts like SOLID, Inheritance, Composition, etc.

Demo

Built With

Tool	Use Case
Ruby	Programming Language
RSpec	Unit Tests
Git & GitHub	Source Code Management

Try Yourself

Online

You can try in mobile also... Here's the LINK to try online.

Local

Prerequisites

ruby 3 - Recommended
ruby 2.7.4 or higher - Will work

Step 1: Clone the Repository

git clone [email protected]:Maheshkumar-novice/chess.git

Step 2: Move to Chess Directory

cd chess

Step 3: Run the main ruby file

ruby main.rb

Bonus: Pass Custom FEN

ruby main.rb 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1'

This will load the given FEN to create the game state.

To Run the Test Suite

Step 1: Install RSpec

gem install rspec

Step 2: Run the Test Suite

rspec

How To Play

General Instructions

• Run the game
• Choose Mode
• Create names if asked
• Board will be shown
• First prompt will ask you to choose a source, that is the cell of the piece you want to move
• You can enter cmd in this step to enter command mode
• Second prompt will ask you to choose a destination, that is the cell you want your piece to go

Command Mode

• Available Commands: draw, resign, save, fen, exit
• draw - It'll propose draw to your opponent after the completion of your current move
• resign - It'll announce opponent as a winner
• save - Save your current game, named as your-name-vs-opponent-name-date-time.yml format
• fen - Shows the current FEN notation of the game
• exit - Exits from the command mode to the game

Workflow

General

• Research & Plan the feature by writing it down in a text editor
• Implement the feature
• Refactor
• Write Tests
• Refactor
• If the game playable, test it by playing

Git

• Long Running Branches workflow
• main branch with most stable version
• dev branch with new feature updates, partially stable, will be merged into main once become stable
• feature branches to create new features and will be merged into dev

Features

Core

• Basic movements and captures
• Check
• Checkmate
• Stalemate
• Castling
• En Passant
• Promotion

Additional

• 50 move rule Draw
• Manual Draw
• Resignation
• Command Mode
• Save & Load games
• Copy FEN
• Load a FEN game of your wish by passing it as a command line argument

Others

• Colorful UI
• Mobile support

Possible Enhancements

• Refactor Game class
• Validator for FEN
• 5 fold repetition Draw
• Insufficient material Draw
• Bot player improvement

Implementation Details

Board is inspired from the Graph data strucutre. Board holds 64 cell objects, where each cell object know who is their neighbour. It is, each cell object stores the location of their row_right, row_left, column_above, column_below, top_left_diagonal, top_right_diagonal, bottom_right_diagonal, bottom_left_diagonal neighbours.

Board

• Hash with 64 pieces
• Key: Symbol represent the cell coordinate (e.g. :a8)
• Value: A cell object represents the board cell

Cell

• Object that holds the piece
• It stores the location of their neighbours

flowchart LR
cell --- row_right
cell --- row_left
cell --- column_above
cell --- column_below
cell --- top_left_diagonal
cell --- top_right_diagonal
cell --- bottom_right_diagonal
cell --- bottom_left_diagonal

Check

Whenever a player make a move their king shouldn't be in check.

Knight Move

I designed knight's move as, one step forward in the four directions it can step and the diagonal moves related to that forward step. For example, If the knight generate moves for it's left side,

• It can step on the left side
• It can go to either the top left diagonal or the bottom left diagonal

Then we use other objects to operate and manipulate this board and the pieces in the cells to play the game of chess.

What I Learned

• Importance of Refactoring
• Importance of Planning
• Importance of Tests
• SOLID priniciples of OOP
• More about Composition
• More about Inheritance
• And more....

Acknowledgements

• The Odin Project
• Lichess
• Chess.com
• Replit
• Wikipedia
• Chess Variants
• Chess Programming

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