WordFall

Requirements

• Swift 5.1
• iOS 13+

Idea

Write a small game. The player will see a word in language „one“ on the screen. While this word is displayed, a word in language „two“ will fall down on the screen. The player will have to choose if the falling word is the correct translation or a wrong translation. The player needs to answer, before the word reaches the bottom of the screen. A counter that gives the player feedback should be included.

Concept

• Game will choose 10 (by default) random words from a words souce
• Game will give user 2 (by default) chances (lifes) to make an error
• Every time user makes an error, user loses a life
• If user lost all lifes by missing translation, user lose
• User will confirm translation by tapping on a falling word
• User will see action/no actionfeedback when:
  • Taps on a word to confirm translation - word becomes green
  • Doesn't tap on a word and word reaches boundary - word becomes red
• User will see his/her score in the top left corner
• User will see his/her lifes count in the right corner

Time Distribution

Design/Concept	Model	Views	Game Mechanics
~1.5h	~1h	1h	~2h

Technical Desicions

Architecture

MVVM-C has been choosen as an app architecture for an assignment. MVVM-C plays very nicely with the Combine framework and allows to have a clear separation between the View and ViewModel. Also, it shall pretty straightforward to refactor the UI layer to SwiftUI without changing the view models at all.

Coordinators for routing

Coordinator pattern is being used because there was a plan to implement multiple screen (e.g. Settings Screen).

Dependecy Injection

All the dependencies are injected using constructor injection. This makes it easier to replace concrete implementation with mocks for unit testing or have a different implementation of some functionality depending on the actual need. For example, we can have multiple implementation of the WordsSource protocol, one for loading the data from a local resource and another one for loading the data from a remote resource.

Game Implementation

The following options were considered:

• SpriteKit - probably the most obvious choice for any 2D game if iOS platform is the only target. SpriteKit wasn't used cuz it feels a little bit too heavy for such a small game.
• UIKit Dynamics - very easy to use, provides all the game functionality out of the box, almost no setup required, easy to extend with a new functionality. Feels like a good compromise between UIView Animation\CoreAnimation and SpriteKit.
• UIView Animations\CoreAnimation - will require an additional setup in comparison to UIKit Dynamics, lots of code overhead, CADisplayLink requirement for a smooth animations, hard to extend with a new functionality.

Decisions Made bacause of resticted time and Improvements

• There was an idea to implement an additional screen like settings that would allow to configure certain game parameters like game speed, number of lifes per fame and number of words per game.
• Dependency Injection is done in the Coordinator. I would prefer to have a separate depdency container. I also like the idea of utilizing the property wrappers which make the DI very straightforward. The proper container implementation either requires external dependencies and additional time.
• There was an idea to implement RemoteWordsSource and use words.json from the Github gist and use LocalWordsSource as a backup if there is no internet connection or any other error occured.
• I guess, game state management could be better. I really like the behind the RxFeedback or CombineFeedback and I think a similar approach could be used there to improve state management.
• UITests to make sure that everything works end to end.