Badges And Achievements

The task from iPhone Photography School.

Assumptions

These have been the assumptions while working on the test application.

User can have many achievements and vice versa.
User can have many badges and vice versa.
The events Lesson Watched and Comment Written are fired whenever a user watches a video or comments down, and the application acts according to that.
The application has following achievements:
1. First CommentWritten
2. Three Comments Written
3. FiveCommentsWritten
4. TenCommentsWritten
5. TwentyCommentsWritten
6. FirstLessonWatched
7. 5 Lessons Watched
8. 25 Lessons Watched
9. 50 Lessons Watched
The application has following badges:
1. Beginner: 0 Achievements
2. Intermediate: 4 Achievements
3. Advanced: 8 Achievements
4. Master: 10 Achievements

Solution formulation

Steps I thought of and executed for solving the given problem:

Prepare database tables which can persist the assignment of badges and achievements for retrieval.
Hook the event-listeners of CommentWritten, LessonWatched and handle the logic of assigning achievements of either comment written or lesson watched.
1. Add those achievements classes by their respective types either lesson_watched or comment_written within the app and a service provider AchievementServiceProvider.The boot method for this provider loops over the classes and instantiates and keeps them inside a singleton class within the container.
2. Afterwards when a user comments or watches video the respective events fire and the listeners AwardAchievementsForCommentsWritten,AwardAchievementsForLessonWatched handle method access the achievements from the container and determine the event with the help of a property achievementType within the achievement classes and sends them to proper achievements to check whether the subject in question qualifies for the event or not.
3. If they qualify for the achievement add the record to the user_achievements table and fire event AchievementUnlocked as the task has asked.
Add badge classes in the Badges directory and allow them to determine badges.
1. Assign badge to the user in question when they receive an achievement with the help of the event AchievementUnlocked and listener AssignBadges. It also uses the exact approach of handling achievements, the only difference is the logic to ask the subject in question to award a badge. Please refer to BadgeServiceProvider and the classes inside the Badge directory to find more.
Add a console command to sync the achievements of existing users.
1. The achievements have a type of comment_written and lesson_watched and for the case of existing users the commands php artisan sync-achievements comment_written and php artisan sync-achievements lesson_watched help them sync their achievements.

Libraries/Tools used

No any third party library other than the framework itself provides.
Uses php 8.0, but php >= 7.4 can also be used.
Uses phpunit for testing and xDebug 3.0 for code coverage analysis.

Installation

Run the following commands to set up the application, given that php and composer are available:

git clone https://github.com/ravisharmaa/badges-and-achievements.git
cd badges-and-achievements
composer install
cp .env.example .env

Running Tests

vendor/bin/phpunit
For code coverage: vendor/bin/phpunit --coverage-text
Additionally a report can also be generated using the command vendor/bin/phpunit --coverage-html=reports

The current code coverage is 91%. Given the laravel frameworks code which show uncovered while using xDebug.

Usage of the project

The tests provide a basic overview of the application. Some steps can be done to see the application in action, which are.

The data for comments and lessons can be seeded via Tinker and achievements and badges can be seen.

php artisan tinker

$user = User::factory()->create();

 Comment::factory()->count(10)->create([
    'user_id' => $user->id,
]);

 $user->lessons()->attach(Lesson::factory()->count(10)->create(),['watched' => true]);
 
 php artisan sync-achievements comment_written
 php artisan sync-achievements lesson_watched

Which results in the output for url /users/1/achievements

{
    "unlocked_achievements": [
        "First Comment Written",
        "3 Comments Written",
        "5 Comments Written",
        "10 Comments Written",
        "First Lesson Watched",
        "5 Lessons Watched",
        "10 Lessons Watched"
    ],
    "next_available_achievements": [
        "20 Comments Written",
        "20 Lessons Watched",
        "25 Lessons Watched",
        "50 Lessons Watched"
    ],
    "current_badge": "Intermediate",
    "next_badge": "Advanced",
    "remaining_to_unlock_next_badge": 4
}

Decisions, tradeoffs and constraints

I have used an implicit way of storing achievement, and badge names into the database while a user's achievements are calculated via the event. The constructor for each achievement add the necessary name for the achievement. An admin might want to edit their properties which currently, is a bit difficult. If there were a proper backend application which could help manage updates and addition of badges and achievements but it was out of the scope regarding the task and given time frame.
I have also added a property achievement_type in the database which seems redundant as it is used in the achievement class and in the table. Nevertheless, it might help in grouping the users via their achievement types.
I have also assumed that the next badge is in an incrementing order, which might not be the case always. I thought of adding a next_badge in the badges table but somehow opted from that.
There are places to improve. Still, I would not opt to do them all for a small problem domain like this one. As software engineers we need to find a balance.

Future Improvements.

It was a challenge. However, if I had to improve upon this:

I would work out to find out a proper way to store next badges.
Achievements could be editable, or a command to create the achievements and the related class would be great! The developer then only had to add the related class and qualifier logic and be done.
For a team project, it will be good to have the project dockerized.

ravisharmaa/badges-and-achievements