Enhance Exercise App: Muscle Group Association

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Enhance Exercise App: Muscle Group Association

Hey folks! 👋 Let's dive into a neat upgrade for our exercise app. We're gonna ditch the old muscle_group enum in the Exercise model and swap it with a shiny new MuscleGroup association. This means a more organized and flexible way to link exercises with the muscle groups they target. This update will make our app more robust, and easier to manage! 💪

🎯 Goal: Muscle Group Association

Our main goal is simple: Replace the muscle_group enum with a proper belongs_to :muscle_group association. This change will give us a more structured and extensible approach to managing muscle groups within our exercise data. This is a fundamental change, impacting various parts of our application.

Why This Matters

Switching to an association has several advantages. It allows for:

  • Flexibility: Easily add or modify muscle groups without changing the core exercise model.
  • Data Integrity: Enforce relationships and ensure data consistency.
  • Scalability: Makes it easier to handle a growing number of muscle groups and exercises.

This refactor is essential for long-term maintainability and scalability of our exercise tracking system. This improves the data model for our exercises.

🧩 Tasks: The Step-by-Step Guide

Let's break down the tasks involved in this transition. We have several steps, which when done, will provide an amazing user experience.

1. Migration: Database Makeover

First things first, we need to adjust our database schema. This involves creating a migration to remove the old column and add the new one. Here's what we need to do:

  • Remove the muscle_group column from exercises. Goodbye, old enum!
  • Add a foreign key muscle_group_id (integer, not nullable, indexed). This will link exercises to the MuscleGroup table.

Let's get this migration started to ensure our data structure is up to par.

rails generate migration RemoveMuscleGroupFromExercisesAndAddMuscleGroupId

Inside the migration file, we will have something like this.

class RemoveMuscleGroupFromExercisesAndAddMuscleGroupId < ActiveRecord::Migration[7.0]
  def change
    remove_column :exercises, :muscle_group, :integer
    add_reference :exercises, :muscle_group, null: false, foreign_key: true
  end
end

Make sure to run the migration with rails db:migrate.

2. Model (Exercise): The Heart of the Matter

Next, let's update the Exercise model. Here's what needs to be done:

  • Add belongs_to :muscle_group. This establishes the association with the MuscleGroup model.
  • Remove the old enum and any validations tied to muscle_group. Out with the old, in with the new.

Here is how we adjust the exercise.rb model file.

class Exercise < ApplicationRecord
  belongs_to :muscle_group
  # ... other code ...
end

This simple addition links each exercise to a specific muscle group, and this is the core of our changes!

3. Locales: Language Updates

Time to clean up our language files. We need to remove any translations and error messages related to the old muscle_group enum from our locale files. This usually involves removing lines from:

  • config/locales/en.yml
  • config/locales/fr.yml (or any other language files)

Make sure your app's language files are streamlined and accurate, reflecting the changes we've made to the data structure.

4. Seeds: Populating the Database

Let's update our seed data. Instead of using enum values, we'll assign exercises using existing MuscleGroup records.

  • Update db/seeds.rb. This file is crucial for pre-populating our database with initial data. Instead of hardcoded enum values, we will now use existing MuscleGroup records to assign muscle groups to our exercises.

First, make sure you have some muscle groups seeded. Then, when creating exercises, you will need to find the specific muscle group and assign it to the exercise.

# Example of creating muscle groups (if not already created)
MuscleGroup.find_or_create_by(name: 'Chest')
MuscleGroup.find_or_create_by(name: 'Legs')

# Example of creating an exercise and associating it with a muscle group
exercise = Exercise.create(title: 'Bench Press', muscle_group: MuscleGroup.find_by(name: 'Chest'))

This change ensures our database is populated correctly from the start.

5. Factory: Testing Data

Next up, we need to update the Exercise factory to correctly associate a MuscleGroup. This step ensures our tests are set up correctly.

In our factory, we will have something like this, that will help to generate the correct data.

FactoryBot.define do
  factory :exercise do
    title { 'Bench Press' }
    association :muscle_group
  end
end

With these changes, our tests will create and link exercises to muscle groups. This means our tests will be accurate and effective.

6. Views: Showing Off the Changes

Now, let's update our views to reflect the changes:

  • app/views/admin/exercises/_search_form.html.erb: Replace the enum-based filter with a collection_select (or f.association) using MuscleGroup.all.
  • Index view: Display the muscle group via exercise.muscle_group.name.

Here are some examples of what to do.

# _search_form.html.erb
<%= f.collection_select :muscle_group_id, MuscleGroup.all, :id, :name, { include_blank: true } %>

# index view
<%= exercise.muscle_group.name %>

This is a critical part of the user experience. These updates will make the filtering and displaying of exercises accurate and user-friendly.

7. Controller (Admin::ExercisesController): The Command Center

We need to update our controller to include the new association. Here's how we update Admin::ExercisesController#index:

def index
  @q = Exercise.ransack(params[:q])
  @exercises = @q.result(distinct: true)
                 .includes(:muscle_group)
                 .page(params[:page])
                 .per(10)
end

This adjustment ensures that when the index action is called, the muscle group data is correctly included and accessible.

8. Ransack Configuration: Searchability

Let's configure Ransack to work with our new association. We need to update the Exercise model methods.

def self.ransackable_attributes(_auth_object = nil)
  %w[title muscle_group_id]
end

def self.ransackable_associations(_auth_object = nil)
  %w[muscle_group]
end

This change ensures that exercises can be filtered based on the muscle_group.

9. Tests: Ensuring Everything Works

Finally, let's update our tests to ensure everything is working correctly:

  • Remove any tests referencing the old enum. Get rid of the old test.
  • Update or add tests for the new belongs_to :muscle_group association. Add new tests to make sure that the new data model functions correctly.

Ensure that your tests now cover the new association and that everything is functioning as expected. It is a critical step for data integrity!

🤖 Ready to Go? Let's Get Coding!

That's the plan, folks! By following these steps, we'll successfully replace the muscle_group enum with a belongs_to :muscle_group association. This will lead to a more maintainable, flexible, and scalable application. This enhancement will also significantly improve the organization and management of exercise data within our app.