fitness/app/Models/Exercise.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Support\Facades\Auth;

class Exercise extends Model
{
    protected $fillable = [
        'name',
        'slug',
        'exercise_db_id',
        'gif_url',
        'instructions',
    ];

    // relations
    public function targetMuscles()
    {
        return $this->belongsToMany(Muscle::class, 'exercise_target_muscle');
    }

    public function secondaryMuscles()
    {
        return $this->belongsToMany(Muscle::class, 'exercise_secondary_muscle');
    }

    public function bodyParts()
    {
        return $this->belongsToMany(BodyPart::class, 'body_part_exercise');
    }

    public function equipments()
    {
        return $this->belongsToMany(Equipment::class, 'equipment_exercise');
    }

    public function workoutExercises()
    {
        return $this->hasMany(WorkoutExercise::class);
    }

    public function favoritedBy()
    {
        return $this->belongsToMany(User::class, 'exercise_favorites')->withTimestamps();
    }

    public function aliases()
    {
        return $this->hasMany(ExerciseAlias::class);
    }

    public function getDisplayNameAttribute(): string
    {
        $name = (string) $this->attributes['name'] ?? '';
        $userId = Auth::id();
        if (!$userId) {
            return $name;
        }
        // Use already loaded relation if present to avoid querying N+1
        if ($this->relationLoaded('aliases')) {
            $alias = $this->aliases->firstWhere('user_id', $userId);
            return $alias?->name ?: $name;
        }
        $alias = $this->aliases()->where('user_id', $userId)->first();
        return $alias?->name ?: $name;
    }
}