fitness/app/Models/Workout.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;
use Illuminate\Database\Eloquent\Relations\HasMany;

class Workout extends Model
{
    use HasFactory;

    protected $fillable = [
        'user_id',
        'title',
        'notes',
        'estimated_minutes',
    ];

    protected $casts = [
        'estimated_minutes' => 'integer',
    ];

    public function user(): BelongsTo
    {
        return $this->belongsTo(User::class);
    }

    public function items(): HasMany
    {
        return $this->hasMany(WorkoutExercise::class)->orderBy('position');
    }

    public function exercises(): BelongsToMany
    {
        return $this->belongsToMany(Exercise::class, 'workout_exercises')
            ->withPivot(['id', 'position', 'sets', 'reps', 'weight', 'rest_seconds', 'notes'])
            ->withTimestamps()
            ->orderBy('workout_exercises.position');
    }

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