construprogress/app/Models/Phase.php

<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;

class Phase extends Model
{
    use SoftDeletes;

    protected $fillable = [
        'project_id', 'name', 'description', 'order', 'color', 'progress_percent',
        'planned_start', 'planned_end', 'actual_start', 'actual_end'
    ];

    protected $casts = [
        'planned_start' => 'date',
        'planned_end'   => 'date',
        'actual_start'  => 'date',
        'actual_end'    => 'date',
    ];

    public function project()         { return $this->belongsTo(Project::class); }
    public function layers()          { return $this->hasMany(Layer::class); }
    public function progressUpdates() { return $this->hasMany(ProgressUpdate::class); }
    public function currentLayer()    { return $this->hasOne(Layer::class)->latestOfMany(); }
    public function features()        { return $this->hasManyThrough(Feature::class, Layer::class); }
    public function media()           { return $this->morphMany(Media::class, 'mediable'); }
    public function images()          { return $this->morphMany(Media::class, 'mediable')->where('category', 'image'); }

    public function getDeviationDaysAttribute(): ?int
    {
        if (!$this->planned_end) return null;
        $end = $this->actual_end ?? now();
        return $this->planned_end->diffInDays($end, false);
    }
}