SpiceManagementSystem/app/Models/Batch.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Batch extends Model
{
    protected $fillable = [
        'lot_number', 'product_id', 'size_id', 'recipe_id',
        'units_produced', 'quantity_g', 'produced_at', 'expires_at',
    ];

    protected $casts = [
        'produced_at' => 'date',
        'expires_at'  => 'date',
    ];

    public function product()
    {
        return $this->belongsTo(Product::class);
    }

    public function size()
    {
        return $this->belongsTo(ProductSize::class);
    }

    public function recipe()
    {
        return $this->belongsTo(Recipe::class);
    }

    public function origins()
    {
        return $this->hasMany(BatchOrigin::class);
    }

    protected static function booted(): void
    {
        static::saving(function (Batch $batch) {
            if ($batch->units_produced && $batch->size_id) {
                $batch->quantity_g = $batch->units_produced * ($batch->size?->packing?->size ?? 0);
            }
        });

        static::created(function (Batch $batch) {
            $batch->writeSpiceMovements();
        });

        static::updated(function (Batch $batch) {
            if ($batch->wasChanged(['recipe_id', 'size_id', 'units_produced'])) {
                $batch->deleteSpiceMovements();
                $batch->writeSpiceMovements();
            }
        });

        static::deleting(function (Batch $batch) {
            $batch->deleteSpiceMovements();
        });
    }

    private function writeSpiceMovements(): void
    {
        if (! $this->quantity_g || ! $this->recipe_id) {
            return;
        }

        $recipe = Recipe::with('spices')->find($this->recipe_id);
        if (! $recipe) {
            return;
        }

        foreach ($recipe->spices as $spice) {
            $grams = $this->quantity_g * $spice->pivot->amount_in_percent / 100;
            SpiceStockMovement::create([
                'spice_id'    => $spice->id,
                'amount'      => -$grams,
                'source_type' => 'batch',
                'source_id'   => $this->id,
                'description' => 'Charge ' . $this->lot_number . ' (' . $spice->pivot->amount_in_percent . '%)',
            ]);
            $spice->recalculateQuantity();
        }
    }

    private function deleteSpiceMovements(): void
    {
        $spiceIds = SpiceStockMovement::where('source_type', 'batch')
            ->where('source_id', $this->id)
            ->pluck('spice_id');

        SpiceStockMovement::where('source_type', 'batch')
            ->where('source_id', $this->id)
            ->delete();

        Spice::whereIn('id', $spiceIds)->get()->each->recalculateQuantity();
    }
}