create stock and stock logs

app/Models/StockLog.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace App\Models;
+
+use App\Enums\StockChangeType;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+class StockLog extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'stock_id',
+        'source_type',
+        'source_id',
+        'previous_quantity',
+        'new_quantity',
+        'quantity_change',
+        'change_type',
+        'description',
+        'user_id'
+    ];
+
+    protected $casts = [
+        'change_type' => StockChangeType::class,
+        'previous_quantity' => 'decimal:2',
+        'new_quantity' => 'decimal:2',
+        'quantity_change' => 'decimal:2'
+    ];
+
+    protected static function booted()
+    {
+        static::creating(function ($stockLog) {
+            // Hitung quantity_change
+            $stockLog->quantity_change = $stockLog->new_quantity - $stockLog->previous_quantity;
+            
+            // Tentukan change_type berdasarkan quantity_change
+            if ($stockLog->quantity_change == 0) {
+                // Jika quantity sama persis (tanpa toleransi)
+                $stockLog->change_type = StockChangeType::NO_CHANGE;
+            } else if ($stockLog->quantity_change > 0) {
+                $stockLog->change_type = StockChangeType::INCREASE;
+            } else {
+                $stockLog->change_type = StockChangeType::DECREASE;
+            }
+        });
+    }
+
+    public function stock()
+    {
+        return $this->belongsTo(Stock::class);
+    }
+
+    public function user()
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function source()
+    {
+        return $this->morphTo();
+    }
+
+    // Helper method untuk mendapatkan label change_type
+    public function getChangeTypeLabelAttribute()
+    {
+        return $this->change_type->label();
+    }
+}