reconstruction of the project

app/Models/PurchaseOrderItem.php

@@ -3,11 +3,12 @@
 namespace App\Models;
 
 use App\Models\BaseModel;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
 
 class PurchaseOrderItem extends BaseModel
 {
     protected $table = 'purchase_order_items';
-    protected $primaryKey     = 'id';
+
     protected $fillable = [
         'purchase_order_id',
         'supply_id',
@@ -16,12 +17,71 @@ class PurchaseOrderItem extends BaseModel
         'received_qty',
         'unit_cost',
     ];
+
     public $timestamps = true;
 
-    protected $validationRules = [
-        'purchase_order_id' => 'required|is_natural_no_zero',
-        'supply_id'         => 'required|is_natural_no_zero',
-        'quantity'          => 'required|is_natural_no_zero',
-        'unit_cost'         => 'required|decimal',
+    protected $casts = [
+        'purchase_order_id' => 'integer',
+        'supply_id'         => 'integer',
+        'quantity'          => 'integer',
+        'received_qty'      => 'integer',
+        'unit_cost'         => 'decimal:2',   // adjust scale to match DB (e.g., decimal:4)
+        'created_at'        => 'datetime',
+        'updated_at'        => 'datetime',
     ];
-}
+
+    /* ============================================================
+     * Relationships (optional but recommended)
+     * ============================================================
+     */
+
+    public function purchaseOrder(): BelongsTo
+    {
+        return $this->belongsTo(PurchaseOrder::class, 'purchase_order_id');
+    }
+
+    public function supply(): BelongsTo
+    {
+        return $this->belongsTo(Supply::class, 'supply_id');
+    }
+
+    /* ============================================================
+     * Accessors (handy for totals / UI)
+     * ============================================================
+     */
+
+    // total ordered cost
+    public function getLineTotalAttribute(): float
+    {
+        $qty  = (int) ($this->quantity ?? 0);
+        $cost = (float) ($this->unit_cost ?? 0);
+        return $qty * $cost;
+    }
+
+    // total received cost
+    public function getReceivedLineTotalAttribute(): float
+    {
+        $qty  = (int) ($this->received_qty ?? 0);
+        $cost = (float) ($this->unit_cost ?? 0);
+        return $qty * $cost;
+    }
+
+    /* ============================================================
+     * Validation rules (use in FormRequest or controller)
+     * ============================================================
+     */
+
+    public static function rules(bool $updating = false): array
+    {
+        // if updating, you might allow partial updates (sometimes)
+        // keep strict by default to match CI behavior
+        return [
+            'purchase_order_id' => [$updating ? 'sometimes' : 'required', 'integer', 'min:1', 'exists:purchase_orders,id'],
+            'supply_id'         => [$updating ? 'sometimes' : 'required', 'integer', 'min:1', 'exists:supplies,id'],
+            'description'       => ['nullable', 'string', 'max:1000'],
+            'quantity'          => [$updating ? 'sometimes' : 'required', 'integer', 'min:1'],
+            'received_qty'      => ['nullable', 'integer', 'min:0', 'lte:quantity'],
+            'unit_cost'         => [$updating ? 'sometimes' : 'required', 'numeric', 'min:0'],
+        ];
+    }
+}