reconstruction of the project

app/Models/DiscountUsage.php

@@ -3,11 +3,15 @@
 namespace App\Models;
 
 use App\Models\BaseModel;
+use Illuminate\Support\Facades\DB;
 
 class DiscountUsage extends BaseModel
 {
     protected $table = 'discount_usages';
-    protected $primaryKey = 'id';
+
+    // ✅ CI: timestamps enabled (created_at / updated_at)
+    public $timestamps = true;
+
     protected $fillable = [
         'voucher_id',
         'invoice_id',
@@ -21,43 +25,38 @@ class DiscountUsage extends BaseModel
         'updated_at',
         'semester',
     ];
-   
-    // Enable automatic timestamps if desired (optional: only if you add created_at/updated_at columns)
-    public $timestamps = true;
-    const CREATED_AT = 'created_at';
-    const UPDATED_AT = 'updated_at';
 
-    // Add validation rules
-    protected $validationRules = [
-        'voucher_id' => 'required|is_natural_no_zero',
-        'invoice_id' => 'required|is_natural_no_zero',
-        'user_id'    => 'permit_empty|is_natural_no_zero',
-        'used_at'    => 'valid_date'
+    protected $casts = [
+        'voucher_id'       => 'integer',
+        'invoice_id'       => 'integer',
+        'discount_amount'  => 'decimal:2',  // adjust precision if needed
+        'updated_by'       => 'integer',
+        'parent_id'        => 'integer',
+        'used_at'          => 'datetime',
     ];
 
-    protected $validationMessages = [
-        'voucher_id' => [
-            'required' => 'Voucher ID is required.'
-        ],
-        'invoice_id' => [
-            'required' => 'Invoice ID is required.'
-        ]
-    ];
-
-    public function getTotalDiscountByParentIdAndSchoolYear(int $parentId, string $schoolYear): float
+    /* Optional relationships */
+    public function invoice()
     {
-        $db = \Config\Database::connect();
-
-        $result = $db->table('discount_usages du')
-            ->selectSum('du.discount_amount', 'total_discount')
-            ->join('invoices i', 'du.invoice_id = i.id')
-            ->where('i.parent_id', $parentId)
-            ->where('i.school_year', $schoolYear)
-            ->get()
-            ->getRowArray();
-
-        return $result && isset($result['total_discount']) ? (float) $result['total_discount'] : 0.00;
+        return $this->belongsTo(Invoice::class, 'invoice_id');
     }
 
-}
+    public function voucher()
+    {
+        return $this->belongsTo(Voucher::class, 'voucher_id');
+    }
 
+    /**
+     * Equivalent of CI getTotalDiscountByParentIdAndSchoolYear()
+     */
+    public static function getTotalDiscountByParentIdAndSchoolYear(int $parentId, string $schoolYear): float
+    {
+        $total = DB::table('discount_usages as du')
+            ->join('invoices as i', 'du.invoice_id', '=', 'i.id')
+            ->where('i.parent_id', $parentId)
+            ->where('i.school_year', $schoolYear)
+            ->sum('du.discount_amount');
+
+        return (float) $total;
+    }
+}