reconstruction of the project

app/Models/PurchaseOrder.php

@@ -2,12 +2,18 @@
 
 namespace App\Models;
 
+use Illuminate\Database\Eloquent\Builder;
 use App\Models\BaseModel;
+use Illuminate\Database\Eloquent\SoftDeletes;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 
 class PurchaseOrder extends BaseModel
 {
+    use SoftDeletes;
+
     protected $table = 'purchase_orders';
-    protected $primaryKey     = 'id';
+
     protected $fillable = [
         'po_number',
         'supplier_id',
@@ -19,12 +25,136 @@ class PurchaseOrder extends BaseModel
         'total',
         'notes',
     ];
-    public $timestamps = true;
-    protected $useSoftDeletes = true;
 
-    protected $validationRules = [
-        'po_number'   => 'required|max_length[60]|is_unique[purchase_orders.po_number,id,{id}]',
-        'supplier_id' => 'required|is_natural_no_zero',
-        'status'      => 'in_list[draft,ordered,received,canceled]',
+    public $timestamps = true;
+
+    protected $casts = [
+        'supplier_id'    => 'integer',
+        'order_date'     => 'date',        // or 'datetime' if your DB stores time too
+        'expected_date'  => 'date',
+        'subtotal'       => 'decimal:2',
+        'tax'            => 'decimal:2',
+        'total'          => 'decimal:2',
+        'created_at'     => 'datetime',
+        'updated_at'     => 'datetime',
+        'deleted_at'     => 'datetime',
     ];
-}
+
+    /* ============================================================
+     * Status (enum-like)
+     * ============================================================
+     */
+
+    public const STATUS_DRAFT    = 'draft';
+    public const STATUS_ORDERED  = 'ordered';
+    public const STATUS_RECEIVED = 'received';
+    public const STATUS_CANCELED = 'canceled';
+
+    public static function allowedStatuses(): array
+    {
+        return [
+            self::STATUS_DRAFT,
+            self::STATUS_ORDERED,
+            self::STATUS_RECEIVED,
+            self::STATUS_CANCELED,
+        ];
+    }
+
+    /* ============================================================
+     * Relationships
+     * ============================================================
+     */
+
+    public function supplier(): BelongsTo
+    {
+        return $this->belongsTo(Supplier::class, 'supplier_id');
+    }
+
+    public function items(): HasMany
+    {
+        return $this->hasMany(PurchaseOrderItem::class, 'purchase_order_id');
+    }
+
+    /* ============================================================
+     * Scopes
+     * ============================================================
+     */
+
+    public function scopeStatus(Builder $q, string $status): Builder
+    {
+        return $q->where('status', $status);
+    }
+
+    public function scopeOpen(Builder $q): Builder
+    {
+        return $q->whereIn('status', [self::STATUS_DRAFT, self::STATUS_ORDERED]);
+    }
+
+    /* ============================================================
+     * Helpers / computed totals
+     * ============================================================
+     */
+
+    /**
+     * Recalculate subtotal/tax/total from items.
+     * Tax rate is optional. If you store tax as absolute amount, pass null and keep existing tax.
+     */
+    public function recalcTotals(?float $taxRate = null): self
+    {
+        $subtotal = (float) $this->items()
+            ->selectRaw('COALESCE(SUM(quantity * unit_cost), 0) as s')
+            ->value('s');
+
+        $tax = $taxRate === null
+            ? (float) ($this->tax ?? 0)
+            : round($subtotal * $taxRate, 2);
+
+        $total = $subtotal + $tax;
+
+        $this->subtotal = $subtotal;
+        $this->tax      = $tax;
+        $this->total    = $total;
+
+        return $this;
+    }
+
+    public function markOrdered(): self
+    {
+        $this->status = self::STATUS_ORDERED;
+        return $this;
+    }
+
+    public function markReceived(): self
+    {
+        $this->status = self::STATUS_RECEIVED;
+        return $this;
+    }
+
+    public function markCanceled(): self
+    {
+        $this->status = self::STATUS_CANCELED;
+        return $this;
+    }
+
+    /* ============================================================
+     * Validation rules (controller/FormRequest reuse)
+     * ============================================================
+     */
+
+    public static function rules(?int $id = null): array
+    {
+        // Mirrors CI: unique purchase_orders.po_number except current id.
+        return [
+            'po_number'   => ['required', 'string', 'max:60', 'unique:purchase_orders,po_number,' . ($id ?? 'NULL') . ',id'],
+            'supplier_id' => ['required', 'integer', 'min:1', 'exists:suppliers,id'],
+            'status'      => ['nullable', 'string', 'in:' . implode(',', self::allowedStatuses())],
+
+            'order_date'     => ['nullable', 'date'],
+            'expected_date'  => ['nullable', 'date', 'after_or_equal:order_date'],
+            'subtotal'       => ['nullable', 'numeric', 'min:0'],
+            'tax'            => ['nullable', 'numeric', 'min:0'],
+            'total'          => ['nullable', 'numeric', 'min:0'],
+            'notes'          => ['nullable', 'string', 'max:5000'],
+        ];
+    }
+}