Support discounts specifying fields in the discount UI

docs/core/extending/discounts.md

@@ -45,3 +45,50 @@ class MyCustomDiscountType extends AbstractDiscountType
     }
 }
 ```
+
+
+## Adding form fields for your discount in the admin panel
+
+If you require fields in the Lunar admin for your discount type, ensure your discount implements `Lunar\Admin\Base\LunarPanelDiscountInterface`. You will need to provide the `lunarPanelSchema`, `lunarPanelOnFill` and `lunarPanelOnSave` methods.
+
+```php
+<?php
+
+namespace App\DiscountTypes;
+
+use Lunar\Admin\Base\LunarPanelDiscountInterface;
+use Lunar\DiscountTypes\AbstractDiscountType;
+
+class MyCustomDiscountType extends AbstractDiscountType implements LunarPanelDiscountInterface
+{
+    /**
+     * Return the schema to use in the Lunar admin panel
+     */
+    public function lunarPanelSchema(): array
+    {
+        return [
+            Forms\Components\TextInput::make('my_field')
+               ->label('My label')
+               ->required(),
+        ];
+    }
+
+    /**
+     * Mutate the model data before displaying it in the admin form.
+     */
+    public function lunarPanelOnFill(array $data): array
+    {
+        // optionally do something with $data
+        return $data;
+    }
+
+    /**
+     * Mutate the form data before saving it to the discount model.
+     */
+    public function lunarPanelOnSave(array $data): array
+    {
+        // optionally do something with $data
+        return $data;
+    }
+}
+```

packages/admin/src/Base/LunarPanelDiscountInterface.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace Lunar\Admin\Base;
+
+interface LunarPanelDiscountInterface
+{
+    /**
+     * Return the schema to use in the Lunar admin panel
+     */
+    public function lunarPanelSchema(): array;
+
+    /**
+     * Mutate the model data before displaying it in the admin form.
+     */
+    public function lunarPanelOnFill(array $data): array;
+
+    /**
+     * Mutate the form data before saving it to the discount model.
+     */
+    public function lunarPanelOnSave(array $data): array;
+}

packages/admin/src/Filament/Resources/DiscountResource.php

@@ -11,6 +11,7 @@
 use Filament\Tables;
 use Filament\Tables\Table;
 use Illuminate\Support\Str;
+use Lunar\Admin\Base\LunarPanelDiscountInterface;
 use Lunar\Admin\Filament\Resources\DiscountResource\Pages;
 use Lunar\Admin\Filament\Resources\DiscountResource\RelationManagers\BrandLimitationRelationManager;
 use Lunar\Admin\Filament\Resources\DiscountResource\RelationManagers\CollectionLimitationRelationManager;
@@ -57,6 +58,18 @@ public static function getNavigationGroup(): ?string
 
     public static function getDefaultForm(Form $form): Form
     {
+        $discountSchemas = Discounts::getTypes()->map(function ($discount) {
+            if (! $discount instanceof LunarPanelDiscountInterface) {
+                return;
+            }
+
+            return Forms\Components\Section::make(Str::slug(get_class($discount)))
+                ->heading($discount->getName())
+                ->visible(
+                    fn (Forms\Get $get) => $get('type') == get_class($discount)
+                )->schema($discount->lunarPanelSchema());
+        })->filter();
+
         return $form->schema([
             Forms\Components\Section::make('')->schema(
                 static::getMainFormComponents()
@@ -84,6 +97,7 @@ public static function getDefaultForm(Form $form): Form
                 )->schema(
                     static::getAmountOffFormComponents()
                 ),
+            ...$discountSchemas,
         ]);
     }
 

packages/admin/src/Filament/Resources/DiscountResource/Pages/EditDiscount.php

@@ -3,6 +3,7 @@
 namespace Lunar\Admin\Filament\Resources\DiscountResource\Pages;
 
 use Filament\Actions;
+use Lunar\Admin\Base\LunarPanelDiscountInterface;
 use Lunar\Admin\Filament\Resources\DiscountResource;
 use Lunar\Admin\Support\Pages\BaseEditRecord;
 use Lunar\DiscountTypes\BuyXGetY;
@@ -19,8 +20,29 @@ protected function getDefaultHeaderActions(): array
         ];
     }
 
+    protected function mutateFormDataBeforeFill(array $data): array
+    {
+        if (class_exists($data['type'])) {
+            $type = new $data['type'];
+
+            if ($type instanceof LunarPanelDiscountInterface) {
+                return $type->lunarPanelOnFill($data);
+            }
+        }
+
+        return $data;
+    }
+
     protected function mutateFormDataBeforeSave(array $data): array
     {
+        if (class_exists($data['type'])) {
+            $type = new $data['type'];
+
+            if ($type instanceof LunarPanelDiscountInterface) {
+                return $type->lunarPanelOnSave($data);
+            }
+        }
+
         $minPrices = $data['data']['min_prices'] ?? [];
         $fixedPrices = $data['data']['fixed_values'] ?? [];
         $currencies = Currency::enabled()->get();