#7 - QR Codes & payments

includes/Services/Forms/Pricing/RsvFormPriceCalculator.php

@@ -0,0 +1,21 @@
+<?php
+
+/** Computes a form's total price as the sum of its elements' prices. */
+class RsvFormPriceCalculator {
+    public function calculate(RsvFormDefinition $definition, RsvFormData $data): float {
+        global $rsv_form_price_registry;
+
+        $total = 0.0;
+
+        foreach ($definition->getElements() as $element) {
+            $calculator = $rsv_form_price_registry->get($element->getType());
+            if ($calculator === null) {
+                continue; // Unpriced element type contributes nothing.
+            }
+
+            $total += (float) $calculator($element, $data->getValue($element->getName()));
+        }
+
+        return $total;
+    }
+}

includes/Services/Forms/Pricing/RsvFormPriceCalculatorRegistry.php

@@ -0,0 +1,21 @@
+<?php
+
+class RsvFormPriceCalculatorRegistry {
+    /** @var array<string, callable(RsvFormElementDefinition, mixed): float> */
+    private array $calculators = [];
+
+    public function register(string $type, callable $calculator): void {
+        $this->calculators[$type] = $calculator;
+    }
+
+    public function get(string $type): ?callable {
+        return $this->calculators[$type] ?? null;
+    }
+
+    /** Builds the registry and lets other modules contribute calculators. */
+    public static function boot(): self {
+        $registry = new self();
+        do_action('rsv-register-price-calculator', $registry);
+        return $registry;
+    }
+}

includes/Services/Forms/RsvFormCalculatedValues.php

@@ -0,0 +1,19 @@
+<?php
+
+/** Values derived from a submission (not entered by the visitor), exposed to templates. */
+final class RsvFormCalculatedValues {
+    /** @return array<string, mixed> */
+    public function for(RsvFormDefinition $definition, RsvFormData $data): array {
+        return [
+            'price' => (new RsvFormPriceCalculator())->calculate($definition, $data),
+        ];
+    }
+
+    /**
+     * The names these values expose, so template validation accepts {{ price }}.
+     * @return list<string>
+     */
+    public static function names(): array {
+        return ['price'];
+    }
+}

includes/Services/Forms/RsvFormDefinitionValidator.php

@@ -44,7 +44,7 @@ final class RsvFormDefinitionValidator {
      * @return list<string>
      */
     private function symbols(array $elements): array {
-        $names = [];
+        $names = RsvFormCalculatedValues::names(); // calculated values are referencable too
         foreach ($elements as $el) {
             $name = is_array($el) ? ($el['name'] ?? '') : '';
             if (is_string($name) && $name !== '') {