feat: implement AI styling foundation and billing scope rework

app/Services/AiEditing/EventAiEditingPolicyService.php

@@ -0,0 +1,90 @@
+<?php
+
+namespace App\Services\AiEditing;
+
+use App\Models\AiStyle;
+use App\Models\Event;
+use Illuminate\Support\Arr;
+use Illuminate\Support\Collection;
+
+class EventAiEditingPolicyService
+{
+    /**
+     * @return array{
+     *     enabled: bool,
+     *     allow_custom_prompt: bool,
+     *     allowed_style_keys: array<int, string>,
+     *     policy_message: ?string
+     * }
+     */
+    public function resolve(Event $event): array
+    {
+        $settings = is_array($event->settings) ? $event->settings : [];
+        $aiSettings = Arr::get($settings, 'ai_editing', []);
+        $aiSettings = is_array($aiSettings) ? $aiSettings : [];
+
+        $enabled = array_key_exists('enabled', $aiSettings)
+            ? (bool) $aiSettings['enabled']
+            : true;
+        $allowCustomPrompt = array_key_exists('allow_custom_prompt', $aiSettings)
+            ? (bool) $aiSettings['allow_custom_prompt']
+            : true;
+
+        $allowedStyleKeys = collect($aiSettings['allowed_style_keys'] ?? [])
+            ->filter(fn (mixed $value): bool => is_string($value) && trim($value) !== '')
+            ->map(fn (string $value): string => trim($value))
+            ->unique()
+            ->values()
+            ->all();
+
+        $policyMessage = trim((string) ($aiSettings['policy_message'] ?? ''));
+
+        return [
+            'enabled' => $enabled,
+            'allow_custom_prompt' => $allowCustomPrompt,
+            'allowed_style_keys' => $allowedStyleKeys,
+            'policy_message' => $policyMessage !== '' ? $policyMessage : null,
+        ];
+    }
+
+    public function isEnabled(Event $event): bool
+    {
+        return (bool) $this->resolve($event)['enabled'];
+    }
+
+    public function isStyleAllowed(Event $event, ?AiStyle $style): bool
+    {
+        $policy = $this->resolve($event);
+
+        if ($style === null) {
+            return (bool) $policy['allow_custom_prompt'];
+        }
+
+        /** @var array<int, string> $allowedStyleKeys */
+        $allowedStyleKeys = $policy['allowed_style_keys'];
+        if ($allowedStyleKeys === []) {
+            return true;
+        }
+
+        return in_array($style->key, $allowedStyleKeys, true);
+    }
+
+    /**
+     * @param  Collection<int, AiStyle>  $styles
+     * @return Collection<int, AiStyle>
+     */
+    public function filterStyles(Event $event, Collection $styles): Collection
+    {
+        $policy = $this->resolve($event);
+
+        /** @var array<int, string> $allowedStyleKeys */
+        $allowedStyleKeys = $policy['allowed_style_keys'];
+        if ($allowedStyleKeys === []) {
+            return $styles->values();
+        }
+
+        return $styles
+            ->filter(fn (AiStyle $style): bool => in_array($style->key, $allowedStyleKeys, true))
+            ->values();
+    }
+}