add nova

nova/src/Fields/DeterminesIfCreateRelationCanBeShown.php

@@ -0,0 +1,75 @@
+<?php
+
+namespace Laravel\Nova\Fields;
+
+use Laravel\Nova\Http\Requests\NovaRequest;
+
+trait DeterminesIfCreateRelationCanBeShown
+{
+    /**
+     * The callback used to determine if the create relation button should be shown.
+     *
+     * @var (callable(\Laravel\Nova\Http\Requests\NovaRequest):(bool))|bool
+     */
+    public $showCreateRelationButtonCallback;
+
+    /**
+     * Indicates the size the create relation modal should be.
+     *
+     * @var string
+     */
+    public $modalSize = '2xl';
+
+    /**
+     * Set the callback used to determine if the field is required.
+     *
+     * @param  (callable(\Laravel\Nova\Http\Requests\NovaRequest):(bool))|bool  $callback
+     * @return $this
+     */
+    public function showCreateRelationButton($callback = true)
+    {
+        $this->showCreateRelationButtonCallback = $callback;
+
+        return $this;
+    }
+
+    /**
+     * Hide the create relation button from forms.
+     *
+     * @return $this
+     */
+    public function hideCreateRelationButton()
+    {
+        $this->showCreateRelationButtonCallback = false;
+
+        return $this;
+    }
+
+    /**
+     * Set the size used for the create relation modal.
+     *
+     * @param  string  $size
+     * @return $this
+     */
+    public function modalSize($size)
+    {
+        return $this->withMeta(['modalSize' => $size]);
+    }
+
+    /**
+     * Determine if Nova should show the edit pivot relation button.
+     *
+     * @param  \Laravel\Nova\Http\Requests\NovaRequest  $request
+     * @return bool
+     */
+    public function createRelationShouldBeShown(NovaRequest $request)
+    {
+        return with($this->showCreateRelationButtonCallback, function ($callback) use ($request) {
+            if ($callback === true || (is_callable($callback) && call_user_func($callback, $request))) {
+                return true;
+            }
+
+            return false;
+        });
+    }
+}