Improve installed database detection

app/Space/InstallUtils.php

@@ -0,0 +1,86 @@
+<?php
+
+namespace InvoiceShelf\Space;
+
+use League\Flysystem\FilesystemException;
+
+class InstallUtils
+{
+    /**
+     * Check if database is created
+     *
+     * @return bool|int|string
+     */
+    public static function isDbCreated()
+    {
+        return self::tableExists('users');
+    }
+
+    /**
+     * Check if database is created
+     *
+     * @return bool|int|string
+     */
+    public static function tableExists($table)
+    {
+        static $cache = [];
+
+        if (isset($cache[$table])) {
+            return $cache[$table];
+        }
+
+        try {
+            $flag = self::dbMarkerExists();
+            if ($flag) {
+                $flag &= \Schema::hasTable($table);
+            }
+        } catch (\Illuminate\Database\QueryException $e) {
+            $flag = false;
+        } catch (\Exception $e) {
+            $flag = false;
+        }
+
+        $cache[$table] = $flag;
+
+        return $flag;
+    }
+
+    /**
+     * Check if database created marker exists
+     *
+     * @return bool
+     */
+    public static function dbMarkerExists()
+    {
+        try {
+            $flag = \Storage::disk('local')->has('database_created');
+        } catch (FilesystemException $e) {
+            $flag = false;
+        }
+
+        return $flag;
+    }
+
+    /**
+     * Creates the database marker
+     *
+     * @return void
+     */
+    public static function createDbMarker()
+    {
+        \Storage::disk('local')->put('database_created', 'database_created');
+    }
+
+    /**
+     * Deletes the database marker
+     *
+     * @return void
+     */
+    public static function deleteDbMarker()
+    {
+        try {
+            \Storage::disk('local')->delete('database_created');
+        } catch (\Exception $e) {
+        }
+    }
+}