First code for file import.

app/Import/JobConfiguration/JobConfigurationInterface.php

@@ -0,0 +1,73 @@
+<?php
+/**
+ * JobConfigurationInterface.php
+ * Copyright (c) 2018 thegrumpydictator@gmail.com
+ *
+ * This file is part of Firefly III.
+ *
+ * Firefly III is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Firefly III is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Firefly III. If not, see <http://www.gnu.org/licenses/>.
+ */
+declare(strict_types=1);
+
+namespace FireflyIII\Import\JobConfiguration;
+
+use FireflyIII\Models\ImportJob;
+use Illuminate\Support\MessageBag;
+
+/**
+ * Interface JobConfigurationInterface.
+ */
+interface JobConfigurationInterface
+{
+    /**
+     * ConfiguratorInterface constructor.
+     */
+    public function __construct();
+
+    /**
+     * Store any data from the $data array into the job. Anything in the message bag will be flashed
+     * as an error to the user, regardless of its content.
+     *
+     * @param array $data
+     *
+     * @return MessageBag
+     */
+    public function configureJob(array $data): MessageBag;
+
+    /**
+     * Return the data required for the next step in the job configuration.
+     *
+     * @return array
+     */
+    public function getNextData(): array;
+
+    /**
+     * Returns the view of the next step in the job configuration.
+     *
+     * @return string
+     */
+    public function getNextView(): string;
+
+    /**
+     * Returns true when the initial configuration for this job is complete.
+     *
+     * @return bool
+     */
+    public function configurationComplete(): bool;
+
+    /**
+     * @param ImportJob $job
+     */
+    public function setJob(ImportJob $job): void;
+}