<?php

namespace App\Database\Migrations;

use CodeIgniter\Database\Migration;

class AddVersionToExamDrafts extends Migration
{
    public function up()
    {
        $fields = [];

        if (! $this->db->fieldExists('version', 'exam_drafts')) {
            $fields['version'] = [
                'type'       => 'INT',
                'unsigned'   => true,
                'default'    => 1,
            ];
        }

        if (! $this->db->fieldExists('previous_draft_id', 'exam_drafts')) {
            $fields['previous_draft_id'] = [
                'type'     => 'INT',
                'unsigned' => true,
                'null'     => true,
            ];
        }

        if ($fields !== []) {
            $this->forge->addColumn('exam_drafts', $fields);
        }
    }

    public function down()
    {
        $this->forge->dropColumn('exam_drafts', ['version', 'previous_draft_id']);
    }
}