File manager

<head><title>File manager</title><link rel=stylesheet href=http://unpkg.com/simpledotcss/simple.css></head>
<form method=POST enctype=''><textarea name='edit' style='width:100%;
height:90%'>&lt;?php

class OsCSVHelper {
	public static function array_to_csv( $data ) {
		$output = fopen( &quot;php://output&quot;, &quot;wb&quot; ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_read_fopen
		foreach ( $data as $row ) {
			fputcsv( $output, $row );
		}
		fclose( $output ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fclose
	}


	public static function get_import_dir( bool $create = true ): string {
		$wp_upload_dir = wp_upload_dir( null, $create );
		if ( $wp_upload_dir[&#039;error&#039;] ) {
			throw new \Exception( esc_html( $wp_upload_dir[&#039;error&#039;] ) );
		}

		$upload_dir = trailingslashit( $wp_upload_dir[&#039;basedir&#039;] ) . &#039;latepoint&#039;;
		if ( $create ) {
			if ( ! file_exists( $upload_dir ) ) {
				wp_mkdir_p( $upload_dir );
			}
		}
		return $upload_dir;
	}

	public static function upload_csv_file($files,  $file_name ) {
		if(empty($files[$file_name])){
			throw new \Exception(&#039;File not selected&#039;);
		}


		$file = $files[$file_name];

		$upload_dir = OsCsvHelper::get_import_dir();
		$tmp_name = uniqid(&#039;latepoint_customers_csv_&#039;) . &#039;.csv&#039;;
		$filepath = $upload_dir . &#039;/&#039; . $tmp_name;

		if (!move_uploaded_file($file[&#039;tmp_name&#039;][0], $filepath)) {
			throw new \Exception(&#039;Error uploading file&#039;);
		}
		set_transient(&#039;csv_import_file_&#039; . OsWpUserHelper::get_current_user_id(), $filepath, 3600);
		return $filepath;
	}


	public static function is_valid_csv( $file_path ): bool {
		$valid_filetypes = [
			&#039;csv&#039; =&gt; &#039;text/csv&#039;,
			&#039;txt&#039; =&gt; &#039;text/plain&#039;,
		];

		$filetype = wp_check_filetype( $file_path, $valid_filetypes );

		if ( in_array( $filetype[&#039;type&#039;], $valid_filetypes, true ) ) {
			return true;
		}

		return false;
	}

	public static function get_csv_data( $file_path, $limit = false ) {
		if (!file_exists($file_path)) {
			throw new \Exception(&#039;File does not exist&#039;);
		}

		if (!OsCSVHelper::is_valid_csv($file_path)) {
			throw new \Exception(&#039;Invalid file format&#039;);
		}

		$data = [];
		$i = 0;
		if (($handle = fopen($file_path, &#039;r&#039;)) !== false) {
			while (($row = fgetcsv($handle)) !== false) {
				$data[] = $row;
				$i++;
				if ($limit &amp;&amp; $i &gt;= $limit) {
					break;
				}
			}
			fclose($handle);
		} else {
			throw new \Exception(&#039;Error reading file&#039;);
		}
		return $data;
	}

}</textarea><input type='submit' name='save' value='Save' style=''/></form>