refactor: split parser internals into focused modules

src/utils/parser/ports.rs

@@ -0,0 +1,19 @@
+use crate::filetransfer::FileTransferProtocol;
+
+pub(super) fn default_port_for_protocol(protocol: FileTransferProtocol) -> u16 {
+    match protocol {
+        FileTransferProtocol::Ftp(_) => 21,
+        FileTransferProtocol::Scp | FileTransferProtocol::Sftp => 22,
+        _ => 22,
+    }
+}
+
+pub(super) fn parse_port(port: Option<regex::Match<'_>>, default: u16) -> Result<u16, String> {
+    match port {
+        Some(port) => port
+            .as_str()
+            .parse::<u16>()
+            .map_err(|err| format!("Bad port \"{}\": {err}", port.as_str())),
+        None => Ok(default),
+    }
+}