Add ServerReference and parse methods for Server

src/main.rs

@@ -1,7 +1,9 @@
-use clap::builder::Str;
 use clap::{Parser, Subcommand, ValueEnum};
 use std::env;
+use std::error::Error;
+use std::fmt::{Display, Formatter};
 use std::path::PathBuf;
+use std::str::FromStr;
 
 const SERVERS_ENV_VAR: &str = "MSSH_SERVERS";
 
@@ -20,8 +22,8 @@ struct Args {
   #[command(subcommand)]
   command: Command,
   /// The ssh names and optionally home directories of the servers to perform the action on
-  #[arg(num_args = 1..)]
-  servers: Vec<String>, //TODO directly parse servers and their directories
+  #[arg(num_args = 1.., value_parser = ServerReference::from_str)]
+  servers: Vec<ServerReference>,
 }
 
 #[derive(Subcommand, Debug)]
@@ -54,12 +56,81 @@ enum OldVersionPolicy {
   Delete,
 }
 
+#[derive(Debug, Clone)]
+enum ServerReference {
+  Resolved(Server),
+  Name(String),
+}
+
+impl ServerReference {
+  //TODO lazy resolve method which gets a provider for configured servers
+  pub fn resolve(self, configured_servers: &[Server]) -> Option<Server> {
+    match self {
+      ServerReference::Resolved(server) => Some(server),
+      ServerReference::Name(name) => configured_servers
+        .iter()
+        .find(|server| server.ssh_name == name)
+        .cloned(),
+    }
+  }
+}
+
+impl FromStr for ServerReference {
+  type Err = ServerParseError;
+
+  fn from_str(s: &str) -> Result<Self, Self::Err> {
+    Server::from_str(s)
+      .map(Self::Resolved)
+      .or_else(|_| Ok(Self::Name(s.to_string())))
+  }
+}
+
 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
 struct Server {
   pub ssh_name: String,
   pub server_directory_path: PathBuf,
 }
 
+impl FromStr for Server {
+  type Err = ServerParseError;
+
+  fn from_str(s: &str) -> Result<Self, Self::Err> {
+    s.split_once(':')
+      .ok_or(ServerParseError::MissingServerDirectory)
+      .map(|(name, directory)| Self {
+        ssh_name: name.to_string(),
+        server_directory_path: PathBuf::from(directory),
+      })
+  }
+}
+
+impl Display for Server {
+  fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+    write!(f, "{}:{:?}", self.ssh_name, self.server_directory_path)
+  }
+}
+
+#[derive(Debug)]
+enum ServerParseError {
+  MissingServerDirectory,
+}
+
+impl Display for ServerParseError {
+  fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+    match self {
+      ServerParseError::MissingServerDirectory => {
+        write!(
+          f,
+          "String is not specifying a server directory. Please use an empty string after a \
+          double colon to point to the home directory, e.g: 'lobby:'"
+        )
+      }
+    }
+  }
+}
+
+impl Error for ServerParseError {}
+
 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
 struct PluginInfo {
   pub name: String,
@@ -73,19 +144,6 @@ fn main() -> Result<(), String> {
   let configured_servers = parse_server_configuration_from_env()?;
   dbg!(&configured_servers);
 
-  let servers = args
-    .servers
-    .iter()
-    .map(|server_name| {
-      configured_servers
-        .iter()
-        .find(|server| server.ssh_name == *server_name)
-        .ok_or(format!(
-          "no server with the name '{server_name}' has been configured"
-        ))
-    })
-    .collect::<Result<Vec<_>, _>>()?;
-
   Ok(())
 }
 
@@ -96,13 +154,13 @@ fn parse_server_configuration_from_env() -> Result<Vec<Server>, String> {
 }
 
 fn parse_server_configuration(config_str: &str) -> Result<Vec<Server>, String> {
-  config_str.split(',').map(|server_entry| {
-    let (name, server_directory) = server_entry.split_once(':').ok_or(format!("Server entry doesn't specify a server directory (separate name and directory via double colon) for entry '{}'", server_entry))?;
-    Ok(Server {
-      ssh_name: name.to_string(),
-      server_directory_path: PathBuf::from(server_directory),
+  config_str
+    .split(',')
+    .map(|server_entry| {
+      Server::from_str(server_entry)
+        .map_err(|e| format!("Invalid server entry '{server_entry}': {e}"))
     })
-  }).collect()
+    .collect()
 }
 
 #[cfg(test)]