add help command

pumpkin/src/commands/cmd_gamemode.rs

@@ -14,7 +14,7 @@ use crate::entity::player::GameMode;
 
 pub(crate) const NAME: &str = "gamemode";
 
-const DESCRIPTION: &str = "Changes the gamemode for a Player";
+const DESCRIPTION: &str = "Change a player's gamemode.";
 
 const ARG_GAMEMODE: &str = "gamemode";
 const ARG_TARGET: &str = "target";

pumpkin/src/commands/cmd_help.rs

@@ -0,0 +1,61 @@
+use crate::commands::{CommandSender, DISPATCHER, dispatcher_init};
+use crate::commands::dispatcher::{CommandDispatcher, InvalidTreeError};
+use crate::commands::dispatcher::InvalidTreeError::InvalidConsumptionError;
+use crate::commands::tree::{CommandTree, ConsumedArgs, RawArgs};
+use crate::commands::tree_builder::argument;
+
+pub(crate) const NAME: &str = "help";
+pub(crate) const ALIAS: &str = "?";
+
+const DESCRIPTION: &str = "Print a help message.";
+
+const ARG_COMMAND: &str = "command";
+
+fn consume_arg_command(_src: &CommandSender, args: &mut RawArgs) -> Option<String> {
+    let s = args.pop()?;
+
+    let dispatcher = DISPATCHER;
+    let dispatcher = dispatcher.get_or_init(dispatcher_init);
+
+    if dispatcher.commands.contains_key(s) { Some(s.into()) }
+    else { None }
+}
+
+fn parse_arg_command<'a>(consumed_args: &'a ConsumedArgs, dispatcher: &'a CommandDispatcher) -> Result<(&'a str, &'a CommandTree<'a>), InvalidTreeError> {
+    let command_name = consumed_args.get(ARG_COMMAND)
+        .ok_or(InvalidConsumptionError(None))?;
+
+    if let Some(tree) = dispatcher.commands.get::<&str>(&command_name.as_str()) {
+        Ok((command_name, tree))
+    } else {
+        Err(InvalidConsumptionError(Some(command_name.into())))
+    }
+}
+
+pub(crate) fn init_command_tree<'a>() -> CommandTree<'a> {
+    CommandTree::new(DESCRIPTION).with_child(
+        argument(ARG_COMMAND, consume_arg_command).execute(&|sender, args| {
+            let dispatcher = DISPATCHER;
+            let dispatcher = dispatcher.get_or_init(dispatcher_init);
+            
+            let (name, tree) = parse_arg_command(args, dispatcher)?;
+            
+            sender.send_message(
+                format!("{} - {} Usage:{}", name, tree.description, tree.paths_formatted(name)).into()
+            );
+            
+            Ok(())
+        })
+    ).execute(&|sender, _args| {
+        let dispatcher = DISPATCHER;
+        let dispatcher = dispatcher.get_or_init(dispatcher_init);
+
+        for (name, tree) in &dispatcher.commands {
+            sender.send_message(
+                format!("{} - {} Usage:{}", name, tree.description, tree.paths_formatted(name)).into()
+            );
+        };
+
+        Ok(())
+    })
+}

pumpkin/src/commands/cmd_pumpkin.rs

@@ -6,7 +6,7 @@ use crate::commands::tree::CommandTree;
 
 pub(crate) const NAME: &str = "pumpkin";
 
-const DESCRIPTION: &str = "Displays information about Pumpkin";
+const DESCRIPTION: &str = "Display information about Pumpkin.";
 
 pub(crate) fn init_command_tree<'a>() -> CommandTree<'a> {
     CommandTree::new(DESCRIPTION).execute(&|sender, _| {

pumpkin/src/commands/cmd_stop.rs

@@ -3,7 +3,7 @@ use crate::commands::tree_builder::require;
 
 pub(crate) const NAME: &str = "stop";
 
-const DESCRIPTION: &str = "Stops the server";
+const DESCRIPTION: &str = "Stop the server.";
 
 pub(crate) fn init_command_tree<'a>() -> CommandTree<'a> {
     CommandTree::new(DESCRIPTION).with_child(

pumpkin/src/commands/mod.rs

@@ -4,8 +4,6 @@ use pumpkin_text::TextComponent;
 
 use crate::client::Client;
 use crate::commands::dispatcher::CommandDispatcher;
-use crate::server::Server;
-
 mod cmd_gamemode;
 mod cmd_pumpkin;
 mod cmd_stop;
@@ -14,6 +12,7 @@ mod tree_builder;
 mod dispatcher;
 mod arg_player;
 mod cmd_teleport;
+mod cmd_help;
 
 pub enum CommandSender<'a> {
     Rcon(&'a mut Vec<String>),
@@ -73,6 +72,8 @@ fn dispatcher_init<'a>() -> CommandDispatcher<'a> {
     map.insert(cmd_pumpkin::NAME, cmd_pumpkin::init_command_tree());
     map.insert(cmd_gamemode::NAME, cmd_gamemode::init_command_tree());
     map.insert(cmd_stop::NAME, cmd_stop::init_command_tree());
+    map.insert(cmd_help::NAME, cmd_help::init_command_tree());
+    map.insert(cmd_help::ALIAS, cmd_help::init_command_tree());
 
     CommandDispatcher {
         commands: map,

pumpkin/src/commands/tree.rs

@@ -70,8 +70,8 @@ impl <'a> CommandTree<'a> {
         
         let mut s = String::with_capacity(len);
 
-        for path in paths {
-            s.push('\n');
+        for path in paths.iter() {
+            s.push(if paths.len() > 1 { '\n' } else { ' ' });
             s.push('/');
             s.push_str(name);
             for node in path {