feat(commands): show command suggestions if a command was not found

PluralKit.Bot/CommandSystem/Parameters.cs

@@ -26,10 +26,10 @@ public class Parameters
     // just used for errors, temporarily
     public string FullCommand { get; init; }
 
-    public Parameters(string cmd)
+    public Parameters(string prefix, string cmd)
     {
         FullCommand = cmd;
-        var result = CommandsMethods.ParseCommand(cmd);
+        var result = CommandsMethods.ParseCommand(prefix, cmd);
         if (result is CommandResult.Ok)
         {
             var command = ((CommandResult.Ok)result).@command;

PluralKit.Bot/Handlers/MessageCreated.cs

@@ -142,7 +142,7 @@ public class MessageCreated: IEventHandler<MessageCreateEvent>
             Parameters parameters;
             try
             {
-                parameters = new Parameters(evt.Content?.Substring(cmdStart));
+                parameters = new Parameters(evt.Content?.Substring(0, cmdStart), evt.Content?.Substring(cmdStart));
             }
             catch (PKError e)
             {

crates/commands/src/commands.rs

@@ -57,7 +57,7 @@ impl Display for Command {
                 write!(f, " ")?;
             }
         }
-        write!(f, " - {}", self.help)
+        Ok(())
     }
 }
 

crates/commands/src/commands.udl

@@ -1,5 +1,5 @@
 namespace commands {
-    CommandResult parse_command(string input);
+    CommandResult parse_command(string prefix, string input);
 };
 [Enum]
 interface CommandResult {

crates/commands/src/lib.rs

@@ -9,6 +9,7 @@ uniffi::include_scaffolding!("commands");
 
 use core::panic;
 use std::collections::HashMap;
+use std::fmt::Write;
 
 use smol_str::{format_smolstr, SmolStr};
 use tree::TreeBranch;
@@ -51,7 +52,7 @@ pub struct ParsedCommand {
     pub flags: HashMap<String, Option<String>>,
 }
 
-pub fn parse_command(input: String) -> CommandResult {
+pub fn parse_command(prefix: String, input: String) -> CommandResult {
     let input: SmolStr = input.into();
     let mut local_tree: TreeBranch = COMMAND_TREE.clone();
 
@@ -91,11 +92,11 @@ pub fn parse_command(input: String) -> CommandResult {
                 }
             }
             Err(None) => {
-                if let Some(command_ref) = local_tree.callback() {
-                    println!("{command_ref} {params:?}");
+                if let Some(command) = local_tree.command() {
+                    println!("{} {params:?}", command.cb);
                     return CommandResult::Ok {
                         command: ParsedCommand {
-                            command_ref: command_ref.into(),
+                            command_ref: command.cb.into(),
                             params,
                             args,
                             flags,
@@ -103,13 +104,26 @@ pub fn parse_command(input: String) -> CommandResult {
                     };
                 }
 
-                println!("{possible_tokens:?}");
+                let mut error = format!("Unknown command `{prefix}{input}`.");
+
+                let possible_commands = local_tree.possible_commands(2);
+                if !possible_commands.is_empty() {
+                    error.push_str(" Perhaps you meant to use one of the commands below:\n");
+                    for command in possible_commands {
+                        writeln!(&mut error, "- **{prefix}{command}** - *{}*", command.help)
+                            .expect("oom");
+                    }
+                } else {
+                    error.push_str("\n");
+                }
+
+                error.push_str(
+                    "For a list of possible commands, see <https://pluralkit.me/commands>.",
+                );
 
                 // todo: check if last token is a common incorrect unquote (multi-member names etc)
                 // todo: check if this is a system name in pk;s command
-                return CommandResult::Err {
-                    error: format!("Unknown command `{input}`. For a list of possible commands, see <https://pluralkit.me/commands>."),
-                };
+                return CommandResult::Err { error };
             }
             Err(Some(short_circuit)) => {
                 return CommandResult::Err {

crates/commands/src/main.rs

@@ -8,8 +8,12 @@ fn main() {
         .intersperse(" ".to_string())
         .collect::<String>();
     if !cmd.is_empty() {
-        let parsed = commands::parse_command(cmd);
-        println!("{:#?}", parsed);
+        use commands::CommandResult;
+        let parsed = commands::parse_command("pk;".to_string(), cmd);
+        match parsed {
+            CommandResult::Ok { command } => println!("{command:#?}"),
+            CommandResult::Err { error } => println!("{error}"),
+        }
     } else {
         for command in cmds::all() {
             println!("{}", command);

crates/commands/src/tree.rs

@@ -1,18 +1,17 @@
 use ordermap::OrderMap;
-use smol_str::SmolStr;
 
 use crate::{commands::Command, Token};
 
 #[derive(Debug, Clone)]
 pub struct TreeBranch {
-    current_command_key: Option<SmolStr>,
+    current_command: Option<Command>,
     branches: OrderMap<Token, TreeBranch>,
 }
 
 impl TreeBranch {
     pub fn empty() -> Self {
         Self {
-            current_command_key: None,
+            current_command: None,
             branches: OrderMap::new(),
         }
     }
@@ -20,10 +19,10 @@ impl TreeBranch {
     pub fn register_command(&mut self, command: Command) {
         let mut current_branch = self;
         // iterate over tokens in command
-        for token in command.tokens {
+        for token in command.tokens.clone() {
             // recursively get or create a sub-branch for each token
             current_branch = current_branch.branches.entry(token).or_insert(TreeBranch {
-                current_command_key: None,
+                current_command: None,
                 branches: OrderMap::new(),
             })
         }
@@ -31,20 +30,38 @@ impl TreeBranch {
         current_branch.branches.insert(
             Token::Empty,
             TreeBranch {
-                current_command_key: Some(command.cb),
+                current_command: Some(command),
                 branches: OrderMap::new(),
             },
         );
     }
 
-    pub fn callback(&self) -> Option<SmolStr> {
-        self.current_command_key.clone()
+    pub fn command(&self) -> Option<Command> {
+        self.current_command.clone()
     }
 
     pub fn possible_tokens(&self) -> impl Iterator<Item = &Token> {
         self.branches.keys()
     }
 
+    pub fn possible_commands(&self, max_depth: usize) -> Vec<Command> {
+        if max_depth == 0 {
+            return Vec::new();
+        }
+        let mut commands = Vec::new();
+        for token in self.possible_tokens() {
+            if let Some(tree) = self.get_branch(token) {
+                if let Some(command) = tree.command() {
+                    commands.push(command);
+                    // we dont need to look further if we found a command
+                    continue;
+                }
+                commands.append(&mut tree.possible_commands(max_depth - 1));
+            }
+        }
+        commands
+    }
+
     pub fn get_branch(&self, token: &Token) -> Option<&TreeBranch> {
         self.branches.get(token)
     }