add HELP command

sable_ircd/src/command/handlers/help.rs

@@ -0,0 +1,74 @@
+use super::*;
+
+use itertools::Itertools;
+
+#[command_handler("HELP", "UHELP")]
+/// HELP [<topic>]
+///
+/// HELP displays information for topic requested.
+/// If no topic is requested, it will list available
+/// help topics.
+fn help_handler(
+    command: &dyn Command,
+    response: &dyn CommandResponse,
+    server: &ClientServer,
+    source: UserSource,
+    topic: Option<&str>,
+) -> CommandResult {
+    // TODO: oper help? (and if oper help is on the same command, UHELP like solanum?)
+    // TODO: non-command help topics
+    let is_oper = command.command().to_ascii_uppercase() != "UHELP" && source.is_oper();
+
+    match topic {
+        Some(s) => {
+            let topic = s.to_ascii_uppercase();
+            let topic = topic
+                .split_once(' ')
+                .map_or(topic.clone(), |(t, _)| t.to_string());
+
+            if let Some(cmd) = server.get_command(&topic) {
+                if cmd.docs.len() > 0 {
+                    // TODO
+                    if cmd.restricted && is_oper {
+                        response.numeric(make_numeric!(HelpNotFound, &topic));
+                        return Ok(());
+                    }
+                    let mut lines = cmd.docs.iter();
+                    response.numeric(make_numeric!(
+                        HelpStart,
+                        &topic,
+                        lines.next().unwrap_or(&topic.as_str())
+                    ));
+                    for line in lines {
+                        response.numeric(make_numeric!(HelpText, &topic, line));
+                    }
+                    response.numeric(make_numeric!(EndOfHelp, &topic));
+                    return Ok(());
+                }
+            }
+            response.numeric(make_numeric!(HelpNotFound, &topic));
+        }
+        None => {
+            let topic = "*";
+            response.numeric(make_numeric!(HelpStart, topic, "Available help topics:"));
+            response.numeric(make_numeric!(HelpText, topic, ""));
+            for chunk in &server
+                .iter_commands()
+                .filter_map(|(k, v)| {
+                    if !v.restricted || is_oper {
+                        Some(k.to_ascii_uppercase())
+                    } else {
+                        None
+                    }
+                })
+                .sorted()
+                .chunks(4)
+            {
+                let line = format!("{:16}", chunk.format(" "));
+                response.numeric(make_numeric!(HelpText, topic, &line));
+            }
+            response.numeric(make_numeric!(EndOfHelp, topic));
+        }
+    };
+    Ok(())
+}

sable_ircd/src/command/mod.rs

@@ -42,6 +42,7 @@ mod handlers {
     mod ban;
     mod cap;
     mod chathistory;
+    mod help;
     mod info;
     mod invite;
     mod join;

sable_ircd/src/messages/numeric.rs

@@ -70,6 +70,10 @@ define_messages! {
     371(Info)                   => { (line: &str)               => ":{line}" },
     374(EndOfInfo)              => { ()                         => ":End of /INFO list" },
 
+    704(HelpStart)              => { (subj: &str, line: &str)   => "{subj} :{line}" },
+    705(HelpText)               => { (subj: &str, line: &str)   => "{subj} :{line}" },
+    706(EndOfHelp)              => { (subj: &str)               => "{subj} :End of /HELP" },
+
 
     401(NoSuchTarget)           => { (unknown: &str)            => "{unknown} :No such nick/channel" },
     402(NoSuchServer)           => { (server_name: &ServerName) => "{server_name} :No such server" },
@@ -125,6 +129,8 @@ define_messages! {
 
     440(ServicesNotAvailable) => { () => ":Services are not available"},
 
+    524(HelpNotFound)           => { (subj: &str)               => "{subj} :No help available on this topic" },
+
     // https://ircv3.net/specs/extensions/monitor
     730(MonOnline)          => { (content: &str )               => ":{content}" },
     731(MonOffline)         => { (content: &str )               => ":{content}" },