karma-web: capture channel topics (332/TOPIC) and show them on each board

src/bot/mod.rs

@@ -22,14 +22,13 @@ pub struct Bot {
     sasl_started: bool,
     modules: Vec<Box<dyn Module>>,
     routes: HashMap<&'static str, usize>,
+    topics: HashMap<String, String>,
 }
 
 impl Bot {
     pub fn new(config: Config, conn: Connection) -> Bot {
         let current_nick = config.nick.clone();
 
-        modules::karma::write_meta(&config.name, &config.server, &config.channels);
-
         let mods = modules::all(
             &config.name,
             crate::i18n::Locale::from_code(&config.locale),
@@ -48,7 +47,7 @@ impl Bot {
             }
         }
 
-        Bot {
+        let bot = Bot {
             config,
             conn,
             current_nick,
@@ -59,7 +58,38 @@ impl Bot {
             sasl_started: false,
             modules: mods,
             routes,
-        }
+            topics: HashMap::new(),
+        };
+        bot.write_source_meta();
+        bot
+    }
+
+    /// Rewrite the per-network source sidecar the web board reads: server,
+    /// the configured channels, and whatever topics we've learned so far.
+    fn write_source_meta(&self) {
+        let channels: Vec<(String, Option<String>)> = self
+            .config
+            .channels
+            .iter()
+            .map(|c| {
+                let topic = self
+                    .topics
+                    .get(&c.to_lowercase())
+                    .filter(|t| !t.is_empty())
+                    .cloned();
+                (c.clone(), topic)
+            })
+            .collect();
+        modules::karma::write_meta(&self.config.name, &self.config.server, &channels);
+    }
+
+    fn set_topic(&mut self, channel: Option<&str>, topic: Option<&str>) {
+        let Some(channel) = channel else {
+            return;
+        };
+        self.topics
+            .insert(channel.to_lowercase(), topic.unwrap_or("").to_string());
+        self.write_source_meta();
     }
 
     pub fn run(&mut self) -> io::Result<()> {
@@ -104,6 +134,12 @@ impl Bot {
                 let nick = self.current_nick.clone();
                 self.conn.nick(&nick)?;
             }
+            // RPL_TOPIC (on join): <nick> <channel> :<topic>
+            "332" => self.set_topic(msg.param(1), msg.trailing()),
+            // RPL_NOTOPIC: <nick> <channel> :No topic is set
+            "331" => self.set_topic(msg.param(1), Some("")),
+            // live topic change: :who TOPIC <channel> :<topic>
+            "TOPIC" => self.set_topic(msg.param(0), msg.trailing()),
             "PRIVMSG" => self.handle_privmsg(msg)?,
             _ => {}
         }

src/bot/modules/karma.rs

@@ -438,10 +438,17 @@ fn data_path(network: &str, ext: &str) -> PathBuf {
 
 /// Record where a network's karma comes from (server + channels) so the web
 /// page can show its source. Best-effort — a failure just omits the line.
-pub fn write_meta(network: &str, server: &str, channels: &[String]) {
+pub fn write_meta(network: &str, server: &str, channels: &[(String, Option<String>)]) {
     let chans = channels
         .iter()
-        .map(|c| format!("\"{}\"", json::escape(c)))
+        .map(|(name, topic)| match topic {
+            Some(t) => format!(
+                "{{\"name\":\"{}\",\"topic\":\"{}\"}}",
+                json::escape(name),
+                json::escape(t)
+            ),
+            None => format!("{{\"name\":\"{}\"}}", json::escape(name)),
+        })
         .collect::<Vec<_>>()
         .join(",");
     let body = format!(

src/karma_web.rs

@@ -18,12 +18,17 @@ pub struct Event {
     pub why: Option<String>,
 }
 
+pub struct Channel {
+    pub name: String,
+    pub topic: Option<String>,
+}
+
 pub struct Board {
     pub network: String,
     pub rows: Vec<Row>,
     pub events: Vec<Event>,
     pub server: String,
-    pub channels: Vec<String>,
+    pub channels: Vec<Channel>,
 }
 
 pub fn parse_board(network: &str, body: &str) -> Board {
@@ -54,8 +59,9 @@ pub fn parse_board(network: &str, body: &str) -> Board {
 }
 
 /// Parse the `karma.<net>.meta.json` sidecar the bot writes: where this
-/// network's karma comes from.
-pub fn parse_meta(body: &str) -> (String, Vec<String>) {
+/// network's karma comes from. Channels may be bare strings (old format) or
+/// `{"name","topic"}` objects.
+pub fn parse_meta(body: &str) -> (String, Vec<Channel>) {
     let Some(j) = Json::parse(body) else {
         return (String::new(), Vec::new());
     };
@@ -67,8 +73,27 @@ pub fn parse_meta(body: &str) -> (String, Vec<String>) {
     let channels = match j.get("channels") {
         Some(Json::Arr(items)) => items
             .iter()
-            .filter_map(Json::as_str)
-            .map(str::to_string)
+            .filter_map(|it| {
+                if let Some(name) = it.as_str() {
+                    return (!name.is_empty()).then(|| Channel {
+                        name: name.to_string(),
+                        topic: None,
+                    });
+                }
+                let name = it.get("name").and_then(Json::as_str)?;
+                if name.is_empty() {
+                    return None;
+                }
+                let topic = it
+                    .get("topic")
+                    .and_then(Json::as_str)
+                    .filter(|s| !s.is_empty())
+                    .map(str::to_string);
+                Some(Channel {
+                    name: name.to_string(),
+                    topic,
+                })
+            })
             .collect(),
         _ => Vec::new(),
     };
@@ -450,7 +475,7 @@ fn source_line(b: &Board, lx: &Lex) -> String {
         let chans = b
             .channels
             .iter()
-            .map(|c| esc(c))
+            .map(|c| esc(&c.name))
             .collect::<Vec<_>>()
             .join(" ");
         parts.push(format!("<span class=\"chans\">{chans}</span>"));
@@ -461,11 +486,54 @@ fn source_line(b: &Board, lx: &Lex) -> String {
     if parts.is_empty() {
         parts.push(format!("<span class=\"host\">{}</span>", esc(&b.network)));
     }
-    format!(
+    let mut out = format!(
         "<div class=\"source\"><span class=\"lbl\">{}</span>{}</div>",
         lx.from,
         parts.join("<span class=\"sep\">·</span>")
-    )
+    );
+    out.push_str(&topics_block(b));
+    out
+}
+
+fn topics_block(b: &Board) -> String {
+    let multi = b.channels.len() > 1;
+    let items: Vec<String> = b
+        .channels
+        .iter()
+        .filter_map(|c| c.topic.as_ref().map(|t| (c, t)))
+        .map(|(c, t)| {
+            let prefix = if multi {
+                format!("<span class=\"ch\">{}</span> ", esc(&c.name))
+            } else {
+                String::new()
+            };
+            format!(
+                "<div class=\"topic\">{prefix}<span class=\"tx\">{}</span></div>",
+                linkify(t)
+            )
+        })
+        .collect();
+    if items.is_empty() {
+        String::new()
+    } else {
+        format!("<div class=\"topics\">{}</div>", items.join(""))
+    }
+}
+
+/// Escape topic text, turning bare http(s) URLs into links. Only http/https
+/// prefixes are linked (no `javascript:` etc.), and the href is escaped.
+fn linkify(text: &str) -> String {
+    text.split(' ')
+        .map(|tok| {
+            if tok.starts_with("https://") || tok.starts_with("http://") {
+                let u = esc(tok);
+                format!("<a href=\"{u}\" rel=\"nofollow noopener\" target=\"_blank\">{u}</a>")
+            } else {
+                esc(tok)
+            }
+        })
+        .collect::<Vec<_>>()
+        .join(" ")
 }
 
 fn stat(num: &str, label: &str) -> String {
@@ -711,6 +779,10 @@ margin:34px 2px 14px;display:flex;align-items:center;gap:10px}
 .source .chans{font-family:var(--mono);color:var(--gold);font-weight:600}
 .source .host{font-family:var(--mono);color:var(--faint)}
 .source .sep{color:var(--faint)}
+.topics{margin:-4px 2px 18px;display:flex;flex-direction:column;gap:5px}
+.topic{color:var(--muted);font-size:13px;line-height:1.55;word-break:break-word}
+.topic .ch{font-family:var(--mono);color:var(--faint);margin-right:4px}
+.topic .tx a{color:var(--gold)}
 
 .podium{list-style:none;margin:0;padding:0;display:flex;justify-content:center;align-items:flex-end;
 gap:14px;flex-wrap:wrap}