3 files changed, 183 insertions, 12 deletions

diff --git a/crates/dinggerd/src/main.rs b/crates/dinggerd/src/main.rs
index f046732..4c8521c 100644
--- a/crates/dinggerd/src/main.rs
+++ b/crates/dinggerd/src/main.rs
@@ -33,6 +33,12 @@ enum Command {
         #[command(subcommand)]
         command: ManifestCommand,
     },
+    /// Switch to the agent that has been waiting the longest (FIFO). Bound to
+    /// a mouse click on the tmux status line by the packaged config.
+    Focus {
+        /// Name of the tmux client that clicked, passed as #{client_name}.
+        client: Option<String>,
+    },
 }
 
 #[derive(Subcommand)]
@@ -73,7 +79,43 @@ fn main() {
                 }
             }
         },
+        Command::Focus { client } => {
+            if let Err(err) = focus(client) {
+                eprintln!("dingger: {err}");
+                std::process::exit(1);
+            }
+        }
+    }
+}
+
+/// Jump to the head of the ready queue (oldest waiting agent) and ack it, so
+/// the next focus moves on to the following one.
+fn focus(client: Option<String>) -> Result<(), String> {
+    let queue = tmux::show_global("@dingger_queue")
+        .unwrap_or_default()
+        .split(',')
+        .filter(|entry| !entry.is_empty())
+        .map(|entry| entry.split(':').next().unwrap_or("").to_string())
+        .collect::<Vec<_>>();
+    let Some(pane_id) = queue.first() else {
+        return Ok(()); // nothing waiting
+    };
+    let target = tmux::show_pane_format(pane_id, "#{session_name}:#{window_index}.#{pane_index}")
+        .unwrap_or_default();
+    if target.is_empty() {
+        return Err("ready pane no longer exists".to_string());
+    }
+    tmux::ack(pane_id)?;
+    let mut args = vec!["switch-client".to_string()];
+    if let Some(client) = client {
+        args.push("-c".to_string());
+        args.push(client);
     }
+    args.push("-t".to_string());
+    args.push(target);
+    tmux::run_tmux_client(
+        &args.iter().map(String::as_str).collect::<Vec<_>>(),
+    )
 }
 
 fn status() -> Result<(), String> {
diff --git a/crates/dinggerd/src/tmux.rs b/crates/dinggerd/src/tmux.rs
index edd44aa..cba1ca6 100644
--- a/crates/dinggerd/src/tmux.rs
+++ b/crates/dinggerd/src/tmux.rs
@@ -26,6 +26,9 @@ pub struct Pane {
     pub written_state: String,
     /// The `@agent` user option (agent label) previously written, if any.
     pub written_agent: String,
+    /// The `@dingger_ack` user option: "1" when the user already jumped to
+    /// this pane in its current ready episode.
+    pub written_ack: String,
 }
 
 impl Pane {
@@ -70,7 +73,8 @@ pub fn list_panes() -> Result<Vec<Pane>, String> {
         "#{pane_start_command}\t",
         "#{pane_pid}\t",
         "#{@agent_state}\t",
-        "#{@agent}"
+        "#{@agent}\t",
+        "#{@dingger_ack}"
     );
     let out = run_tmux(&["list-panes", "-a", "-F", format])?;
     let mut panes = Vec::new();
@@ -104,6 +108,7 @@ pub fn list_panes() -> Result<Vec<Pane>, String> {
             agent,
             written_state: fields[9].to_string(),
             written_agent: fields[10].to_string(),
+            written_ack: fields.get(11).copied().unwrap_or("").to_string(),
         });
     }
     Ok(panes)
@@ -166,6 +171,19 @@ fn fetch_process_tree() -> ProcessTree {
     (children, comm)
 }
 
+/// Run a tmux command whose effect is an action (e.g. switch-client), not
+/// output to parse.
+pub fn run_tmux_client(args: &[&str]) -> Result<(), String> {
+    run_tmux(args).map(|_| ())
+}
+
+/// Read a format expansion for one pane.
+pub fn show_pane_format(pane_id: &str, format: &str) -> Option<String> {
+    run_tmux(&["display-message", "-p", "-t", pane_id, format])
+        .ok()
+        .map(|value| value.trim().to_string())
+}
+
 /// Capture the pane's visible screen as plain text — the exact input shape
 /// the detection manifests expect.
 pub fn capture_pane(pane_id: &str) -> Result<String, String> {
@@ -187,6 +205,28 @@ pub fn set_agent_state(pane_id: &str, state: AgentState) -> Result<(), String> {
 /// Label the pane with the agent running in it, for tmux status-line and
 /// menu-bar rendering; clears the label when the pane stops running one.
 pub fn set_agent(pane_id: &str, agent: Option<Agent>) -> Result<(), String> {
-    let label = agent.map(detect_core::agent_label).unwrap_or("");
-    run_tmux(&["set-option", "-p", "-t", pane_id, "@agent", label]).map(|_| ())
+        let label = agent.map(detect_core::agent_label).unwrap_or("");
+        run_tmux(&["set-option", "-p", "-t", pane_id, "@agent", label]).map(|_| ())
+}
+
+/// Write a server-global option (readable from any client and from formats).
+pub fn set_global(name: &str, value: &str) -> Result<(), String> {
+    run_tmux(&["set-option", "-g", name, value]).map(|_| ())
+}
+
+pub fn show_global(name: &str) -> Option<String> {
+    run_tmux(&["show-option", "-gv", name])
+        .ok()
+        .map(|value| value.trim().to_string())
+        .filter(|value| !value.is_empty())
+}
+
+/// Mark a pane as seen by the user after `dingger focus`: taken out of the
+/// ready queue until its next state transition.
+pub fn ack(pane_id: &str) -> Result<(), String> {
+    run_tmux(&["set-option", "-p", "-t", pane_id, "@dingger_ack", "1"]).map(|_| ())
+}
+
+pub fn clear_ack(pane_id: &str) -> Result<(), String> {
+    run_tmux(&["set-option", "-p", "-t", pane_id, "-u", "@dingger_ack"]).map(|_| ())
 }
diff --git a/crates/dinggerd/src/watcher.rs b/crates/dinggerd/src/watcher.rs
index f039456..9fd999d 100644
--- a/crates/dinggerd/src/watcher.rs
+++ b/crates/dinggerd/src/watcher.rs
@@ -9,14 +9,30 @@ use tracing::{debug, info, warn};
 use crate::notify::{play_sound, send_notification, NotificationKind};
 use crate::tmux;
 
+/// When a pane became ready for the user, as unix seconds. Ready means the
+/// agent is waiting on the user: idle at its prompt or blocked on input.
+fn is_ready(state: AgentState) -> bool {
+    matches!(state, AgentState::Idle | AgentState::Blocked)
+}
+
 pub struct Watcher {
-    /// Last published state per pane id. `status` reads the same values back
-    /// from tmux's `@agent_state`, so no other state is needed.
-    states: HashMap<String, AgentState>,
+    /// Published state plus the unix second it became ready, per pane id.
+    /// Published state plus the unix second it became ready, per pane id.
+    /// `status` reads the same values back from tmux's `@agent_state`, so no
+    /// other durable state is needed.
+    panes: HashMap<String, PaneTrack>,
+    /// Last (queue, counts) written to the global options; avoids rewriting
+    /// them every tick.
+    last_published: Option<(String, (String, String, String))>,
     interval_secs: u64,
     sounds: bool,
 }
 
+struct PaneTrack {
+    state: AgentState,
+    ready_since: Option<u64>,
+}
+
 /// herdr's notification policy (`notification_toast_for_state_change`).
 pub fn notification_kind_for_transition(
     prev_state: AgentState,
@@ -39,7 +55,8 @@ pub fn notification_kind_for_transition(
 impl Watcher {
     pub fn new(interval_secs: u64, sounds: bool) -> Self {
         Self {
-            states: HashMap::new(),
+            panes: HashMap::new(),
+            last_published: None,
             interval_secs: interval_secs.max(1),
             sounds,
         }
@@ -74,14 +91,14 @@ impl Watcher {
         let panes = tmux::list_panes()?;
 
         // Forget panes that went away.
-        self.states
+        self.panes
             .retain(|pane_id, _| panes.iter().any(|pane| pane.pane_id == *pane_id));
 
-        for pane in panes {
+        for pane in &panes {
             let prev_state = self
-                .states
+                .panes
                 .get(&pane.pane_id)
-                .copied()
+                .map(|track| track.state)
                 .unwrap_or(AgentState::Unknown);
 
             // The detection result is an observation of live agent state.
@@ -130,12 +147,22 @@ impl Watcher {
             if new_state == prev_state {
                 continue;
             }
-            self.states.insert(pane.pane_id.clone(), new_state);
+            let ready_since = is_ready(new_state).then(unix_now);
+            self.panes.insert(
+                pane.pane_id.clone(),
+                PaneTrack {
+                    state: new_state,
+                    ready_since,
+                },
+            );
             debug!(target = %pane.target, ?prev_state, ?new_state, "state change");
 
             if let Err(err) = tmux::set_agent_state(&pane.pane_id, new_state) {
                 warn!(target = %pane.target, %err, "failed to write @agent_state");
             }
+            // A fresh transition re-enters the ready queue even if the user
+            // already jumped to this pane in a previous ready episode.
+            let _ = tmux::clear_ack(&pane.pane_id);
 
 
             if let Some(kind) = notification_kind_for_transition(prev_state, new_state) {
@@ -151,8 +178,70 @@ impl Watcher {
             }
         }
 
+        self.publish_ready_queue(&panes);
         Ok(())
     }
+
+    /// Publish the FIFO ready queue (oldest first) as a server-global option;
+    /// `dingger focus` pops its head, and the tmux status line renders counts.
+    fn publish_ready_queue(&mut self, panes: &[tmux::Pane]) {
+        let mut ready: Vec<(&str, String, u64)> = Vec::new(); // (pane_id, target, ready_since)
+        let mut blocked = 0usize;
+        let mut working = 0usize;
+        for pane in panes {
+            let Some(track) = self.panes.get(&pane.pane_id) else {
+                continue;
+            };
+            match track.state {
+                AgentState::Working => working += 1,
+                AgentState::Idle | AgentState::Blocked => {
+                    let acked = pane.written_ack == "1";
+                    if !acked {
+                        if let Some(since) = track.ready_since {
+                            if track.state == AgentState::Blocked {
+                                blocked += 1;
+                            }
+                            ready.push((pane.pane_id.as_str(), pane.target.clone(), since));
+                        }
+                    }
+                }
+                AgentState::Unknown => {}
+            }
+        }
+        ready.sort_by_key(|(_, _, since)| *since);
+
+        let queue = ready
+            .iter()
+            .map(|(pane_id, _, since)| format!("{pane_id}:{since}"))
+            .collect::<Vec<_>>()
+            .join(",");
+        let counts = (
+            ready.len().to_string(),
+            blocked.to_string(),
+            working.to_string(),
+        );
+        let next = (queue.clone(), counts.clone());
+        if self.last_published.as_ref() != Some(&next) {
+            self.last_published = Some(next);
+            for (name, value) in [
+                ("@dingger_queue", queue.as_str()),
+                ("@dingger_ready", counts.0.as_str()),
+                ("@dingger_blocked", counts.1.as_str()),
+                ("@dingger_working", counts.2.as_str()),
+            ] {
+                if let Err(err) = tmux::set_global(name, value) {
+                    warn!(%err, "failed to write {name}");
+                }
+            }
+        }
+    }
+}
+
+fn unix_now() -> u64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .map(|d| d.as_secs())
+        .unwrap_or(0)
 }
 
 #[cfg(test)]