feat: add ecc2 session messaging primitives

ecc2/src/comms/mod.rs

@@ -24,13 +24,63 @@ pub enum MessageType {
 /// Send a structured message between sessions.
 pub fn send(db: &StateStore, from: &str, to: &str, msg: &MessageType) -> Result<()> {
     let content = serde_json::to_string(msg)?;
-    let msg_type = match msg {
+    let msg_type = message_type_name(msg);
+    db.send_message(from, to, &content, msg_type)?;
+    Ok(())
+}
+
+pub fn message_type_name(msg: &MessageType) -> &'static str {
+    match msg {
         MessageType::TaskHandoff { .. } => "task_handoff",
         MessageType::Query { .. } => "query",
         MessageType::Response { .. } => "response",
         MessageType::Completed { .. } => "completed",
         MessageType::Conflict { .. } => "conflict",
-    };
-    db.send_message(from, to, &content, msg_type)?;
-    Ok(())
+    }
+}
+
+pub fn parse(content: &str) -> Option<MessageType> {
+    serde_json::from_str(content).ok()
+}
+
+pub fn preview(msg_type: &str, content: &str) -> String {
+    match parse(content) {
+        Some(MessageType::TaskHandoff { task, .. }) => {
+            format!("handoff {}", truncate(&task, 56))
+        }
+        Some(MessageType::Query { question }) => {
+            format!("query {}", truncate(&question, 56))
+        }
+        Some(MessageType::Response { answer }) => {
+            format!("response {}", truncate(&answer, 56))
+        }
+        Some(MessageType::Completed {
+            summary,
+            files_changed,
+        }) => {
+            if files_changed.is_empty() {
+                format!("completed {}", truncate(&summary, 48))
+            } else {
+                format!(
+                    "completed {} | {} files",
+                    truncate(&summary, 40),
+                    files_changed.len()
+                )
+            }
+        }
+        Some(MessageType::Conflict { file, description }) => {
+            format!("conflict {} | {}", file, truncate(&description, 40))
+        }
+        None => format!("{} {}", msg_type.replace('_', " "), truncate(content, 56)),
+    }
+}
+
+fn truncate(value: &str, max_chars: usize) -> String {
+    let trimmed = value.trim();
+    if trimmed.chars().count() <= max_chars {
+        return trimmed.to_string();
+    }
+
+    let truncated: String = trimmed.chars().take(max_chars.saturating_sub(1)).collect();
+    format!("{truncated}…")
 }