matrix: hive-matrix-mcp crate (daemon+stdio bridge) + harness wiring (#548 phase 3)

hive-matrix-mcp/src/wake.rs

@@ -0,0 +1,116 @@
+//! Wake-signal writer: notifies the hyperhive harness when an incoming
+//! matrix event arrives so claude drives a new turn.
+//!
+//! Same wire shape as `hive-ag3nt::forge_notify`'s wake: a single JSON
+//! line written to the hyperhive control socket (`/run/hive/mcp.sock`
+//! by default) carrying an `AgentRequest::Wake { from, body }`.
+//! The agent harness's `agent_server` parses it and treats it as a
+//! `Wake` from the matrix subsystem.
+//!
+//! Per mara's call on #548 phase 3: the body is a SHORT TEASER, not
+//! the full message — the agent then reads the unmarked event via
+//! the `read_room` MCP tool. Truncation to ~100 chars keeps the wake
+//! prompt focused (`forge_notify` embeds longer excerpts because the
+//! agent doesn't have a follow-up read-the-original tool for forge).
+
+use std::path::Path;
+
+use anyhow::{Context, Result};
+use tokio::io::AsyncWriteExt;
+use tokio::net::UnixStream;
+
+/// Max characters of `body` to embed in the wake payload. Shorter than
+/// `forge_notify`'s 500-byte excerpt because the agent has a follow-up
+/// `read_room` tool to fetch the full event.
+pub const WAKE_BODY_TRUNCATE: usize = 100;
+
+/// Send an `AgentRequest::Wake { from: "matrix", body }` to the hyperhive
+/// control socket at `socket`. Best-effort: returns Err on any plumbing
+/// failure; callers log + ignore so a wake delivery hiccup doesn't tear
+/// down the matrix sync loop.
+pub async fn send_wake(socket: &Path, body: impl AsRef<str>) -> Result<()> {
+    let payload = serde_json::json!({
+        "kind": "wake",
+        "from": "matrix",
+        "body": body.as_ref(),
+    });
+    let line = format!("{}\n", serde_json::to_string(&payload)?);
+    let mut stream = UnixStream::connect(socket)
+        .await
+        .with_context(|| format!("connect hyperhive socket {}", socket.display()))?;
+    stream
+        .write_all(line.as_bytes())
+        .await
+        .with_context(|| format!("write wake to {}", socket.display()))?;
+    stream
+        .shutdown()
+        .await
+        .with_context(|| format!("shutdown write to {}", socket.display()))?;
+    Ok(())
+}
+
+/// Format a wake-message body from a matrix event's sender + room
+/// canonical alias + body text. Truncates at [`WAKE_BODY_TRUNCATE`]
+/// chars with an ellipsis. Shape: `[matrix] <sender> in <room>: <text>`
+/// matches the `forge_notify` `[issue …]` framing convention.
+#[must_use]
+pub fn format_wake_body(sender: &str, room: &str, text: &str) -> String {
+    let truncated = truncate_chars(text, WAKE_BODY_TRUNCATE);
+    format!("[matrix] {sender} in {room}: {truncated}")
+}
+
+/// Truncate `s` to `max` Unicode chars, appending `…` when cut.
+/// Char-based not byte-based so multi-byte content (most chat) doesn't
+/// get cut mid-codepoint.
+fn truncate_chars(s: &str, max: usize) -> String {
+    let mut end = s.len();
+    for (count, (i, _)) in s.char_indices().enumerate() {
+        if count == max {
+            end = i;
+            break;
+        }
+    }
+    if end == s.len() {
+        s.to_owned()
+    } else {
+        format!("{}…", &s[..end])
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn format_wake_body_short_passes_through() {
+        let body = format_wake_body("@iris:matrix.darkest.space", "#general", "hi all");
+        assert_eq!(body, "[matrix] @iris:matrix.darkest.space in #general: hi all");
+    }
+
+    #[test]
+    fn format_wake_body_long_truncates_with_ellipsis() {
+        let long = "x".repeat(200);
+        let body = format_wake_body("@iris:m", "#x", &long);
+        assert!(body.contains("xxxxxxx"));
+        assert!(body.ends_with("…"));
+        // Header + truncated body should be well under the absolute
+        // wake-message ceiling (forge_notify uses ~600 bytes; we're
+        // way under that).
+        assert!(body.len() < 200);
+    }
+
+    #[test]
+    fn truncate_chars_handles_multibyte() {
+        // `ü` is 2 bytes / 1 char. truncating to 3 chars on "üüüüüü"
+        // should yield "üüü…" not "üü\xc3…" (mid-codepoint).
+        let s = "üüüüüü";
+        let t = truncate_chars(s, 3);
+        assert_eq!(t, "üüü…");
+    }
+
+    #[test]
+    fn truncate_chars_no_op_below_limit() {
+        let s = "hi";
+        assert_eq!(truncate_chars(s, 100), "hi");
+    }
+}