From 715cb8583fe221964d98b8c14b8e7d7e5af1a9a2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E6=A9=98?= <xiaoju@shazhou.work>
Date: Mon, 27 Apr 2026 05:29:47 +0000
Subject: [PATCH] feat(daemon): auto-persist signals to sense DB
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Every sense now gets a _signals table (id, payload, timestamp) created
automatically. When compute() returns non-null, the signal is persisted
to the sense's own SQLite DB before being sent to the Signal Bus.

This makes `nerve sense query <name>` return signal history out of the
box — no manual INSERT needed in compute functions.

CLI's pickDefaultPreviewTable now prioritizes _signals over other tables.
---
 packages/cli/src/sense-sqlite.ts              |  4 +++-
 .../src/__tests__/sense-runtime.test.ts       |  3 ++-
 packages/daemon/src/sense-runtime.ts          | 21 +++++++++++++++++--
 packages/daemon/src/sense-worker.ts           | 11 +++++++++-
 4 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/packages/cli/src/sense-sqlite.ts b/packages/cli/src/sense-sqlite.ts
index af82885..fc52530 100644
--- a/packages/cli/src/sense-sqlite.ts
+++ b/packages/cli/src/sense-sqlite.ts
@@ -42,7 +42,9 @@ export function pickDefaultPreviewTable(db: DatabaseSync): string | null {
        WHERE type = 'table' AND sql IS NOT NULL
          AND name NOT LIKE 'sqlite\\_%' ESCAPE '\\'
        ORDER BY
-         CASE WHEN name = '_migrations' THEN 1 ELSE 0 END,
+         CASE WHEN name = '_signals' THEN 0
+              WHEN name = '_migrations' THEN 2
+              ELSE 1 END,
          name
        LIMIT 1`,
     )
diff --git a/packages/daemon/src/__tests__/sense-runtime.test.ts b/packages/daemon/src/__tests__/sense-runtime.test.ts
index 32258c0..d94e5bc 100644
--- a/packages/daemon/src/__tests__/sense-runtime.test.ts
+++ b/packages/daemon/src/__tests__/sense-runtime.test.ts
@@ -176,7 +176,7 @@ describe("executeCompute", () => {
     sqlite.exec(INIT_SQL);
     const db = drizzle({ client: sqlite }) as DrizzleDB;
     return {
-      runtime: { name: "test-sense", db, compute: computeFn },
+      runtime: { name: "test-sense", db, compute: computeFn, persistSignal: () => {} },
       sqlite,
     };
   }
@@ -287,6 +287,7 @@ describe("executeCompute", () => {
         await d.insert(samples).values({ ts: 1000, value: 1.23 });
         return 1.23;
       },
+      persistSignal: () => {},
     };
 
     const result = await executeCompute(runtime, {});
diff --git a/packages/daemon/src/sense-runtime.ts b/packages/daemon/src/sense-runtime.ts
index 5456270..16921a8 100644
--- a/packages/daemon/src/sense-runtime.ts
+++ b/packages/daemon/src/sense-runtime.ts
@@ -40,6 +40,7 @@ export type SenseRuntime = {
   name: string;
   db: DrizzleDB;
   compute: ComputeFn;
+  persistSignal: (payload: unknown) => void;
 };
 
 function ensureMigrationsTable(sqlite: DatabaseSync): Result<void> {
@@ -131,7 +132,7 @@ export function runMigrations(sqlite: DatabaseSync, migrationsDir: string): Resu
 export function openSenseDb(
   dbPath: string,
   migrationsDir: string,
-): Result<{ sqlite: DatabaseSync; db: DrizzleDB }> {
+): Result<{ sqlite: DatabaseSync; db: DrizzleDB; persistSignal: (payload: unknown) => void }> {
   let sqlite: DatabaseSync;
 
   try {
@@ -146,9 +147,25 @@ export function openSenseDb(
   const migResult = runMigrations(sqlite, migrationsDir);
   if (!migResult.ok) return migResult;
 
+  // Auto-create _signals table for signal persistence (all senses get this)
+  sqlite.exec(
+    `CREATE TABLE IF NOT EXISTS _signals (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      payload TEXT NOT NULL,
+      timestamp INTEGER NOT NULL
+    )`,
+  );
+
+  const insertStmt = sqlite.prepare("INSERT INTO _signals (payload, timestamp) VALUES (?, ?)");
+
+  function persistSignal(payload: unknown): void {
+    const json = JSON.stringify(payload);
+    insertStmt.run(json, Date.now());
+  }
+
   // Drizzle infers a schema-specific DB type; senses are schema-agnostic at this layer.
   const db = drizzle({ client: sqlite }) as DrizzleDB;
-  return ok({ sqlite, db });
+  return ok({ sqlite, db, persistSignal });
 }
 
 /**
diff --git a/packages/daemon/src/sense-worker.ts b/packages/daemon/src/sense-worker.ts
index d726c83..4c296dd 100644
--- a/packages/daemon/src/sense-worker.ts
+++ b/packages/daemon/src/sense-worker.ts
@@ -91,7 +91,15 @@ async function initSense(
   }
 
   const { db } = dbResult.value;
-  return { db, runtime: { name: senseName, db, compute: computeResult.value } };
+  return {
+    db,
+    runtime: {
+      name: senseName,
+      db,
+      compute: computeResult.value,
+      persistSignal: dbResult.value.persistSignal,
+    },
+  };
 }
 
 function buildPeers(
@@ -178,6 +186,7 @@ async function runCompute(
     }
     clearGracePeriodTimer(senseName);
     if (result.value !== null) {
+      runtime.persistSignal(result.value);
       sendSignal(senseName, result.value);
     }
   } catch (e: unknown) {
-- 
2.43.0