feat: add thread info and status reads

tests/test_store_sqlite.py

@@ -1,5 +1,6 @@
 import pathlib
 import tempfile
+import uuid
 
 from agentmsgs.stores.sqlite import SQLiteStore
 
@@ -59,3 +60,74 @@ def test_sqlite_concurrent_append():
         finally:
             s2.close()
             s1.close()
+
+
+def test_sqlite_thread_info_and_read_state():
+    with tempfile.TemporaryDirectory() as d:
+        p = pathlib.Path(d) / "info.db"
+        s = SQLiteStore(p)
+        try:
+            a = s.get_or_create_agent("A")
+            b = s.get_or_create_agent("B")
+            t = s.create_thread({a, b})
+            s.append_message(t.id, a, "one")
+            s.append_message(t.id, b, "two")
+            latest = s.append_message(t.id, a, "three")
+
+            info = s.get_thread_info(t.id)
+            assert info is not None
+            assert info.thread == t
+            assert info.message_count == 3
+            assert info.latest_message == latest
+
+            state = s.get_thread_read_state(t.id, a)
+            assert state.agent == a
+            assert state.cursor_seq == 0
+            assert state.latest_seq == 3
+            assert state.unread_count == 3
+            assert state.unread_from_others_count == 1
+
+            s.set_cursor(t.id, a, 2)
+            state = s.get_thread_read_state(t.id, a)
+            assert state.cursor_seq == 2
+            assert state.unread_count == 1
+            assert state.unread_from_others_count == 0
+            assert s.get_thread_info(uuid.uuid4()) is None
+            assert s.get_thread_read_state(uuid.uuid4(), a) is None
+        finally:
+            s.close()
+
+
+def test_sqlite_thread_read_state_uses_consistent_snapshot():
+    with tempfile.TemporaryDirectory() as d:
+        p = pathlib.Path(d) / "snapshot.db"
+        reader = SQLiteStore(p)
+        writer = SQLiteStore(p)
+        try:
+            a = reader.get_or_create_agent("A")
+            b = reader.get_or_create_agent("B")
+            thread = reader.create_thread({a, b})
+            reader.append_message(thread.id, a, "one")
+            injected = False
+
+            def append_before_unread_query(statement: str) -> None:
+                nonlocal injected
+                if (
+                    not injected
+                    and statement.startswith("SELECT COUNT(*) FROM messages")
+                    and " AND seq>" in statement
+                    and "sender_id" not in statement
+                ):
+                    injected = True
+                    writer.append_message(thread.id, b, "concurrent")
+
+            reader._db.set_trace_callback(append_before_unread_query)
+            state = reader.get_thread_read_state(thread.id, a)
+
+            assert injected is True
+            assert state.latest_seq == 1
+            assert state.unread_count == 1
+            assert state.unread_from_others_count == 0
+        finally:
+            reader.close()
+            writer.close()