Refine chat controls and add explicit owner recovery reset

Simplify the ASCII interface, expose owner setup, and load any selected number of messages using bounded history batches. Add backend-only owner reset with a matching public fingerprint and stopped-service guards, and document the loss of old history and key continuity.

1 files changed, 61 insertions, 0 deletions

diff --git a/crates/chat-server/src/maintenance.rs b/crates/chat-server/src/maintenance.rs
new file mode 100644
index 0000000..eac689d
--- /dev/null
+++ b/crates/chat-server/src/maintenance.rs
@@ -0,0 +1,61 @@
+// Copyright (C) 2026 Doan Luu Duc Tai <doan@luuduct.ai>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use crate::store::Store;
+use anyhow::{Context, Result, ensure};
+use std::fs::{File, OpenOptions};
+use std::io::Write;
+use std::net::{SocketAddr, TcpListener};
+use std::os::unix::fs::OpenOptionsExt;
+use std::path::Path;
+
+pub(crate) fn lock(directory: &Path) -> Result<File> {
+    let file = OpenOptions::new()
+        .read(true)
+        .write(true)
+        .create(true)
+        .truncate(false)
+        .mode(0o600)
+        .open(directory.join("server.lock"))?;
+    file.try_lock().context(
+        "Chat is already running. Stop it before starting another server or resetting the owner.",
+    )?;
+    Ok(file)
+}
+
+pub(crate) fn fingerprint(store: &Store) -> Result<()> {
+    let certificate = store.owner()?.context("No owner identity is registered")?;
+    writeln!(
+        std::io::stdout().lock(),
+        "{}",
+        stack_chat_crypto::public_identity(&certificate)?
+    )?;
+    Ok(())
+}
+
+pub(crate) fn reset(store: &mut Store, expected: &str, address: SocketAddr) -> Result<()> {
+    ensure!(
+        address.ip().is_loopback(),
+        "Reset must use the local chat address"
+    );
+    let _port =
+        TcpListener::bind(address).context("Stop the chat server before resetting its owner")?;
+    store.reset_owner(expected)?;
+    writeln!(
+        std::io::stdout().lock(),
+        "Owner registration and chat history cleared. Restart chat and use OWNER SETUP to create a new owner file. Existing backup archives were not changed."
+    )?;
+    Ok(())
+}