feat: add rate-limited update check with desktop notification

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/ahfail-gtklock/src/handler.rs

@@ -86,6 +86,10 @@ impl WindowHandler {
                     data.ready_players.push(new_player);
                 }
             });
+
+            std::thread::spawn(|| {
+                ahfail_ui::update::check_for_update(ahfail_ui::VERSION);
+            });
         });
 
         unsafe {

crates/ahfail-ui/src/update.rs

@@ -1 +1,87 @@
-pub fn check_for_update(_current_version: &str) {}
+use std::path::PathBuf;
+use std::process::Command;
+use std::time::SystemTime;
+use std::fs;
+
+const GITEA_API: &str =
+    "https://gitea.weircon.dk/api/v1/repos/agw/gtk-ahfail/releases/latest";
+const UPDATE_NOTIFY_MSG: &str =
+    "Update available — visit https://gitea.weircon.dk/agw/gtk-ahfail/releases";
+const CHECK_INTERVAL_SECS: u64 = 86_400;
+
+pub fn is_newer(latest: &str, current: &str) -> bool {
+    let parse = |s: &str| -> Option<(u32, u32, u32)> {
+        let s = s.trim_start_matches('v');
+        let p: Vec<&str> = s.splitn(3, '.').collect();
+        if p.len() != 3 { return None; }
+        Some((p[0].parse().ok()?, p[1].parse().ok()?, p[2].parse().ok()?))
+    };
+    match (parse(latest), parse(current)) {
+        (Some(l), Some(c)) => l > c,
+        _ => false,
+    }
+}
+
+fn cache_file() -> PathBuf {
+    let dir = std::env::var("HOME")
+        .map(|h| PathBuf::from(h).join(".cache/ahfail"))
+        .unwrap_or_else(|_| PathBuf::from("/tmp/ahfail-cache"));
+    let _ = fs::create_dir_all(&dir);
+    dir.join("last_update_check")
+}
+
+fn rate_limited() -> bool {
+    let path = cache_file();
+    if let Ok(meta) = fs::metadata(&path) {
+        if let Ok(modified) = meta.modified() {
+            let age = SystemTime::now()
+                .duration_since(modified)
+                .unwrap_or_default();
+            return age.as_secs() < CHECK_INTERVAL_SECS;
+        }
+    }
+    false
+}
+
+fn touch_cache() {
+    let _ = fs::write(cache_file(), b"");
+}
+
+fn send_notification() {
+    #[cfg(target_os = "linux")]
+    let _ = Command::new("notify-send")
+        .args(["ahfail", UPDATE_NOTIFY_MSG])
+        .spawn();
+
+    #[cfg(target_os = "macos")]
+    let _ = Command::new("osascript")
+        .args(["-e", &format!(
+            "display notification \"{}\" with title \"ahfail\"",
+            UPDATE_NOTIFY_MSG
+        )])
+        .spawn();
+}
+
+/// Run in a background thread. Checks Gitea for a newer release and sends a
+/// desktop notification if one exists. Rate-limited to once per 24 hours.
+/// Fails silently on any error.
+pub fn check_for_update(current_version: &str) {
+    if rate_limited() { return; }
+    touch_cache();
+
+    let Ok(resp) = ureq::get(GITEA_API).call() else { return };
+    let Ok(body) = resp.into_string() else { return };
+
+    if let Some(tag) = extract_tag_name(&body) {
+        if is_newer(&tag, current_version) {
+            send_notification();
+        }
+    }
+}
+
+fn extract_tag_name(json: &str) -> Option<String> {
+    let key = "\"tag_name\":\"";
+    let start = json.find(key)? + key.len();
+    let end = json[start..].find('"')? + start;
+    Some(json[start..end].to_string())
+}

crates/ahfail-ui/tests/update_tests.rs

@@ -0,0 +1,14 @@
+use ahfail_ui::update::is_newer;
+
+#[test]
+fn newer_version_detected() {
+    assert!(is_newer("v0.2.0", "v0.1.0"));
+    assert!(!is_newer("v0.1.0", "v0.1.0"));
+    assert!(!is_newer("v0.1.0", "v0.2.0"));
+    assert!(!is_newer("garbage", "v0.1.0"));
+}
+
+#[test]
+fn strips_v_prefix() {
+    assert!(is_newer("0.2.0", "0.1.0"));
+}