feat: add timeturner for time offsets and migrate config to YAML

Co-authored-by: aider (gemini/gemini-2.5-pro-preview-05-06) <aider@aider.chat>

Cargo.toml

@@ -10,6 +10,7 @@ crossterm   = "0.29"
 regex       = "1.11"
 serde       = { version = "1.0", features = ["derive"] }
 serde_json  = "1.0.141"
+serde_yaml = "0.9"
 notify      = "8.1.0"
 get_if_addrs = "0.5"
 actix-web = "4"

config.yml

@@ -1 +1,10 @@
-hardware_offset_ms: 20
+# Hardware offset in milliseconds for correcting capture latency.
+hardwareOffsetMs: 20
+
+# Time-turning offsets. All values are added to the incoming LTC time.
+# These can be positive or negative.
+timeturnerOffset:
+  hours: 0
+  minutes: 0
+  seconds: 0
+  frames: 0

src/api.rs

@@ -7,7 +7,7 @@ use serde::{Deserialize, Serialize};
 use serde_json;
 use std::sync::{Arc, Mutex};
 
-use crate::config::{self, Config};
+use crate::config::{self, Config, TimeturnerOffset};
 use crate::sync_logic::LtcState;
 use crate::ui;
 
@@ -31,13 +31,14 @@ struct ApiStatus {
 // AppState to hold shared data
 pub struct AppState {
     pub ltc_state: Arc<Mutex<LtcState>>,
-    pub hw_offset: Arc<Mutex<i64>>,
+    pub config: Arc<Mutex<Config>>,
 }
 
 #[get("/api/status")]
 async fn get_status(data: web::Data<AppState>) -> impl Responder {
     let state = data.ltc_state.lock().unwrap();
-    let hw_offset_ms = *data.hw_offset.lock().unwrap();
+    let config = data.config.lock().unwrap();
+    let hw_offset_ms = config.hardware_offset_ms;
 
     let ltc_status = state.latest.as_ref().map_or("(waiting)".to_string(), |f| f.status.clone());
     let ltc_timecode = state.latest.as_ref().map_or("…".to_string(), |f| {
@@ -63,7 +64,7 @@ async fn get_status(data: web::Data<AppState>) -> impl Responder {
         delta_frames = ((avg_delta as f64 / frame_ms).round()) as i64;
     }
 
-    let sync_status = ui::get_sync_status(avg_delta).to_string();
+    let sync_status = ui::get_sync_status(avg_delta, &config).to_string();
     let jitter_status = ui::get_jitter_status(state.average_jitter()).to_string();
     let lock_ratio = state.lock_ratio();
 
@@ -94,8 +95,9 @@ async fn get_status(data: web::Data<AppState>) -> impl Responder {
 #[post("/api/sync")]
 async fn manual_sync(data: web::Data<AppState>) -> impl Responder {
     let state = data.ltc_state.lock().unwrap();
+    let config = data.config.lock().unwrap();
     if let Some(frame) = &state.latest {
-        if ui::trigger_sync(frame).is_ok() {
+        if ui::trigger_sync(frame, &config).is_ok() {
             HttpResponse::Ok().json(serde_json::json!({ "status": "success", "message": "Sync command issued." }))
         } else {
             HttpResponse::InternalServerError().json(serde_json::json!({ "status": "error", "message": "Sync command failed." }))
@@ -105,49 +107,35 @@ async fn manual_sync(data: web::Data<AppState>) -> impl Responder {
     }
 }
 
-#[derive(Serialize, Deserialize)]
-struct ConfigResponse {
-    hardware_offset_ms: i64,
-}
-
 #[get("/api/config")]
 async fn get_config(data: web::Data<AppState>) -> impl Responder {
-    let hw_offset_ms = *data.hw_offset.lock().unwrap();
+    let config = data.config.lock().unwrap();
-    HttpResponse::Ok().json(ConfigResponse { hardware_offset_ms: hw_offset_ms })
+    HttpResponse::Ok().json(&*config)
-}
-
-#[derive(Deserialize)]
-struct UpdateConfigRequest {
-    hardware_offset_ms: i64,
 }
 
 #[post("/api/config")]
 async fn update_config(
     data: web::Data<AppState>,
-    req: web::Json<UpdateConfigRequest>,
+    req: web::Json<Config>,
 ) -> impl Responder {
-    let mut hw_offset = data.hw_offset.lock().unwrap();
+    let mut config = data.config.lock().unwrap();
-    *hw_offset = req.hardware_offset_ms;
+    *config = req.into_inner();
 
-    let new_config = Config {
+    if config::save_config("config.yml", &config).is_ok() {
-        hardware_offset_ms: *hw_offset,
+        eprintln!("🔄 Saved config via API: {:?}", *config);
-    };
+        HttpResponse::Ok().json(&*config)
-
-    if config::save_config("config.json", &new_config).is_ok() {
-        eprintln!("🔄 Saved hardware_offset_ms = {} via API", *hw_offset);
-        HttpResponse::Ok().json(&new_config)
     } else {
-        HttpResponse::InternalServerError().json(serde_json::json!({ "status": "error", "message": "Failed to write config.json" }))
+        HttpResponse::InternalServerError().json(serde_json::json!({ "status": "error", "message": "Failed to write config.yml" }))
     }
 }
 
 pub async fn start_api_server(
     state: Arc<Mutex<LtcState>>,
-    offset: Arc<Mutex<i64>>,
+    config: Arc<Mutex<Config>>,
 ) -> std::io::Result<()> {
     let app_state = web::Data::new(AppState {
         ltc_state: state,
-        hw_offset: offset,
+        config: config,
     });
 
     println!("🚀 Starting API server at http://0.0.0.0:8080");
@@ -177,7 +165,7 @@ mod tests {
     use std::fs;
 
     // Helper to create a default LtcState for tests
-    fn get_test_state() -> LtcState {
+    fn get_test_ltc_state() -> LtcState {
         LtcState {
             latest: Some(LtcFrame {
                 status: "LOCK".to_string(),
@@ -197,16 +185,21 @@ mod tests {
         }
     }
 
+    // Helper to create a default AppState for tests
+    fn get_test_app_state() -> web::Data<AppState> {
+        let ltc_state = Arc::new(Mutex::new(get_test_ltc_state()));
+        let config = Arc::new(Mutex::new(Config {
+            hardware_offset_ms: 10,
+            timeturner_offset: TimeturnerOffset {
+                hours: 0, minutes: 0, seconds: 0, frames: 0
+            }
+        }));
+        web::Data::new(AppState { ltc_state, config })
+    }
+
     #[actix_web::test]
     async fn test_get_status() {
-        let ltc_state = Arc::new(Mutex::new(get_test_state()));
+        let app_state = get_test_app_state();
-        let hw_offset = Arc::new(Mutex::new(10i64));
-
-        let app_state = web::Data::new(AppState {
-            ltc_state: ltc_state.clone(),
-            hw_offset: hw_offset.clone(),
-        });
-
         let app = test::init_service(
             App::new()
                 .app_data(app_state.clone())
@@ -225,13 +218,8 @@ mod tests {
 
     #[actix_web::test]
     async fn test_get_config() {
-        let ltc_state = Arc::new(Mutex::new(LtcState::new()));
+        let app_state = get_test_app_state();
-        let hw_offset = Arc::new(Mutex::new(25i64));
+        app_state.config.lock().unwrap().hardware_offset_ms = 25;
-
-        let app_state = web::Data::new(AppState {
-            ltc_state: ltc_state.clone(),
-            hw_offset: hw_offset.clone(),
-        });
 
         let app = test::init_service(
             App::new()
@@ -241,26 +229,20 @@ mod tests {
         .await;
 
         let req = test::TestRequest::get().uri("/api/config").to_request();
-        let resp: ConfigResponse = test::call_and_read_body_json(&app, req).await;
+        let resp: Config = test::call_and_read_body_json(&app, req).await;
 
         assert_eq!(resp.hardware_offset_ms, 25);
     }
 
     #[actix_web::test]
     async fn test_update_config() {
-        let ltc_state = Arc::new(Mutex::new(LtcState::new()));
+        let app_state = get_test_app_state();
-        let hw_offset = Arc::new(Mutex::new(0i64));
+        let config_path = "config.yml";
-        let config_path = "config.json";
 
-        // This test has the side effect of writing to `config.json`.
+        // This test has the side effect of writing to `config.yml`.
         // We ensure it's cleaned up after.
         let _ = fs::remove_file(config_path);
 
-        let app_state = web::Data::new(AppState {
-            ltc_state: ltc_state.clone(),
-            hw_offset: hw_offset.clone(),
-        });
-
         let app = test::init_service(
             App::new()
                 .app_data(app_state.clone())
@@ -268,20 +250,29 @@ mod tests {
         )
         .await;
 
+        let new_config_json = serde_json::json!({
+            "hardwareOffsetMs": 55,
+            "timeturnerOffset": { "hours": 1, "minutes": 2, "seconds": 3, "frames": 4 }
+        });
+
         let req = test::TestRequest::post()
             .uri("/api/config")
-            .set_json(&serde_json::json!({ "hardware_offset_ms": 55 }))
+            .set_json(&new_config_json)
             .to_request();
 
         let resp: Config = test::call_and_read_body_json(&app, req).await;
 
         assert_eq!(resp.hardware_offset_ms, 55);
-        assert_eq!(*hw_offset.lock().unwrap(), 55);
+        assert_eq!(resp.timeturner_offset.hours, 1);
+        let final_config = app_state.config.lock().unwrap();
+        assert_eq!(final_config.hardware_offset_ms, 55);
+        assert_eq!(final_config.timeturner_offset.hours, 1);
 
         // Test that the file was written
         assert!(fs::metadata(config_path).is_ok());
         let contents = fs::read_to_string(config_path).unwrap();
-        assert!(contents.contains("\"hardware_offset_ms\": 55"));
+        assert!(contents.contains("hardwareOffsetMs: 55"));
+        assert!(contents.contains("hours: 1"));
 
         // Cleanup
         let _ = fs::remove_file(config_path);
@@ -289,14 +280,9 @@ mod tests {
 
     #[actix_web::test]
     async fn test_manual_sync_no_ltc() {
+        let app_state = get_test_app_state();
         // State with no LTC frame
-        let ltc_state = Arc::new(Mutex::new(LtcState::new()));
+        app_state.ltc_state.lock().unwrap().latest = None;
-        let hw_offset = Arc::new(Mutex::new(0i64));
-
-        let app_state = web::Data::new(AppState {
-            ltc_state: ltc_state.clone(),
-            hw_offset: hw_offset.clone(),
-        });
 
         let app = test::init_service(
             App::new()

src/config.rs

@@ -1,5 +1,4 @@
 // src/config.rs
-
 use notify::{
     recommended_watcher, Event, EventKind, RecommendedWatcher, RecursiveMode, Result as NotifyResult,
     Watcher,
@@ -13,63 +12,90 @@ use std::{
     sync::{Arc, Mutex},
 };
 
-#[derive(Deserialize, Serialize, Clone)]
+#[derive(Deserialize, Serialize, Clone, Debug, Default)]
+#[serde(rename_all = "camelCase")]
+pub struct TimeturnerOffset {
+    pub hours: i64,
+    pub minutes: i64,
+    pub seconds: i64,
+    pub frames: i64,
+}
+
+impl TimeturnerOffset {
+    pub fn is_active(&self) -> bool {
+        self.hours != 0 || self.minutes != 0 || self.seconds != 0 || self.frames != 0
+    }
+}
+
+#[derive(Deserialize, Serialize, Clone, Debug)]
+#[serde(rename_all = "camelCase")]
 pub struct Config {
     pub hardware_offset_ms: i64,
+    #[serde(default)]
+    pub timeturner_offset: TimeturnerOffset,
 }
 
 impl Config {
     pub fn load(path: &PathBuf) -> Self {
         let mut file = match File::open(path) {
             Ok(f) => f,
-            Err(_) => return Self { hardware_offset_ms: 0 },
+            Err(_) => return Self::default(),
         };
         let mut contents = String::new();
         if file.read_to_string(&mut contents).is_err() {
-            return Self { hardware_offset_ms: 0 };
+            return Self::default();
         }
-        serde_json::from_str(&contents).unwrap_or(Self { hardware_offset_ms: 0 })
+        serde_yaml::from_str(&contents).unwrap_or_else(|e| {
+            eprintln!("Failed to parse config, using default: {}", e);
+            Self::default()
+        })
     }
 }
 
-pub fn save_config(path: &str, config: &Config) -> std::io::Result<()> {
+impl Default for Config {
-    let contents = serde_json::to_string_pretty(config)?;
+    fn default() -> Self {
-    fs::write(path, contents)
+        Self {
+            hardware_offset_ms: 0,
+            timeturner_offset: TimeturnerOffset::default(),
+        }
+    }
 }
 
-pub fn watch_config(path: &str) -> Arc<Mutex<i64>> {
+pub fn save_config(path: &str, config: &Config) -> Result<(), Box<dyn std::error::Error>> {
-    let initial = Config::load(&PathBuf::from(path)).hardware_offset_ms;
+    let contents = serde_yaml::to_string(config)?;
-    let offset = Arc::new(Mutex::new(initial));
+    fs::write(path, contents)?;
+    Ok(())
+}
+
+pub fn watch_config(path: &str) -> Arc<Mutex<Config>> {
+    let initial_config = Config::load(&PathBuf::from(path));
+    let config = Arc::new(Mutex::new(initial_config));
 
-    // Owned PathBuf for watch() call
     let watch_path = PathBuf::from(path);
-    // Clone for moving into the closure
     let watch_path_for_cb = watch_path.clone();
-    let offset_for_cb = Arc::clone(&offset);
+    let config_for_cb = Arc::clone(&config);
 
     std::thread::spawn(move || {
-        // Move `watch_path_for_cb` into the callback
         let mut watcher: RecommendedWatcher = recommended_watcher(move |res: NotifyResult<Event>| {
             if let Ok(evt) = res {
                 if matches!(evt.kind, EventKind::Modify(_)) {
                     let new_cfg = Config::load(&watch_path_for_cb);
-                    let mut hw = offset_for_cb.lock().unwrap();
+                    let mut cfg = config_for_cb.lock().unwrap();
-                    *hw = new_cfg.hardware_offset_ms;
+                    *cfg = new_cfg;
-                    eprintln!("🔄 Reloaded hardware_offset_ms = {}", *hw);
+                    eprintln!("🔄 Reloaded config.yml: {:?}", *cfg);
                 }
             }
         })
         .expect("Failed to create file watcher");
 
-        // Use the original `watch_path` here
         watcher
             .watch(&watch_path, RecursiveMode::NonRecursive)
-            .expect("Failed to watch config.json");
+            .expect("Failed to watch config.yml");
 
         loop {
             std::thread::sleep(std::time::Duration::from_secs(60));
         }
     });
 
-    offset
+    config
 }

src/main.rs

@@ -7,7 +7,7 @@ mod serial_input;
 mod ui;
 
 use crate::api::start_api_server;
-use crate::config::watch_config;
+use crate::config::{watch_config, Config};
 use crate::sync_logic::LtcState;
 use crate::serial_input::start_serial_thread;
 use crate::ui::start_ui;
@@ -21,17 +21,26 @@ use std::{
 use tokio::task::{self, LocalSet};
 
 /// Default config content, embedded in the binary.
-const DEFAULT_CONFIG: &str = r#"{
+const DEFAULT_CONFIG: &str = r#"
-  "hardware_offset_ms": 20
+# Hardware offset in milliseconds for correcting capture latency.
-}"#;
+hardwareOffsetMs: 20
 
-/// If no `config.json` exists alongside the binary, write out the default.
+# Time-turning offsets. All values are added to the incoming LTC time.
+# These can be positive or negative.
+timeturnerOffset:
+  hours: 0
+  minutes: 0
+  seconds: 0
+  frames: 0
+"#;
+
+/// If no `config.yml` exists alongside the binary, write out the default.
 fn ensure_config() {
-    let p = Path::new("config.json");
+    let p = Path::new("config.yml");
     if !p.exists() {
-        fs::write(p, DEFAULT_CONFIG)
+        fs::write(p, DEFAULT_CONFIG.trim())
-            .expect("Failed to write default config.json");
+            .expect("Failed to write default config.yml");
-        eprintln!("⚙️  Emitted default config.json");
+        eprintln!("⚙️  Emitted default config.yml");
     }
 }
 
@@ -40,9 +49,9 @@ async fn main() {
     // 🔄 Ensure there's always a config.json present
     ensure_config();
 
-    // 1️⃣ Start watching config.json for changes
+    // 1️⃣ Start watching config.yml for changes
-    let hw_offset = watch_config("config.json");
+    let config = watch_config("config.yml");
-    println!("🔧 Watching config.json (hardware_offset_ms)...");
+    println!("🔧 Watching config.yml...");
 
     // 2️⃣ Channel for raw LTC frames
     let (tx, rx) = mpsc::channel();
@@ -68,14 +77,14 @@ async fn main() {
         });
     }
 
-    // 5️⃣ Spawn the UI renderer thread, passing the live offset Arc
+    // 5️⃣ Spawn the UI renderer thread, passing the live config Arc
     {
         let ui_state     = ltc_state.clone();
-        let offset_clone = hw_offset.clone();
+        let config_clone = config.clone();
         let port         = "/dev/ttyACM0".to_string();
         thread::spawn(move || {
             println!("🖥️ UI thread launched");
-            start_ui(ui_state, port, offset_clone);
+            start_ui(ui_state, port, config_clone);
         });
     }
 
@@ -86,9 +95,9 @@ async fn main() {
             // 7️⃣ Spawn the API server thread
             {
                 let api_state = ltc_state.clone();
-                let offset_clone = hw_offset.clone();
+                let config_clone = config.clone();
                 task::spawn_local(async move {
-                    if let Err(e) = start_api_server(api_state, offset_clone).await {
+                    if let Err(e) = start_api_server(api_state, config_clone).await {
                         eprintln!("API server error: {}", e);
                     }
                 });
@@ -118,7 +127,7 @@ mod tests {
 
     impl Drop for ConfigGuard {
         fn drop(&mut self) {
-            let _ = fs::remove_file("config.json");
+            let _ = fs::remove_file("config.yml");
         }
     }
 
@@ -127,28 +136,28 @@ mod tests {
         let _guard = ConfigGuard; // Cleanup when _guard goes out of scope.
 
         // --- Test 1: File creation ---
-        // Pre-condition: config.json does not exist.
+        // Pre-condition: config.yml does not exist.
-        let _ = fs::remove_file("config.json");
+        let _ = fs::remove_file("config.yml");
 
         ensure_config();
 
-        // Post-condition: config.json exists and has default content.
+        // Post-condition: config.yml exists and has default content.
-        let p = Path::new("config.json");
+        let p = Path::new("config.yml");
-        assert!(p.exists(), "config.json should have been created");
+        assert!(p.exists(), "config.yml should have been created");
-        let contents = fs::read_to_string(p).expect("Failed to read created config.json");
+        let contents = fs::read_to_string(p).expect("Failed to read created config.yml");
-        assert_eq!(contents, DEFAULT_CONFIG, "config.json content should match default");
+        assert_eq!(contents, DEFAULT_CONFIG.trim(), "config.yml content should match default");
 
         // --- Test 2: File is not overwritten ---
-        // Pre-condition: config.json exists with different content.
+        // Pre-condition: config.yml exists with different content.
-        let custom_content = "{\"hardware_offset_ms\": 999}";
+        let custom_content = "hardwareOffsetMs: 999";
-        fs::write("config.json", custom_content)
+        fs::write("config.yml", custom_content)
-            .expect("Failed to write custom config.json for test");
+            .expect("Failed to write custom config.yml for test");
 
         ensure_config();
 
-        // Post-condition: config.json still has the custom content.
+        // Post-condition: config.yml still has the custom content.
-        let contents_after = fs::read_to_string("config.json")
+        let contents_after = fs::read_to_string("config.yml")
-            .expect("Failed to read config.json after second ensure_config call");
+            .expect("Failed to read config.yml after second ensure_config call");
-        assert_eq!(contents_after, custom_content, "config.json should not be overwritten");
+        assert_eq!(contents_after, custom_content, "config.yml should not be overwritten");
     }
 }

src/ui.rs

@@ -9,7 +9,7 @@ use std::collections::VecDeque;
 
 use chrono::{
     DateTime, Local, Timelike, Utc,
-    NaiveTime, TimeZone,
+    NaiveTime, TimeZone, Duration as ChronoDuration,
 };
 use crossterm::{
     cursor::{Hide, MoveTo, Show},
@@ -19,6 +19,7 @@ use crossterm::{
     terminal::{self, Clear, ClearType, EnterAlternateScreen, LeaveAlternateScreen},
 };
 
+use crate::config::Config;
 use get_if_addrs::get_if_addrs;
 use crate::sync_logic::{LtcFrame, LtcState};
 
@@ -39,8 +40,10 @@ fn ntp_service_toggle(start: bool) {
     let _ = Command::new("systemctl").args(&[action, "chrony"]).status();
 }
 
-pub fn get_sync_status(delta_ms: i64) -> &'static str {
+pub fn get_sync_status(delta_ms: i64, config: &Config) -> &'static str {
-    if delta_ms.abs() <= 8 {
+    if config.timeturner_offset.is_active() {
+        "TIMETURNING"
+    } else if delta_ms.abs() <= 8 {
         "IN SYNC"
     } else if delta_ms > 10 {
         "CLOCK AHEAD"
@@ -59,18 +62,27 @@ pub fn get_jitter_status(jitter_ms: i64) -> &'static str {
     }
 }
 
-pub fn trigger_sync(frame: &LtcFrame) -> Result<String, ()> {
+pub fn trigger_sync(frame: &LtcFrame, config: &Config) -> Result<String, ()> {
     let today_local = Local::now().date_naive();
-    let ms = ((frame.frames as f64 / frame.frame_rate) * 1000.0)
+    let ms = ((frame.frames as f64 / frame.frame_rate) * 1000.0).round() as u32;
-        .round() as u32;
+    let timecode = NaiveTime::from_hms_milli_opt(frame.hours, frame.minutes, frame.seconds, ms)
-    let timecode = NaiveTime::from_hms_milli_opt(
+        .expect("Invalid LTC timecode");
-        frame.hours, frame.minutes, frame.seconds, ms,
+
-    ).expect("Invalid LTC timecode");
     let naive_dt = today_local.and_time(timecode);
-    let dt_local = Local
+    let mut dt_local = Local
         .from_local_datetime(&naive_dt)
         .single()
         .expect("Ambiguous or invalid local time");
+
+    // Apply timeturner offset
+    let offset = &config.timeturner_offset;
+    dt_local = dt_local
+        + ChronoDuration::hours(offset.hours)
+        + ChronoDuration::minutes(offset.minutes)
+        + ChronoDuration::seconds(offset.seconds);
+    // Frame offset needs to be converted to milliseconds
+    let frame_offset_ms = (offset.frames as f64 / frame.frame_rate * 1000.0).round() as i64;
+    dt_local = dt_local + ChronoDuration::milliseconds(frame_offset_ms);
     #[cfg(target_os = "linux")]
     let (ts, success) = {
         let ts = dt_local.format("%H:%M:%S.%3f").to_string();
@@ -115,7 +127,7 @@ pub fn trigger_sync(frame: &LtcFrame) -> Result<String, ()> {
 pub fn start_ui(
     state: Arc<Mutex<LtcState>>,
     serial_port: String,
-    offset: Arc<Mutex<i64>>,
+    config: Arc<Mutex<Config>>,
 ) {
     let mut stdout = stdout();
     execute!(stdout, EnterAlternateScreen, Hide).unwrap();
@@ -128,8 +140,9 @@ pub fn start_ui(
     let mut cached_delta_frames: i64 = 0;
 
     loop {
-        // 1️⃣ hardware offset
+        // 1️⃣ config
-        let hw_offset_ms = *offset.lock().unwrap();
+        let cfg = config.lock().unwrap().clone();
+        let hw_offset_ms = cfg.hardware_offset_ms;
 
         // 2️⃣ Chrony + interfaces
         let ntp_active = ntp_service_active();
@@ -151,18 +164,27 @@ pub fn start_ui(
                     let measured = raw - hw_offset_ms;
                     st.record_offset(measured);
 
-                    // Δ = system clock - LTC timecode (use LOCAL time)
+                    // Δ = system clock - LTC timecode (use LOCAL time, with offset)
                     let today_local = Local::now().date_naive();
-                    let ms = ((frame.frames as f64 / frame.frame_rate) * 1000.0)
+                    let ms = ((frame.frames as f64 / frame.frame_rate) * 1000.0).round() as u32;
-                        .round() as u32;
                     let tc_naive = NaiveTime::from_hms_milli_opt(
                         frame.hours, frame.minutes, frame.seconds, ms,
                     ).expect("Invalid LTC timecode");
                     let naive_dt_local = today_local.and_time(tc_naive);
-                    let dt_local = Local
+                    let mut dt_local = Local
                         .from_local_datetime(&naive_dt_local)
                         .single()
                         .expect("Invalid local time");
+
+                    // Apply timeturner offset before calculating delta
+                    let offset = &cfg.timeturner_offset;
+                    dt_local = dt_local
+                        + ChronoDuration::hours(offset.hours)
+                        + ChronoDuration::minutes(offset.minutes)
+                        + ChronoDuration::seconds(offset.seconds);
+                    let frame_offset_ms = (offset.frames as f64 / frame.frame_rate * 1000.0).round() as i64;
+                    dt_local = dt_local + ChronoDuration::milliseconds(frame_offset_ms);
+
                     let delta_ms = (Local::now() - dt_local).num_milliseconds();
                     st.record_clock_delta(delta_ms);
                 } else {
@@ -197,14 +219,14 @@ pub fn start_ui(
         }
 
         // 6️⃣ sync status wording
-        let sync_status = get_sync_status(cached_delta_ms);
+        let sync_status = get_sync_status(cached_delta_ms, &cfg);
 
         // 7️⃣ auto‑sync (same as manual but delayed)
-        if sync_status != "IN SYNC" {
+        if sync_status != "IN SYNC" && sync_status != "TIMETURNING" {
             if let Some(start) = out_of_sync_since {
                 if start.elapsed() >= Duration::from_secs(5) {
                     if let Some(frame) = &state.lock().unwrap().latest {
-                        let entry = match trigger_sync(frame) {
+                        let entry = match trigger_sync(frame, &cfg) {
                             Ok(ts) => format!("🔄 Auto‑synced to LTC: {}", ts),
                             Err(_) => "❌ Auto‑sync failed".into(),
                         };
@@ -283,6 +305,8 @@ pub fn start_ui(
         // sync status
         let scol = if sync_status == "IN SYNC" {
             Color::Green
+        } else if sync_status == "TIMETURNING" {
+            Color::Cyan
         } else {
             Color::Red
         };
@@ -337,7 +361,7 @@ pub fn start_ui(
                     }
                     KeyCode::Char(c) if c.eq_ignore_ascii_case(&'s') => {
                         if let Some(frame) = &state.lock().unwrap().latest {
-                            let entry = match trigger_sync(frame) {
+                            let entry = match trigger_sync(frame, &cfg) {
                                 Ok(ts) => format!("✔ Synced exactly to LTC: {}", ts),
                                 Err(_) => "❌ date cmd failed".into(),
                             };
@@ -358,16 +382,24 @@ pub fn start_ui(
 mod tests {
     use super::*;
 
+    use crate::config::TimeturnerOffset;
+
     #[test]
     fn test_get_sync_status() {
-        assert_eq!(get_sync_status(0), "IN SYNC");
+        let mut config = Config::default();
-        assert_eq!(get_sync_status(8), "IN SYNC");
+        assert_eq!(get_sync_status(0, &config), "IN SYNC");
-        assert_eq!(get_sync_status(-8), "IN SYNC");
+        assert_eq!(get_sync_status(8, &config), "IN SYNC");
-        assert_eq!(get_sync_status(9), "CLOCK BEHIND");
+        assert_eq!(get_sync_status(-8, &config), "IN SYNC");
-        assert_eq!(get_sync_status(10), "CLOCK BEHIND");
+        assert_eq!(get_sync_status(9, &config), "CLOCK BEHIND");
-        assert_eq!(get_sync_status(11), "CLOCK AHEAD");
+        assert_eq!(get_sync_status(10, &config), "CLOCK BEHIND");
-        assert_eq!(get_sync_status(-9), "CLOCK BEHIND");
+        assert_eq!(get_sync_status(11, &config), "CLOCK AHEAD");
-        assert_eq!(get_sync_status(-100), "CLOCK BEHIND");
+        assert_eq!(get_sync_status(-9, &config), "CLOCK BEHIND");
+        assert_eq!(get_sync_status(-100, &config), "CLOCK BEHIND");
+
+        // Test TIMETURNING status
+        config.timeturner_offset = TimeturnerOffset { hours: 1, minutes: 0, seconds: 0, frames: 0 };
+        assert_eq!(get_sync_status(0, &config), "TIMETURNING");
+        assert_eq!(get_sync_status(100, &config), "TIMETURNING");
     }
 
     #[test]

static/index.html

@@ -48,9 +48,16 @@
                 <div class="control-group">
                     <label for="hw-offset">Hardware Offset (ms):</label>
                     <input type="number" id="hw-offset" name="hw-offset">
-                    <button id="save-offset">Save</button>
                 </div>
                 <div class="control-group">
+                    <label>Timeturner Offset:</label>
+                    <input type="number" id="offset-h" placeholder="H">
+                    <input type="number" id="offset-m" placeholder="M">
+                    <input type="number" id="offset-s" placeholder="S">
+                    <input type="number" id="offset-f" placeholder="F">
+                </div>
+                 <div class="control-group">
+                    <button id="save-config">Save Config</button>
                     <button id="manual-sync">Manual Sync</button>
                     <span id="sync-message"></span>
                 </div>

static/script.js

@@ -14,7 +14,13 @@ document.addEventListener('DOMContentLoaded', () => {
     };
 
     const hwOffsetInput = document.getElementById('hw-offset');
-    const saveOffsetButton = document.getElementById('save-offset');
+    const offsetInputs = {
+        h: document.getElementById('offset-h'),
+        m: document.getElementById('offset-m'),
+        s: document.getElementById('offset-s'),
+        f: document.getElementById('offset-f'),
+    };
+    const saveConfigButton = document.getElementById('save-config');
     const manualSyncButton = document.getElementById('manual-sync');
     const syncMessage = document.getElementById('sync-message');
 
@@ -67,24 +73,32 @@ document.addEventListener('DOMContentLoaded', () => {
             const response = await fetch('/api/config');
             if (!response.ok) throw new Error('Failed to fetch config');
             const data = await response.json();
-            hwOffsetInput.value = data.hardware_offset_ms;
+            hwOffsetInput.value = data.hardwareOffsetMs;
+            offsetInputs.h.value = data.timeturnerOffset.hours;
+            offsetInputs.m.value = data.timeturnerOffset.minutes;
+            offsetInputs.s.value = data.timeturnerOffset.seconds;
+            offsetInputs.f.value = data.timeturnerOffset.frames;
         } catch (error) {
             console.error('Error fetching config:', error);
         }
     }
 
     async function saveConfig() {
-        const offset = parseInt(hwOffsetInput.value, 10);
+        const config = {
-        if (isNaN(offset)) {
+            hardwareOffsetMs: parseInt(hwOffsetInput.value, 10) || 0,
-            alert('Invalid hardware offset value.');
+            timeturnerOffset: {
-            return;
+                hours:   parseInt(offsetInputs.h.value, 10) || 0,
-        }
+                minutes: parseInt(offsetInputs.m.value, 10) || 0,
+                seconds: parseInt(offsetInputs.s.value, 10) || 0,
+                frames:  parseInt(offsetInputs.f.value, 10) || 0,
+            }
+        };
 
         try {
             const response = await fetch('/api/config', {
                 method: 'POST',
                 headers: { 'Content-Type': 'application/json' },
-                body: JSON.stringify({ hardware_offset_ms: offset }),
+                body: JSON.stringify(config),
             });
             if (!response.ok) throw new Error('Failed to save config');
             alert('Configuration saved.');
@@ -111,7 +125,7 @@ document.addEventListener('DOMContentLoaded', () => {
         setTimeout(() => { syncMessage.textContent = ''; }, 5000);
     }
 
-    saveOffsetButton.addEventListener('click', saveConfig);
+    saveConfigButton.addEventListener('click', saveConfig);
     manualSyncButton.addEventListener('click', triggerManualSync);
 
     // Initial data load

static/style.css

@@ -85,6 +85,7 @@ button:hover {
 /* Status-specific colors */
 #sync-status.in-sync, #jitter-status.good { font-weight: bold; color: #28a745; }
 #sync-status.clock-ahead, #sync-status.clock-behind, #jitter-status.average { font-weight: bold; color: #ffc107; }
+#sync-status.timeturning { font-weight: bold; color: #17a2b8; }
 #jitter-status.bad { font-weight: bold; color: #dc3545; }
 #ntp-active.active { font-weight: bold; color: #28a745; }
 #ntp-active.inactive { font-weight: bold; color: #dc3545; }