feat: add daemon mode and systemd service

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

src/system.rs

@@ -0,0 +1,83 @@
+use crate::config::Config;
+use crate::sync_logic::LtcFrame;
+use chrono::{Duration as ChronoDuration, Local, NaiveTime, TimeZone};
+use std::process::Command;
+
+/// Check if Chrony is active
+pub fn ntp_service_active() -> bool {
+    if let Ok(output) = Command::new("systemctl").args(&["is-active", "chrony"]).output() {
+        output.status.success()
+            && String::from_utf8_lossy(&output.stdout).trim() == "active"
+    } else {
+        false
+    }
+}
+
+/// Toggle Chrony (not used yet)
+#[allow(dead_code)]
+pub fn ntp_service_toggle(start: bool) {
+    let action = if start { "start" } else { "stop" };
+    let _ = Command::new("systemctl").args(&[action, "chrony"]).status();
+}
+
+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).round() as u32;
+    let timecode = NaiveTime::from_hms_milli_opt(frame.hours, frame.minutes, frame.seconds, ms)
+        .expect("Invalid LTC timecode");
+
+    let naive_dt = today_local.and_time(timecode);
+    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();
+        let success = Command::new("sudo")
+            .arg("date")
+            .arg("-s")
+            .arg(&ts)
+            .status()
+            .map(|s| s.success())
+            .unwrap_or(false);
+        (ts, success)
+    };
+
+    #[cfg(target_os = "macos")]
+    let (ts, success) = {
+        // macOS `date` command format is `mmddHHMMccyy.SS`
+        let ts = dt_local.format("%m%d%H%M%y.%S").to_string();
+        let success = Command::new("sudo")
+            .arg("date")
+            .arg(&ts)
+            .status()
+            .map(|s| s.success())
+            .unwrap_or(false);
+        (ts, success)
+    };
+
+    #[cfg(not(any(target_os = "linux", target_os = "macos")))]
+    let (ts, success) = {
+        // Unsupported OS, always fail
+        let ts = dt_local.format("%H:%M:%S.%3f").to_string();
+        eprintln!("Unsupported OS for time synchronization");
+        (ts, false)
+    };
+
+    if success {
+        Ok(ts)
+    } else {
+        Err(())
+    }
+}