impl -d 1h2m3s to modify duration of an add

src/main.rs

@@ -42,25 +42,28 @@ fn main() {
    let mut flags = Flags::parse();
    flags.log = flags.log || flags.since.is_some();
 
-   clock(&flags.f, &flags.clock).unwrap();
-   add(&flags.f, &flags.add, &flags.tag).unwrap();
+   let duration = parse_duration(&flags.duration).unwrap();
+
+   clock(&flags.f, &(flags.clock || flags.duration.is_some()), &duration).unwrap();
+   add(&flags.f, &flags.add, &flags.tag, &0).unwrap();
    log(&flags.f, &flags.log, &flags.since, &flags.verbose, &flags.precision.unwrap_or(0)).unwrap();
 }
 
-fn clock(f: &String, clock: &bool) -> Result<(), String> {
+fn clock(f: &String, clock: &bool, duration: &u64) -> Result<(), String> {
    match clock {
-      true => add(&f, &Some("".to_string()), &None),
+      true => add(&f, &Some("".to_string()), &None, duration),
       false => Ok(()),
    }
 }
 
-fn add(f: &String, x: &Option<String>, tag: &Option<String>) -> Result<(), String> {
+fn add(f: &String, x: &Option<String>, tag: &Option<String>, duration: &u64) -> Result<(), String> {
    match x {
       Some(x) => {
          let mut tsheet = load(&f)?;
          tsheet.add(
             x.to_string(),
             tag.clone().unwrap_or("".to_string()),
+            *duration,
          );
          save(&f, tsheet)?;
       },
@@ -315,8 +318,13 @@ impl TSheet {
       result
    }
 
-   fn add(&mut self, x: String, tag: String) {
-      self.xs.push(new_x(SystemTime::now(), x, tag));
+   fn add(&mut self, x: String, tag: String, duration: u64) {
+      let now = system_time_to_unix_seconds(&SystemTime::now());
+      self.xs.push(new_x(
+         now - duration as i64,
+         x,
+         tag,
+      ));
    }
 
    fn sorted(&self) -> TSheet {
@@ -345,9 +353,9 @@ fn timestamp(t: &i64) -> String {
    dt.format("%Y-%m-%d").to_string()
 }
 
-fn new_x(t: SystemTime, x: String, tag: String) -> X {
+fn new_x(t: i64, x: String, tag: String) -> X {
    X{
-      t: system_time_to_unix_seconds(&t),
+      t: t,
       x: x,
       tag: tag,
    }
@@ -362,7 +370,7 @@ mod test_tsheet {
       let mut given = TSheet{xs: vec![
          X{t: 1, x: "def".to_string(), tag: "abc".to_string()},
       ]};
-      given.add("ghi".to_string(), "".to_string());
+      given.add("ghi".to_string(), "".to_string(), 0);
       assert_eq!(given.xs.len(), 2);
       assert!(given.xs[1].t != 1);
       assert_eq!(given.xs[1].x, "ghi".to_string());