Start building fmrc utils

src/tools/date.rs

@@ -1,11 +1,16 @@
 use chrono::{DateTime, Duration, Timelike, Utc};
 
-/// Creates a datetime object for the most recent model run output for stations data given the logic that
-/// weather models run at 0Z, 6Z, 12Z, and 18Z
-pub fn closest_gfs_model_stations_datetime(datetime: &DateTime<Utc>) -> DateTime<Utc> {
-    let adjusted = *datetime + Duration::hours(-6);
-    let latest_model_hour = adjusted.hour() % 6;
-    (adjusted - Duration::hours(latest_model_hour as i64))
+// Rounds the datetime to the nearest multiple hour
+// For example, if the datetime is 2023-04-13 23:00:00 and the multiplier is 6, the result would be 2023-04-13 18:00:00
+// If the datetime is 2023-04-13 23:00:00 and the multiplier is 3, the result would be 2023-04-13 21:00:00
+// This operation is a floor, meaning that it will only round down to the nearest multiple hour
+pub fn round_to_nearest_multiple_hour(datetime: &DateTime<Utc>, multiplier: u32) -> DateTime<Utc> {
+    let hour = datetime.hour();
+    let remainder = hour % multiplier;
+    let rounded_hour = hour - remainder;
+    datetime
+        .with_hour(rounded_hour)
+        .unwrap()
         .with_minute(0)
         .unwrap()
         .with_second(0)
@@ -14,18 +19,31 @@ pub fn closest_gfs_model_stations_datetime(datetime: &DateTime<Utc>) -> DateTime
         .unwrap()
 }
 
+/// Creates a datetime object for the most recent model run output for stations data given the logic that
+/// weather models run at 0Z, 6Z, 12Z, and 18Z
+pub fn closest_gfs_model_stations_datetime(datetime: &DateTime<Utc>) -> DateTime<Utc> {
+    let adjusted = *datetime + Duration::hours(-6);
+    round_to_nearest_multiple_hour(&adjusted, 6)
+}
+
 /// Creates a datetime object for the most recent model run for gridded data given the logic that
 /// weather models run at 0Z, 6Z, 12Z, and 18Z
 pub fn closest_gfs_model_gridded_datetime(datetime: &DateTime<Utc>) -> DateTime<Utc> {
     let adjusted = *datetime + Duration::hours(-5);
-    let latest_model_hour = adjusted.hour() % 6;
-    (adjusted - Duration::hours(latest_model_hour as i64))
-        .with_minute(0)
-        .unwrap()
-        .with_second(0)
-        .unwrap()
-        .with_nanosecond(0)
-        .unwrap()
+    round_to_nearest_multiple_hour(&adjusted, 6)
+}
+
+// TODO: Fix and document this function
+pub fn gfs_model_gridded_fmrc_datetimes(
+    (start, end): (DateTime<Utc>, DateTime<Utc>),
+) -> Vec<DateTime<Utc>> {
+    let mut datetimes = vec![];
+    let mut current = start;
+    while current <= end {
+        datetimes.push(closest_gfs_model_gridded_datetime(&current));
+        current = current + Duration::hours(6);
+    }
+    datetimes
 }
 
 /// Creates a datetime object for the most recent model run given the logic that
@@ -43,12 +61,32 @@ pub fn closest_hourly_model_datetime(datetime: &DateTime<Utc>) -> DateTime<Utc>
 
 #[cfg(test)]
 mod test {
-    use crate::tools::date::{closest_gfs_model_gridded_datetime, closest_gfs_model_stations_datetime};
+    use crate::tools::date::{
+        closest_gfs_model_gridded_datetime, closest_gfs_model_stations_datetime,
+        closest_hourly_model_datetime, round_to_nearest_multiple_hour,
+    };
+    use chrono::prelude::*;
 
     #[test]
-    fn test_closest_station_model_datetime() {
-        use chrono::prelude::*; 
+    fn test_round_to_nearest_multiple_hour() {
+        let datetime = Utc.with_ymd_and_hms(2023, 4, 13, 23, 0, 0).unwrap();
+        let expected = Utc.with_ymd_and_hms(2023, 4, 13, 18, 0, 0).unwrap();
+        let result = round_to_nearest_multiple_hour(&datetime, 6);
+        assert_eq!(result, expected);
+
+        let datetime = Utc.with_ymd_and_hms(2023, 4, 13, 23, 0, 0).unwrap();
+        let expected = Utc.with_ymd_and_hms(2023, 4, 13, 21, 0, 0).unwrap();
+        let result = round_to_nearest_multiple_hour(&datetime, 3);
+        assert_eq!(result, expected);
 
+        let datetime = Utc.with_ymd_and_hms(2023, 4, 13, 23, 0, 0).unwrap();
+        let expected = Utc.with_ymd_and_hms(2023, 4, 13, 23, 0, 0).unwrap();
+        let result = round_to_nearest_multiple_hour(&datetime, 1);
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_gfs_closest_station_model_datetime() {
         let datetime = Utc.with_ymd_and_hms(2023, 4, 13, 23, 0, 0).unwrap();
         let expected = Utc.with_ymd_and_hms(2023, 4, 13, 12, 0, 0).unwrap();
 
@@ -57,13 +95,29 @@ mod test {
     }
 
     #[test]
-    fn test_closest_gridded_model_datetime() {
-        use chrono::prelude::*; 
-
+    fn test_gfs_closest_gridded_model_datetime() {
         let datetime = Utc.with_ymd_and_hms(2023, 4, 13, 23, 0, 0).unwrap();
         let expected = Utc.with_ymd_and_hms(2023, 4, 13, 18, 0, 0).unwrap();
 
         let result = closest_gfs_model_gridded_datetime(&datetime);
         assert_eq!(result, expected);
     }
-}
+
+    // #[test]
+    // fn test_gfs_gridded_model_fmrc_datetime() {
+    //     let start = Utc.with_ymd_and_hms(2023, 4, 13, 0, 0, 0).unwrap();
+    //     let end = Utc.with_ymd_and_hms(2023, 4, 14, 0, 0, 0).unwrap();
+
+    //     let result = gfs_model_gridded_fmrc_datetimes((start, end));
+    //     println!("{:?}", result);
+    // }
+
+    #[test]
+    fn test_closest_hourly_model_datetime() {
+        let datetime = Utc.with_ymd_and_hms(2023, 4, 13, 23, 0, 0).unwrap();
+        let expected = Utc.with_ymd_and_hms(2023, 4, 13, 21, 0, 0).unwrap();
+
+        let result = closest_hourly_model_datetime(&datetime);
+        assert_eq!(result, expected);
+    }
+}