change: use u32 instead of i32 for lower/upper windows

The Python Prophet library expects the lower window to be negative
and the upper window to be positive, but here it makes more sense
to restrict both to being positive and just assume that the lower
window refers to 'before the holiday date'.

crates/augurs-prophet/src/features.rs

@@ -17,8 +17,8 @@ pub enum FeatureMode {
 #[derive(Debug, Clone)]
 pub struct Holiday {
     pub(crate) ds: Vec<TimestampSeconds>,
-    pub(crate) lower_window: Option<Vec<i32>>,
-    pub(crate) upper_window: Option<Vec<i32>>,
+    pub(crate) lower_window: Option<Vec<u32>>,
+    pub(crate) upper_window: Option<Vec<u32>>,
     pub(crate) prior_scale: Option<PositiveFloat>,
 }
 
@@ -37,9 +37,9 @@ impl Holiday {
     ///
     /// The lower window is the number of days before the holiday
     /// that it is observed. For example, if the holiday is on
-    /// 2023-01-01 and the lower window is -1, then the holiday will
+    /// 2023-01-01 and the lower window is 1, then the holiday will
     /// _also_ be observed on 2022-12-31.
-    pub fn with_lower_window(mut self, lower_window: Vec<i32>) -> Result<Self, Error> {
+    pub fn with_lower_window(mut self, lower_window: Vec<u32>) -> Result<Self, Error> {
         if self.ds.len() != lower_window.len() {
             return Err(Error::MismatchedLengths {
                 a_name: "ds".to_string(),
@@ -58,7 +58,7 @@ impl Holiday {
     /// that it is observed. For example, if the holiday is on
     /// 2023-01-01 and the upper window is 1, then the holiday will
     /// _also_ be observed on 2023-01-02.
-    pub fn with_upper_window(mut self, upper_window: Vec<i32>) -> Result<Self, Error> {
+    pub fn with_upper_window(mut self, upper_window: Vec<u32>) -> Result<Self, Error> {
         if self.ds.len() != upper_window.len() {
             return Err(Error::MismatchedLengths {
                 a_name: "ds".to_string(),

crates/augurs-prophet/src/prophet/prep.rs

@@ -664,12 +664,16 @@ impl<O> Prophet<O> {
             let lower = holiday
                 .lower_window
                 .as_ref()
-                .map(|x| Box::new(x.iter().copied()) as Box<dyn Iterator<Item = i32>>)
+                .map(|x| {
+                    Box::new(x.iter().copied().map(|x| x as i32)) as Box<dyn Iterator<Item = i32>>
+                })
                 .unwrap_or_else(|| Box::new(std::iter::repeat(0)));
             let upper = holiday
                 .upper_window
                 .as_ref()
-                .map(|x| Box::new(x.iter().copied()) as Box<dyn Iterator<Item = i32>>)
+                .map(|x| {
+                    Box::new(x.iter().copied().map(|x| x as i32)) as Box<dyn Iterator<Item = i32>>
+                })
                 .unwrap_or_else(|| Box::new(std::iter::repeat(0)));
 
             for (dt, lower, upper) in izip!(holiday.ds, lower, upper) {
@@ -678,7 +682,9 @@ impl<O> Prophet<O> {
                 let dt_date = dt - remainder;
 
                 // Check each of the possible offsets allowed by the lower/upper windows.
-                for offset in lower..=upper {
+                // We know that the lower window is always positive since it was originally
+                // a u32, so we can use `-lower..upper` here.
+                for offset in -lower..=upper {
                     let offset_seconds = offset as i64 * ONE_DAY_IN_SECONDS as i64;
                     let occurrence = dt_date + offset_seconds;
                     let col_name = FeatureName::Holiday {

js/augurs-prophet-js/src/lib.rs

@@ -1230,10 +1230,10 @@ pub struct Holiday {
     ///
     /// The lower window is the number of days before the holiday
     /// that it is observed. For example, if the holiday is on
-    /// 2023-01-01 and the lower window is -1, then the holiday will
+    /// 2023-01-01 and the lower window is 1, then the holiday will
     /// _also_ be observed on 2022-12-31.
     #[tsify(optional)]
-    pub lower_window: Option<Vec<i32>>,
+    pub lower_window: Option<Vec<u32>>,
 
     /// The upper window for the holiday.
     ///
@@ -1242,7 +1242,7 @@ pub struct Holiday {
     /// 2023-01-01 and the upper window is 1, then the holiday will
     /// _also_ be observed on 2023-01-02.
     #[tsify(optional)]
-    pub upper_window: Option<Vec<i32>>,
+    pub upper_window: Option<Vec<u32>>,
 
     /// The prior scale for the holiday.
     #[tsify(optional)]