specifiing dates

src/cli/mod.rs

@@ -1,3 +1,4 @@
+use chrono::{Datelike, NaiveDate};
 use clap::Parser;
 
 #[derive(Parser, Debug)]
@@ -10,6 +11,9 @@ pub struct Args {
     #[arg(short = 'C', long)]
     pub current_config: bool,
 
+    /// view a specific date's file (YYYY-MM-DD)
+    #[arg(short, long)]
+    pub date: Option<String>,
     /// view previous day's notes
     #[arg(short = 'p', long, default_value_t = 0)]
     pub previous: u16,
@@ -27,3 +31,74 @@ pub struct Args {
     #[arg(short, long, action = clap::ArgAction::Count)]
     pub verbose: u8,
 }
+
+pub fn smart_parse_date(date_str: &str, cur_date: &NaiveDate) -> Option<NaiveDate> {
+    let full_date_fmt = "%Y-%m-%d";
+
+    if let Ok(date) = NaiveDate::parse_from_str(date_str, &full_date_fmt) {
+        return Some(date);
+    }
+    let parts: Vec<&str> = date_str.split('-').collect();
+
+    match parts.len() {
+        1 => cur_date.with_day(parts[0].parse().unwrap_or(cur_date.day())),
+        2 => cur_date
+            .with_day(parts[1].parse().unwrap_or(cur_date.day()))?
+            .with_month(parts[0].parse().unwrap_or(cur_date.month())),
+        3 => NaiveDate::from_ymd_opt(
+            parts[0].parse().ok()?,
+            parts[1].parse().ok()?,
+            parts[2].parse().ok()?,
+        ),
+        _ => None,
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_smart_parse_date() {
+        let good_date = NaiveDate::from_ymd_opt(2024, 01, 03).expect("Invalid date specified");
+        let good_date_str = good_date.format("%Y-%m-%d").to_string();
+
+        assert_eq!(
+            Some(good_date),
+            smart_parse_date(&good_date_str, &good_date)
+        );
+        let no_padding_date_str = "2024-1-3";
+        assert_eq!(
+            Some(good_date),
+            smart_parse_date(no_padding_date_str, &good_date)
+        );
+
+        let bad_day_str = "2024-01-99";
+        assert_eq!(None, smart_parse_date(bad_day_str, &good_date));
+        let no_day_str = "2024-01";
+        assert_eq!(None, smart_parse_date(no_day_str, &good_date));
+
+        let bad_month_str = "2024-25-01";
+        assert_eq!(None, smart_parse_date(bad_month_str, &good_date));
+        let no_month_str = "2024-14";
+        assert_eq!(None, smart_parse_date(no_month_str, &good_date));
+
+        let no_year_str = "01-03";
+        assert_eq!(Some(good_date), smart_parse_date(no_year_str, &good_date));
+        let bad_month_no_year_str = "25-01";
+        assert_eq!(None, smart_parse_date(bad_month_no_year_str, &good_date));
+        let bad_day_no_year_str = "01-35";
+        assert_eq!(None, smart_parse_date(bad_day_no_year_str, &good_date));
+
+        let no_year_month_str = "03";
+        assert_eq!(
+            Some(good_date),
+            smart_parse_date(no_year_month_str, &good_date)
+        );
+        let bad_day_no_year_month_str = "35";
+        assert_eq!(
+            None,
+            smart_parse_date(bad_day_no_year_month_str, &good_date)
+        );
+    }
+}