Evaluate BDATEs again

src/eval/command/birthday.rs

@@ -1,10 +1,51 @@
+use chrono::{Datelike, NaiveDate};
+
+use crate::eval::date::Dates;
 use crate::files::commands::BirthdaySpec;
 
 use super::super::command::CommandState;
-use super::super::Result;
+use super::super::{Entry, EntryKind};
 
 impl<'a> CommandState<'a> {
-    pub fn eval_birthday_spec(&mut self, spec: &BirthdaySpec) -> Result<()> {
-        todo!()
+    pub fn eval_birthday_spec(&mut self, spec: &BirthdaySpec) {
+        // This could be optimized by restricting the range via FROM and UNTIL,
+        // but I don't think that kind of optimization will be necessary any
+        // time soon.
+        for year in self.range.years() {
+            let mut title = self.title();
+
+            if spec.year_known {
+                let age = year - spec.date.year();
+                if age < 0 {
+                    continue;
+                }
+                title.push_str(&format!(" ({})", age));
+            }
+
+            if let Some(date) = spec.date.with_year(year) {
+                self.add(Entry {
+                    kind: EntryKind::Birthday,
+                    title,
+                    desc: self.desc(),
+                    source: self.source(),
+                    root: Some(date),
+                    dates: Some(Dates::new(date, date)),
+                });
+            } else {
+                assert_eq!(spec.date.month(), 2);
+                assert_eq!(spec.date.day(), 29);
+
+                let first = NaiveDate::from_ymd(year, 2, 28);
+                let second = NaiveDate::from_ymd(year, 3, 1);
+                self.add(Entry {
+                    kind: EntryKind::Birthday,
+                    title,
+                    desc: self.desc(),
+                    source: self.source(),
+                    root: Some(first), // This doesn't matter too much
+                    dates: Some(Dates::new(first, second)),
+                });
+            }
+        }
     }
 }