2 files changed, 47 insertions, 11 deletions
diff --git a/src/date.rs b/src/date.rs
index b703766..f77b5d5 100644
--- a/src/date.rs
+++ b/src/date.rs
@@ -4,7 +4,7 @@ use std::ops::Add;
 use errors::EventError;
 
 use chrono;
-use chrono::{TimeZone, Duration};
+use chrono::{TimeZone, Duration, Datelike};
 use chrono::offset::Utc;
 use chrono_tz::{Tz, UTC};
 
@@ -64,6 +64,34 @@ impl Date {
         };
         Ok(date)
     }
+
+    pub fn month(&self) -> u32 {
+        match *self {
+            Date::Time(t) => t.month(),
+            Date::AllDay(d) => d.month(),
+        }
+    }
+
+    pub fn with_month(&self, month: u32) -> Option<Date> {
+        Some(match *self {
+            Date::Time(t) => Date::Time(t.with_month(month)?),
+            Date::AllDay(d) => Date::AllDay(d.with_month(month)?),
+        })
+    }
+
+    pub fn year(&self) -> i32 {
+        match *self {
+            Date::Time(t) => t.year(),
+            Date::AllDay(d) => d.year(),
+        }
+    }
+
+    pub fn with_year(&self, year: i32) -> Option<Date> {
+        Some(match *self {
+            Date::Time(t) => Date::Time(t.with_year(year)?),
+            Date::AllDay(d) => Date::AllDay(d.with_year(year)?),
+        })
+    }
 }
 
 impl Ord for Date {
diff --git a/src/periodic.rs b/src/periodic.rs
index af9810c..b4bf7bf 100644
--- a/src/periodic.rs
+++ b/src/periodic.rs
@@ -68,8 +68,8 @@ impl Periodic {
                 events.push(e);
                 count += count;
             }
-            start = start + self.freq.duration(self.interval);
-            end = end + self.freq.duration(self.interval);
+            start = self.freq.next_date(start, self.interval);
+            end = self.freq.next_date(end, self.interval);
         }
         events
     }
@@ -87,15 +87,23 @@ impl fmt::Display for Periodic {
 }
 
 impl Freq {
-    pub fn duration(&self, count: i64) -> Duration {
+    pub fn next_date(&self, date: Date, count: i64) -> Date {
         match self {
-            Freq::Secondly => Duration::seconds(count),
-            Freq::Minutely => Duration::minutes(count),
-            Freq::Hourly => Duration::hours(count),
-            Freq::Daily => Duration::days(count),
-            Freq::Weekly => Duration::weeks(count),
-            Freq::Monthly => Duration::days(count * 30), // FIXME
-            Freq::Yearly => Duration::days(count * 365), // FIXME
+            Freq::Secondly => date + Duration::seconds(count),
+            Freq::Minutely => date + Duration::minutes(count),
+            Freq::Hourly => date + Duration::hours(count),
+            Freq::Daily => date + Duration::days(count),
+            Freq::Weekly => date + Duration::weeks(count),
+            Freq::Monthly => {
+                let month = date.month();
+                if month == 12 {
+                    let date = date.with_month(1).unwrap();
+                    date.with_year(date.year() + 1).unwrap()
+                } else {
+                    date.with_month(month + 1).unwrap()
+                }
+            }
+            Freq::Yearly => date.with_year(date.year() + 1).unwrap(),
         }
     }
 }