Move ical-related stuff to dedicated rustical_ical crate

crates/ical/src/timezone.rs

@@ -0,0 +1,86 @@
+use chrono::{Local, NaiveDate, NaiveDateTime, TimeZone, Utc};
+use chrono_tz::Tz;
+use derive_more::{Display, From};
+
+#[derive(Debug, Clone, From)]
+pub enum CalTimezone {
+    Local,
+    Utc,
+    Olson(Tz),
+}
+
+#[derive(Debug, Clone, PartialEq, Display)]
+pub enum CalTimezoneOffset {
+    Local(chrono::FixedOffset),
+    Utc(chrono::Utc),
+    Olson(chrono_tz::TzOffset),
+}
+
+impl chrono::Offset for CalTimezoneOffset {
+    fn fix(&self) -> chrono::FixedOffset {
+        match self {
+            Self::Local(local) => local.fix(),
+            Self::Utc(utc) => utc.fix(),
+            Self::Olson(olson) => olson.fix(),
+        }
+    }
+}
+
+impl TimeZone for CalTimezone {
+    type Offset = CalTimezoneOffset;
+
+    fn from_offset(offset: &Self::Offset) -> Self {
+        match offset {
+            CalTimezoneOffset::Local(_) => Self::Local,
+            CalTimezoneOffset::Utc(_) => Self::Utc,
+            CalTimezoneOffset::Olson(offset) => Self::Olson(Tz::from_offset(offset)),
+        }
+    }
+
+    fn offset_from_local_date(&self, local: &NaiveDate) -> chrono::MappedLocalTime<Self::Offset> {
+        match self {
+            Self::Local => Local
+                .offset_from_local_date(local)
+                .map(CalTimezoneOffset::Local),
+            Self::Utc => Utc
+                .offset_from_local_date(local)
+                .map(CalTimezoneOffset::Utc),
+            Self::Olson(tz) => tz
+                .offset_from_local_date(local)
+                .map(CalTimezoneOffset::Olson),
+        }
+    }
+
+    fn offset_from_local_datetime(
+        &self,
+        local: &NaiveDateTime,
+    ) -> chrono::MappedLocalTime<Self::Offset> {
+        match self {
+            Self::Local => Local
+                .offset_from_local_datetime(local)
+                .map(CalTimezoneOffset::Local),
+            Self::Utc => Utc
+                .offset_from_local_datetime(local)
+                .map(CalTimezoneOffset::Utc),
+            Self::Olson(tz) => tz
+                .offset_from_local_datetime(local)
+                .map(CalTimezoneOffset::Olson),
+        }
+    }
+
+    fn offset_from_utc_datetime(&self, utc: &NaiveDateTime) -> Self::Offset {
+        match self {
+            Self::Local => CalTimezoneOffset::Local(Local.offset_from_utc_datetime(utc)),
+            Self::Utc => CalTimezoneOffset::Utc(Utc.offset_from_utc_datetime(utc)),
+            Self::Olson(tz) => CalTimezoneOffset::Olson(tz.offset_from_utc_datetime(utc)),
+        }
+    }
+
+    fn offset_from_utc_date(&self, utc: &NaiveDate) -> Self::Offset {
+        match self {
+            Self::Local => CalTimezoneOffset::Local(Local.offset_from_utc_date(utc)),
+            Self::Utc => CalTimezoneOffset::Utc(Utc.offset_from_utc_date(utc)),
+            Self::Olson(tz) => CalTimezoneOffset::Olson(tz.offset_from_utc_date(utc)),
+        }
+    }
+}