Using our own newtype from now on

src/date.rs

@@ -0,0 +1,98 @@
+/*
+   TU - Time's Up!
+   Copyright (C) 2020  Julio Biason
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+use std::convert::TryFrom;
+
+use chrono::prelude::*;
+use chrono::LocalResult;
+
+#[derive(Debug, Eq, PartialEq)]
+pub enum DateError {
+    InvalidDate,
+}
+
+impl From<std::num::ParseIntError> for DateError {
+    fn from(_: std::num::ParseIntError) -> DateError {
+        DateError::InvalidDate
+    }
+}
+
+#[derive(Debug)]
+pub struct Date(chrono::Date<Local>);
+
+impl Date {
+    /// Returns Ok with the Date or Error in an invalid Date.
+    pub fn new(year: u16, month: u8, day: u8) -> Result<Date, DateError> {
+        match Local.ymd_opt(year as i32, month as u32, day as u32) {
+            LocalResult::Single(x) => Ok(Date(x)),
+            LocalResult::None => Err(DateError::InvalidDate),
+            LocalResult::Ambiguous(_, _) => Err(DateError::InvalidDate),
+        }
+    }
+
+    pub fn year(&self) -> u16 {
+        self.0.year() as u16
+    }
+
+    pub fn month(&self) -> u8 {
+        self.0.month() as u8
+    }
+
+    pub fn day(&self) -> u8 {
+        self.0.day() as u8
+    }
+}
+
+impl TryFrom<&str> for Date {
+    type Error = DateError;
+
+    fn try_from(origin: &str) -> Result<Self, Self::Error> {
+        let mut frags = origin.split("-");
+        Date::new(
+            frags.next().ok_or(DateError::InvalidDate)?.parse()?,
+            frags.next().ok_or(DateError::InvalidDate)?.parse()?,
+            frags.next().ok_or(DateError::InvalidDate)?.parse()?,
+        )
+    }
+}
+
+#[cfg(test)]
+#[test]
+pub fn invalid_date() {
+    assert!(Date::new(2020, 127, 26).is_err());
+    assert!(Date::new(2020, 5, 127).is_err());
+    assert!(Date::new(2020, 0, 0).is_err());
+}
+
+#[cfg(test)]
+#[test]
+pub fn valid_date() {
+    assert!(Date::new(2020, 5, 26).is_ok());
+}
+
+#[cfg(test)]
+#[test]
+pub fn from_string() {
+    if let Ok(dt) = Date::try_from("2020-05-26") {
+        assert_eq!(dt.year(), 2020);
+        assert_eq!(dt.month(), 5);
+        assert_eq!(dt.day(), 26);
+    } else {
+        panic!("Can't parse 2020-05-26")
+    }
+}