1 files changed, 115 insertions, 0 deletions
diff --git a/src/timetype.rs b/src/timetype.rs
index 4e2575e..e064f35 100644
--- a/src/timetype.rs
+++ b/src/timetype.rs
@@ -6,6 +6,8 @@ use chrono::NaiveDateTime;
 use std::ops::Add;
 use std::ops::Sub;
 
+use result::Result;
+
 /// A Type of Time, currently based on chrono::NaiveDateTime
 #[derive(Debug)]
 pub enum TimeType {
@@ -39,6 +41,54 @@ impl Sub for TimeType {
     }
 }
 
+impl TimeType {
+
+    fn calculate(self) -> Result<TimeType> {
+        use timetype::TimeType as TT;
+
+        match self {
+            TT::Addition(a, b)    => add(a, b),
+            TT::Subtraction(a, b) => sub(a, b),
+            x                     => Ok(x)
+        }
+    }
+}
+
+fn add(a: Box<TimeType>, b: Box<TimeType>) -> Result<TimeType> {
+    use timetype::TimeType as TT;
+
+    match (*a, *b) {
+        (TT::Seconds(a), TT::Seconds(b)) => Ok(TT::Seconds(a + b)),
+        (TT::Minutes(a), TT::Minutes(b)) => unimplemented!(),
+        (TT::Hours(a), TT::Hours(b))     => unimplemented!(),
+        (TT::Days(a), TT::Days(b))       => unimplemented!(),
+        (TT::Weeks(a), TT::Weeks(b))     => unimplemented!(),
+        (TT::Months(a), TT::Months(b))   => unimplemented!(),
+        (TT::Years(a), TT::Years(b))     => unimplemented!(),
+        (TT::Addition(a, b), other)      => add(a, b)
+            .map(Box::new)
+            .and_then(|bx| add(bx, Box::new(other))),
+        others                           => unimplemented!(),
+    }
+}
+
+fn sub(a: Box<TimeType>, b: Box<TimeType>) -> Result<TimeType> {
+    use timetype::TimeType as TT;
+
+    match (*a, *b) {
+        (TT::Seconds(a), TT::Seconds(b)) => Ok(TT::Seconds(a - b)),
+        (TT::Minutes(a), TT::Minutes(b)) => unimplemented!(),
+        (TT::Hours(a), TT::Hours(b))     => unimplemented!(),
+        (TT::Days(a), TT::Days(b))       => unimplemented!(),
+        (TT::Weeks(a), TT::Weeks(b))     => unimplemented!(),
+        (TT::Months(a), TT::Months(b))   => unimplemented!(),
+        (TT::Years(a), TT::Years(b))     => unimplemented!(),
+        (TT::Subtraction(a, b), other)   => sub(a, b)
+            .map(Box::new)
+            .and_then(|bx| sub(bx, Box::new(other))),
+        others                           => unimplemented!(),
+    }
+}
 
 #[cfg(test)]
 mod tests {
@@ -124,5 +174,70 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_addition_of_seconds_calculate() {
+        let a = TT::Seconds(0);
+        let b = TT::Seconds(1);
+
+        let c = (a + b).calculate();
+
+        assert!(c.is_ok());
+        let c = c.unwrap();
+
+        match c {
+            TT::Seconds(1) => assert!(true),
+            _ => assert!(false, "Addition failed"),
+        }
+    }
+
+    #[test]
+    fn test_addition_of_seconds_multiple_calculate() {
+        let a = TT::Seconds(0);
+        let b = TT::Seconds(1);
+        let c = TT::Seconds(2);
+
+        let d = (a + b + c).calculate();
+
+        assert!(d.is_ok());
+        let d = d.unwrap();
+
+        match d {
+            TT::Seconds(3) => assert!(true),
+            _ => assert!(false, "Addition failed"),
+        }
+    }
+
+    #[test]
+    fn test_subtraction_of_seconds_calculate() {
+        let a = TT::Seconds(5);
+        let b = TT::Seconds(3);
+
+        let c = (a - b).calculate();
+
+        assert!(c.is_ok());
+        let c = c.unwrap();
+
+        match c {
+            TT::Seconds(2) => assert!(true),
+            _ => assert!(false, "Subtraction failed"),
+        }
+    }
+
+    #[test]
+    fn test_subtraction_of_seconds_multiple_calculate() {
+        let a = TT::Seconds(3);
+        let b = TT::Seconds(2);
+        let c = TT::Seconds(1);
+
+        let d = (a - b - c).calculate();
+
+        assert!(d.is_ok());
+        let d = d.unwrap();
+
+        match d {
+            TT::Seconds(0) => assert!(true),
+            _ => assert!(false, "Subtraction failed"),
+        }
+    }
 }