Simplify DoneDate when formatting

CHANGELOG.md

@@ -27,6 +27,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - When saving...
     - Unchanged files are no longer overwritten
     - Commands are no longer reordered
+    - Done and cancel dates are simplified
 - Always prints import-based path, not absolute path
 
 ### Fixed

src/eval/date.rs

@@ -149,32 +149,16 @@ impl From<DoneDate> for Dates {
 
 impl From<Dates> for DoneDate {
     fn from(dates: Dates) -> Self {
-        if dates.root == dates.other {
-            match dates.times {
-                Some(times) if times.root == times.other => Self::DateTime {
-                    root: dates.root,
-                    root_time: times.root,
+        let (root, other) = dates.dates();
+        match dates.times() {
+            Some((root_time, other_time)) => Self::DateTimeToDateTime {
+                root,
+                root_time,
+                other,
+                other_time,
             },
-                Some(times) => Self::DateTimeToTime {
-                    root: dates.root,
-                    root_time: times.root,
-                    other_time: times.other,
-                },
-                None => Self::Date { root: dates.root },
-            }
-        } else {
-            match dates.times {
-                Some(times) => Self::DateTimeToDateTime {
-                    root: dates.root,
-                    root_time: times.root,
-                    other: dates.other,
-                    other_time: times.other,
-                },
-                None => Self::DateToDate {
-                    root: dates.root,
-                    other: dates.other,
-                },
-            }
+            None => Self::DateToDate { root, other },
         }
+        .simplified()
     }
 }

src/files/commands.rs

@@ -307,6 +307,33 @@ impl DoneDate {
             DoneDate::DateTimeToDateTime { root, .. } => root,
         }
     }
+
+    /// Remove redundancies like the same date or time specified twice.
+    pub fn simplified(self) -> Self {
+        let result = match self {
+            Self::DateToDate { root, other } if root == other => Self::Date { root },
+            Self::DateTimeToDateTime {
+                root,
+                root_time,
+                other,
+                other_time,
+            } if root == other => Self::DateTimeToTime {
+                root,
+                root_time,
+                other_time,
+            },
+            other => other,
+        };
+
+        match result {
+            Self::DateTimeToTime {
+                root,
+                root_time,
+                other_time,
+            } if root_time == other_time => Self::DateTime { root, root_time },
+            other => other,
+        }
+    }
 }
 
 #[derive(Debug)]

src/files/format.rs

@@ -239,8 +239,7 @@ impl fmt::Display for Statement {
 
 impl fmt::Display for DoneDate {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        // TODO Remove redundant dates
-        match self {
+        match self.simplified() {
             DoneDate::Date { root } => write!(f, "{}", root),
             DoneDate::DateTime { root, root_time } => write!(f, "{} {}", root, root_time),
             DoneDate::DateToDate { root, other } => write!(f, "{} -- {}", root, other),