feat: TaskProgress accumulation struct

src/tasks.rs

@@ -86,18 +86,16 @@ impl Tasks {
     }
 
     fn total_progress(&self, id: &EventId) -> Option<f32> {
-        self.get_by_id(id).and_then(|t| match t.pure_state() {
-            State::Closed => None,
-            State::Done => Some(1.0),
-            _ => {
-                let count = t.children.len() as f32;
-                Some(
-                    t.children
-                        .iter()
-                        .filter_map(|e| self.total_progress(e).map(|p| p / count))
-                        .sum(),
-                )
+        self.tasks.get(id).map(|t| {
+            let state = t.pure_state();
+            let mut prog = TaskProgress::from(&state);
+            if state.is_open() {
+                prog = prog + t.children
+                    .iter()
+                    .filter_map(|e| self.total_progress(e))
+                    .sum()
             }
+            prog
         })
     }
 
@@ -486,6 +484,45 @@ impl<'a> Iterator for ParentIterator<'a> {
     }
 }
 
+#[derive(Default, Copy, Clone)]
+struct TaskProgress {
+    total: usize,
+    done: usize,
+}
+impl TaskProgress {
+    fn fraction(&self) -> f32 {
+        (self.done as f32) / (self.total as f32)
+    }
+}
+impl From<&State> for TaskProgress {
+    fn from(value: &State) -> Self {
+        TaskProgress {
+            total: (value != &State::Closed).into(),
+            done: (value == &State::Done).into(),
+        }
+    }
+}
+impl Display for TaskProgress {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}/{}", self.done, self.total,)
+    }
+}
+impl Add for TaskProgress {
+    type Output = TaskProgress;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        TaskProgress {
+            done: self.done + rhs.done,
+            total: self.total + rhs.total,
+        }
+    }
+}
+impl Sum<TaskProgress> for TaskProgress {
+    fn sum<I: Iterator<Item = TaskProgress>>(iter: I) -> Self {
+        iter.fold(TaskProgress::default(), |acc, val| acc + val)
+    }
+}
+
 #[test]
 fn test_depth() {
     use std::sync::mpsc;