refactor: update ordering function

Author: sookwalinga

webapp/src/ts/reducers/tasks.ts

@@ -14,20 +14,60 @@ const initialState = {
   },
 };
 
-const orderByDueDate = (t1, t2) => {
-  const lhs = t1?.dueDate;
-  const rhs = t2?.dueDate;
-  if (!lhs && !rhs) {
-    return 0;
-  }
-  if (!lhs) {
-    return 1;
+/**
+ * Task prioritization algorithm that combines:
+ * 1. Overdue status (most urgent)
+ * 2. Due today status (high urgency)
+ * 3. Priority (importance)
+ * 4. Due date (soonest first)
+ * 5. Tasks without due dates (lowest priority)
+ * 
+ * Sorting rules (in order):
+ * 1. Overdue tasks appear first (most urgent), sorted by priority (higher first)
+ * 2. Tasks due today appear next, sorted by priority (higher first)
+ * 3. Then sort other dates too by date and priority (high to low)
+ * 4. For equal priority, sort by due date (earlier first)
+ * 5. Tasks without due dates appear last
+ */
+const orderByDueDateAndPriority = (t1, t2) => {
+  const getPriorityScore = (t) => {
+    if (t?.priority === 'high') {
+      return 10;
+    } else if (t?.priority === 'medium') {
+      return 6;
+    } else if (typeof t?.priority === 'string') {
+      return 0;
+    } else {
+      return t?.priority ?? 0;
+    }
+  };
+
+  const now = new Date();
+  const startOfToday = new Date(now.getFullYear(), now.getMonth(), now.getDate()).getTime();
+  
+  const getDateScore = (t) => {
+    if (!t?.dueDate) return Infinity;
+    const date = new Date(t.dueDate).getTime();
+    return Math.floor((date - startOfToday) / (1000 * 60 * 60 * 24));
+  };
+
+  const p1 = getPriorityScore(t1);
+  const p2 = getPriorityScore(t2);
+  const days1 = getDateScore(t1);
+  const days2 = getDateScore(t2);
+
+  // Compare by due date (earlier first)
+  if (days1 !== days2) {
+    return days1 - days2;
   }
-  if (!rhs) {
-    return -1;
+
+  // Compare by priority (higher first)
+  if (p1 !== p2) {
+    return p2 - p1;
   }
 
-  return lhs < rhs ? -1 : 1;
+  // Otherwise maintain original order
+  return 0;
 };
 
 const _tasksReducer = createReducer(
@@ -37,7 +77,7 @@ const _tasksReducer = createReducer(
   on(Actions.setTasksList, (state, { payload: { tasks } }) => {
     return {
       ...state,
-      tasksList: [...tasks].sort(orderByDueDate),
+      tasksList: [...tasks].sort(orderByDueDateAndPriority),
     };
   }),