performance optimization via atoms (#108)

components/HabitStreak.tsx

@@ -2,10 +2,10 @@
 
 import { Habit } from '@/lib/types'
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card"
-import { d2s, getNow, t2d, getCompletedHabitsForDate } from '@/lib/utils'
+import { d2s, getNow, t2d } from '@/lib/utils' // Removed getCompletedHabitsForDate
 import { LineChart, Line, XAxis, YAxis, CartesianGrid, Tooltip, ResponsiveContainer } from 'recharts'
 import { useAtom } from 'jotai'
-import { settingsAtom, hasTasksAtom } from '@/lib/atoms'
+import { settingsAtom, hasTasksAtom, completedHabitsMapAtom } from '@/lib/atoms' // Added completedHabitsMapAtom
 
 interface HabitStreakProps {
   habits: Habit[]
@@ -14,6 +14,8 @@ interface HabitStreakProps {
 export default function HabitStreak({ habits }: HabitStreakProps) {
   const [settings] = useAtom(settingsAtom)
   const [hasTasks] = useAtom(hasTasksAtom)
+  const [completedHabitsMap] = useAtom(completedHabitsMapAtom) // Use the atom
+
   // Get the last 7 days of data
   const dates = Array.from({ length: 7 }, (_, i) => {
     const d = getNow({ timezone: settings.system.timezone });
@@ -21,20 +23,17 @@ export default function HabitStreak({ habits }: HabitStreakProps) {
   }).reverse()
 
   const completions = dates.map(date => {
-    const completedHabits = getCompletedHabitsForDate({
-      habits: habits.filter(h => !h.isTask),
-      date: t2d({ timestamp: date, timezone: settings.system.timezone }),
-      timezone: settings.system.timezone
-    });
-    const completedTasks = getCompletedHabitsForDate({
-      habits: habits.filter(h => h.isTask),
-      date: t2d({ timestamp: date, timezone: settings.system.timezone }),
-      timezone: settings.system.timezone
-    });
+    // Get completed habits for the date from the map
+    const completedOnDate = completedHabitsMap.get(date) || [];
+
+    // Filter the completed list to count habits and tasks
+    const completedHabitsCount = completedOnDate.filter(h => !h.isTask).length;
+    const completedTasksCount = completedOnDate.filter(h => h.isTask).length;
+
     return {
       date,
-      habits: completedHabits.length,
-      tasks: completedTasks.length
+      habits: completedHabitsCount,
+      tasks: completedTasksCount
     };
   });