fix: resolve DST time conversion, task timezone filtering, and reminder retry loop

src/db/in-memory-repository.ts

@@ -19,6 +19,7 @@ import {
   MemoryCategory,
   MemoryRelationship,
 } from '../memory/types.js';
+import { parseLocalToUtc } from '../shared/time.js';
 
 export class InMemoryDatabaseRepository implements DatabaseRepository {
   public users: Map<string, AppUser> = new Map();
@@ -150,7 +151,8 @@ export class InMemoryDatabaseRepository implements DatabaseRepository {
 
   async listTasks(
     userId: string,
-    filter: 'all' | 'today' | 'upcoming' | 'completed' = 'all'
+    filter: 'all' | 'today' | 'upcoming' | 'completed' = 'all',
+    userTimezone: string = 'Asia/Kolkata'
   ): Promise<Task[]> {
     const userTasks = Array.from(this.tasks.values()).filter((t) => t.user_id === userId);
 
@@ -162,8 +164,11 @@ export class InMemoryDatabaseRepository implements DatabaseRepository {
 
     if (filter === 'today') {
       const now = this.clock.now();
-      const startOfDay = new Date(now.getFullYear(), now.getMonth(), now.getDate()).getTime();
-      const endOfDay = startOfDay + 24 * 60 * 60 * 1000;
+      const localDate = new Intl.DateTimeFormat('en-CA', { timeZone: userTimezone }).format(now);
+      const startOfDay = parseLocalToUtc(`${localDate}T00:00:00`, userTimezone).getTime();
+      const nextDayDate = new Date(startOfDay + 26 * 60 * 60 * 1000);
+      const nextLocalDate = new Intl.DateTimeFormat('en-CA', { timeZone: userTimezone }).format(nextDayDate);
+      const endOfDay = parseLocalToUtc(`${nextLocalDate}T00:00:00`, userTimezone).getTime();
 
       return openTasks.filter((t) => {
         if (!t.due_at) return false;
@@ -536,16 +541,25 @@ export class InMemoryDatabaseRepository implements DatabaseRepository {
     reminderId: string,
     workerToken: string,
     error: string,
-    retryAt: string
+    retryAt: string | null,
+    newFollowUpCount?: number
   ): Promise<boolean> {
     const reminder = this.reminders.get(reminderId);
     if (!reminder || reminder.lease_token !== workerToken) {
       return false;
     }
 
     const now = this.clock.now().toISOString();
-    reminder.status = 'scheduled'; // Schedule for retry
-    reminder.scheduled_at = retryAt;
+    if (newFollowUpCount !== undefined) {
+      reminder.follow_up_count = newFollowUpCount;
+    }
+
+    if (retryAt) {
+      reminder.status = 'scheduled'; // Schedule for retry
+      reminder.scheduled_at = retryAt;
+    } else {
+      reminder.status = 'failed';
+    }
     reminder.last_error = error;
     reminder.lease_token = null;
     reminder.lease_until = null;
@@ -554,7 +568,7 @@ export class InMemoryDatabaseRepository implements DatabaseRepository {
     await this.recordEvent(
       reminder.user_id,
       'reminder_send_failed',
-      { error, retryAt },
+      { error, retryAt, status: reminder.status },
       reminderId,
       reminder.task_id
     );

src/db/repository.ts

@@ -125,7 +125,8 @@ export interface DatabaseRepository {
     reminderId: string,
     workerToken: string,
     error: string,
-    retryAt: string
+    retryAt: string | null,
+    newFollowUpCount?: number
   ): Promise<boolean>;
 
   // Audit Events

src/db/supabase-repository.ts

@@ -18,6 +18,7 @@ import {
   MemoryCategory,
   MemoryRelationship,
 } from '../memory/types.js';
+import { parseLocalToUtc } from '../shared/time.js';
 
 export interface SupabaseConfig {
   supabaseUrl: string;
@@ -176,7 +177,8 @@ export class SupabaseDatabaseRepository implements DatabaseRepository {
 
   async listTasks(
     userId: string,
-    filter: 'all' | 'today' | 'upcoming' | 'completed' = 'all'
+    filter: 'all' | 'today' | 'upcoming' | 'completed' = 'all',
+    userTimezone: string = 'Asia/Kolkata'
   ): Promise<Task[]> {
     let query = this.client
       .from('tasks')
@@ -199,8 +201,11 @@ export class SupabaseDatabaseRepository implements DatabaseRepository {
 
     if (filter === 'today') {
       const now = new Date();
-      const startOfDay = new Date(now.getFullYear(), now.getMonth(), now.getDate()).getTime();
-      const endOfDay = startOfDay + 24 * 60 * 60 * 1000;
+      const localDate = new Intl.DateTimeFormat('en-CA', { timeZone: userTimezone }).format(now);
+      const startOfDay = parseLocalToUtc(`${localDate}T00:00:00`, userTimezone).getTime();
+      const nextDayDate = new Date(startOfDay + 26 * 60 * 60 * 1000);
+      const nextLocalDate = new Intl.DateTimeFormat('en-CA', { timeZone: userTimezone }).format(nextDayDate);
+      const endOfDay = parseLocalToUtc(`${nextLocalDate}T00:00:00`, userTimezone).getTime();
 
       return tasks.filter((t) => {
         if (!t.due_at) return false;
@@ -595,19 +600,27 @@ export class SupabaseDatabaseRepository implements DatabaseRepository {
     reminderId: string,
     workerToken: string,
     error: string,
-    retryAt: string
+    retryAt: string | null,
+    newFollowUpCount?: number
   ): Promise<boolean> {
     const now = new Date().toISOString();
+    const updatePayload: Record<string, unknown> = {
+      status: retryAt ? 'scheduled' : 'failed',
+      last_error: error,
+      lease_token: null,
+      lease_until: null,
+      updated_at: now,
+    };
+    if (retryAt) {
+      updatePayload.scheduled_at = retryAt;
+    }
+    if (newFollowUpCount !== undefined) {
+      updatePayload.follow_up_count = newFollowUpCount;
+    }
+
     const { data } = await this.client
       .from('reminders')
-      .update({
-        status: 'scheduled',
-        scheduled_at: retryAt,
-        last_error: error,
-        lease_token: null,
-        lease_until: null,
-        updated_at: now,
-      })
+      .update(updatePayload)
       .eq('id', reminderId)
       .eq('lease_token', workerToken)
       .select('id, user_id, task_id')
@@ -617,7 +630,7 @@ export class SupabaseDatabaseRepository implements DatabaseRepository {
       await this.recordEvent(
         data.user_id,
         'reminder_send_failed',
-        { error, retryAt },
+        { error, retryAt, status: updatePayload.status },
         reminderId,
         data.task_id
       );

src/reminders/worker.ts

@@ -33,6 +33,18 @@ export interface WorkerRunResult {
   }>;
 }
 
+export function isPermanentTelegramError(error?: string): boolean {
+  if (!error) return false;
+  const lower = error.toLowerCase();
+  return (
+    lower.includes('403') ||
+    lower.includes('blocked') ||
+    lower.includes('chat not found') ||
+    lower.includes('deactivated') ||
+    lower.includes("bot can't initiate")
+  );
+}
+
 export class ReminderWorker {
   private readonly db: DatabaseRepository;
   private readonly notification: NotificationProvider;
@@ -148,13 +160,31 @@ export class ReminderWorker {
         });
       }
     } else {
-      // Definite send failure: retry in 2 minutes
-      const retryAt = new Date(now.getTime() + 2 * 60 * 1000).toISOString();
+      const isPermanent = isPermanentTelegramError(sendResult.error);
+      const newFollowUpCount = reminder.follow_up_count + 1;
+      const isMaxReached = this.policy.isMaxReached(
+        newFollowUpCount,
+        reminder.max_follow_ups
+      );
+
+      let retryAt: string | null = null;
+      if (!isPermanent && !isMaxReached) {
+        // Exponential backoff for transient errors: 2, 4, 8... min (capped at 60 min)
+        const backoffMinutes = Math.min(
+          60,
+          2 * Math.pow(2, reminder.follow_up_count)
+        );
+        retryAt = new Date(
+          now.getTime() + backoffMinutes * 60 * 1000
+        ).toISOString();
+      }
+
       await this.db.recordReminderFailure(
         reminder.reminder_id,
         workerToken,
         sendResult.error || 'Unknown Telegram send error',
-        retryAt
+        retryAt,
+        newFollowUpCount
       );
 
       result.failedCount++;

src/shared/time.ts

@@ -93,28 +93,33 @@ export function parseLocalToUtc(localIsoString: string, timeZone: string = 'Asia
     hour12: false,
   });
 
-  const formattedParts = formatter.formatToParts(utcGuess);
-  const partMap: Record<string, number> = {};
-  for (const part of formattedParts) {
-    if (part.type !== 'literal') {
-      partMap[part.type] = parseInt(part.value, 10);
+  const getOffsetMs = (date: Date): number => {
+    const formattedParts = formatter.formatToParts(date);
+    const partMap: Record<string, number> = {};
+    for (const part of formattedParts) {
+      if (part.type !== 'literal') {
+        partMap[part.type] = parseInt(part.value, 10);
+      }
     }
-  }
 
-  // Formatted parts in target timezone for the guess
-  const tzHour = partMap.hour === 24 ? 0 : partMap.hour;
-  const targetTimeInTz = Date.UTC(
-    partMap.year,
-    partMap.month - 1,
-    partMap.day,
-    tzHour,
-    partMap.minute,
-    partMap.second
-  );
+    const tzHour = partMap.hour === 24 ? 0 : partMap.hour;
+    const targetTimeInTz = Date.UTC(
+      partMap.year,
+      partMap.month - 1,
+      partMap.day,
+      tzHour,
+      partMap.minute,
+      partMap.second
+    );
+    return targetTimeInTz - date.getTime();
+  };
 
-  // Offset in milliseconds between UTC guess and target timezone representation
-  const offsetMs = targetTimeInTz - utcGuess.getTime();
+  // Two-pass offset evaluation handles DST transitions
+  const offset1 = getOffsetMs(utcGuess);
+  const firstResult = new Date(utcGuess.getTime() - offset1);
+  const offset2 = getOffsetMs(firstResult);
 
-  // The actual UTC date is utcGuess - offsetMs
-  return new Date(utcGuess.getTime() - offsetMs);
+  return offset1 === offset2
+    ? firstResult
+    : new Date(utcGuess.getTime() - offset2);
 }