fix: sidebar thread group by date

[mayur9210]

This pull request fixes the way thread dates are handled and grouped in the sidebar, ensuring that threads are accurately categorized as "today," "yesterday," "last week," or "older" based on the user's local timezone. It also fixes potential issues with interpreting timestamps from the database, especially those lacking timezone information.

As a test in before/after the todays chat was going on Last 7 days section , this fix will make sure to use TZ timezone, the other way around is changing schema from timestamp to timestampz for all dates.

Before

timezone.mov

After

Improvements to date handling and grouping:

• Refactored date grouping logic in AppSidebarThreads to consistently use the user's local timezone when determining if a thread belongs to "today," "yesterday," or "last week." This prevents misclassification of threads near midnight or in different timezones. [1] [2]

Database timestamp interpretation:

• Updated pgChatRepository to treat lastMessageAt timestamps from PostgreSQL as UTC if they lack timezone information, ensuring accurate conversion to JavaScript timestamps regardless of server or client timezone.

[vercel]

@mayur9210 is attempting to deploy a commit to the cgoinglove's projects Team on Vercel.

A member of the Team first needs to authorize it.

[cgoinglove]

/gemini reivew

[gemini-code-assist]

It looks like there might be a typo in your command. If you intended to request a code review, please use /gemini review.

[cgoinglove]

/gemini review

[gemini-code-assist]

Code Review

This pull request effectively addresses the issue of incorrect thread date grouping caused by timezone discrepancies. The approach of treating database timestamps as UTC and then converting to the user's local timezone in the frontend is correct. The implementation is solid, but I've identified a couple of areas for improvement. One is a potential issue with date calculations around Daylight Saving Time, and the other is a brittle check for timezone information in timestamp strings. My review includes suggestions to make the code more robust in these areas.

[Copilot]

Pull Request Overview

This PR fixes timezone handling issues when displaying chat threads grouped by date. The changes ensure that timestamp comparisons correctly account for UTC storage in the database versus local timezone display in the UI.

Key changes:

• Modified PostgreSQL repository to explicitly treat timestamps as UTC by appending 'Z' suffix when converting to JavaScript timestamps
• Updated thread grouping logic to use consistent local timezone date calculations for bucketing threads into "Today", "Yesterday", "Last Week", and "Older" categories

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/lib/db/pg/repositories/chat-repository.pg.ts	Added UTC timestamp handling logic to properly convert PostgreSQL timestamp strings to JavaScript timestamps with explicit UTC treatment
src/components/layouts/app-sidebar-threads.tsx	Refactored date comparison logic to use consistent local timezone calculations for thread grouping, replacing the previous approach that mixed date mutations and comparisons

Comments suppressed due to low confidence (1)

src/components/layouts/app-sidebar-threads.tsx:1

• Using now.getDate() - 1 and now.getDate() - 7 directly in the Date constructor can produce incorrect results when crossing month boundaries. For example, if today is March 1st (getDate() = 1), now.getDate() - 1 equals 0, which creates an invalid date. Use the same pattern as todayLocal by creating the date first, then using setDate() or subtracting milliseconds from todayStart.

"use client";

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.