Advanced date override handling and timezone compatibility improvements

[akshayutture-augment]

Test 7

---

Replicated from ai-code-review-evaluation/cal.com-greptile#7

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[akshayutture-augment]

@greptileai

[greptile-apps]

Greptile Overview

Confidence Score: 1/5

• This PR contains critical logic bugs that will cause incorrect slot availability calculations
• Two critical bugs in the slot availability validation logic will cause runtime errors in availability calculations, making the scheduling system unreliable
• Pay close attention to packages/trpc/server/routers/viewer/slots.ts - the bugs on lines 114 and 142 must be fixed before merge

Important Files Changed

File Analysis

Filename	Score	Overview
packages/trpc/server/routers/viewer/slots.ts	1/5	Added timezone-aware date override handling and working hours validation, but contains two critical bugs: incorrect end time calculation and broken dayjs equality check
packages/lib/slots.ts	4/5	Improved timezone handling for date overrides by calculating UTC offset differences between organizer and invitee timezones
packages/types/schedule.d.ts	5/5	Added optional timeZone field to TimeRange type to support timezone-aware date overrides
apps/web/test/lib/getSchedule.test.ts	5/5	Added test case to verify date override handling works correctly across different timezones

Sequence Diagram

sequenceDiagram
    participant Client
    participant getSchedule
    participant getUserAvailability
    participant getSlots
    participant checkIfIsAvailable

    Client->>getSchedule: request slots (eventTypeId, timeZone, dateRange)
    getSchedule->>getUserAvailability: get user availability
    getUserAvailability-->>getSchedule: return (busy, workingHours, dateOverrides, timeZone)
    
    Note over getSchedule: Flatten dateOverrides from all users<br/>and add timeZone to each override
    
    getSchedule->>getSlots: generate time slots
    Note over getSlots: Calculate timezone offset between<br/>organizer and invitee
    getSlots->>getSlots: Apply date overrides with<br/>timezone adjustments
    getSlots-->>getSchedule: return raw time slots
    
    loop For each time slot
        getSchedule->>checkIfIsAvailable: check slot availability
        Note over checkIfIsAvailable: 1. Check if date override exists<br/>2. Validate against working hours<br/>3. Check busy times
        checkIfIsAvailable-->>getSchedule: return isAvailable
    end
    
    getSchedule-->>Client: return available slots

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[greptile-apps]

_{4 files reviewed, 2 comments}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

logic: end is incorrectly set to the same value as start, causing slotEndTime to never be checked

Suggested change

	const start = slotStartTime.hour() * 60 + slotStartTime.minute();
	const end = slotStartTime.hour() * 60 + slotStartTime.minute();
	const start = slotStartTime.hour() * 60 + slotStartTime.minute();
	const end = slotEndTime.hour() * 60 + slotEndTime.minute();

Prompt To Fix With AI

This is a comment left during a code review.
Path: packages/trpc/server/routers/viewer/slots.ts
Line: 141:142

Comment:
**logic:** `end` is incorrectly set to the same value as `start`, causing `slotEndTime` to never be checked

```suggestion
        const start = slotStartTime.hour() * 60 + slotStartTime.minute();
        const end = slotEndTime.hour() * 60 + slotEndTime.minute();
```

How can I resolve this? If you propose a fix, please make it concise.

[greptile-apps]

logic: using === to compare dayjs objects will always return false since it compares object references, not values

Suggested change

	if (dayjs(date.start).add(utcOffset, "minutes") === dayjs(date.end).add(utcOffset, "minutes")) {
	if (dayjs(date.start).add(utcOffset, "minutes").isSame(dayjs(date.end).add(utcOffset, "minutes"))) {

Prompt To Fix With AI

This is a comment left during a code review.
Path: packages/trpc/server/routers/viewer/slots.ts
Line: 114:114

Comment:
**logic:** using `===` to compare dayjs objects will always return false since it compares object references, not values

```suggestion
        if (dayjs(date.start).add(utcOffset, "minutes").isSame(dayjs(date.end).add(utcOffset, "minutes"))) {
```

How can I resolve this? If you propose a fix, please make it concise.