feat: Add support for daylight saving time in genTime cluster

[DerDreschner]

Currently, there is no support for daylight saving time in zigbee-herdsman. Some devices ask the coordinator repeatedly this information if there is no answer or just the default value as answer (looking at you, Bosch!). To avoid that, there was the need for an customReadResponse function, which isn't that great.

This pull request changes that and includes support for daylight saving time. As the whole topic can be pretty complex, I've settled on the basics: daylight saving time is well-established in the timezone. This is important, as countries can leave or introduce daylight saving time (happened a lot over the past 10-20 years). In that case, I leave the default values, which should match the current behavior.

This is a follow-up to #1515.

[Nerivec]

For ref, here's a code snippet of the handling from Silabs:
https://github.com/SiliconLabs/simplicity_sdk/blob/sisdk-2025.6/protocol/zigbee/app/framework/plugin/time-server/time-server.c

[DerDreschner]

I've looked into the converters to see how other devices handle genTime requests apart from what is being done in zigbee-herdsman. Here are a few findings:

• Usage of standard UNIX timestamp instead of Zigbee UTC time by Sonoff in at least one case.
• The behavior I found above for Aqara is already being implemented and used in this case and that strangely global case (index.ts being used).
• Multiple devices that don't request the time during interview and expect it to be set by the coordinator. Regarding the discussion above, it would be interesting to see how the timeStatus looks like on these devices. Some devices expect the time regularly as well. My bet would be that these devices expect it every time their ValidUntilTime expires or is about to expire.
• Multiple devices try to read the time from the coordinator, but the read request is being ignored for some reason.
• Some devices seem to use their Time and LastSetTime attributes (not the server side we discuss here) as "last time since reboot". I don't know if that is because these devices expect the time to be explicitly set as well or if that's the way it should be. Considering this abuse of the dstStart and dstEnd fields, my bet would be the latter...

It might be sensible to expose the timeService to the converters for this cases, as a lot of them just copied the previous code we now replace. Maybe we should implement a utils.time file there or some methods in modernExtend.ts to handle such non-specification-compliant cases (or at least a subset of commonly used cases) in a central place.

[Koenkk]

Multiple devices try to read the time from the coordinator, but the read request is being ignored for some reason.

It's an ignore converter to suppress the "No converter available.." message, but since it's not logged anyway for these clusters we can remove this. This converter does not prevent zigbee-herdsman from responding, it was purely there to suppress the log message (before ignoreClusters was introduced). I'll cleanup the converters.

[Nerivec]

I'll cleanup the converters.

Mighty nice cleanup!

[DerDreschner]

@Nerivec: Are there any open tasks for me to do that block a possible merge?

[Copilot]

Pull Request Overview

This PR adds comprehensive support for daylight saving time (DST) in the genTime cluster, replacing the previous basic time zone handling with a sophisticated system that can handle DST transitions for both Northern and Southern hemispheres. The implementation caches DST calculations for 24-hour periods to improve performance while ensuring accurate time information is provided to Zigbee devices.

Key changes:

• New timeService module that calculates all genTime cluster attributes including DST start/end times and offsets
• Updated controller to use the time service instead of inline time calculations
• Comprehensive test suite covering various timezone scenarios and DST edge cases

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/utils/timeService.ts	New module implementing DST-aware time cluster attribute calculation with caching
src/controller/model/device.ts	Refactored to use timeService for genTime read responses instead of inline calculations
src/index.ts	Exports the new getTimeClusterAttributes function from timeService
test/timeService.test.ts	Comprehensive test suite for the new time service functionality
test/controller.test.ts	Updated genTime read test to verify integration with timeService
package.json	Added @date-fns/tz dependency for timezone calculations

Files not reviewed (1)

• pnpm-lock.yaml: Language not supported

[Koenkk]

Thanks!