Alarm clock support

[Nezz]

Context

I started implementing alarm clock support in home-assistant/core#117755, but I was guided here to propose and have a discussion over it.

Currently, setting up an alarm clock in Home Assistant requires multiple entities, which are cumbersome and inconsistent:

• Switch entity for turning on/off the alarm
• Time entity for the alarm's time
• Select entity for choosing between days. However, this only supports one selection. Therefore a text entity might be used but is really clumsy.

Example from https://github.com/theneweinstein/somneo:

Due to this, they are often not implemented (see #1046 and lukas-clarke/eight_sleep#19) even though the functionality is similar to the existing timer integration.

Objectives

• Simplify the process of setting and managing alarms in Home Assistant.
• Provide a unified entity and user interface for alarm clock functionality.
• Enable seamless integration with existing and future alarm-related integrations, including voice.

Components

Unified Alarm Clock Entity:

• Allows scheduling alarms for a certain time of day
• Allows repeating alarms on certain days, or one-off alarms
• Can be turned on and off
• Fire events, which allows automatons can listen to the alarm going off and turn on lights, open covers, etc.

I did not include any snooze functionality in this because it requires interaction, therefore it's probably best implemented by the actual integration and left out of the entity model.

Frontend

• Ability to set and modify alarm time.
• Toggle alarm on/off.
• Select multiple days for the alarm (e.g., weekdays, weekends).
• Ability to create alarms as helpers.

[parautenbach]

May I add?

The ability to skip the next alarm (followed by reverting to the existing schedule after that).

[Nezz]

That's a good idea. Philips does not support it, but Eight Sleep does. They have implemented it in a way that when you change or turn off the alarm, it asks if you want to do it for tomorrow only or change the routine. Not sure how they implemented it under the hood though.

[parautenbach]

Nice. I was going on what my iOS alarm clock does, which I replicated in my HA setup. In my larger setup (just out of interest) I look at workdays and can also add a vacation entry to a calendar to automatically disable the morning alarm (and accompanying morning routine), but sometimes I/we simply want to skip the next one (so that's the context).