Template: User stories

If you wish to file a user story, please copy and paste the template below.

The only section that is entirely required is # What I'd like to do. Other sections are provided to add details once mechanisms for implementing the story emerge.

Meta-bug: #2 .

# What I'd like to do

>    During the day, temperature of the heater should be set to 19C, but
>    during the night, reduce the temperature of heaters to 16C.

# Can be expressed as

1. When the value of `a channel "get time of day" of service "foxbox clock"` is above 7pm do
    send `temperature: 16C` to `all channels "set temperature"`.
2. When the value of `a channel "get time of day" of service "foxbox clock"` is between 6am and 7pm do
    send `temperature: 19C` to `all channels "set temperature"`.

# Getter channels

    We need a service "foxbox clock" with a getter channel "get time of day". This service is built-in the foxbox and does not need any discovery.

# Setter channels

    We need services with channels that support "set temperature". The actual set of services is discovered dynamically, whenever we send the message, so as to support adding/removing heaters without having to alter the script.

# Values

* Time of day. Represented in UTC, displayed in local time by the UX.
* Temperature. Represented in units, to avoid grave accidents.

# Open questions

* How do we handle overlapping intervals?