Command scheduling, event handling improvements

[kuba2k2]

This is the second part of my PR (#631), which was previously reverted to remove changes unrelated to PC port.

This PR adds the following features:

---

1. Command scheduling - schedule command, which allows to run another command at a set interval. Any supported command can be executed. It has the following syntax:
   • schedule set <id> <period(ms) <cmd...> - add/update a scheduled task
     • id is a user-chosen integer identifier of the task
     • period is the interval in milliseconds
     • cmd is the command to run; it can consist of multiple space-separated words
   • schedule del <id> - remove a previously scheduled task
   • schedule start <id> - start (enable) a previously scheduled task (enabled by default)
   • schedule stop <id> - stop (disable) a previously scheduled task, without removing it

---

2. Event variable substitution (I couldn't find a better name) - replace %var% tags in commands of objects' "action" field with a value from the event JSON. For example, this jsonl:

   {"page":2,"id":105,"obj":"label","text":"Brightness"}
   {"page":2,"id":106,"obj":"slider","action":{"changed":"p2b105.text %val%"}}

   will update the label's text whenever the slider emits a changed event. Any supported command can be executed, and any value from the JSON event can be used in substitution.

NOTE: That feature is disabled by default on non-PC builds, not to impact performance/memory usage on ESP32/Arduino builds. In particular, it requires deserialization of the JSON event prior to publishing, as well as running std::string::replace() a few times. It can be enabled using HASP_USE_EVENT_DATA_SUBST=1.

---

3. Setting "action" on all types of controls - previously, only a few controls allowed to run commands on events (script_event_handler()). Now, all controls call event_send_object_data() only, which then calls script_event_handler().

If there is an "action" tag on the object, the command is executed and MQTT message is not published.

An example can be seen above (with the slider).

---

4. Publishing MQTT messages along with event commands - if the "action" tag of an object has an additional property "pub": true, the action command is ran AND a message is published to MQTT.

This property defaults to false, which matches the behavior from previous versions.

Example:

{"page":2,"id":106,"obj":"slider","action":{"changed":"p2b105.text %val%","pub":true}}

This slider's events will be published to MQTT, additionally the changed event will run a command.

---

I have one more "feature" that was left out of #631, that is setting LVGL max framerate. If you want, I can add it to this PR, otherwise I will probably create another one.

[dgomes]

@kuba2k2 it would be best if each of these point (1..4) could be separate PR's :)

[kuba2k2]

These features are directly related to each other. I think it doesn't really make sense to split it, after all this PR is only 3 commits. You can review these commits separately and it will (more or less) match these 4 points.

[kuba2k2]

Hi, any news about this? :slightly_smiling_face: Anything that needs to be fixed before merging?

[fvanroie]

My only note is that HASP_USE_EVENT_DATA_SUBST is for PC only, so there will be a difference according to platform. It seems substitution is only implemented for single textline commands, but for a consistent approach should also account for json, jsonl payloads etc. But since it's only enabled on PX, that shouldn't impact many users.

I think you previously mentioned that you didn't test on ESP32, which is why I'm a bit apprehensive when general dispatch or event functions are refactored.

[kuba2k2]

Yes, the substitution may not apply to all commands. It should apply to everything that is executed as a text command. Since it is only useful in event actions (because otherwise data will be empty anyway, e.g. on MQTT command) it should apply to all commands executed this way.

I do not have an ESP32 platform with a compatible LCD, that's why I can't test it. I can only say that I was very careful to keep the existing behavior of the code, not to impact other users.