Suggested directory / module structure for multi-channel Yii2 app - refactoring

Question

I started my scheduling app with a basic app template for my app, it worked pretty well. Initially, it was only for IVR, now it started to add multiple channels (ivr, web, sms, etc). Each channel handles the user request differently and communicates the request in the requested channel, but all it does is scheduling. So, I started off with the following structure,
backend
common
frontend
modules
ivr
web
appt
For me, appt is going to be the core module and will be used by all channel modules. ivr and web modules handles request from different channels. If someone requests for appt, how can I pass the request data to appt module and send the appt's response back to user?
If it is an app without modules, it would be an instantiation of model and assigning form collected values to model, validate them, save and send the response in the request synchronously. How I can do the same, if my module depends on another module to perform validation and other business logic?
Can anyone shed some light on my approach? Should I go with module and just go back with the plain single app structure?
Edit:
My main confusion is whether IVR should go as a module or it should go as separate app as backend, frontend & console app does with Yii2 advanced template. The other modules that I'm considering are subscribe, script, notifier. Some modules are common to all channels and some others are specific to IVR.
When I considered 'appointment (appt)' as module and attempted to make appt from web module, I got stuck at how to instantiate models & retrieve error message.
I think modules should be loosed coupled, but for me, it appears to tightly integrated with other modules. What do you suggest from the following?
every purpose / feature as module and should be able to handle requests / response for all channels (ivr, web, etc)
every channel should be projected as module and should interact with feature modules. Does this over complate the module system?
Bring IVR as a separate app and import the necessary modules in it and add modules as needed?

Answer 1

Your question is a bit of a general nature and therefore are not able to give you a precise answer, however with Yii2 can pass information in multiple ways. You can redirect calls to redirect but I think the best solution is to instantiate in your module appt the services that you need. including the correct namespace with use ----\modules\ivr ... and then use the most appropriate methods of the modules that you need.
For the response to be sent to users must return obviously the information provided in different formats and so you must watch to the correct format for each channel type, but having successfully organized the different forms you will need, I think, limit yourself to make or specialize a render / echo appropriate.
Reply
Compared to Your I would keep in mind the following aspects: the various channels may well be separate modules strongly be decoupled between them.
The problem of integration and the coupling between the various components it would go to manage with a single module (appt) who cares to integrate and coordinate user requests and relay the various tasks on the specific functions of the channel.
It must also take account of the opportunity to manage the various features through a proper object-oriented architecture that would allow a further centralization of coordination actions between module functions and especially creandio an abstract channel from which specialize functions Common Channel (and relationship with the system components).
I look with particular interest in the fact of concenpire the IVR module as a module too different from the channels. Certainly it has some intrinsic speficità but try to work more in terms of modularity homogenous.
The discussion is still very wide. and we should be more specific to the needs of interaction and telecommunications that will set us as objective functional application.
I hope this will be useful