Laravel 5.4 multiple dropdown on belongstomany over two pivots - php

Question

I'm trying to connect companies that are used by specific user role. A user with a specific role can "work" for multiple companies. A company can "employ" multiple users. I have 5 tables (users, role_user, roles, companies and company_user)
Models relations:
App\User:
public function roles()
{
return $this
->belongsToMany('App\Role')
->withTimestamps();
}
public function companies()
{
return $this
->belongsToMany('App\Company')
->withTimestamps();
}
App\Role:
public function users()
{
return $this
->belongsToMany('App\User')
->withTimestamps();
}
App\Companies:
public function users()
{
return $this->belongsToMany('App\User'); // with user_role ??
}
Companies Controller
public function edit(Request $request, $id) {
$company = Company::findOrFail($id);
$users = User::where('role_id',4)->pluck('username')->all(); // no role_id column
$users = User::pluck('username','id')->all(); // returns all users
return view('companies.edit', compact(['company','users']));
}
public function update(Request $request, $id) {
/* TODO */
}
Edit view
{!! Form::select('users[]', $users, null, ['class' => 'form-control', 'multiple' => 'multiple']) !!}
I want to asign users whith a specific user role to these companies. Is there a way to setup the relation or perhaps a scope?
Bonus question :) Is there a simple way to display concatinated value in a dropdown? First name + Last name instead of username?

Answer 1

Perhaps not the tidiest solution but it seems to work :)
Model
public function scopeOfRole($query, $role) {
return $query->
join('role_user', 'role_user.user_id', '=', 'users.id')->
join('roles', 'roles.id', '=', 'role_user.role_id')->
select(
DB::raw('GROUP_CONCAT(users.first_name," ",users.last_name) as username'),
'users.id')->
where('roles.name', $role)->
groupBy('users.id');
}
Controler
public function edit(Request $request, $id) {
$company = Company::findOrFail($id);
$users = User::OfRole('my role')->pluck('username','users.id')->all();
return view('companies.edit', compact(['company','users']));
}
edit view
{!! Form::select('users[]', $users, $company->users()->pluck('users.id'), ['class' => 'form-control', 'multiple' => 'multiple']) !!}