Restructure omni services and add Chatwoot research snapshot

research/chatwoot/app/services/email_templates/db_resolver_service.rb

@@ -0,0 +1,87 @@
+# Code is heavily inspired by panaromic gem
+# https://github.com/andreapavoni/panoramic
+# We will try to find layouts and content from database
+# layout will be rendered with erb and other content in html format
+# Further processing in liquid is implemented in mailers
+
+# NOTE: rails resolver looks for templates in cache first
+# which we don't want to happen here
+# so we are overriding find_all method in action view resolver
+# If anything breaks - look into rails : actionview/lib/action_view/template/resolver.rb
+
+class ::EmailTemplates::DbResolverService < ActionView::Resolver
+  require 'singleton'
+  include Singleton
+
+  # Instantiate Resolver by passing a model.
+  def self.using(model, options = {})
+    class_variable_set(:@@model, model)
+    class_variable_set(:@@resolver_options, options)
+    instance
+  end
+
+  # Since rails picks up files from cache. lets override the method
+  # Normalizes the arguments and passes it on to find_templates.
+  # rubocop:disable Metrics/ParameterLists
+  def find_all(name, prefix = nil, partial = false, details = {}, key = nil, locals = [])
+    locals = locals.map(&:to_s).sort!.freeze
+    _find_all(name, prefix, partial, details, key, locals)
+  end
+  # rubocop:enable Metrics/ParameterLists
+
+  # the function has to accept(name, prefix, partial, _details, _locals = [])
+  # _details contain local info which we can leverage in future
+  # cause of codeclimate issue with 4 args, relying on (*args)
+  def find_templates(name, prefix, partial, *_args)
+    @template_name = name
+    @template_type = prefix.include?('layout') ? 'layout' : 'content'
+    @db_template = find_db_template
+
+    return [] if @db_template.blank?
+
+    path = build_path(prefix)
+    handler = ActionView::Template.registered_template_handler(:liquid)
+
+    template_details = {
+      locals: [],
+      format: Mime['html'].to_sym,
+      virtual_path: virtual_path(path, partial)
+    }
+
+    [ActionView::Template.new(@db_template.body, "DB Template - #{@db_template.id}", handler, **template_details)]
+  end
+
+  private
+
+  def find_db_template
+    find_account_template || find_installation_template
+  end
+
+  def find_account_template
+    return unless Current.account
+
+    @@model.find_by(name: @template_name, template_type: @template_type, account: Current.account)
+  end
+
+  def find_installation_template
+    @@model.find_by(name: @template_name, template_type: @template_type, account: nil)
+  end
+
+  # Build path with eventual prefix
+  def build_path(prefix)
+    prefix.present? ? "#{prefix}/#{@template_name}" : @template_name
+  end
+
+  # returns a path depending if its a partial or template
+  # params path: path/to/file.ext  partial: true/false
+  # the function appends _to make the file name _file.ext if partial: true
+  def virtual_path(path, partial)
+    return path unless partial
+
+    if (index = path.rindex('/'))
+      path.insert(index + 1, '_')
+    else
+      "_#{path}"
+    end
+  end
+end