Restructure omni services and add Chatwoot research snapshot

research/chatwoot/app/builders/contact_inbox_builder.rb

@@ -0,0 +1,107 @@
+# This Builder will create a contact inbox with specified attributes. If the contact inbox already exists, it will be returned.
+# For Specific Channels like whatsapp, email etc . it smartly generated appropriate the source id when none is provided.
+
+class ContactInboxBuilder
+  pattr_initialize [:contact, :inbox, :source_id, { hmac_verified: false }]
+
+  def perform
+    @source_id ||= generate_source_id
+    create_contact_inbox if source_id.present?
+  end
+
+  private
+
+  def generate_source_id
+    case @inbox.channel_type
+    when 'Channel::TwilioSms'
+      twilio_source_id
+    when 'Channel::Whatsapp'
+      wa_source_id
+    when 'Channel::Email'
+      email_source_id
+    when 'Channel::Sms'
+      phone_source_id
+    when 'Channel::Api', 'Channel::WebWidget'
+      SecureRandom.uuid
+    else
+      raise "Unsupported operation for this channel: #{@inbox.channel_type}"
+    end
+  end
+
+  def email_source_id
+    raise ActionController::ParameterMissing, 'contact email' unless @contact.email
+
+    @contact.email
+  end
+
+  def phone_source_id
+    raise ActionController::ParameterMissing, 'contact phone number' unless @contact.phone_number
+
+    @contact.phone_number
+  end
+
+  def wa_source_id
+    raise ActionController::ParameterMissing, 'contact phone number' unless @contact.phone_number
+
+    # whatsapp doesn't want the + in e164 format
+    @contact.phone_number.delete('+').to_s
+  end
+
+  def twilio_source_id
+    raise ActionController::ParameterMissing, 'contact phone number' unless @contact.phone_number
+
+    case @inbox.channel.medium
+    when 'sms'
+      @contact.phone_number
+    when 'whatsapp'
+      "whatsapp:#{@contact.phone_number}"
+    end
+  end
+
+  def create_contact_inbox
+    attrs = {
+      contact_id: @contact.id,
+      inbox_id: @inbox.id,
+      source_id: @source_id
+    }
+
+    ::ContactInbox.where(attrs).first_or_create!(hmac_verified: hmac_verified || false)
+  rescue ActiveRecord::RecordNotUnique
+    Rails.logger.info("[ContactInboxBuilder] RecordNotUnique #{@source_id} #{@contact.id} #{@inbox.id}")
+    update_old_contact_inbox
+    retry
+  end
+
+  def update_old_contact_inbox
+    # The race condition occurs when there’s a contact inbox with the
+    # same source ID but linked to a different contact. This can happen
+    # if the agent updates the contact’s email or phone number, or
+    # if the contact is merged with another.
+    #
+    # We update the old contact inbox source_id to a random value to
+    # avoid disrupting the current flow. However, the root cause of
+    # this issue is a flaw in the contact inbox model design.
+    # Contact inbox is essentially tracking a session and is not
+    # needed for non-live chat channels.
+    raise ActiveRecord::RecordNotUnique unless allowed_channels?
+
+    contact_inbox = ::ContactInbox.find_by(inbox_id: @inbox.id, source_id: @source_id)
+    return if contact_inbox.blank?
+
+    contact_inbox.update!(source_id: new_source_id)
+  end
+
+  def new_source_id
+    if @inbox.whatsapp? || @inbox.sms? || @inbox.twilio?
+      "whatsapp:#{@source_id}#{rand(100)}"
+    else
+      "#{rand(10)}#{@source_id}"
+    end
+  end
+
+  def allowed_channels?
+    @inbox.email? || @inbox.sms? || @inbox.twilio? || @inbox.whatsapp?
+  end
+end
+
+ContactInboxBuilder.prepend_mod_with('ContactInboxBuilder')