feat: email channel backend (#140) (#1255)

* feat: added support mailbox to handle email channel (#140)

Added a new mailbox called 'SupportMailbox' to handle all the
incoming emails other than reply emails.

An email channel will have a support email and forward email
associated with it. So we filter for the right email inbox based on
the support email of that inbox and route this to this mailbox.

This mailbox finds the account, inbox, contact (create a new one
if it does not exist) and creates a conversation and adds the
email content as the first message in the conversation.

Other minor things handled in this commit:

* renamed the procs for routing emails in application mailbox
* renamed ConversationMailbox to ReplyMailbox
* Added a fallback content in MailPresenter
* Added a record saving (bang) versions of enabling and disabling
features in Featurable module
* added new factory for the email channel

refs: #140

app/mailboxes/application_mailbox.rb

@@ -3,7 +3,7 @@ class ApplicationMailbox < ActionMailbox::Base
   # Eg: email should be something like : reply+6bdc3f4d-0bec-4515-a284-5d916fdde489@domain.com
   REPLY_EMAIL_USERNAME_PATTERN = /^reply\+([0-9a-f]{8}\b-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-\b[0-9a-f]{12})$/i.freeze
 
-  def self.reply_match_proc
+  def self.reply_mail?
     proc do |inbound_mail_obj|
       is_a_reply_email = false
       inbound_mail_obj.mail.to.each do |email|
@@ -18,11 +18,26 @@ class ApplicationMailbox < ActionMailbox::Base
     end
   end
 
-  def self.default_mail_proc
+  def self.support_mail?
+    proc do |inbound_mail_obj|
+      is_a_support_email = false
+      inbound_mail_obj.mail.to.each do |email|
+        channel = Channel::Email.find_by(email: email)
+        if channel.present?
+          is_a_support_email = true
+          break
+        end
+      end
+      is_a_support_email
+    end
+  end
+
+  def self.catch_all_mail?
     proc { |_mail| true }
   end
 
   # routing should be defined below the referenced procs
-  routing(reply_match_proc => :conversation)
-  routing(default_mail_proc => :default)
+  routing(reply_mail? => :reply)
+  routing(support_mail? => :support)
+  routing(catch_all_mail? => :default)
 end

app/mailboxes/mailbox_helper.rb

@@ -0,0 +1,29 @@
+module MailboxHelper
+  private
+
+  def create_message
+    @message = @conversation.messages.create(
+      account_id: @conversation.account_id,
+      sender: @conversation.contact,
+      content: processed_mail.text_content[:reply],
+      inbox_id: @conversation.inbox_id,
+      message_type: 'incoming',
+      content_type: 'incoming_email',
+      source_id: processed_mail.message_id,
+      content_attributes: {
+        email: processed_mail.serialized_data
+      }
+    )
+  end
+
+  def add_attachments_to_message
+    processed_mail.attachments.each do |mail_attachment|
+      attachment = @message.attachments.new(
+        account_id: @conversation.account_id,
+        file_type: 'file'
+      )
+      attachment.file.attach(mail_attachment[:blob])
+    end
+    @message.save!
+  end
+end

app/mailboxes/reply_mailbox.rb

@@ -1,4 +1,6 @@
-class ConversationMailbox < ApplicationMailbox
+class ReplyMailbox < ApplicationMailbox
+  include MailboxHelper
+
   attr_accessor :conversation_uuid, :processed_mail
 
   # Last part is the regex for the UUID
@@ -17,32 +19,6 @@ class ConversationMailbox < ApplicationMailbox
 
   private
 
-  def create_message
-    @message = @conversation.messages.create(
-      account_id: @conversation.account_id,
-      sender: @conversation.contact,
-      content: processed_mail.text_content[:reply],
-      inbox_id: @conversation.inbox_id,
-      message_type: 'incoming',
-      content_type: 'incoming_email',
-      source_id: processed_mail.message_id,
-      content_attributes: {
-        email: processed_mail.serialized_data
-      }
-    )
-  end
-
-  def add_attachments_to_message
-    processed_mail.attachments.each do |mail_attachment|
-      attachment = @message.attachments.new(
-        account_id: @conversation.account_id,
-        file_type: 'file'
-      )
-      attachment.file.attach(mail_attachment[:blob])
-    end
-    @message.save!
-  end
-
   def conversation_uuid_from_to_address
     mail.to.each do |email|
       username = email.split('@')[0]

app/mailboxes/support_mailbox.rb

@@ -0,0 +1,84 @@
+class SupportMailbox < ApplicationMailbox
+  include MailboxHelper
+
+  attr_accessor :channel, :account, :inbox, :conversation, :processed_mail
+
+  before_processing :find_channel,
+                    :load_account,
+                    :load_inbox,
+                    :decorate_mail
+
+  def process
+    find_or_create_contact
+    create_conversation
+    create_message
+    add_attachments_to_message
+  end
+
+  private
+
+  def find_channel
+    mail.to.each do |email|
+      @channel = Channel::Email.find_by(email: email)
+      break if @channel.present?
+    end
+    raise 'Email channel/inbox not found' if @channel.nil?
+
+    @channel
+  end
+
+  def load_account
+    @account = @channel.account
+  end
+
+  def load_inbox
+    @inbox = @channel.inbox
+  end
+
+  def decorate_mail
+    @processed_mail = MailPresenter.new(mail, @account)
+  end
+
+  def create_conversation
+    @conversation = ::Conversation.create!({
+                                             account_id: @account.id,
+                                             inbox_id: @inbox.id,
+                                             contact_id: @contact.id,
+                                             contact_inbox_id: @contact_inbox.id,
+                                             additional_attributes: {
+                                               source: 'email',
+                                               initiated_at: {
+                                                 timestamp: Time.now.utc
+                                               }
+                                             }
+                                           })
+  end
+
+  def find_or_create_contact
+    @contact = @inbox.contacts.find_by(email: processed_mail.from.first)
+    if @contact.present?
+      @contact_inbox = ContactInbox.find_by(inbox: @inbox, contact: @contact)
+    else
+      create_contact
+    end
+  end
+
+  def create_contact
+    @contact_inbox = ::ContactBuilder.new(
+      source_id: "email:#{processed_mail.message_id}",
+      inbox: @inbox,
+      contact_attributes: {
+        name: identify_contact_name,
+        email: processed_mail.from.first,
+        additional_attributes: {
+          source_id: "email:#{processed_mail.message_id}"
+        }
+      }
+    ).perform
+    @contact = @contact_inbox.contact
+  end
+
+  def identify_contact_name
+    processed_mail.from.first.split('@').first
+  end
+end

app/models/concerns/featurable.rb

@@ -24,12 +24,22 @@ module Featurable
     end
   end
 
+  def enable_features!(*names)
+    enable_features(*names)
+    save
+  end
+
   def disable_features(*names)
     names.each do |name|
       send("feature_#{name}=", false)
     end
   end
 
+  def disable_features!(*names)
+    disable_features(*names)
+    save
+  end
+
   def feature_enabled?(name)
     send("feature_#{name}?")
   end

app/presenters/mail_presenter.rb

@@ -12,7 +12,7 @@ class MailPresenter < SimpleDelegator
   end
 
   def text_content
-    @decoded_text_content ||= encode_to_unicode(text_part&.body&.decoded || '')
+    @decoded_text_content ||= encode_to_unicode(text_part&.body&.decoded || fallback_content)
     @text_content ||= {
       full: @decoded_text_content,
       reply: extract_reply(@decoded_text_content)[:reply],
@@ -21,7 +21,7 @@ class MailPresenter < SimpleDelegator
   end
 
   def html_content
-    @decoded_html_content ||= encode_to_unicode(html_part&.body&.decoded || '')
+    @decoded_html_content ||= encode_to_unicode(html_part&.body&.decoded || fallback_content)
     @html_content ||= {
       full: @decoded_html_content,
       reply: extract_reply(@decoded_html_content)[:reply],
@@ -29,6 +29,10 @@ class MailPresenter < SimpleDelegator
     }
   end
 
+  def fallback_content
+    body&.decoded || ''
+  end
+
   def attachments
     # ref : https://github.com/gorails-screencasts/action-mailbox-action-text/blob/master/app/mailboxes/posts_mailbox.rb
     mail.attachments.map do |attachment|