Adds Userlist delivery method

Author: benedikt

Gemfile

@@ -12,3 +12,4 @@ gem 'sidekiq'
 gem 'activejob'
 gem 'uri'
 gem 'irb'
+gem 'mail'

lib/userlist.rb

@@ -6,6 +6,7 @@
 require 'userlist/retryable'
 require 'userlist/push'
 require 'userlist/token'
+require 'userlist/delivery_method'
 
 module Userlist
   class Error < StandardError; end

lib/userlist/delivery_method.rb

@@ -0,0 +1,53 @@
+class Userlist::DeliveryMethod
+  attr_reader :userlist
+  attr_reader :settings
+
+  def initialize(settings = {})
+    @settings = settings
+
+    @userlist = Userlist::Push.new(settings)
+  end
+
+  def deliver!(mail)
+    message = serialize(mail)
+
+    userlist.messages.push(message.merge(theme: nil))
+  end
+
+private
+
+  def serialize(mail)
+    {
+      to: serialize_address(mail.to),
+      from: serialize_address(mail.from),
+      subject: mail.subject,
+      body: serialize_body(mail.body)
+    }.compact
+  end
+
+  def serialize_address(address)
+    address.first.to_s
+  end
+
+  def serialize_body(body)
+    return if body.nil?
+
+    if body.multipart?
+      parts = body.parts.filter_map { |part| serialize_part(part) }
+
+      return parts.first if parts.size == 1
+
+      { type: :multipart, content: parts }
+    else
+      { type: :text, content: body.decoded }
+    end
+  end
+
+  def serialize_part(part)
+    if part.content_type.start_with?('text/html')
+      { type: :html, content: part.decoded }
+    elsif part.content_type.start_with?('text/plain')
+      { type: :text, content: part.decoded }
+    end
+  end
+end

spec/userlist/delivery_method_spec.rb

@@ -0,0 +1,108 @@
+require 'spec_helper'
+require 'mail'
+
+RSpec.describe Userlist::DeliveryMethod do
+  let(:push_client) { instance_double(Userlist::Push) }
+  let(:messages) { instance_double('Messages') }
+  let(:config) { { push_key: 'test-key' } }
+
+  before do
+    allow(Userlist::Push).to receive(:new).with(config).and_return(push_client)
+    allow(push_client).to receive(:messages).and_return(messages)
+    allow(messages).to receive(:push)
+  end
+
+  describe '#deliver!' do
+    let(:delivery_method) { described_class.new(config) }
+
+    context 'with plain text email' do
+      let(:mail) do
+        Mail.new(
+          to: 'Example User <user@example.com>',
+          from: 'Example Sender <sender@example.com>',
+          subject: 'Test Subject',
+          body: 'Hello world'
+        )
+      end
+
+      it 'delivers the message correctly' do
+        expected_payload = {
+          to: 'user@example.com',
+          from: 'sender@example.com',
+          subject: 'Test Subject',
+          body: { type: :text, content: 'Hello world' },
+          theme: nil
+        }
+
+        expect(messages).to receive(:push).with(expected_payload)
+        delivery_method.deliver!(mail)
+      end
+    end
+
+    context 'with HTML email' do
+      let(:mail) do
+        Mail.new do
+          to 'user@example.com'
+          from 'sender@example.com'
+          subject 'Test Subject'
+
+          html_part do
+            content_type 'text/html'
+            body '<p>Hello world</p>'
+          end
+        end
+      end
+
+      it 'delivers the message correctly' do
+        expected_payload = {
+          to: 'user@example.com',
+          from: 'sender@example.com',
+          subject: 'Test Subject',
+          body: { type: :html, content: '<p>Hello world</p>' },
+          theme: nil
+        }
+
+        expect(messages).to receive(:push).with(expected_payload)
+        delivery_method.deliver!(mail)
+      end
+    end
+
+    context 'with multipart email' do
+      let(:mail) do
+        Mail.new do
+          to 'user@example.com'
+          from 'sender@example.com'
+          subject 'Test Subject'
+
+          text_part do
+            body 'Hello world'
+          end
+
+          html_part do
+            content_type 'text/html'
+            body '<p>Hello world</p>'
+          end
+        end
+      end
+
+      it 'delivers the message correctly' do
+        expected_payload = {
+          to: 'user@example.com',
+          from: 'sender@example.com',
+          subject: 'Test Subject',
+          body: {
+            type: :multipart,
+            content: [
+              { type: :text, content: 'Hello world' },
+              { type: :html, content: '<p>Hello world</p>' }
+            ]
+          },
+          theme: nil
+        }
+
+        expect(messages).to receive(:push).with(expected_payload)
+        delivery_method.deliver!(mail)
+      end
+    end
+  end
+end