Improve Threema::Receive::DeliveryReceipt class

lib/threema/receive/delivery_receipt.rb

@@ -1,12 +1,46 @@
 # frozen_string_literal: true
 
+require 'threema/util'
+
 class Threema
   module Receive
     class DeliveryReceipt
-      attr_reader :content
+      STATUS_TYPE_BYTE = {
+        received: "\x01".b,
+        read: "\x02".b,
+        explicitly_acknowledged: "\x03".b,
+        explicity_declined: "\x04".b
+      }.freeze
+      UNHEXIFIED_MESSAGE_ID_LENGTH = 8
+
+      attr_reader :content, :status, :timestamp, :message_ids
 
       def initialize(content:, **)
         @content = content
+        return unless type_by(content).present?
+
+        @status = type_by(content)
+        @timestamp = Time.now.utc.to_i
+        @message_ids = extract_message_ids(content)
+      end
+
+      private
+
+      def type_by(content)
+        STATUS_TYPE_BYTE.key(content.slice(0))
+      end
+
+      def extract_message_ids(content)
+        type_removed = content.slice(1, content.length - 1)
+        num_message_ids = content.length / UNHEXIFIED_MESSAGE_ID_LENGTH
+
+        message_ids = []
+        num_message_ids.times do |index|
+          start_index = index.zero? ? index : (index * UNHEXIFIED_MESSAGE_ID_LENGTH)
+          end_index = (index + 1) * UNHEXIFIED_MESSAGE_ID_LENGTH - 1
+          message_ids << Threema::Util.hexify(type_removed[start_index..end_index])
+        end
+        message_ids
       end
     end
   end

spec/factories/threema_delivery_receipt_receive.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :delivery_receipt_receive, class: Threema::Receive::DeliveryReceipt do
+    content { "\x01\xE0\xC8\x12n8]\xF3\x19".b }
+
+    initialize_with do
+      new(**attributes)
+    end
+  end
+end

spec/threema/receive/delivery_receipt_spec.rb

@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Threema::Receive::DeliveryReceipt do
+  subject { described_class.new(**attributes) }
+  let(:attributes) { attributes_for(:delivery_receipt_receive) }
+
+  context '#content' do
+    it { is_expected.to respond_to(:content) }
+
+    it 'returns the content' do
+      expect(subject.content).to eq(attributes[:content])
+    end
+  end
+
+  context 'message ids' do
+    let(:attributes) { { content: "\x01\xE0\xC8\x12n8]\xF3\x19J\xB4+ \xC9\xAB|\xB6\xAAc#\v|Ro(".b } }
+
+    it 'returns an array of message ids' do
+      expect(subject.message_ids).to be_a(Array)
+    end
+
+    it 'with each message id' do
+      expect(subject.message_ids.length).to eq(3)
+    end
+
+    it 'with correct length' do
+      expect(subject.message_ids.all? { |string| string.length.eql?(16) }).to be(true)
+    end
+  end
+
+  context 'timestamp' do
+    it 'returns a timestamp' do
+      expect(subject.timestamp).to be_an_instance_of(Integer)
+      expect(Time.at(subject.timestamp, in: 'UTC')).to be_an_instance_of(Time)
+    end
+  end
+
+  context 'received type' do
+    it 'returns status received' do
+      expect(subject.status).to eq(:received)
+    end
+  end
+
+  context 'read type' do
+    let(:attributes) { { content: "\x02\xE0\xC8\x12n8]\xF3\x19".b } }
+
+    it 'returns status read' do
+      expect(subject.status).to eq(:read)
+    end
+  end
+
+  context 'explicitly_acknowledged type' do
+    let(:attributes) { { content: "\x03\xE0\xC8\x12n8]\xF3\x19".b } }
+
+    it 'returns status explicitly_acknowledged' do
+      expect(subject.status).to eq(:explicitly_acknowledged)
+    end
+  end
+
+  context 'explicity_declined type' do
+    let(:attributes) { { content: "\x04\xE0\xC8\x12n8]\xF3\x19".b } }
+
+    it 'returns status explicity_declined' do
+      expect(subject.status).to eq(:explicity_declined)
+    end
+  end
+end