Improve Threema::Receive::DeliveryReceipt class

lib/threema/receive/delivery_receipt.rb

@@ -1,12 +1,39 @@
 # frozen_string_literal: true
 
+require 'threema/util'
+
 class Threema
   module Receive
     class DeliveryReceipt
-      attr_reader :content
+      STATUS_BYTE_MAPPING = {
+        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
+        @status = type_by(content)
+        return unless @status
+
+        @timestamp = Time.now.utc.to_i
+        @message_ids = extract_message_ids(content.slice(1, content.length - 1))
+      end
+
+      private
+
+      def type_by(content)
+        STATUS_BYTE_MAPPING.key(content.slice(0))
+      end
+
+      def extract_message_ids(message_ids_payload)
+        message_ids_payload.scan(/.{,#{UNHEXIFIED_MESSAGE_ID_LENGTH}}/).reject(&:empty?).map do |message_id|
+          Threema::Util.hexify(message_id)
+        end
       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 +1,65 @@
+# 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 '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 } }
+
+    describe 'given a content string with three unhexified message ids' do
+      it 'returns the hexified message ids' do
+        expect(subject.message_ids).to eq(%w[e0c8126e385df319 4ab42b20c9ab7cb6 aa63230b7c526f28])
+      end
+    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 '#status' do
+    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 'the recipient explicitly reacts to the message by long pressing on it and' do
+      context 'acknowledges it by tapping on the thumbs up' 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 'declines it by tapping on the thumbs down' 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
+  end
+end