Improve Threema::Receive::DeliveryReceipt class

lib/threema/receive/delivery_receipt.rb

@@ -5,7 +5,7 @@
 class Threema
   module Receive
     class DeliveryReceipt
-      STATUS_TYPE_BYTE = {
+      STATUS_BYTE_MAPPING = {
         received: "\x01".b,
         read: "\x02".b,
         explicitly_acknowledged: "\x03".b,
@@ -17,30 +17,23 @@ class DeliveryReceipt
 
       def initialize(content:, **)
         @content = content
-        return unless type_by(content).present?
-
         @status = type_by(content)
+        return unless @status
+
         @timestamp = Time.now.utc.to_i
-        @message_ids = extract_message_ids(content)
+        @message_ids = extract_message_ids(content.slice(1, content.length - 1))
       end
 
       private
 
       def type_by(content)
-        STATUS_TYPE_BYTE.key(content.slice(0))
+        STATUS_BYTE_MAPPING.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])
+      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
-        message_ids
       end
     end
   end

spec/threema/receive/delivery_receipt_spec.rb

@@ -7,63 +7,59 @@
   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
+  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)
+    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
+  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)
+  context '#status' do
+    context 'received type' do
+      it 'returns status received' do
+        expect(subject.status).to eq(:received)
+      end
     end
-  end
 
-  context 'read type' do
-    let(:attributes) { { content: "\x02\xE0\xC8\x12n8]\xF3\x19".b } }
+    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)
+      it 'returns status read' do
+        expect(subject.status).to eq(:read)
+      end
     end
-  end
 
-  context 'explicitly_acknowledged type' do
-    let(:attributes) { { content: "\x03\xE0\xC8\x12n8]\xF3\x19".b } }
+    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
+        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 } }
+      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)
+        it 'returns status explicity_declined' do
+          expect(subject.status).to eq(:explicity_declined)
+        end
+      end
     end
   end
 end