add Messages.counts_by_status (#17)

db/migrate/create_outboxer_messages.rb

@@ -9,6 +9,7 @@ def up
       t.timestamps
     end
 
+    add_index :outboxer_messages, :status
     add_index :outboxer_messages, %i[status created_at]
   end
 

lib/outboxer/messages.rb

@@ -8,6 +8,18 @@ module Messages
     class Error < Outboxer::Error; end;
     class InvalidTransition < Error; end
 
+    def counts_by_status
+      status_counts = Models::Message::STATUSES.each_with_object({}) do |status, hash|
+        hash[status.to_s] = 0
+      end
+
+      Models::Message.group(:status).count.each do |status, count|
+        status_counts[status.to_s] = count
+      end
+
+      status_counts
+    end
+
     def unpublished!(limit: 1, order: :asc)
       ActiveRecord::Base.connection_pool.with_connection do
         message_ids = ActiveRecord::Base.transaction do

lib/outboxer/models/message.rb

@@ -22,11 +22,10 @@ class Message < ::ActiveRecord::Base
       module Status
         UNPUBLISHED = 'unpublished'
         PUBLISHING = 'publishing'
-        PUBLISHED = 'published'
         FAILED = 'failed'
       end
 
-      STATUSES = [Status::UNPUBLISHED, Status::PUBLISHING, Status::PUBLISHED, Status::FAILED]
+      STATUSES = [Status::UNPUBLISHED, Status::PUBLISHING, Status::FAILED]
 
       scope :unpublished, -> { where(status: Status::UNPUBLISHED) }
       scope :publishing, -> { where(status: Status::PUBLISHING) }

spec/lib/outboxer/messages/counts_by_status_spec.rb

@@ -0,0 +1,29 @@
+require 'spec_helper'
+
+module Outboxer
+  RSpec.describe Message do
+    describe '.counts_by_status' do
+      context 'when no messages exist' do
+        it 'returns 0 for all statuses' do
+          expected_counts = { 'unpublished' => 0, 'publishing' => 0, 'failed' => 0 }
+
+          expect(Outboxer::Messages.counts_by_status).to eq(expected_counts)
+        end
+      end
+
+      context 'when messages exist' do
+        before do
+          create_list(:outboxer_message, 2, :unpublished)
+          create_list(:outboxer_message, 3, :publishing)
+          create_list(:outboxer_message, 4, :failed)
+        end
+
+        it 'returns correct counts for each status' do
+          expected_counts = { 'unpublished' => 2, 'publishing' => 3, 'failed' => 4 }
+
+          expect(Messages.counts_by_status).to eq(expected_counts)
+        end
+      end
+    end
+  end
+end