Add conversations API (#8832)

* Add conversations API

* Add web UI for conversations

* Add test for conversations API

* Add tests for ConversationAccount

* Improve web UI

* Rename ConversationAccount to AccountConversation

* Remove conversations on block and mute

* Change last_status_id to be a denormalization of status_ids

* Add optimistic locking

spec/controllers/api/v1/conversations_controller_spec.rb

@@ -0,0 +1,37 @@
+require 'rails_helper'
+
+RSpec.describe Api::V1::ConversationsController, type: :controller do
+  render_views
+
+  let!(:user) { Fabricate(:user, account: Fabricate(:account, username: 'alice')) }
+  let(:token) { Fabricate(:accessible_access_token, resource_owner_id: user.id, scopes: scopes) }
+  let(:other) { Fabricate(:user, account: Fabricate(:account, username: 'bob')) }
+
+  before do
+    allow(controller).to receive(:doorkeeper_token) { token }
+  end
+
+  describe 'GET #index' do
+    let(:scopes) { 'read:statuses' }
+
+    before do
+      PostStatusService.new.call(other.account, 'Hey @alice', nil, visibility: 'direct')
+    end
+
+    it 'returns http success' do
+      get :index
+      expect(response).to have_http_status(200)
+    end
+
+    it 'returns pagination headers' do
+      get :index, params: { limit: 1 }
+      expect(response.headers['Link'].links.size).to eq(2)
+    end
+
+    it 'returns conversations' do
+      get :index
+      json = body_as_json
+      expect(json.size).to eq 1
+    end
+  end
+end

spec/fabricators/conversation_account_fabricator.rb

@@ -0,0 +1,6 @@
+Fabricator(:conversation_account) do
+  account                 nil
+  conversation            nil
+  participant_account_ids ""
+  last_status             nil
+end

spec/models/account_conversation_spec.rb

@@ -0,0 +1,72 @@
+require 'rails_helper'
+
+RSpec.describe AccountConversation, type: :model do
+  let!(:alice) { Fabricate(:account, username: 'alice') }
+  let!(:bob)   { Fabricate(:account, username: 'bob') }
+  let!(:mark)  { Fabricate(:account, username: 'mark') }
+
+  describe '.add_status' do
+    it 'creates new record when no others exist' do
+      status = Fabricate(:status, account: alice, visibility: :direct)
+      status.mentions.create(account: bob)
+
+      conversation = AccountConversation.add_status(alice, status)
+
+      expect(conversation.participant_accounts).to include(bob)
+      expect(conversation.last_status).to eq status
+      expect(conversation.status_ids).to eq [status.id]
+    end
+
+    it 'appends to old record when there is a match' do
+      last_status  = Fabricate(:status, account: alice, visibility: :direct)
+      conversation = AccountConversation.create!(account: alice, conversation: last_status.conversation, participant_account_ids: [bob.id], status_ids: [last_status.id])
+
+      status = Fabricate(:status, account: bob, visibility: :direct, thread: last_status)
+      status.mentions.create(account: alice)
+
+      new_conversation = AccountConversation.add_status(alice, status)
+
+      expect(new_conversation.id).to eq conversation.id
+      expect(new_conversation.participant_accounts).to include(bob)
+      expect(new_conversation.last_status).to eq status
+      expect(new_conversation.status_ids).to eq [last_status.id, status.id]
+    end
+
+    it 'creates new record when new participants are added' do
+      last_status  = Fabricate(:status, account: alice, visibility: :direct)
+      conversation = AccountConversation.create!(account: alice, conversation: last_status.conversation, participant_account_ids: [bob.id], status_ids: [last_status.id])
+
+      status = Fabricate(:status, account: bob, visibility: :direct, thread: last_status)
+      status.mentions.create(account: alice)
+      status.mentions.create(account: mark)
+
+      new_conversation = AccountConversation.add_status(alice, status)
+
+      expect(new_conversation.id).to_not eq conversation.id
+      expect(new_conversation.participant_accounts).to include(bob, mark)
+      expect(new_conversation.last_status).to eq status
+      expect(new_conversation.status_ids).to eq [status.id]
+    end
+  end
+
+  describe '.remove_status' do
+    it 'updates last status to a previous value' do
+      last_status  = Fabricate(:status, account: alice, visibility: :direct)
+      status       = Fabricate(:status, account: alice, visibility: :direct)
+      conversation = AccountConversation.create!(account: alice, conversation: last_status.conversation, participant_account_ids: [bob.id], status_ids: [status.id, last_status.id])
+      last_status.mentions.create(account: bob)
+      last_status.destroy!
+      conversation.reload
+      expect(conversation.last_status).to eq status
+      expect(conversation.status_ids).to eq [status.id]
+    end
+
+    it 'removes the record if no other statuses are referenced' do
+      last_status  = Fabricate(:status, account: alice, visibility: :direct)
+      conversation = AccountConversation.create!(account: alice, conversation: last_status.conversation, participant_account_ids: [bob.id], status_ids: [last_status.id])
+      last_status.mentions.create(account: bob)
+      last_status.destroy!
+      expect(AccountConversation.where(id: conversation.id).count).to eq 0
+    end
+  end
+end