feat: Assignable agents API (#2131)

`inboxes/id/assignable_agents` returns all users that have permission to a conversation happening in that inbox.

app/controllers/api/v1/accounts/inboxes_controller.rb

@@ -7,6 +7,10 @@ class Api::V1::Accounts::InboxesController < Api::V1::Accounts::BaseController
     @inboxes = policy_scope(Current.account.inboxes.order_by_name.includes(:channel, { avatar_attachment: [:blob] }))
   end
 
+  def assignable_agents
+    @assignable_agents = (Current.account.users.where(id: @inbox.members.select(:user_id)) + Current.account.administrators).uniq
+  end
+
   def create
     ActiveRecord::Base.transaction do
       channel = create_channel

app/policies/inbox_policy.rb

@@ -23,6 +23,10 @@ class InboxPolicy < ApplicationPolicy
     true
   end
 
+  def assignable_agents?
+    true
+  end
+
   def create?
     @account_user.administrator?
   end

app/views/api/v1/accounts/inboxes/assignable_agents.json.jbuilder

@@ -0,0 +1,5 @@
+json.payload do
+  json.array! @assignable_agents do |agent|
+    json.partial! 'api/v1/models/agent.json.jbuilder', resource: agent
+  end
+end

config/routes.rb

@@ -88,6 +88,7 @@ Rails.application.routes.draw do
           end
 
           resources :inboxes, only: [:index, :create, :update, :destroy] do
+            get :assignable_agents, on: :member
             post :set_agent_bot, on: :member
           end
           resources :inbox_members, only: [:create, :show], param: :inbox_id

spec/controllers/api/v1/accounts/inboxes_controller_spec.rb

@@ -42,6 +42,38 @@ RSpec.describe 'Inboxes API', type: :request do
     end
   end
 
+  describe 'GET /api/v1/accounts/{account.id}/inboxes/{inbox.id}/assignable_agents' do
+    let(:inbox) { create(:inbox, account: account) }
+
+    context 'when it is an unauthenticated user' do
+      it 'returns unauthorized' do
+        get "/api/v1/accounts/#{account.id}/inboxes/#{inbox.id}/assignable_agents"
+
+        expect(response).to have_http_status(:unauthorized)
+      end
+    end
+
+    context 'when it is an authenticated user' do
+      let(:agent) { create(:user, account: account, role: :agent) }
+      let(:admin) { create(:user, account: account, role: :administrator) }
+
+      before do
+        create(:inbox_member, user: agent, inbox: inbox)
+      end
+
+      it 'returns all assignable inbox members along with administrators' do
+        get "/api/v1/accounts/#{account.id}/inboxes/#{inbox.id}/assignable_agents",
+            headers: admin.create_new_auth_token,
+            as: :json
+
+        expect(response).to have_http_status(:success)
+        response_data = JSON.parse(response.body, symbolize_names: true)[:payload]
+        expect(response_data.size).to eq(2)
+        expect(response_data.pluck(:role)).to include('agent', 'administrator')
+      end
+    end
+  end
+
   describe 'DELETE /api/v1/accounts/{account.id}/inboxes/:id' do
     let(:inbox) { create(:inbox, account: account) }