feat: Add SLA metrics API (#9132)

enterprise/app/controllers/api/v1/accounts/applied_slas_controller.rb

@@ -0,0 +1,58 @@
+class Api::V1::Accounts::AppliedSlasController < Api::V1::Accounts::EnterpriseAccountsController
+  include Sift
+  include DateRangeHelper
+
+  RESULTS_PER_PAGE = 25
+
+  before_action :set_applied_slas, only: [:index, :metrics]
+  before_action :set_current_page, only: [:index]
+  before_action :paginate_slas, only: [:index]
+  before_action :check_admin_authorization?
+
+  sort_on :created_at, type: :datetime
+
+  def index; end
+
+  def metrics
+    @total_applied_slas = total_applied_slas
+    @number_of_sla_breaches = number_of_sla_breaches
+    @hit_rate = hit_rate
+  end
+
+  private
+
+  def total_applied_slas
+    @total_applied_slas ||= @applied_slas.count
+  end
+
+  def number_of_sla_breaches
+    @number_of_sla_breaches ||= @applied_slas.missed.count
+  end
+
+  def hit_rate
+    number_of_sla_breaches.zero? ? '100%' : "#{hit_rate_percentage}%"
+  end
+
+  def hit_rate_percentage
+    ((total_applied_slas - number_of_sla_breaches) / total_applied_slas.to_f * 100).round(2)
+  end
+
+  def set_applied_slas
+    initial_query = Current.account.applied_slas.includes(:conversation)
+    @applied_slas = initial_query
+                    .filter_by_date_range(range)
+                    .filter_by_inbox_id(params[:inbox_id])
+                    .filter_by_team_id(params[:team_id])
+                    .filter_by_sla_policy_id(params[:sla_policy_id])
+                    .filter_by_label_list(params[:label_list])
+                    .filter_by_assigned_agent_id(params[:assigned_agent_id])
+  end
+
+  def paginate_slas
+    @applied_slas = @applied_slas.page(@current_page).per(RESULTS_PER_PAGE)
+  end
+
+  def set_current_page
+    @current_page = params[:page] || 1
+  end
+end