require 'slack-notifier'

module Minicron
  module Alert
    # Allows the sending of Slack alerts
    class Slack
      # Used to set up on the Slack::Notifier
      def initialize
        # Get an instance of the slack client
        @client = ::Slack::Notifier.new(
          Minicron.config['alerts']['slack']['webhook_url'],
          channel: Minicron.config['alerts']['slack']['channel'],
          username: 'minicron'
        )
      end

      # Return the message for an alert
      #
      # @option options [Minicron::Hub::Model::Job] job a job instance
      # @option options [String] kind 'fail' or 'miss'
      # @option options [Integer, nil] schedule_id only applies to 'miss' alerts
      # @option options [Integer, nil] execution_id only used by 'fail' alerts
      # @option options [Integer] job_id used to look up the job name for the alert message
      # @option options [Time] expected_at when the schedule was expected to execute
      # @option options [String] medium the medium to send the alert via
      def get_message(options = {})
        case options[:kind]
        when 'miss'
          "Job '#{options[:job][:name]}' (##{options[:job_id]}) failed to execute at its expected time - #{options[:expected_at]}"
        when 'fail'
          "Execution ##{options[:execution_id]} of Job '#{options[:job][:name]}' (##{options[:job_id]}) failed"
        else
          raise Minicron::ArgumentError, "The kind '#{options[:kind]} is not supported!"
        end
      end

      def send(message)
        @client.ping message
      end
    end
  end
end
