# Invoice object
class Fastly
  # An invoice for a time period
  class Invoice < Base
    attr_accessor :service_id, :service_name, :start_time, :end_time, :total, :regions

    ##
    # :attr: service_id
    #
    # The id of the service this invoice is for
    #

    ##
    # :attr: service_name
    #
    # The id of the service this invoice is for
    #

    ##
    # :attr: start_time
    #
    # The earliest date and time this invoice covers
    #

    ##
    # :attr: end_time
    #
    # The latest date and time this invoice covers
    #

    ##
    # :attr: total
    #
    # The total for this invoice in US dollars
    #

    ##
    # :attr: regions
    #
    # A hash reference with all the different regions and their subtotals

    # Get the start time of this invoice as a DateTime object in UTC
    def start
      DateTime.parse(start_time).new_offset(0)
    end

    # Get the end time of this invoice as a DateTime object in UTC
    def end
      DateTime.parse(end_time).new_offset(0)
    end

    private

    def self.get_path(*args)
      opts = args.size > 0 ? args[0] : {}

      url  = '/billing'

      url += "/service/#{opts[:service_id]}" if opts.key?(:service_id)

      if opts.key?(:year) && opts.key?(:month)
        url += "/year/#{opts[:year]}/month/#{opts[:month]}"
      end

      url
    end

    def self.list_path(*args)
      get_path(*args)
    end

    def self.post_path
      fail "You can't POST to an invoice"
    end

    def self.put_path
      fail "You can't PUT to an invoice"
    end

    def self.delete_path
      fail "You can't DELETE to an invoice"
    end

    def save!
      fail "You can't save an invoice"
    end

    def delete!
      fail "You can't delete an invoice"
    end
  end

  # Return an array of Invoice objects representing invoices for all services.
  #
  # If a year and month are passed in returns the invoices for that whole month.
  #
  # Otherwise it returns the invoices for the current month so far.
  def get_invoice(year = nil, month = nil)
    opts = {}
    unless year.nil? || month.nil?
      opts[:year]  = year
      opts[:month] = month
    end

    get(Invoice, opts)
  end
end