# frozen_string_literal: true

# module definition
module Invoices; end

# The invoice number is based on the previous invoice
class Invoices::NumberService
  class << self
    # Get the order number or reference number for the given invoice (not the whole identifier).
    # The date part, online payment part, etc. will be excluded and only the number part will be returned.
    # @param document [PaymentDocument,NilClass]
    # @param setting [String] 'invoice_reference' | 'invoice_order-nb'
    # @return [Integer,NilClass]
    def number(document, setting = 'invoice_reference')
      raise TypeError, "invalid setting #{setting}" unless %w[invoice_order-nb invoice_reference].include?(setting)
      return nil if document.nil?

      saved_number = setting == 'invoice_reference' ? document.reference : document.order_number
      return nil if saved_number.nil?

      indices = number_indices(document, setting)
      saved_number[indices[0]..indices[1]]&.to_i
    end

    # Replace the number of the reference of the given document and return the new reference
    # @param document [PaymentDocument,NilClass]
    # @param setting [String] 'invoice_reference' | 'invoice_order-nb'
    # @return [String,NilClass]
    def change_number(document, new_number, setting = 'invoice_reference')
      raise TypeError, "invalid setting #{setting}" unless %w[invoice_order-nb invoice_reference].include?(setting)
      return nil if document.nil?

      saved_number = setting == 'invoice_reference' ? document.reference : document.order_number
      return nil if saved_number.nil?

      indices = number_indices(document, setting)
      saved_number[indices[0]..indices[1]] = pad_and_truncate(new_number, indices[1] - indices[0])
      saved_number
    end

    # @param document [PaymentDocument,NilClass]
    # @param setting [String] 'invoice_reference' | 'invoice_order-nb'
    # @return [String,NilClass] 'global' | 'year' | 'month' | 'day'
    def number_periodicity(document, setting = 'invoice_reference')
      raise TypeError, "invalid setting #{setting}" unless %w[invoice_order-nb invoice_reference].include?(setting)
      return nil if document.nil?

      pattern = pattern(document, setting)
      pattern = PaymentDocumentService.send(:replace_document_type_pattern, document, pattern)

      return 'global' if pattern.match?(/n+/)
      return 'year' if pattern.match?(/y+/)
      return 'month' if pattern.match?(/m+/)
      return 'day' if pattern.match?(/d+/)

      nil
    end

    # Get the pattern applicable to generate the number of the given invoice.
    # @param document [PaymentDocument]
    # @param setting [String] 'invoice_reference' | 'invoice_order-nb'
    # @return [String]
    def pattern(document, setting = 'invoice_reference')
      raise TypeError, "invalid setting #{setting}" unless %w[invoice_order-nb invoice_reference].include?(setting)

      value = Setting.find_by(name: setting).value_at(document.created_at)
      value || if document.created_at < Setting.find_by(name: setting).first_update
                 Setting.find_by(name: setting).first_value
               else
                 Setting.get(setting)
               end
    end

    private

    # Output the given integer with leading zeros. If the given value is longer than the given
    # length, it will be truncated.
    # @param value [Integer] the integer to pad
    # @param length [Integer] the length of the resulting string.
    def pad_and_truncate(value, length)
      value.to_s.rjust(length, '0').gsub(/^.*(.{#{length},}?)$/m, '\1')
    end

    # Return the indices of the number in the document's reference
    # @param document [PaymentDocument,NilClass]
    # @param setting [String] 'invoice_reference' | 'invoice_order-nb'
    # @return [Array<Integer>]
    def number_indices(document, setting = 'invoice_reference')
      raise TypeError, "invalid setting #{setting}" unless %w[invoice_order-nb invoice_reference].include?(setting)
      return nil if document.nil?

      pattern = pattern(document, setting)
      pattern = PaymentDocumentService.send(:replace_document_type_pattern, document, pattern)
      start_idx = pattern.index(/n+|y+|m+|d+/)
      end_idx = pattern.rindex(/n+|y+|m+|d+/)
      [start_idx, end_idx]
    end
  end
end