example

example.rb

class FinalResult
  def results(filename)
    @filename = filename
    prepare
    output
  end

  def prepare
    CSV.foreach(file) do |row|
      records << row_record(row) if row.length == 16
    end

    records.compact
  end
  
  def row_record(row)
    {
      amount: {
        currency: headers[0],
        subunits: (amount(row) * 100).to_i
      },
      bank_account_name: account_name(row),
      bank_account_number: account_number(row),
      bank_branch_code: branch_code(row),
      bank_code: bank_code(row),
      end_to_end_id: e2e(row)
    }
  end
  
  def bank_code(row)
    row[0]
  end

  def file
    @file ||= File.open(filename, 'r')
  end
  
  def headers
    @headers ||= CSV.parse_line(file) 
  end

  def output
    {
      filename: File.basename(filename),
      document: file,
      failure_code: headers[1],
      failure_message: headers[2],
      records: records
    }
  end

  def records
    @records ||= []
  end

  def amount(row)
    row[8].nil? || row[8] == '0' ? 0 : row[8].to_f
  end

  def account_number(row)
    row[6]&.to_i || 'Bank account number missing'
  end

  def branch_code(row)
    row[2] || 'Bank branch code missing'
  end

  def e2e(row)
    row[10].nil? && row[11].nil? ? 'End to end id missing' : r[10] + r[11]
  end

  def account_name(row)
    row[7].downcase.gsub(' ', '_')
  end
end