These are all the methods that we use in order to return the top x merchants by revenue. It seems ugly and it's spread out between 3 or so classes. Also, we aren't sure how to handle converting total revenue and money into a BigDecimal. We just end up with a number like 0.237864E7637 instead of a readable number. Any thoughts on how we can impro…

Merchant.most_revenue(x).rb

#First method starts in the Merchant class

def self.most_revenue(rank)
    if rank == 0
      rank = 1
    end
    Transaction.get_successful_transaction
    @merchant_revenues_array[0..(rank - 1)]
end

#Move into the Transaction class

def self.get_successful_transaction
    successful_transactions = @@transactions.select { |transaction| transaction.result == 'success' }
    InvoiceItem.gather_invoice_items_from_successful_transactions(successful_transactions)
end

#Move into the InvoiceItem class

def self.gather_invoice_items_from_successful_transactions(successful_transactions)
    invoice_items = []
    successful_transactions.each do |transaction|
      invoice_items << InvoiceItem.find_all_by_invoice_id(transaction.invoice_id)
    end
    invoice_items.flatten!
    sum_invoice_items_for_each_invoice(invoice_items)
end

def self.sum_invoice_items_for_each_invoice(invoice_items)
    invoice_totals = Hash.new(0)
    invoice_items.each do |invoice_item|
        value = (invoice_item.quantity * invoice_item.unit_price)
        value = BigDecimal.new(value)
        value = value.truncate(2)
        key = invoice_item.invoice_id
        invoice_totals[key] += value
    end
    Merchant.sum_invoice_revenue_by_merchant_id(invoice_totals)
end

#Finally move back into the Merchant class to finish

def self.sum_invoice_revenue_by_merchant_id(invoice_totals)
    merchant_revenues = Hash.new(0)
    invoice_totals.each_pair do |k, v|
      invoice = Invoice.find_by_id(k)
      key = invoice.merchant_id
      merchant_revenues[key] += v
    end
    @merchant_revenues_array = merchant_revenues.sort_by { |k,v| v }.reverse
end