Is this an efficient way of producing sales reporting / analytics? - ruby-on-rails

Question

I have an app where I receive & ingest daily sales reports from multiple sources. All are structured differently so I store down into my Postgres db in separate tables.
I'm currently doing something like this to iterate over the last 30 days sales for one report source and it seems to work quite nicely. My concern is how efficient & scaleable this will be when I add additional report sources as the way I currently have it structured means I'd have to add and repeat large amounts of the code for each new source.
<% from = Date.today - 30 %> #30 days ago
<% to = Date.today %> #Today
<% step_date = from %>
<% source_one_chart_data = [] %> #Initialise empty array to later pass to JS Chart library
<% begin %>
<% count = #product.sales_source_one.total.where(:report_date => step_date).count %> #check if there are any sales for this product on the current step date
<% if count != 0 %>
<% sale = #product.sum_total_net_by_day(step_date) %>
<% source_one_chart_data.push(sale.to_s) %> #Push sales total to array if sales exist on that date
<% else %>
<% source_one_chart_data.push("0") %> #Otherwise push a zero into array so all 30 days map to a value
<% end %>
<% step_date += 1.day %> #Increase step_date by 1 on each iteration of the loop
<% end while step_date <= to %> #Stop loop when we reach to date
Can anyone offer any guidance on how efficiently bring in additional sales sources without having to repeat code? Also, it would be good if I could change the step from day to week/month/year and have it calculate sales accordingly; so if the sales source is reported daily and the step is week it would sum all values that occur in the step week.

Answer 1

Why do you have all of that code in your view? You should move most of it to your model / controller.
def process_chart_data
from = 1.month.ago.to_date
to = Date.today
step_date = from
chart_data = []
while step_date <= to
sales_total = sales_source_one.total.where(report_date: step_date).count
if sales_total.zero?
chart_data.push(0)
else
sale = sum_total_net_by_day(step_date)
chart_data.push(sale.to_s)
end
step_date += 1
end
return chart_data
end
The above could probably be refactored further, but now if you place it in your Product model then in your controller you can just do:
#product = Product.find(params[:id]) # or whatever
#chart_data = #product.process_chart_data
Then in your view you can use #chart_data.
Moving that code into a method also allows you to update it quicker, lets say I want the user to control how far back records are retrieved:
def process_chart_data(start_date)
from = start_date
...
end
In the controller:
#product = Product.find(params[:id])
#chart_data = #product.process_chart_data(params[:start_date])