Refactor to prepare for getting monthly overview

app/helpers/ReadingsMailer.rb

@@ -25,6 +25,9 @@ class ReadingsMailer
     
     # Fetch today's usage
     usage_today = Reading.diff_on(date)
+    consumption_today, production_today = Reading.consumed_and_produced_for_diff(usage_today)
+
+    # Calculate costs for oxxio and easy energy
     c = Cost.new
     oxxio_cost = c.oxxio_energy_cost(date.to_s,usage_today[:total_kwh_consumed_high]-usage_today[:total_kwh_produced_high], usage_today[:total_kwh_consumed_low]-usage_today[:total_kwh_produced_low])
     easy_cost = c.easy_energy_cost_barplot(date) # side effect: generates a PNG
@@ -41,8 +44,8 @@ class ReadingsMailer
         text_part do
           body "Summary for #{date}\n
                 -------------------------------\n\n
-                Total kWH electricity consumed: #{usage_today[:total_kwh_consumed_high] + usage_today[:total_kwh_consumed_low]}\n
-                Total kWH electricity produced:  #{usage_today[:total_kwh_produced_high] + usage_today[:total_kwh_produced_low]}\n
+                Total kWH electricity consumed: #{consumption_today}\n
+                Total kWH electricity produced:  #{production_today}\n
                 Total m3 gas consumed: #{usage_today[:total_m3_gas_consumed]}\n\n
                 kWH cost (Oxxio): EUR #{ oxxio_cost }\n
                 kWH cost (EasyEnergy): EUR #{ easy_cost }\n

app/models/cost.rb

@@ -116,24 +116,57 @@ class Cost
     g.data :costs, costs
     g.write("plots/easy_tariff_%s.png" % date.strftime("%F"))
   end
-  
-  def easy_energy_cost_barplot(date)
-    hour_start = date.in_time_zone(zone).beginning_of_day
-    day_end = hour_start.advance(days: 1)
+
+  # calculate the hourly cost between start_hour and end_hour
+  def easy_energy_hourly_cost_between(start_hour, end_hour)
+    begin_hour = start_hour
     costs = []
-    while(hour_start < day_end) do
+    while(begin_hour < end_hour) do
        # get usage_kwh/return_kwh for one hour
-       hour_end = hour_start.end_of_hour
-       hour_readings = Reading.where("created_at > :begin AND created_at < :end", {:begin => hour_start, :end => hour_end})
+       begin_hour_plus1 = begin_hour.end_of_hour
+       hour_readings = Reading.where("created_at > :begin AND created_at < :end", {:begin => begin_hour, :end => begin_hour_plus1})
        hour_diff = hour_readings.last ? hour_readings.last.diff(hour_readings.first) : UNKNOWN_READING
-       usage_kwh = hour_diff[:total_kwh_consumed_high] + hour_diff[:total_kwh_consumed_low] 
-       return_kwh = hour_diff[:total_kwh_produced_high] + hour_diff[:total_kwh_produced_low]
-        
-       formatted_hour = hour_start.strftime("%F %H")
+       # helper to remove distiction between low/high tarif consumption
+       usage_kwh, return_kwh = Reading.consumed_and_produced_for_diff(hour_diff)
+
+       formatted_hour = begin_hour.strftime("%F %H")
        costs << easy_energy_cost(formatted_hour, usage_kwh, return_kwh)
        # do the next hour
-       hour_start = hour_start.advance(:hours => 1)
+       begin_hour = begin_hour.advance(:hours => 1)
     end
+    # give the result
+    costs
+  end
+
+  def easy_energy_daily_cost_between(start_day, end_day)
+    curr_day = start_day
+    costs = []
+    while (curr_day <= end_day) do
+      hour_start = curr_day.in_time_zone(zone).beginning_of_day
+      hour_end = hour_start.advance(days: 1)
+
+      costs_24hours = easy_energy_hourly_cost_between(hour_start,hour_end)
+      if costs_24hours.any?{ |e| e.nil? }
+        p "Not all Reading data between %s and %s is available!" % [I18n.localize(start_day, format: "%e %B %Y"), I18n.localize(end_day, format: "%e %B %Y")]
+      end   
+      # add the sum of 24 hours
+      costs << costs_24hours.compact.sum
+      # do the next day
+      curr_day = curr_day.advance(:days => 1)
+    end
+    # give the result
+    costs
+  end  
+
+  def easy_energy_hourly_cost_for(date)
+    hour_start = date.in_time_zone(zone).beginning_of_day
+    day_end = hour_start.advance(days: 1)
+    easy_energy_hourly_cost_between(hour_start, day_end)
+  end  
+  
+  def easy_energy_cost_barplot(date)
+    # get array with 24 hourly cost values
+    costs = easy_energy_hourly_cost_for(date)
     
     # create plot
     hours = (0..23).to_a

app/models/reading.rb

@@ -76,6 +76,14 @@ class Reading < ActiveRecord::Base
       @@max_charge_kwh
     end
     
+    # do not make distinction between high and low consumption/production
+    def consumed_and_produced_for_diff(d)
+
+      usage_kwh = (d[:total_kwh_consumed_high].nil? || d[:total_kwh_consumed_low].nil?) ? nil :  d[:total_kwh_consumed_high] + d[:total_kwh_consumed_low] 
+      return_kwh = (d[:total_kwh_produced_high].nil? || d[:total_kwh_produced_low].nil?) ? nil : d[:total_kwh_produced_high] + d[:total_kwh_produced_low]
+
+      return usage_kwh, return_kwh
+    end
     
     def diff_on(date)
       readings_on = day(date)
@@ -87,5 +95,16 @@ class Reading < ActiveRecord::Base
         { :total_kwh_consumed_high => 0, :total_kwh_consumed_low => 0, :total_kwh_produced_high => 0, :total_kwh_produced_low => 0, :total_m3_gas_consumed => 0 }
       end
     end
+
+    def diff_between(from_date, to_date)
+      readings_on_days = days(from_date, to_date)
+      first = readings_on_days.first
+      last = readings_on_days.last
+      if last
+        last.diff(first)
+      else
+        { :total_kwh_consumed_high => 0, :total_kwh_consumed_low => 0, :total_kwh_produced_high => 0, :total_kwh_produced_low => 0, :total_m3_gas_consumed => 0 }
+      end
+    end
   end
 end