From 39700082e1a4937747ede2e18e73f82553e9cf05 Mon Sep 17 00:00:00 2001
From: Velichko Karakostov <vivo@specto.org>
Date: Tue, 31 Aug 2021 14:36:24 +0300
Subject: [PATCH] Use aggregation for all_balance

---
 reValuate/home/views.py | 46 +++++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 22 deletions(-)

diff --git a/reValuate/home/views.py b/reValuate/home/views.py
index 41556408..a885d830 100644
--- a/reValuate/home/views.py
+++ b/reValuate/home/views.py
@@ -5,18 +5,20 @@ from django.conf import settings
 from users.models import User
 import operator
 from upload.models import Media
+from django.db.models import Sum
+
 
 def homePage(request):
     iter_var = 0
-    all_balance = []
+    all_balance = 0
     Cashier = False
     Processor = False
 
-    
+
     balObject = Balance.objects.filter(user=request.user.id)
     userBalance = balObject.values("balanceValue")
     try:
-        userBalance = userBalance[0]['balanceValue'] 
+        userBalance = userBalance[0]['balanceValue']
     except IndexError:
         userBalance = None
     if request.user.groups.filter(name='Cashier').exists():
@@ -29,24 +31,24 @@ def homePage(request):
         userQR = f"Name = {request.user.username}, Date Joined = {request.user.date_joined.date()}, ID = {request.user.id}, isCashier={Cashier}, isProcessor={Processor}, Balance = {userBalance}"
     else:
         userQR=None
-    a = Balance.objects.all()
 
-    for user in a:
-        all_balance.append(user.balanceValue)
-    print(f"{all_balance}")
-    limited_coins = settings.ALL_COINS - sum(all_balance)
+    # Use aggregation that can be calculated in database (fast)
+    all_balance = Balance.objects.all().aggregate(s=Sum("balanceValue"))['s']
+    # print(f"{all_balance}")
+
+    limited_coins = settings.ALL_COINS - all_balance
     context = {
         "isCashier": Cashier,
         "isProcessor": Processor,
         "userQR":userQR,
         "fullbalance": limited_coins,
-        "currencyTotal": sum(all_balance),
-        "userBalance": userBalance
+        "currencyTotal": all_balance,
+        "userBalance": userBalance,
     }
 
-            
+
     return render(request, "home.html", context)
-    
+
 
 def leaderboard(request):
     users = User.objects.all()
@@ -55,22 +57,22 @@ def leaderboard(request):
         try:
             username = i.username
             balance = i.balance.balanceValue
-            # add media counter and other stuff 
+            # add media counter and other stuff
             if f"{username}" in leaderboard.keys():
                 leaderboard[username] = balance + leaderboard[username]
             else:
-                leaderboard[username] = balance    
+                leaderboard[username] = balance
         except Exception as e:
             pass
-        
+
     leaderboard = dict(sorted(leaderboard.items(), key=operator.itemgetter(0)))
     leaderboard = dict(reversed(list(leaderboard.items())))
 
     while len(leaderboard) > 5:
         leaderboard.pop()
-    
 
-    media = Media.objects.all() 
+
+    media = Media.objects.all()
     user_media = {}
     for i in media:
         username = i.user.username
@@ -78,7 +80,7 @@ def leaderboard(request):
             user_media[username] += 1
         else:
             user_media[username] = 1
-    
+
     user_media = dict(sorted(user_media.items(), key=operator.itemgetter(0)))
     user_media = dict(reversed(list(user_media.items())))
     print(user_media)
@@ -92,7 +94,7 @@ def leaderboard(request):
         else:
             user_data = {i:{"Images":len(iter_user_media.filter(is_video=False))}}
     print(user_data)
-    
+
     while len(user_media) > 5:
         user_media.pop()
 
@@ -103,8 +105,8 @@ def leaderboard(request):
     #     if f"{username}" in media_count.values():
     #         media_count[username] = image + media_count[username].value
     #     else:
-    #         media_count[username] = image   
-    
+    #         media_count[username] = image
+
     # print(media_count)
 
     context = {
@@ -113,4 +115,4 @@ def leaderboard(request):
     }
 
     return render(request, 'leaderboard.html', context)
- 
+