up wall of shame fee to 5% + 5%

also charge on slipping past $-5

chezbetty/datalayer.py

@@ -168,11 +168,61 @@ def purchase(user, account, items):
     assert(len(items) > 0)
 
     # TODO: Parameterize
-    discount = None
+    discount = Decimal(0)
     if user.balance > 20.0:
         discount = Decimal('0.05')
-    elif user.balance <= -5.0:
-        discount = round(Decimal('-0.01')*(5 + math.floor((user.balance+5) / -5)), 2)
+
+    # Need to calculate a total
+    amount = Decimal(0)
+    for item, quantity in items.items():
+        amount += Decimal(item.price * quantity)
+
+    intermediate = amount - (amount * discount).quantize(Decimal('.01'), rounding=ROUND_HALF_UP)
+
+    # Calculate a potential wall of shame fee
+    fee = None
+    fee_amount = Decimal(0)
+    result = user.balance - intermediate
+    fee_percent = Decimal(0)
+    if result <= Decimal('-5'):
+        remainder = (user.balance - intermediate) * Decimal('-1')
+        offset = user.balance * Decimal('-1')
+        if user.balance > Decimal('-5'):
+            offset = Decimal('5')
+        fee_percent = math.floor(offset / Decimal('5')) * Decimal('5')
+
+        while True:
+            extra = remainder - offset
+
+            if remainder < fee_percent + Decimal('5'):
+                fee_amount += ((fee_percent * Decimal('0.01')) * extra)
+                break
+
+            else:
+                fee_amount += ((fee_percent * Decimal('0.01')) * (fee_percent + Decimal('5') - offset))
+                fee_percent += Decimal('5')
+                offset = fee_percent
+
+        fee_percent = (fee_amount / intermediate) * Decimal('100')
+        if fee_percent < Decimal('0.1'):
+            fee_percent = Decimal('0.1')
+
+        fee_amount = (intermediate * (fee_percent * Decimal('0.01'))).quantize(Decimal('.01'), rounding=ROUND_HALF_UP)
+
+
+    if fee_amount != 0:
+        if discount != 0:
+            # Only do this complicated math if we have to merge a good
+            # standing discount with a wall of shame fee
+            final = intermediate + fee_amount
+            discount = (-1 * ((final / amount) - Decimal('1')))
+        else:
+            # Just use wall of shame fee
+            discount = fee_percent * Decimal('0.01')
+
+    if discount == 0:
+        # Make sure we handle the no discount normal case correctly
+        discount = None
 
     e = event.Purchase(user)
     DBSession.add(e)

chezbetty/models/model.py

@@ -1,6 +1,7 @@
 import datetime
 import functools
 from decimal import Decimal
+from decimal import ROUND_HALF_UP
 import decimal
 from sqlalchemy import (
     LargeBinary,

chezbetty/static/js/chezbetty-terminal.js

@@ -105,7 +105,7 @@ function calculate_total () {
 		var discount_percent_td = $("#purchase-discount-percent");
 		var discount_percent_str = discount_percent_td.text().slice(1,-2);
 		var discount_percent = parseFloat(discount_percent_str) * 0.01;
-		var discount = total * discount_percent;
+		var discount = Math.round((total * discount_percent) * 100) / 100;
 
 		// Make sure nothing looks strange
 		if (discount > total) discount = 0.0;
@@ -118,10 +118,10 @@ function calculate_total () {
 		$("#purchase-row-goodstanding").hide();
 	}
 
-	if (balance <= -5.0) {
+	if ((balance - total - discount) <= -5.0) {
 		// Wall of shame fee!
-		var fee_percent = calculate_wallofshame_fee_percent();
-		var fee = total * (fee_percent * 0.01);
+		var fee_percent = calculate_wallofshame_fee_percent(balance, total-discount);
+		var fee = Math.round(((total-discount) * (fee_percent * 0.01)) * 100) / 100;
 
 		// Setup fee row
 		$("#purchase-fee-percent-amount").html(fee_percent.toFixed(1));
@@ -267,14 +267,43 @@ function show_correct_purchase_button () {
 	}
 }
 
-function calculate_wallofshame_fee_percent () {
-	var balance = get_user_balance();
+function calculate_wallofshame_fee_percent (balance, total) {
+	// If not on wall of shame, nor going to be, no fee
+	if (balance - total > -5.0) return 0.0;
+
+	// Calculate the correct fee.
+	// Need to get the amount we will charge the fee on
+	var remainder = (balance - total) * -1;
+	var offset = balance * -1;
+	if (balance > -5) {
+		offset = 5;
+	}
+	var fee_percent = Math.floor(offset / 5.0) * 5;
+	var fee = 0;
 
-	// If not on wall of shame, no fee
-	if (balance > -5.0) return 0.0;
+	// This works only because we increase the fee every $5 dollars
+	// and we increase the fee in 5% increments.
+	while (true) {
+		var extra = remainder - offset;
+
+		if (remainder < fee_percent + 5) {
+			fee += ((fee_percent * 0.01) * extra);
+			break;
+
+		} else {
+			fee += ((fee_percent * 0.01) * (fee_percent + 5 - offset));
+			fee_percent += 5;
+			offset = fee_percent;
+		}
+	}
+
+	fee_percent = (fee / total) * 100;
+
+	if (fee_percent < 0.1) {
+		fee_percent = 0.1;
+	}
 
-	// Else, one percent for every $5 in debt after $-5, 5.0% to start
-	return 5.0 + Math.floor((balance+5.0) / -5.0);
+	return fee_percent;
 }
 
 /*******************************************************************************

chezbetty/templates/public/about.jinja2

@@ -97,7 +97,7 @@
 	{{
 	_("For people on the Wall of Shame (anyone with less than $5 in their account), Betty charges a progressive tax on all purchases.")
 	+ ' ' +
-	_("The tax begins at 5% and increases an additional 1% for every additional $5 you are in debt ($10-15 debt is 6%, $15-20 is 7%, and so on).")
+	_("The tax begins at 5% and increases an additional 5% for every additional $5 you are in debt ($10-15 debt is 10%, $15-20 is 15%, and so on).")
 	+ ' ' +
 	_("If you are on the Wall of Shame, the Betty terminal will very clearly show the tax being applied as you check out.")
 	}}

chezbetty/views_terminal.py

@@ -100,7 +100,7 @@ def terminal(request):
         # Determine initial wall-of-shame fee (if applicable)
         purchase_fee_percent = Decimal(0)
         if user.balance <= Decimal('-5.0'):
-            purchase_fee_percent = 5 + math.floor((user.balance+5) / -5)
+            purchase_fee_percent = 5 + (math.floor((user.balance+5) / -5) * 5)
 
         # Figure out if any pools can be used to pay for this purchase
         purchase_pools = []