Update wlth-tranche-init.rain

- added spread binding and put downstairs
- added the refernces for memory 
- added cost basis function 
- add sets for post trade (needs to be called)

Needs the spread and cost basis applied to be the new moving base. Needs the sets called.

strategies/wlth-tranche-init.rain

@@ -162,6 +162,7 @@ scenarios:
                 amount-is-output: 1
                 io-ratio-expr: '''linear-growth'
                 io-ratio-base: 15
+                io-ratio-spread: 0.025 #this is in %
                 io-ratio-growth: 0.5
                 tranche-size-expr: '''linear-growth'
                 tranche-size-base: 5
@@ -215,6 +216,7 @@ scenarios:
                 amount-is-output: 0
                 io-ratio-expr: '''linear-growth'
                 io-ratio-base: 0.040
+                io-ratio-spread: 0.025 #this is in %
                 io-ratio-growth: 0.001
                 tranche-size-expr: '''linear-growth'
                 tranche-size-base: 5
@@ -407,6 +409,7 @@ deployments:
 
 #tranche-size-expr !The binding to get the tranche size for the current tranche space.
 #tranche-size-base !Base tranche size is the size of the smallest tranche, denominated in output token.
+#io-ratio-spread !The distance the tranche starts from away from the cost basis.
 #tranche-size-growth !The exponential growth factor of the size of each tranche. E.g. 0.01 is 1% output amount growth per tranche.
 
 #io-ratio-expr !The binding to get the IO ratio for the current tranche space.
@@ -439,6 +442,10 @@ deployments:
 #init-key "init"
 #tranche-space-key "tranche-space"
 #update-time-key "update-time"
+#cumulative-sale-volume "cumulative-sale-volume"
+#cumulative-sale-cost "cumulative-sale-cost"
+#cumulative-buy-volume "cumulative-buy-volume"
+#cumulative-buy-cost "cumulative-buy-cost"
 
 #plottables !The binding for additional things we want to plot during testing.
 
@@ -533,6 +540,21 @@ deployments:
 #io-ratio-multiplier-identity
   multiplier: 1;
 
+#calculate-midpoint
+  cumulative-sale-volumeb: get(hash(order-hash() cumulative-sale-volume)),
+  cumulative-sale-costb: get(hash(order-hash() cumulative-sale-cost)),
+  cumulative-buy-volumeb: get(hash(order-hash() cumulative-buy-volume)),
+  cumulative-buy-costb: get(hash(order-hash() cumulative-buy-cost)),
+
+  total-volume: add(cumulative-sale-volumeb cumulative-buy-volumeb),
+
+  sale-cost-basis: div(cumulative-sale-costb cumulative-sale-volumeb),
+  buy-cost-basis: div(cumulative-buy-costb cumulative-buy-volumeb),
+
+  /* ADD : if initized hasnt change then intiilised */
+
+  current-cost-basis: div(add(mul(sale-cost-basis cumulative-sale-volumeb) mul(buy-cost-basis cumulative-buy-volumeb)) total-volume);
+
 #calculate-io
   using-words-from uniswap-words orderbook-subparser
   tranche-space-now
@@ -602,4 +624,35 @@ deployments:
   init-tranche: call<'post-action-tranche>(current-ratio),
   :set(hash(order-hash() init-key) 1),
   :set(hash(order-hash() tranche-space-key) init-tranche),
-  :set(hash(order-hash() update-time-key) now());
+  :set(hash(order-hash() update-time-key) now());
+
+#post-update-cost-basis
+/* will this just run or do i need to call it in handle io?
+
+sudo code of what i want to achieve below, deonminated in USDC
+    if side == 'sell':
+        cumulative_sale_volume += volume
+        cumulative_sale_cost += volume * price
+    elif side == 'buy':
+        cumulative_buy_volume += volume
+        cumulative_buy_cost += volume * price
+*/
+  :set(hash(order-hash() cumulative-buy-volume)
+    if(amount-is-output
+      add(get(hash(order-hash()cumulative-buy-volume)) output-vault-increase()) 
+      get(hash(order-hash()cumulative-buy-volume)))),
+
+  :set(hash(order-hash() cumulative-buy-cost)
+    if(is-zero(amount-is-output) 
+      add(get(hash(order-hash() cumulative-buy-cost)) mul(output-vault-increase() inv(calculated-io-ratio()))) 
+      get(hash(order-hash() cumulative-buy-cost))),
+
+  :set(hash(order-hash()cumulative-sale-volume)
+    if(is-zero(amount-is-output) 
+      add(get(hash(order-hash()cumulative-sale-volume)) input-vault-increase()) 
+      get(hash(order-hash() cumulative-sale-volume)))),
+
+  :set(hash(order-hash()cumulative-sale-cost)
+    if(is-zero(amount-is-output) 
+      add(get(hash(order-hash() cumulative-sale-cost)) mul(input-vault-increase() calculated-io-ratio())) 
+      get(hash(order-hash() cumulative-sale-cost))));