Update wlth-tranche-init.rain

- added spread 
- integrated new io-ratio-base

strategies/wlth-tranche-init.rain

@@ -408,12 +408,12 @@ deployments:
 #tranche-space-recharge-delay !The duration in seconds that no recharging occurs after a trade occurs.
 
 #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-base !Base tranche size is the size of the smallest tranche, denominated in output token. 
 #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.
-#io-ratio-base !The base IO ratio, as a decimal 18 fixed point number. This is the IO ratio at tranche space 0 and grows according to the growth factor per tranche.
+/* #io-ratio-base !The base IO ratio, as a decimal 18 fixed point number. This is the IO ratio at tranche space 0 and grows according to the growth factor per tranche. */
+#io-ratio-spread !The size of the spread in percentage terms which is the distance of the first tranche away from the midpoint.
 #io-ratio-growth !The exponential growth factor of the IO ratio. E.g. 0.01 is 1% io-ratio growth per tranche.
 
 #reference-token !Strategy token for which the budget is written.
@@ -551,15 +551,25 @@ deployments:
   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 */
-
+  /* ADD : if initized hasnt change then use the initialised price*/
+  /* the below should be in dollar terms */
   current-cost-basis: div(add(mul(sale-cost-basis cumulative-sale-volumeb) mul(buy-cost-basis cumulative-buy-volumeb)) total-volume);
 
+#apply-spread
+  amount-is-output :,
+  io-ratio-spread :,
+  cost-basis : call<'calculate-midpoint>(),
+  spread-basis : if(amount-is-output
+    mul(inv(cost-basis) sub(1 io-ratio-spread))
+    mul(cost-basis sub(1 io-ratio-spread)));  /*have to invert the cost basis as its in dollar terms for the buy side*/
+
+
 #calculate-io
   using-words-from uniswap-words orderbook-subparser
   tranche-space-now
   tranche-space-available
   tranche-total-size: call<'calculate-tranche>(),
+  io-ratio-base: call<'apply-spread>(amount-is-output io-ratio-spread),
   tranche-io-ratio: call<'io-ratio-expr>(io-ratio-base io-ratio-growth floor(tranche-space-now)),
   final-io-ratio: mul(tranche-io-ratio call<'io-ratio-multiplier>()),
   amount-available: mul(tranche-total-size tranche-space-available),
@@ -585,7 +595,8 @@ deployments:
     greater-than-or-equal-to(tranche-space-after-snapped add(tranche-space-before min-tranche-space-diff))
     "Minimum trade size not met."
   ),
-  :call<'set-last-tranche>(tranche-space-after-snapped current-time);
+  :call<'set-last-tranche>(tranche-space-after-snapped current-time),
+  :call<'post-update-cost-basis>(amount-is-output);
 
 #post-action-buy
   _: uniswap-v3-twap-output-ratio(
@@ -606,13 +617,15 @@ deployments:
 
 #post-action-tranche-linear
   current-ratio: ,
+  io-ratio-base: ,
   init-tranche: div(
     saturating-sub(current-ratio io-ratio-base)
     io-ratio-growth
   );
 
 #post-action-tranche-exponential
   current-ratio: ,
+  io-ratio-base: ,
   init-tranche: div(
     saturating-sub(ln(current-ratio) ln(io-ratio-base))
     ln(add(1 io-ratio-growth))
@@ -637,15 +650,16 @@ sudo code of what i want to achieve below, deonminated in USDC
         cumulative_buy_volume += volume
         cumulative_buy_cost += volume * price
 */
+  amount-is-output:,
   :set(hash(order-hash() cumulative-buy-volume)
     if(amount-is-output
-      add(get(hash(order-hash()cumulative-buy-volume)) output-vault-increase()) 
+      add(get(hash(order-hash()cumulative-buy-volume)) output-vault-decrease()) 
       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))),
+      add(get(hash(order-hash() cumulative-buy-volume)) mul(output-vault-decrease() inv(calculated-io-ratio()))) 
+      get(hash(order-hash() cumulative-buy-cost)))),
 
   :set(hash(order-hash()cumulative-sale-volume)
     if(is-zero(amount-is-output) 
@@ -654,5 +668,5 @@ sudo code of what i want to achieve below, deonminated in USDC
 
   :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())) 
+      add(get(hash(order-hash() cumulative-sale-volume)) mul(input-vault-increase() calculated-io-ratio())) 
       get(hash(order-hash() cumulative-sale-cost))));