Merge pull request #346 from White-Whale-Defi-Platform/feat/enable-qu…

…ery-reverse-simulate-swap-operations

contracts/liquidity_hub/pool-manager/schema/pool-manager.json

@@ -836,6 +836,7 @@
         "additionalProperties": false
       },
       {
+        "description": "Simulates swap operations.",
         "type": "object",
         "required": [
           "simulate_swap_operations"
@@ -863,6 +864,35 @@
         },
         "additionalProperties": false
       },
+      {
+        "description": "Simulates a reverse swap operations, i.e. given the ask asset, how much of the offer asset is needed to perform the swap.",
+        "type": "object",
+        "required": [
+          "reverse_simulate_swap_operations"
+        ],
+        "properties": {
+          "reverse_simulate_swap_operations": {
+            "type": "object",
+            "required": [
+              "ask_amount",
+              "operations"
+            ],
+            "properties": {
+              "ask_amount": {
+                "$ref": "#/definitions/Uint128"
+              },
+              "operations": {
+                "type": "array",
+                "items": {
+                  "$ref": "#/definitions/SwapOperation"
+                }
+              }
+            },
+            "additionalProperties": false
+          }
+        },
+        "additionalProperties": false
+      },
       {
         "type": "object",
         "required": [
@@ -1378,6 +1408,26 @@
         }
       }
     },
+    "reverse_simulate_swap_operations": {
+      "$schema": "http://json-schema.org/draft-07/schema#",
+      "title": "ReverseSimulateSwapOperationsResponse",
+      "type": "object",
+      "required": [
+        "amount"
+      ],
+      "properties": {
+        "amount": {
+          "$ref": "#/definitions/Uint128"
+        }
+      },
+      "additionalProperties": false,
+      "definitions": {
+        "Uint128": {
+          "description": "A thin wrapper around u128 that is using strings for JSON encoding/decoding, such that the full u128 range can be used for clients that convert JSON numbers to floats, like JavaScript and jq.\n\n# Examples\n\nUse `from` to create instances of this and `u128` to get the value out:\n\n``` # use cosmwasm_std::Uint128; let a = Uint128::from(123u128); assert_eq!(a.u128(), 123);\n\nlet b = Uint128::from(42u64); assert_eq!(b.u128(), 42);\n\nlet c = Uint128::from(70u32); assert_eq!(c.u128(), 70); ```",
+          "type": "string"
+        }
+      }
+    },
     "reverse_simulation": {
       "$schema": "http://json-schema.org/draft-07/schema#",
       "title": "ReverseSimulationResponse",

contracts/liquidity_hub/pool-manager/schema/raw/query.json

@@ -139,6 +139,7 @@
       "additionalProperties": false
     },
     {
+      "description": "Simulates swap operations.",
       "type": "object",
       "required": [
         "simulate_swap_operations"
@@ -166,6 +167,35 @@
       },
       "additionalProperties": false
     },
+    {
+      "description": "Simulates a reverse swap operations, i.e. given the ask asset, how much of the offer asset is needed to perform the swap.",
+      "type": "object",
+      "required": [
+        "reverse_simulate_swap_operations"
+      ],
+      "properties": {
+        "reverse_simulate_swap_operations": {
+          "type": "object",
+          "required": [
+            "ask_amount",
+            "operations"
+          ],
+          "properties": {
+            "ask_amount": {
+              "$ref": "#/definitions/Uint128"
+            },
+            "operations": {
+              "type": "array",
+              "items": {
+                "$ref": "#/definitions/SwapOperation"
+              }
+            }
+          },
+          "additionalProperties": false
+        }
+      },
+      "additionalProperties": false
+    },
     {
       "type": "object",
       "required": [

contracts/liquidity_hub/pool-manager/schema/raw/response_to_reverse_simulate_swap_operations.json

@@ -0,0 +1,20 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "ReverseSimulateSwapOperationsResponse",
+  "type": "object",
+  "required": [
+    "amount"
+  ],
+  "properties": {
+    "amount": {
+      "$ref": "#/definitions/Uint128"
+    }
+  },
+  "additionalProperties": false,
+  "definitions": {
+    "Uint128": {
+      "description": "A thin wrapper around u128 that is using strings for JSON encoding/decoding, such that the full u128 range can be used for clients that convert JSON numbers to floats, like JavaScript and jq.\n\n# Examples\n\nUse `from` to create instances of this and `u128` to get the value out:\n\n``` # use cosmwasm_std::Uint128; let a = Uint128::from(123u128); assert_eq!(a.u128(), 123);\n\nlet b = Uint128::from(42u64); assert_eq!(b.u128(), 42);\n\nlet c = Uint128::from(70u32); assert_eq!(c.u128(), 70); ```",
+      "type": "string"
+    }
+  }
+}

contracts/liquidity_hub/pool-manager/src/contract.rs

@@ -1,5 +1,5 @@
 use crate::error::ContractError;
-use crate::helpers::simulate_swap_operations;
+use crate::helpers::{reverse_simulate_swap_operations, simulate_swap_operations};
 use crate::queries::{get_swap_route, get_swap_route_creator, get_swap_routes};
 use crate::router::commands::{add_swap_routes, remove_swap_routes};
 use crate::state::{Config, MANAGER_CONFIG, PAIRS, PAIR_COUNTER};
@@ -228,12 +228,12 @@ pub fn query(deps: Deps, env: Env, msg: QueryMsg) -> Result<Binary, ContractErro
             offer_amount,
             operations,
         )?)?),
-        // QueryMsg::ReverseSimulateSwapOperations {
-        //     ask_amount,
-        //     operations,
-        // } => Ok(to_binary(&queries::reverse_simulate_swap_operations(
-        //     deps, env, ask_amount, operations,
-        // )?)?),
+        QueryMsg::ReverseSimulateSwapOperations {
+            ask_amount,
+            operations,
+        } => Ok(to_json_binary(&reverse_simulate_swap_operations(
+            deps, ask_amount, operations,
+        )?)?),
         QueryMsg::SwapRoute {
             offer_asset_denom,
             ask_asset_denom,

contracts/liquidity_hub/pool-manager/src/helpers.rs

@@ -620,11 +620,39 @@ pub fn simulate_swap_operations(
                 token_out_denom: _,
                 pool_identifier,
             } => {
-                let res = query_simulation(
-                    deps,
-                    coin(offer_amount.u128(), token_in_denom),
-                    pool_identifier,
-                )?;
+                let res =
+                    query_simulation(deps, coin(amount.u128(), token_in_denom), pool_identifier)?;
+                amount = res.return_amount;
+            }
+        }
+    }
+
+    Ok(SimulateSwapOperationsResponse { amount })
+}
+
+/// This function iterates over the swap operations in the reverse order,
+/// simulates each swap to get the final amount after all the swaps.
+pub fn reverse_simulate_swap_operations(
+    deps: Deps,
+    ask_amount: Uint128,
+    operations: Vec<SwapOperation>,
+) -> Result<SimulateSwapOperationsResponse, ContractError> {
+    let operations_len = operations.len();
+    if operations_len == 0 {
+        return Err(ContractError::NoSwapOperationsProvided {});
+    }
+
+    let mut amount = ask_amount;
+
+    for operation in operations.into_iter().rev() {
+        match operation {
+            SwapOperation::WhaleSwap {
+                token_in_denom: _,
+                token_out_denom,
+                pool_identifier,
+            } => {
+                let res =
+                    query_simulation(deps, coin(amount.u128(), token_out_denom), pool_identifier)?;
                 amount = res.return_amount;
             }
         }