chore: update custom strategy guide

contracts/strategies/README.md

@@ -8,48 +8,91 @@ Portfolio will rely on specific functions that the custom strategy contracts mus
 
 ## Strategy functions
 
-### Swap Lifecycle
+Here is a summary of the workflow between a user, the `Portfolio` contract and a custom strategy contract:
 
 ```
- ┌────┐┌─────────┐     ┌────────┐
- │User││Portfolio│     │Strategy│
- └─┬──┘└────┬────┘     └───┬────┘
-   │        │              │
-   │ swap() │              │
-   │───────>│              │
-   │        │              │
-   │        │validatePool()│
-   │        │─────────────>│
-   │        │              │
-   │        │ beforeSwap() │
-   │        │─────────────>│
-   │        │              │
-   │        │validateSwap()│
-   │        │─────────────>│
- ┌─┴──┐┌────┴────┐     ┌───┴────┐
- │User││Portfolio│     │Strategy│
- └────┘└─────────┘     └────────┘
+ ┌────┐          ┌────────┐    ┌─────────┐
+ │User│          │Strategy│    │Portfolio│
+ └─┬──┘          └───┬────┘    └────┬────┘
+   │                 │              │
+   │getStrategyData()│              │
+   │────────────────>│              │
+   │                 │              │
+   │          createPool()          │
+   │───────────────────────────────>│
+   │                 │              │
+   │                 │validatePool()│
+   │                 │<─────────────│
+   │                 │              │
+   │          updatePool()          │
+   │───────────────────────────────>│
+   │                 │              │
+   │             swap()             │
+   │───────────────────────────────>│
+   │                 │              │
+   │                 │ beforeSwap() │
+   │                 │<─────────────│
+   │                 │              │
+   │                 │validateSwap()│
+   │                 │<─────────────│
+ ┌─┴──┐          ┌───┴────┐    ┌────┴────┐
+ │User│          │Strategy│    │Portfolio│
+ └────┘          └────────┘    └─────────┘
+
  ```
 
+### `getStrategyData()`
+
+```solidity
+function getStrategyData(
+    bytes memory data
+) external pure returns (
+    bytes memory strategyData,
+    uint256 initialX,
+    uint256 initialY
+);
+```
+
+This function is meant to be called by users willing to create a new pool using a custom strategy. This is the only function called directly by the users (instead of `Portfolio` contract itself). It returns the data that should be passed to the `createPool` function of the Portfolio contract.
+
 ### `afterCreate()`
 
 ```solidity
-    function afterCreate(
-        uint64 poolId,
-        bytes calldata strategyArgs
-    ) external returns (bool success);
+function afterCreate(
+    uint64 poolId,
+    bytes calldata strategyArgs
+) external returns (bool success);
 ```
 
-This function is called after the creation of a pool and allows the strategy to perform any initialization logic. The `strategyArgs` parameter is the same as the one passed to the `createPool` function of the Portfolio contract.
+This function is called by `Portfolio` after the creation of a pool in the `Portfolio` contract and allows the strategy to perform any initialization logic. The `strategyArgs` parameter is the same as the one passed to the `createPool` function of the Portfolio contract.
 
 ### `beforeSwap()`
 
 ```solidity
-    function beforeSwap(
-        uint64 poolId,
-        bool sellAsset,
-        address swapper
-    ) external returns (bool success, int256 invariant);
+function beforeSwap(
+    uint64 poolId,
+    bool sellAsset,
+    address swapper
+) external returns (bool success, int256 invariant);
 ```
 
 This function is called before a swap is executed and must return a boolean indicating whether the swap should be allowed or not, along with the current invariant.
+
+### `validateSwap()`
+
+```solidity
+```
+
+This function is called after a swap is executed and allows the strategy to perform any validation logic.
+
+### `updatePool()`
+
+```solidity
+function updatePool(
+    uint64 poolId,
+    address caller,
+    bytes memory data
+) external;
+```
+
+The `updatePool` function provides an flexible way to update pool parameters. It is meant to be called via the `Portfolio` contract and requires a `poolId` along with some data encoded as `bytes`. Keep in mind that the `Portfolio` contract does not perform any validation on the data but simply pass them along.