# Dexter Protocol :: Weighted Pool Dexter's Weighted Pool is based on a particular N-dimensional surface which defines a cost function for the exchange of any pair of tokens held in a Pool which was introduced by Balancer. Dexter's weighted pool accepts maximum 9 tokens and the weights cannot be updated once the pool has been initialized. Unlike pools in other DeFi protocols that only provide 50/50 weightings, Dexter's Weighted Pools enable users to build pools with different token counts and weightings, such as pools with 80/20 or 60/20/20 weightings. Note - Dexter's weighted pool accepts an `exit_fee` parameter during pool initialization. The `exit_fee` is the % fee charged to the user when liquidity is withdrawn from the pool. 100% of the exit fee charged is distributed among the LPs of the Pool. `exit_fee` cannot be more than 1%. ## Contract State | Message | Description | | ------------ | -------------------------------------------------------------------------------- | | `CONFIG` | Stores pool contract's core Configuration parameters in a [`Config`] struct | | `TWAPINFO` | Stores Twap prices for the tokens supported by the pool in a [`Twap`] struct | | `MATHCONFIG` | Stores `exit_fee` and `greatest_precision` configuration parameters for the pool | | `PRECISIONS` | Stores decimal precision for each asset supported by the pool | | `WEIGHTS` | Stores normalized weight for each asset supported by the pool | --- - **Separating Token Accounting and Pool Logic** The Dexter Pools are responsible only for the math computes which dictate number of tokens to be transferred during swaps / liquidity provisioning events, and do not handle the token transfers themselves. Dexter's Vault queries the Pool contracts to compute how many tokens to transfer and processes those transfers itself. This separation simplifies pool contracts, since they no longer need to actively manage their assets; pools only need to calculate amounts for swaps, joins, and exits. Anyone who comes up with a novel idea for a trading system can make a custom pool and have it added to Dexter's PoolType Registery via approval from the Dexter DAO instead of needing to build their own Decentralized Exchange. ## Supported Execute Messages | Message | Description | | ----------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- | | `ExecuteMsg::UpdateConfig` | Executable only by Dexter Vault's owner. Not supported by the Weighted pool | | `ExecuteMsg::UpdateLiquidity` | Executable only by Dexter Vault. Updates locally stored asset balances state in `config.assets` for the pool and updates the TWAP. | ## Supported Query Messages | Message | Description | | -------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `QueryMsg::Config()` | Returns the stored Vault Configuration settings in custom [`ConfigResponse`] struct, including `exit_fee` and normalized token weights | | `QueryMsg::FeeParams()` | Returns the provided [`PoolType`]'s Configuration settings in custom [`FeeResponse`] struct | | `QueryMsg::PoolId()` | Returns Pool ID which is of type [`Uint128`] | | `QueryMsg::OnJoinPool( assets_in, mint_amount , slippage_tolerance )` | Returns [`AfterJoinResponse`] type which contains - `return_assets` info, number of LP shares to be minted, the `response` of type [`ResponseType`] and `fee` of type [`Option`] which is the fee to be charged. | | `QueryMsg::OnExitPool( assets_out, burn_amount )` | Returns [`AfterExitResponse`] type which contains - `assets_out` info, number of LP shares to be burnt, the `response` of type [`ResponseType`] and `fee` of type [`Option`] which is the fee to be charged. | | `QueryMsg::OnSwap( swap_type, offer_asset, ask_asset, amount, max_spread, belief_price )` | Returns [`SwapResponse`] type which contains - `trade_params` info, the `response` of type [`ResponseType`] and `fee` of type [`Option`] which is the fee to be charged. | | `QueryMsg::CumulativePrice( swap_type, offer_asset, ask_asset, amount, max_spread, belief_price )` | Returns information about the cumulative price of the asset in a [`CumulativePriceResponse`] object. | | `QueryMsg::CumulativePrices( )` | Returns information about the cumulative prices in a [`CumulativePricesResponse`] object. | ## Enums & Structs ### `MathConfig` struct - This struct describes the main math configuration of the weighted-pool. ``` struct MathConfig { pub exit_fee: Option, /// The greatest precision of assets in the pool pub greatest_precision: u8, } ``` ### `WeightedAsset` struct - This struct describes a asset (native or CW20) and its normalized weight ``` struct WeightedAsset { /// Information about an asset stored in a [`Asset`] struct pub asset: Asset, /// The weight of the asset pub weight: Decimal, } ``` ### `ResponseType` enum - This enum is used to describe if the math computations (joins/exits/swaps) will be successful or not ``` enum ResponseType { Success {}, Failure (String), } ``` ### `Config` struct - This struct describes the main control config of pool. ``` struct Config { /// ID of contract which is allowed to create pools of this type pub pool_id: Uint128, /// The address of the LP token associated with this pool pub lp_token_addr: Option, /// the vault contract address pub vault_addr: Addr, /// Assets supported by the pool pub assets: Vec, /// The pools type (provided in a [`PoolType`]) pub pool_type: PoolType, /// The Fee details of the pool pub fee_info: FeeStructs, /// The block time when pool liquidity was last updated pub block_time_last: u64, } ``` ### `Trade` struct - This helper struct is used for swap operations ``` struct Trade { /// The number of tokens to be sent by the user to the Vault pub amount_in: Uint128, /// The number of tokens to be received by the user from the Vault pub amount_out: Uint128, /// The spread associated with the swap tx pub spread: Uint128, } ``` ### `AfterJoinResponse` struct - Helper struct for [`QueryMsg::OnJoinPool`] ``` struct AfterJoinResponse { // Is a sorted list consisting of amount of info of tokens which will be provided by the user to the Vault as liquidity pub provided_assets: Vec, // Is the amount of LP tokens to be minted pub new_shares: Uint128, // Is the response type :: Success or Failure pub response: ResponseType, // Is the fee to be charged pub fee: Option, } ``` ### `AfterExitResponse` struct - Helper struct for [`QueryMsg::OnExitPool`] ``` struct AfterExitResponse { /// Assets which will be transferred to the recipient against tokens being burnt pub assets_out: Vec, /// Number of LP tokens to burn pub burn_shares: Uint128, /// Operation will be a `Success` or `Failure` pub response: ResponseType, /// Fee to be charged pub fee: Option, } ``` ### `SwapResponse` struct - Helper struct for [`QueryMsg::OnSwap`] ``` struct SwapResponse { /// Is of type [`Trade`] which contains all params related with the trade pub trade_params: Trade, /// Operation will be a `Success` or `Failure` pub response: ResponseType, /// Fee to be charged pub fee: Option, } ``` ### `CumulativePriceResponse` struct - Helper struct for [`QueryMsg::CumulativePrice`] ``` struct CumulativePriceResponse { pub exchange_info: AssetExchangeRate, pub total_share: Uint128, } ``` ### `CumulativePricesResponse` struct - Helper struct for [`QueryMsg::CumulativePrices`] ``` struct CumulativePricesResponse { pub exchange_info: Vec, pub total_share: Uint128, } ``` ## Build schema and run unit-tests ``` cargo schema cargo test ``` ## License TBD