# MetaSwapDeposit

This contract flattens the LP token in a MetaSwap pool for easier user access. MetaSwap must be deployed before this contract can be initialized successfully.

For example, suppose there exists a base Swap pool consisting of \[DAI, USDC, USDT]. Then a MetaSwap pool can be created with \[sUSD, BaseSwapLPToken] to allow trades between either the LP token or the underlying tokens and sUSD.

MetaSwapDeposit flattens the LP token and remaps them to a single array, allowing users to ignore the dependency on BaseSwapLPToken. Using the above example, MetaSwapDeposit can act as a Swap containing \[sUSD, DAI, USDC, USDT] tokens.

## Functions:

* [`initialize(contract ISwap _baseSwap, contract IMetaSwap _metaSwap, contract IERC20 _metaLPToken)`](#MetaSwapDeposit-initialize-contract-ISwap-contract-IMetaSwap-contract-IERC20-)
* [`swap(uint8 tokenIndexFrom, uint8 tokenIndexTo, uint256 dx, uint256 minDy, uint256 deadline)`](#MetaSwapDeposit-swap-uint8-uint8-uint256-uint256-uint256-)
* [`addLiquidity(uint256[] amounts, uint256 minToMint, uint256 deadline)`](#MetaSwapDeposit-addLiquidity-uint256---uint256-uint256-)
* [`removeLiquidity(uint256 amount, uint256[] minAmounts, uint256 deadline)`](#MetaSwapDeposit-removeLiquidity-uint256-uint256---uint256-)
* [`removeLiquidityOneToken(uint256 tokenAmount, uint8 tokenIndex, uint256 minAmount, uint256 deadline)`](#MetaSwapDeposit-removeLiquidityOneToken-uint256-uint8-uint256-uint256-)
* [`removeLiquidityImbalance(uint256[] amounts, uint256 maxBurnAmount, uint256 deadline)`](#MetaSwapDeposit-removeLiquidityImbalance-uint256---uint256-uint256-)
* [`calculateTokenAmount(uint256[] amounts, bool deposit)`](#MetaSwapDeposit-calculateTokenAmount-uint256---bool-)
* [`calculateRemoveLiquidity(uint256 amount)`](#MetaSwapDeposit-calculateRemoveLiquidity-uint256-)
* [`calculateRemoveLiquidityOneToken(uint256 tokenAmount, uint8 tokenIndex)`](#MetaSwapDeposit-calculateRemoveLiquidityOneToken-uint256-uint8-)
* [`getToken(uint8 index)`](#MetaSwapDeposit-getToken-uint8-)
* [`calculateSwap(uint8 tokenIndexFrom, uint8 tokenIndexTo, uint256 dx)`](#MetaSwapDeposit-calculateSwap-uint8-uint8-uint256-)

## Function `initialize(contract ISwap _baseSwap, contract IMetaSwap _metaSwap, contract IERC20 _metaLPToken)` <a href="#metaswapdeposit-initialize-contract-iswap-contract-imetaswap-contract-ierc20" id="metaswapdeposit-initialize-contract-iswap-contract-imetaswap-contract-ierc20"></a>

Sets the address for the base Swap contract, MetaSwap contract, and the MetaSwap LP token contract.

### Parameters:

* `_baseSwap`: the address of the base Swap contract
* `_metaSwap`: the address of the MetaSwap contract
* `_metaLPToken`: the address of the MetaSwap LP token contract

## Function `swap(uint8 tokenIndexFrom, uint8 tokenIndexTo, uint256 dx, uint256 minDy, uint256 deadline) → uint256` <a href="#metaswapdeposit-swap-uint8-uint8-uint256-uint256-uint256" id="metaswapdeposit-swap-uint8-uint8-uint256-uint256-uint256"></a>

Swap two underlying tokens using the meta pool and the base pool

### Parameters:

* `tokenIndexFrom`: the token the user wants to swap from
* `tokenIndexTo`: the token the user wants to swap to
* `dx`: the amount of tokens the user wants to swap from
* `minDy`: the min amount the user would like to receive, or revert.
* `deadline`: latest timestamp to accept this transaction

## Function `addLiquidity(uint256[] amounts, uint256 minToMint, uint256 deadline) → uint256` <a href="#metaswapdeposit-addliquidity-uint256-uint256-uint256" id="metaswapdeposit-addliquidity-uint256-uint256-uint256"></a>

Add liquidity to the pool with the given amounts of tokens

### Parameters:

* `amounts`: the amounts of each token to add, in their native precision
* `minToMint`: the minimum LP tokens adding this amount of liquidity should mint, otherwise revert. Handy for front-running mitigation
* `deadline`: latest timestamp to accept this transaction

### Return Values:

* amount of LP token user minted and received

## Function `removeLiquidity(uint256 amount, uint256[] minAmounts, uint256 deadline) → uint256[]` <a href="#metaswapdeposit-removeliquidity-uint256-uint256-uint256" id="metaswapdeposit-removeliquidity-uint256-uint256-uint256"></a>

Burn LP tokens to remove liquidity from the pool. Withdraw fee that decays linearly over period of 4 weeks since last deposit will apply.

Liquidity can always be removed, even when the pool is paused.

### Parameters:

* `amount`: the amount of LP tokens to burn
* `minAmounts`: the minimum amounts of each token in the pool acceptable for this burn. Useful as a front-running mitigation
* `deadline`: latest timestamp to accept this transaction

### Return Values:

* amounts of tokens user received

## Function `removeLiquidityOneToken(uint256 tokenAmount, uint8 tokenIndex, uint256 minAmount, uint256 deadline) → uint256` <a href="#metaswapdeposit-removeliquidityonetoken-uint256-uint8-uint256-uint256" id="metaswapdeposit-removeliquidityonetoken-uint256-uint8-uint256-uint256"></a>

Remove liquidity from the pool all in one token. Withdraw fee that decays linearly over period of 4 weeks since last deposit will apply.

### Parameters:

* `tokenAmount`: the amount of the token you want to receive
* `tokenIndex`: the index of the token you want to receive
* `minAmount`: the minimum amount to withdraw, otherwise revert
* `deadline`: latest timestamp to accept this transaction

### Return Values:

* amount of chosen token user received

## Function `removeLiquidityImbalance(uint256[] amounts, uint256 maxBurnAmount, uint256 deadline) → uint256` <a href="#metaswapdeposit-removeliquidityimbalance-uint256-uint256-uint256" id="metaswapdeposit-removeliquidityimbalance-uint256-uint256-uint256"></a>

Remove liquidity from the pool, weighted differently than the pool's current balances. Withdraw fee that decays linearly over period of 4 weeks since last deposit will apply.

### Parameters:

* `amounts`: how much of each token to withdraw
* `maxBurnAmount`: the max LP token provider is willing to pay to remove liquidity. Useful as a front-running mitigation.
* `deadline`: latest timestamp to accept this transaction

### Return Values:

* amount of LP tokens burned

## Function `calculateTokenAmount(uint256[] amounts, bool deposit) → uint256` <a href="#metaswapdeposit-calculatetokenamount-uint256-bool" id="metaswapdeposit-calculatetokenamount-uint256-bool"></a>

A simple method to calculate prices from deposits or withdrawals, excluding fees but including slippage. This is helpful as an input into the various "min" parameters on calls to fight front-running. When withdrawing from the base pool in imbalanced fashion, the recommended slippage setting is 0.2% or higher.

This shouldn't be used outside frontends for user estimates.

### Parameters:

* `amounts`: an array of token amounts to deposit or withdrawal, corresponding to pooledTokens. The amount should be in each pooled token's native precision. If a token charges a fee on transfers, use the amount that gets transferred after the fee.
* `deposit`: whether this is a deposit or a withdrawal

### Return Values:

* token amount the user will receive

## Function `calculateRemoveLiquidity(uint256 amount) → uint256[]` <a href="#metaswapdeposit-calculateremoveliquidity-uint256" id="metaswapdeposit-calculateremoveliquidity-uint256"></a>

A simple method to calculate amount of each underlying tokens that is returned upon burning given amount of LP tokens

### Parameters:

* `amount`: the amount of LP tokens that would be burned on withdrawal

### Return Values:

* array of token balances that the user will receive

## Function `calculateRemoveLiquidityOneToken(uint256 tokenAmount, uint8 tokenIndex) → uint256` <a href="#metaswapdeposit-calculateremoveliquidityonetoken-uint256-uint8" id="metaswapdeposit-calculateremoveliquidityonetoken-uint256-uint8"></a>

Calculate the amount of underlying token available to withdraw when withdrawing via only single token

### Parameters:

* `tokenAmount`: the amount of LP token to burn
* `tokenIndex`: index of which token will be withdrawn

### Return Values:

* availableTokenAmount calculated amount of underlying token available to withdraw

## Function `getToken(uint8 index) → contract IERC20` <a href="#metaswapdeposit-gettoken-uint8" id="metaswapdeposit-gettoken-uint8"></a>

Returns the address of the pooled token at given index. Reverts if tokenIndex is out of range. This is a flattened representation of the pooled tokens.

### Parameters:

* `index`: the index of the token

### Return Values:

* address of the token at given index

## Function `calculateSwap(uint8 tokenIndexFrom, uint8 tokenIndexTo, uint256 dx) → uint256` <a href="#metaswapdeposit-calculateswap-uint8-uint8-uint256" id="metaswapdeposit-calculateswap-uint8-uint8-uint256"></a>

Calculate amount of tokens you receive on swap

### Parameters:

* `tokenIndexFrom`: the token the user wants to sell
* `tokenIndexTo`: the token the user wants to buy
* `dx`: the amount of tokens the user wants to sell. If the token charges a fee on transfers, use the amount that gets transferred after the fee.

### Return Values:

* amount of tokens the user will receive