> For the complete documentation index, see [llms.txt](https://documentation.kodiak.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.kodiak.finance/developers/panda/smart-contract-reference/panda-pool.md).

# Panda Pool

Abstract base contract implementing bonding curve mechanics.

#### Functions

**Trading**

**`buyTokens`**

```solidity
function buyTokens(
    uint256 amountIn,
    uint256 minAmountOut,
    address to
) external nonReentrant returns (uint256 amountOut, uint256 fee)
```

Purchase tokens with the base token.

**Parameters:**

* `amountIn`: Amount of base tokens to spend
* `minAmountOut`: Minimum tokens to receive
* `to`: Recipient address

**Returns:**

* `amountOut`: Amount of tokens received
* `fee`: Fee paid in base tokens

**Errors:**

* `PandaPool: INSUFFICIENT_OUTPUT_AMOUNT` - When amountOut is less than minAmountOut
* `PandaPool: TRADE_BELOW_MIN` - When trade size is below minimum threshold
* `PandaPool: INVALID_TO` - When recipient address is zero
* `PandaPool: GRADUATED` - When pool has already graduated

**`buyTokensWithBera`**

```solidity
function buyTokensWithBera(
    uint256 minAmountOut,
    address to
) external payable returns (uint256 amountOut, uint256 fee)
```

Purchase tokens using native BERA.

**Parameters:**

* `minAmountOut`: Minimum tokens to receive
* `to`: Recipient address

**Returns:**

* `amountOut`: Amount of tokens received
* `fee`: Fee paid in BERA

**Errors:**

* `PandaPool: NOT_BERA_PAIR` - When base token is not WBERA
* `PandaPool: INSUFFICIENT_OUTPUT_AMOUNT` - When amountOut is less than minAmountOut
* `PandaPool: INVALID_TO` - When recipient address is zero
* `PandaPool: GRADUATED` - When pool has already graduated

**`buyAllTokens`**

```solidity
function buyAllTokens(
    address to
) external returns (uint256 amountOut, uint256 fee)
```

Purchase all remaining tokens in the pool.

**Parameters:**

* `to`: Recipient address

**Returns:**

* `amountOut`: Amount of tokens received
* `fee`: Fee paid in base tokens

**Errors:**

* `PandaPool: INVALID_TO` - When recipient address is zero
* `PandaPool: INSUFFICIENT_LIQUIDITY` - When not enough liquidity for trade
* `PandaPool: GRADUATED` - When pool has already graduated

**`sellTokens`**

```solidity
function sellTokens(
    uint256 amountIn,
    uint256 minAmountOut,
    address to
) external nonReentrant returns (uint256 amountOut, uint256 fee)
```

Sell tokens for the base token.

**Parameters:**

* `amountIn`: Amount of tokens to sell
* `minAmountOut`: Minimum base tokens to receive
* `to`: Recipient address

**Returns:**

* `amountOut`: Amount of base tokens received
* `fee`: Fee paid in base tokens

**Errors:**

* `PandaPool: INSUFFICIENT_BUYING` - When selling more than bought
* `PandaPool: INSUFFICIENT_OUTPUT_AMOUNT` - When amountOut is less than minAmountOut
* `PandaPool: INVALID_TO` - When recipient address is zero
* `PandaPool: GRADUATED` - When pool has already graduated

**`sellTokensForBera`**

```solidity
function sellTokensForBera(
    uint256 amountIn,
    uint256 minAmountOut,
    address to
) external returns (uint256 amountOut, uint256 fee)
```

Sell tokens for native BERA.

**Parameters:**

* `amountIn`: Amount of tokens to sell
* `minAmountOut`: Minimum amount of BERA to receive
* `to`: Recipient address for BERA

**Returns:**

* `amountOut`: Amount of BERA received
* `fee`: Fee paid in BERA

**Errors:**

* `PandaPool: NOT_BERA_PAIR` - When base token is not WBERA
* `PandaPool: INSUFFICIENT_BUYING` - When selling more than bought
* `PandaPool: INSUFFICIENT_OUTPUT_AMOUNT` - When amountOut is less than minAmountOut
* `PandaPool: INVALID_TO` - When recipient address is zero

#### Price Discovery Functions

**`getAmountOutBuy`**

```solidity
function getAmountOutBuy(
    uint256 amountIn
) public view returns (
    uint256 amountOut,
    uint256 fee,
    uint256 sqrtP_new
)
```

Calculate expected output for buying tokens.

**Returns:**

* `amountOut`: Expected amount of tokens to receive
* `fee`: Expected fee in base tokens
* `sqrtP_new`: New square root price after the trade

**Errors:**

* `PandaPool: TRADE_BELOW_MIN` - When trade size is below minimum threshold
* `PandaPool: INSUFFICIENT_LIQUIDITY` - When not enough liquidity for trade
* `PandaPool: GRADUATED` - When pool has already graduated

**`getAmountOutSell`**

```solidity
function getAmountOutSell(
    uint256 amountIn
) public view returns (
    uint256 amountOut,
    uint256 fee,
    uint256 sqrtP_new
)
```

Calculate expected output for selling tokens.

**Parameters:**

* `amountIn`: Amount of tokens to sell

**Returns:**

* `amountOut`: Expected amount of base tokens to receive
* `fee`: Expected fee in base tokens
* `sqrtP_new`: New square root price after the trade

**Errors:**

* `PandaPool: TRADE_BELOW_MIN` - When trade size is below minimum threshold
* `PandaPool: INSUFFICIENT_LIQUIDITY` - When not enough liquidity for trade
* `PandaPool: GRADUATED` - When pool has already graduated

**`getAmountInBuy`**

```solidity
function getAmountInBuy(
    uint256 amountOut
) public view returns (
    uint256 amountIn,
    uint256 fee,
    uint256 sqrtP_new
)
```

Calculate required input for desired token output.

**Parameters:**

* `amountOut`: Desired amount of tokens to receive

**Returns:**

* `amountIn`: Required amount of base tokens to spend
* `fee`: Expected fee in base tokens
* `sqrtP_new`: New square root price after the trade

**Errors:**

* `PandaPool: TRADE_BELOW_MIN` - When trade size is below minimum threshold
* `PandaPool: INSUFFICIENT_LIQUIDITY` - When not enough tokens available
* `PandaPool: GRADUATED` - When pool has already graduated

**`getAmountInBuyRemainingTokens`**

```solidity
getAmountInBuyRemainingTokens() 
public view returns (uint256 amountIn)
```

Calculate amount needed to buy all remaining tokens.

**Returns:**

* `amountIn`: Amount of base tokens needed to buy all remaining tokens

#### Balance & Vesting Functions

**`totalBalanceOf`**

```solidity
totalBalanceOf(
    address user
) external view returns (uint256)
```

Get total balance including unvested tokens.

**Parameters:**

* `user`: Address to check balance for

**Returns:**

* Total balance including both vested and unvested tokens

**`vestedBalanceOf`**

```solidity
 vestedBalanceOf(
    address user
) external view returns (uint256)
```

Get available/vested balance.

**Parameters:**

* `user`: Address to check vested balance for

**Returns:**

* Currently vested token balance

**`claimableTokens`**

```solidity
claimableTokens(
    address user
) public view returns (uint256)
```

Get amount of tokens available to claim.

**Parameters:**

* `user`: Address to check claimable tokens for

**Returns:**

* Amount of tokens currently available to claim

**Errors:**

* `PandaPool: VESTING_OFF` - When vesting is not enabled
* `PandaPool: NOT_GRADUATED` - When pool hasn't graduated yet

**`claimTokens`**

```solidity
claimTokens(
    address user
) external returns (uint256)
```

Claim vested tokens.

**Parameters:**

* `user`: Address to claim tokens for

**Returns:**

* Amount of tokens claimed

**Errors:**

* `PandaPool: VESTING_OFF` - When vesting is not enabled
* `PandaPool: NO_CLAIMABLE` - When no tokens are available to claim

#### Pool State Functions

**`remainingTokensInPool`**

```solidity
remainingTokensInPool()
public view returns (uint256)
```

Get remaining tokens available in pool.

**Returns:**

* Amount of tokens remaining in the pool

**`viewExcessTokens`**

```solidity
viewExcessTokens()
public view returns (
    uint256 excessPandaTokens,
    uint256 excessBaseTokens
)
```

View excess tokens in contract.

**Returns:**

* `excessPandaTokens`: Amount of excess Panda tokens
* `excessBaseTokens`: Amount of excess base tokens

**`collectExcessTokens`**

```solidity
collectExcessTokens()
external
```

Transfer excess tokens to treasury.

**Emits:** `ExcessCollected`

#### Events

```solidity
PoolInitialized(
    address pandaToken,
    address baseToken,
    uint256 sqrtPa,
    uint256 sqrtPb,
    uint256 vestingPeriod,
    address deployer,
    bytes data
)
```

Emitted when pool is initialized.

```solidity
Swap(
    address indexed sender,
    uint amount0In,
    uint amount1In,
    uint amount0Out,
    uint amount1Out,
    address indexed to
)
```

Emitted on each swap operation.

```solidity
Sync(
    uint256 pandaReserve,
    uint256 baseReserve,
    uint256 sqrtPrice
)
```

Emitted when pool reserves are synchronized.

```solidity
TokensClaimed(
    address indexed user,
    uint256 amount
)
```

Emitted when tokens are claimed from vesting.

```solidity
ExcessCollected(
    uint256 excessPandaTokens,
    uint256 excessBaseTokens
)
```

Emitted when excess tokens are collected.