# Interactions

### Governance Functions

#### **setBuffer**

Sets the buffer rate percentage that determines how much of each reward goes to the buffer.

```solidity
function setBuffer(uint256 _buffer) external;

```

**Parameters**

| Name      | Type      | Description                                                   |
| --------- | --------- | ------------------------------------------------------------- |
| `_buffer` | `uint256` | The buffer percentage (must be less than BUFFER\_DENOMINATOR) |

**Access Control:** only Owner (Keeper)

#### **setSymbol**

Updates the token symbol.

```solidity
function setSymbol(string memory _symbol) external;

```

**Parameters**

| Name      | Type     | Description          |
| --------- | -------- | -------------------- |
| `_symbol` | `string` | The new token symbol |

**Access Control:** only Owner (Keeper)\
\
**withdrawBuffer**

Withdraw `_amount` from Buffer and mint SPAToken shares to `_to`

```solidity
function withdrawBuffer(address _to, uint256 _amount) external;
```

**Parameters**

| Name      | Type      | Description                                             |
| --------- | --------- | ------------------------------------------------------- |
| `_to`     | `address` | Recipient address that will receive newly-minted shares |
| `_amount` | `uint256` | Token amount to withdraw                                |

**Access:** only Owner (via Keeper)

**transferShares**

Moves `_sharesAmount` token shares from the caller's account to the `_recipient` account.

*Note: The `_sharesAmount` argument is the amount of shares, not tokens.*

```solidity
function transferShares(address _recipient, uint256 _sharesAmount)
    external
    returns (uint256);

```

**Parameters**

| Name            | Type      | Description                                   |
| --------------- | --------- | --------------------------------------------- |
| `_recipient`    | `address` | The address to receive the shares             |
| `_sharesAmount` | `uint256` | The amount of shares to transfer (not tokens) |

**Returns**

| Name     | Type      | Description                      |
| -------- | --------- | -------------------------------- |
| `<none>` | `uint256` | The amount of tokens transferred |

**transferSharesFrom**

Moves `_sharesAmount` token shares from the `_sender` account to the `_recipient` account using the allowance mechanism.

```solidity
function transferSharesFrom(
    address _sender,
    address _recipient,
    uint256 _sharesAmount
)
    external
    returns (uint256);

```

**Parameters**

| Name            | Type      | Description                         |
| --------------- | --------- | ----------------------------------- |
| `_sender`       | `address` | The address to transfer shares from |
| `_recipient`    | `address` | The address to receive the shares   |
| `_sharesAmount` | `uint256` | The amount of shares to transfer    |

**Returns**

| Name     | Type      | Description                      |
| -------- | --------- | -------------------------------- |
| `<none>` | `uint256` | The amount of tokens transferred |

**Requirements:** The caller must have sufficient allowance for the sender's tokens.

**mintShares**

Mints shares for the specified account and transfers them to that account.

```solidity
function mintShares(address _account, uint256 _tokenAmount)
    external;

```

**Parameters**

| Name           | Type      | Description                                               |
| -------------- | --------- | --------------------------------------------------------- |
| `_account`     | `address` | The address to mint shares to                             |
| `_tokenAmount` | `uint256` | The token amount to mint (converted to shares internally) |

**Access Control:** Only callable by the pool contract.

**burnShares**

Burns shares from the caller's account.

```solidity
function burnShares(uint256 _tokenAmount)
    external;

```

**Parameters**

| Name           | Type      | Description                                               |
| -------------- | --------- | --------------------------------------------------------- |
| `_tokenAmount` | `uint256` | The token amount to burn (converted to shares internally) |

**burnSharesFrom**

Burns shares from the specified account using the allowance mechanism.

```solidity
function burnSharesFrom(address _account, uint256 _tokenAmount)
    external;

```

**Parameters**

| Name           | Type      | Description                     |
| -------------- | --------- | ------------------------------- |
| `_account`     | `address` | The address to burn shares from |
| `_tokenAmount` | `uint256` | The token amount to burn        |

**Requirements:** The caller must have sufficient allowance for the account's tokens.

#### Supply Management

**addTotalSupply**

Increases the total supply of SPAToken by staking rewards and swap fees, with automatic buffer allocation.

```solidity
function addTotalSupply(uint256 _amount)
    external;

```

**Parameters**

| Name      | Type      | Description                       |
| --------- | --------- | --------------------------------- |
| `_amount` | `uint256` | The amount to add to total supply |

**Access Control:** Only callable by the pool contract.

**Behavior:**

* payFirst pays down any existing buffer bad debt
* Allocates a percentage to the buffer based on `bufferPercent`
* Remainder increases the actual total supply

**removeTotalSupply**

Decreases the total supply of SPAToken due to losses, with options for buffer usage and debt tracking.

```solidity
function removeTotalSupply(uint256 _amount, bool isBuffer, bool withDebt)
    external;

```

**Parameters**

| Name       | Type      | Description                                         |
| ---------- | --------- | --------------------------------------------------- |
| `_amount`  | `uint256` | The amount to remove from total supply              |
| `isBuffer` | `bool`    | Whether to use buffer funds instead of total supply |
| `withDebt` | `bool`    | Whether to add the amount to buffer bad debt        |

**Access Control:** Only callable by the pool contract.

**addBuffer**

Directly increases the buffer amount without affecting total supply.

```solidity
function addBuffer(uint256 _amount)
    external;

```

**Parameters**

| Name      | Type      | Description                     |
| --------- | --------- | ------------------------------- |
| `_amount` | `uint256` | The amount to add to the buffer |

**Access Control:** Only callable by the pool contract.

### View Functions

**sharesOf**

Returns the amount of shares owned by an account.

```solidity
function sharesOf(address _account)
    external
    view
    returns (uint256);

```

**Parameters**

| Name       | Type      | Description                     |
| ---------- | --------- | ------------------------------- |
| `_account` | `address` | The account to query shares for |

**Returns**

| Name     | Type      | Description                               |
| -------- | --------- | ----------------------------------------- |
| `<none>` | `uint256` | The amount of shares owned by the account |

**getPeggedTokenByShares**

Converts a share amount to the corresponding token amount.

```solidity
function getPeggedTokenByShares(uint256 _sharesAmount)
    public
    view
    returns (uint256);

```

**Parameters**

| Name            | Type      | Description                     |
| --------------- | --------- | ------------------------------- |
| `_sharesAmount` | `uint256` | The amount of shares to convert |

**Returns**

| Name     | Type      | Description                    |
| -------- | --------- | ------------------------------ |
| `<none>` | `uint256` | The corresponding token amount |

**getSharesByPeggedToken**

Converts a token amount to the corresponding share amount.

```solidity
function getSharesByPeggedToken(uint256 _spaTokenAmount)
    public
    view
    returns (uint256);

```

**Parameters**

| Name              | Type      | Description                 |
| ----------------- | --------- | --------------------------- |
| `_spaTokenAmount` | `uint256` | The token amount to convert |

**Returns**

| Name     | Type      | Description                    |
| -------- | --------- | ------------------------------ |
| `<none>` | `uint256` | The corresponding share amount |