# Fixed Strike oTokens

### Overview

Option Tokens (oTokens) are issued by a Option Teller to represent American-style options on the underlying token. Call option tokens can be exercised for the underlying token 1:1 by paying the amount \* strike price in the quote token at any time between the eligible and expiry timestamps. Put option tokens can be exercised for the underlying token 1:1 by paying the amount of the underlying token to receive the amount \* strike price in the quote token at any time between the eligible and expiry timestamps.

The Fixed Strike Option Token contract is a specific implementation of oTokens where the strike price is specified and fixed on creation.

oTokens are unique to the combination of parameters that they are deployed with. Eligible and expiry timestamps are rounded down to the nearest day (using UTC) to reduce the possible number of tokens.

This contract uses [Clones With Immutable Args](https://github.com/wighawag/clones-with-immutable-args) to save gas on deployment and is based on [VestedERC20](https://github.com/ZeframLou/vested-erc20).

<figure><img src="https://content.gitbook.com/content/RLNHGppzWLIBhbHOvrRS/blobs/0ZjVUU96BSpa3YyFphst/Fixed%20Strike%20oToken%20Inheritance.jpeg" alt=""><figcaption></figcaption></figure>

## FixedStrikeOptionToken Contract

[Git Source](https://github.com/Bond-Protocol/option-contracts/blob/master/src/fixed-strike/FixedStrikeOptionToken.sol)

### Immutable Args

#### payout

The token that the option is on

```solidity
function payout() public pure returns (ERC20 _payout);
```

#### quote

The token that the option is quoted in

```solidity
function quote() public pure returns (ERC20 _quote);
```

#### eligible

Timestamp at which the Option token can first be exercised

```solidity
function eligible() public pure returns (uint48 _eligible);
```

#### expiry

Timestamp at which the Option token cannot be exercised after

```solidity
function expiry() public pure returns (uint48 _expiry);
```

#### receiver

Address that will receive the proceeds when option tokens are exercised. Also, the only address that can reclaim collateral from expired oTokens.

```solidity
function receiver() public pure returns (address _receiver);
```

#### call

Whether the option is a call (true) or a put (false)

```solidity
function call() public pure returns (bool _call);
```

#### teller

Address of the Teller that created the token

```solidity
function teller() public pure returns (address _teller);
```

#### strike

The strike price of the option (in quote token units)

```solidity
function strike() public pure returns (uint256 _strike);
```

### Functions

#### mint

Mint option tokens

Only callable by the Teller that created the token

```solidity
function mint(address to, uint256 amount) external;
```

**Parameters**

| Name     | Type      | Description            |
| -------- | --------- | ---------------------- |
| `to`     | `address` | The address to mint to |
| `amount` | `uint256` | The amount to mint     |

#### burn

Burn option tokens

Only callable by the Teller that created the token

```solidity
function burn(address from, uint256 amount) external;
```

**Parameters**

| Name     | Type      | Description              |
| -------- | --------- | ------------------------ |
| `from`   | `address` | The address to burn from |
| `amount` | `uint256` | The amount to burtn      |

#### getOptionParameters

Get collection of option parameters in a single call

```solidity
function getOptionParameters()
    external
    pure
    returns (
        uint8 decimals_,
        ERC20 payout_,
        ERC20 quote_,
        uint48 eligible_,
        uint48 expiry_,
        address receiver_,
        bool call_,
        uint256 strike_
    );
```

**Returns**

| Name        | Type      | Description                                                                          |
| ----------- | --------- | ------------------------------------------------------------------------------------ |
| `decimals_` | `uint8`   | The number of decimals for the option token (same as payout token)                   |
| `payout_`   | `ERC20`   | The address of the payout token                                                      |
| `quote_`    | `ERC20`   | The address of the quote token                                                       |
| `eligible_` | `uint48`  | The option exercise eligibility timestamp                                            |
| `expiry_`   | `uint48`  | The option exercise expiry timestamp                                                 |
| `receiver_` | `address` | The address of the receiver                                                          |
| `call_`     | `bool`    | Whether the option is a call (true) or a put (false)                                 |
| `strike_`   | `uint256` | The option strike price specified in the amount of quote tokens per underlying token |

### Errors

#### OptionToken\_OnlyTeller

```solidity
error OptionToken_OnlyTeller();
```