> For the complete documentation index, see [llms.txt](https://helmet-insure.gitbook.io/helmet/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://helmet-insure.gitbook.io/helmet/contract-guide.md).

# Contract Guide

> These guidelines are fully hardcoded into the Helemet Smart Contract(s).The various parameters of the helmet platform are fully market-priced and contracts are automatically executed. Helmet team will not intervene in the policy price at any time or make changes to the contract unless it is necessary.

### Guide book to Helmet Smart Contracts 

Helmet.insurance's smart contracts are divided into core and peripheral two parts. The option logic is implemented in the core, including the **OptionFactory**, **LongOption**, and **ShortOption** contracts, the periphery implements policy buying and selling and flat-rate farming and harvesting, including the **OptionOrder**, **HELMET Token**, and **Farm contracts**.

**OptionFactory** is used for creating insurance policy contracts, minting Tokens, destroying Tokens, enabling policy activated and settlement. 

* LongOption is the buyer's certificate to activate the policy.
* ShortOption is the seller's certificate for clearing back the denominated and the underlying assets.
* OptionOrder is the policy marketplace, where supplier publish policies and holders buy policies, as well as the entry point for buyers to activate policy.

#### OptionFactory main function:

`function createOption(bool _private, address _collateral, address _underlying, uint _strikePrice, uint _expiry) public returns (address long, address short);`

`function mint(bool _private, address _collateral, address _underlying, uint _strikePrice, uint _expiry, uint volume) public returns (address long, address short, uint vol);`

`function burn(address _creator, address _collateral, address _underlying, uint _strikePrice, uint _expiry, uint volume) public returns (address long, address short, uint vol);`

`function calcExerciseAmount(address _long, uint volume) public view returns (uint);` 

`function exercise(address _long, uint volume, address[] memory path) public returns (uint vol, uint fee, uint amt);` 

`function settleable(address short, uint volume) public view returns (uint vol, uint col, uint fee, uint und);` 

`function settle(address short, uint volume) public returns (uint vol, uint col, uint fee, uint und);` 

#### LongOption main function：

`function exercise(uint volume, address[] memory path) public returns (uint vol, uint fee, uint amt);` 

#### ShortOption main function：

`function settleable(address seller) public view returns (uint vol, uint col, uint fee, uint und);` 

`function settle(uint volume) external returns (uint vol, uint col, uint fee, uint und);` 

#### OptionOrder main function：

`function sell(bool _private, address _collateral, address _underlying, uint _strikePrice, uint _expiry, uint volume, address settleToken, uint price) virtual public returns (uint askID);` 

`function reprice(uint askID, uint newPrice) virtual external returns (uint newAskID);` 

`function cancel(uint askID) virtual external returns (uint vol);` 

`function buy(uint askID, uint volume) virtual public returns (uint bidID, uint vol, uint amt);` 

`function exercise(uint bidID, uint volume, address[] memory path) virtual public returns (uint vol, uint fee, uint amt);` 

`function waive(uint bidID, uint volume) virtual public returns (uint vol);` 

## Buy\&Sell

### 
sell a policy

Using the `sell function` of the OptionOrder contract.：

```javascript
 function sell(
     bool _private, 
     address _collateral, 
     address _underlying, 
     uint _strikePrice, 
     uint _expiry, 
     uint volume, 
     address settleToken, 
     uint price
 ) 
     virtual 
     public 
     returns (uint askID);
```

Example

| <p><strong>Denominated</strong> </p><p><strong>Asset</strong></p> | <p><strong>Underlying</strong> </p><p><strong>Asset</strong></p> | <p>Policy </p><p>Price</p> | **Premium** | Amount |    <p>Expeir </p><p>At</p>    |
| :---------------------------------------------------------------: | :--------------------------------------------------------------: | :------------------------: | :---------: | ------ | :---------------------------: |
|                                BNB                                |                              HELMET                              |           0.1BNB           |  0.2 Helmet | 10 BNB | <p>2021/1/1 <br>0:0:0 UMT</p> |

```javascript
OptionOrder.sell(
    false, 
    0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c, 
    0x4E76DfeA6Fb3726e9A77628AAa23839E3298BC37, 
    10000000000000000000, 
    1609459200, 
    123000000000000000000, 
    0x4E76DfeA6Fb3726e9A77628AAa23839E3298BC37, 
    200000000000000000);
```

### Buy a policy

Using the `buy function` of the OptionOrder contract.：&#x20;

```javascript
function buy(uint askID, uint volume) 
    virtual 
    public 
    returns (uint bidID, uint vol, uint amt);
```

Example

| ID  | Policy price |
| --- | ------------ |
| 456 | 123bnb       |

```javascript
OptionOrder.buy(456, 123000000000000000000);
```

### Activate the policy

Using the `exercise function` of the OptionOrder contract.：&#x20;

```javascript
function exercise(
    uint bidID, 
    uint volume, 
    address[] memory path
) 
    virtual 
    public 
    returns (uint vol, uint fee, uint amt);
```

Example:

if it's a cover off policy&#x20;

```javascript
OptionOrder.exercise(789, 123000000000000000000, []);
```

If it's a cover up policy&#x20;

```javascript
OptionOrder.exercise(
    789, 
    123000000000000000000, 
    [0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c,
    0x4E76DfeA6Fb3726e9A77628AAa23839E3298BC37]);
```

### Get back the settlement

Using the `settle function` of the OptionFactory contract:

```javascript
function settle(
    address _creator, 
    address _collateral, 
    address _underlying, 
    uint _strikePrice, 
    uint _expiry, 
    uint volume
) 
    external 
    returns (uint vol, uint col, uint fee, uint und);
```

Example&#x20;

```javascript
OptionFactory.settle(
    address(0), 
    0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c, 
    0x4E76DfeA6Fb3726e9A77628AAa23839E3298BC37, 
    10000000000000000000, 
    1609459200, 
    123000000000000000000);
```