# Single Random Winner

The Single Random Winner prize strategy periodically selects a random winner and awards to them all the prizes available in the Prize Pool.

A Single Random Winner prize strategy is initialized with:

**Prize Period Start:** the timestamp at which the prize period should start

**Prize Period Seconds**: the duration of time between prizes

[**Ticket**](https://v3.docs.pooltogether.com/v3.0.1/protocol/prize-strategy/single-random-winner/ticket)**:** The interface to use to select winners

[**Sponsorship**](https://v3.docs.pooltogether.com/v3.0.1/protocol/prize-strategy/single-random-winner/sponsorship): The token that represents sponsorship

[**Random Number Generator**](https://v3.docs.pooltogether.com/v3.0.1/protocol/random-number-generator): used to generate random numbers for winner selection

## Awarding

Anyone may start the award process.

```javascript
function startAward() external
```

**startAward():**

* Requires that either:
  * the current time is greater than or equal to start time + prize period
  * there is an active random number request and it has timed out
* Locks the pool. Tickets cannot be minted or redeemed
* Requests a random number from the RNG service

Once the random number is available, a user can call:

```javascript
function completeAward() external
```

**completeAward():**

* Requires that **startAward()** has been called
* Unlocks the pool
* Disburses the prize
* Moves the prize start time forward
* Clears the random number request

You can check the above required conditions using canStartAward() and canCompleteAward():

```javascript
function canStartAward() external view returns (bool);
```

and

```javascript
function canCompleteAward() external view returns (bool);
```

## Prizes

### Current Yield Prize

To retrieve amount of accrued prize interest so far you may call:

```javascript
function currentPrize() external returns (uint256);
```

### Estimating Prize

To estimate what the prize will be you can call:

```javascript
function estimatePrize() external returns (uint256);
```

## External Prizes

The owner can add "external" ERC20 tokens as prizes.  The strategy will award the entire balance held by the Prize Pool to the winner.

```javascript
function addExternalErc20Award(address _externalErc20) external onlyOwner;
```

The owner can add "external" ERC721 tokens as prizes.  These tokens will be transferred to the winner.

```javascript
function addExternalErc721Award(
    address _externalErc721,
    uint256[] calldata _tokenIds
) external onlyOwner
```

## Time

To retrieve when the current prize started:

```javascript
function prizePeriodStartedAt() external view returns (uint256)
```

To retrieve when the prize will end:

```javascript
function prizePeriodEndAt() external view returns (uint256)
```

## Miscellaneous

| Function                                                                                                                          | Description                                   |
| --------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------- |
| function sponsorship() returns ([ERC20](https://eips.ethereum.org/EIPS/eip-20))                                                   | Returns the address of the sponsorship token. |
| function ticket() returns ([Ticket](https://v3.docs.pooltogether.com/v3.0.1/protocol/prize-strategy/single-random-winner/ticket)) | Returns the address of the ticket token.      |