# Oracle-based Auctioneers

The Oracle-based Auctioneer contracts allow market creators to create bond markets that use external price feeds to stay in line with market prices. There are two variants of Oracle-based Auctioneers:

* Oracle Fixed Discount Auctioneer (OFDA)
* Oracle Sequential Dutch Auctioneer (OSDA)

The IBondOracle interface is required to be implemented for a contract that will serve as an oracle. Bond protocol has created a Base Oracle abstract and implemented a sample oracle contract for Chainlink price feeds that can be used by market issuers. With the sample contract, each issuer deploys their own oracle contract so they have control over the configuration.

## IBondOracle

### Methods

#### currentPrice

```solidity
function currentPrice(uint256 id_) external view returns (uint256)
```

Returns the price as a ratio of quote tokens to base tokens for the provided market ID scaled by `10^decimals(id_)`.

*Market ID is not known prior to market creation. This version is used by the Bond system after market creation.*

**Parameters**

| Name | Type    | Description |
| ---- | ------- | ----------- |
| id\_ | uint256 | Market ID   |

**Returns**

| Name  | Type    | Description  |
| ----- | ------- | ------------ |
| price | uint256 | Oracle price |

#### currentPrice

```solidity
function currentPrice(contract ERC20 quoteToken_, contract ERC20 payoutToken_) external view returns (uint256)
```

Returns the price as a ratio of quote tokens to base tokens for the provided token pair scaled by `10^decimals(quoteToken_, payoutToken_)`

*Not used directly by the bond system, but useful for checking whether the oracle parameters are setup correctly before deploying a bond market.*

**Parameters**

| Name          | Type           | Description                                                              |
| ------------- | -------------- | ------------------------------------------------------------------------ |
| quoteToken\_  | contract ERC20 | Token that purchasers provide to the market and creators receive.        |
| payoutToken\_ | contract ERC20 | Token that creators provide and purchasers will receive from the market. |

**Returns**

| Name  | Type    | Description  |
| ----- | ------- | ------------ |
| price | uint256 | Oracle price |

#### decimals

```solidity
function decimals(uint256 id_) external view returns (uint8)
```

Returns the number of configured decimals of the price value for the provided market ID

*Market ID is not known prior to market creation. This version is used by the Bond system after market creation.*

**Parameters**

| Name | Type    | Description |
| ---- | ------- | ----------- |
| id\_ | uint256 | Market ID   |

**Returns**

| Name     | Type  | Description                                      |
| -------- | ----- | ------------------------------------------------ |
| decimals | uint8 | Number of decimals to assume for Market ID price |

#### decimals

```solidity
function decimals(contract ERC20 quoteToken_, contract ERC20 payoutToken_) external view returns (uint8)
```

Returns the number of configured decimals of the price value for the provided token pair

**Parameters**

| Name          | Type           | Description                                                              |
| ------------- | -------------- | ------------------------------------------------------------------------ |
| quoteToken\_  | contract ERC20 | Token that purchasers provide to the market and creators receive.        |
| payoutToken\_ | contract ERC20 | Token that creators provide and purchasers will receive from the market. |

**Returns**

| Name     | Type  | Description                                       |
| -------- | ----- | ------------------------------------------------- |
| decimals | uint8 | Number of decimals to assume for token pair price |

#### registerMarket

```solidity
function registerMarket(uint256 id_, contract ERC20 quoteToken_, contract ERC20 payoutToken_) external nonpayable
```

Register a new bond market on the oracle

*Used by the bond system to register the market ID and token pair. Must permission the auctioneer to use this function.*

**Parameters**

| Name          | Type           | Description                                                              |
| ------------- | -------------- | ------------------------------------------------------------------------ |
| id\_          | uint256        | Market ID                                                                |
| quoteToken\_  | contract ERC20 | Token that purchasers provide to the market and creators receive.        |
| payoutToken\_ | contract ERC20 | Token that creators provide and purchasers will receive from the market. |


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://dev.bondprotocol.finance/smart-contracts/bond-system/auctioneer/oracle-based-auctioneers.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.