# ComptrollerLens

## ComptrollerLens Contract

The ComptrollerLens contract has functions to get the number of tokens that can be seized through liquidation, hypothetical account liquidity and shortfall of an account.

## Solidity API

```solidity
struct AccountLiquidityLocalVars {
  uint256 sumCollateral;
  uint256 sumBorrowPlusEffects;
  uint256 vTokenBalance;
  uint256 borrowBalance;
  uint256 exchangeRateMantissa;
  uint256 oraclePriceMantissa;
  struct ExponentialNoError.Exp weightedFactor;
  struct ExponentialNoError.Exp exchangeRate;
  struct ExponentialNoError.Exp oraclePrice;
  struct ExponentialNoError.Exp tokensToDenom;
}
```

#### liquidateCalculateSeizeTokens

Computes the number of collateral tokens to be seized in a liquidation event

```solidity
function liquidateCalculateSeizeTokens(address comptroller, address vTokenBorrowed, address vTokenCollateral, uint256 actualRepayAmount) external view returns (uint256, uint256)
```

**Parameters**

| Name              | Type    | Description                                                       |
| ----------------- | ------- | ----------------------------------------------------------------- |
| comptroller       | address | Address of comptroller                                            |
| vTokenBorrowed    | address | Address of the borrowed vToken                                    |
| vTokenCollateral  | address | Address of collateral for the borrow                              |
| actualRepayAmount | uint256 | Repayment amount i.e amount to be repaid of total borrowed amount |

**Return Values**

| Name | Type    | Description                                |
| ---- | ------- | ------------------------------------------ |
| \[0] | uint256 | A tuple of error code, and tokens to seize |
| \[1] | uint256 |                                            |

***

#### liquidateCalculateSeizeTokens

Computes the number of collateral tokens to be seized in a liquidation event

```solidity
function liquidateCalculateSeizeTokens(address borrower, address comptroller, address vTokenBorrowed, address vTokenCollateral, uint256 actualRepayAmount) external view returns (uint256, uint256)
```

**Parameters**

| Name              | Type    | Description                                                       |
| ----------------- | ------- | ----------------------------------------------------------------- |
| borrower          | address | Address of borrower whose collateral is being seized              |
| comptroller       | address | Address of comptroller                                            |
| vTokenBorrowed    | address | Address of the borrowed vToken                                    |
| vTokenCollateral  | address | Address of collateral for the borrow                              |
| actualRepayAmount | uint256 | Repayment amount i.e amount to be repaid of total borrowed amount |

**Return Values**

| Name | Type    | Description                                |
| ---- | ------- | ------------------------------------------ |
| \[0] | uint256 | A tuple of error code, and tokens to seize |
| \[1] | uint256 |                                            |

***

#### liquidateVAICalculateSeizeTokens

Computes the number of VAI tokens to be seized in a liquidation event

```solidity
function liquidateVAICalculateSeizeTokens(address comptroller, address vTokenCollateral, uint256 actualRepayAmount) external view returns (uint256, uint256)
```

**Parameters**

| Name              | Type    | Description                                                           |
| ----------------- | ------- | --------------------------------------------------------------------- |
| comptroller       | address | Address of comptroller                                                |
| vTokenCollateral  | address | Address of collateral for vToken                                      |
| actualRepayAmount | uint256 | Repayment amount i.e amount to be repaid of the total borrowed amount |

**Return Values**

| Name | Type    | Description                                |
| ---- | ------- | ------------------------------------------ |
| \[0] | uint256 | A tuple of error code, and tokens to seize |
| \[1] | uint256 |                                            |

***

#### getHypotheticalAccountLiquidity

Computes the hypothetical liquidity and shortfall of an account given a hypothetical borrow A snapshot of the account is taken and the total borrow amount of the account is calculated

```solidity
function getHypotheticalAccountLiquidity(address comptroller, address account, contract VToken vTokenModify, uint256 redeemTokens, uint256 borrowAmount, enum WeightFunction weightingStrategy) external view returns (uint256, uint256, uint256)
```

**Parameters**

| Name              | Type                | Description                                                                                                                                                                |
| ----------------- | ------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| comptroller       | address             | Address of comptroller                                                                                                                                                     |
| account           | address             | Address of the borrowed vToken                                                                                                                                             |
| vTokenModify      | contract VToken     | Address of collateral for vToken                                                                                                                                           |
| redeemTokens      | uint256             | Number of vTokens being redeemed                                                                                                                                           |
| borrowAmount      | uint256             | Amount borrowed                                                                                                                                                            |
| weightingStrategy | enum WeightFunction | The weighting strategy to use: - `WeightFunction.USE_COLLATERAL_FACTOR` to use collateral factor - `WeightFunction.USE_LIQUIDATION_THRESHOLD` to use liquidation threshold |

**Return Values**

| Name | Type    | Description                                             |
| ---- | ------- | ------------------------------------------------------- |
| \[0] | uint256 | Returns a tuple of error code, liquidity, and shortfall |
| \[1] | uint256 |                                                         |
| \[2] | uint256 |                                                         |

***


---

# 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://docs-v4.venus.io/technical-reference/reference-core-pool/comptroller/comptroller-lens.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.