> ## Documentation Index
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> Use this file to discover all available pages before exploring further.

# MainnetRouter

Router implementation with functions to interact with DAI on Ethereum Mainnet.

## Variables

### DAI

```solidity theme={null}
contract IERC20 DAI
```

*DAI address.*

### sDAI

```solidity theme={null}
contract SavingsDai sDAI
```

*SavingsDai address.*

## Functions

### constructor

```solidity theme={null}
constructor(contract IConditionalTokens _conditionalTokens, contract IWrapped1155Factory _wrapped1155Factory) public
```

*Constructor.*

**Parameters**

| Name | Type | Description |
| - | - | - |
| \_conditionalTokens | contract IConditionalTokens | Conditional Tokens contract. |
| \_wrapped1155Factory | contract IWrapped1155Factory | Wrapped1155Factory contract. |

### splitFromDai

```solidity theme={null}
function splitFromDai(contract Market market, uint256 amount) external
```

Splits a position using DAI and sends the ERC20 outcome tokens back to the user.

*The ERC20 associated to each outcome must be previously created on the wrapped1155Factory.*

**Parameters**

| Name | Type | Description |
| - | - | - |
| market | contract Market | The Market to split. |
| amount | uint256 | The amount of collateral to split. |

**Pre-condition**

1. The ERC20 associated to each outcome must be previously created on the wrapped1155Factory.

**Logic**

1. Transfer DAI from the user to `MainnetRouter`, which will be converted to Savings DAI (sDAI).
2. Call `conditionalTokens.splitPosition`  to transfer sDAI from`MainnetRouter` to `ConditionalTokens`, while minting corresponding ERC1155 outcome tokens to `MainnetRouter`.
3. Transfer ERC1155 outcome tokens from `MainnetRouter` to `Wrapped1155Factory` contract. There is a callback function in `Wrapped1155Factory` that will wrap the tokens into ERC20 tokens, then transfer the wrapped tokens back to the original user.

### mergeToDai

```solidity theme={null}
function mergeToDai(contract Market market, uint256 amount) external
```

Merges positions and sends DAI to the user.

*The ERC20 associated to each outcome must be previously created on the wrapped1155Factory.*

**Parameters**

| Name | Type | Description |
| - | - | - |
| market | contract Market | The Market to merge. |
| amount | uint256 | The amount of outcome tokens to merge. |

**Pre-condition**

1. The ERC20 associated to each outcome must be previously created on the wrapped1155Factory.
2. The caller must have \<amount> ERC20 tokens of all the outcomes of a market. For example, to call `mergeToDai` of a market with 3 outcomes: Yes, No, Invalid, the caller must have \<amount> tokens for each outcome.

**Logic**

Merging positions does precisely the opposite of what splitting a position does.

1. Unwraps ERC20 outcome tokens (which will burn these tokens and transfer corresponding ERC1155 outcome tokens tokens back to the `Router` contract).
2. Call `conditionalTokens.mergePositions` to burn ERC1155 outcome tokens.
3. Return sDAI to `MainnetRouter` , which will then be converted to DAI and sent to the user.

### redeemToDai

```solidity theme={null}
function redeemToDai(contract Market market, uint256[] outcomeIndexes, uint256[] amounts) external
```

Redeems positions and sends DAI to the user.

*The ERC20 associated to each outcome must be previously created on the wrapped1155Factory.*

**Parameters**

| Name | Type | Description |
| - | - | - |
| market | contract Market | The Market to redeem. |
| outcomeIndexes | uint256\[] | The index of the outcomes to redeem. |
| amounts | uint256\[] | Amount to redeem of each outcome. |

**Pre-condition**

1. The ERC20 associated to each outcome must be previously created on the wrapped1155Factory.
2. The caller must have ERC20 tokens of the outcomes they want to redeem. For example, to call `redeemToDai` for outcome Yes of a market with 3 outcomes: Yes, No, Invalid, the caller must have Yes tokens. (The call will still be processed even if the caller does not have tokens, but it will have no effect).
3. `conditionalTokens.reportPayouts` has been called by an oracle.

**Logic**

1. Unwraps ERC20 outcome tokens (which will burn these tokens and transfer corresponding ERC1155 outcome tokens back to the `MainnetRouter` contract).
2. Call `conditionalTokens.redeemPositions` to burn ERC1155 outcome tokens.
3. Return sDAI to `MainnetRouter` . `MainnetRouter` will calculate the sDAI difference before and after redeeming, which will then be converted to DAI and sent to the user.


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