# BtcRelay\<V, T, B, Signer>

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:11](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L11)

Represents a BTC relay bitcoin light client contract, which verifies the bitcoin blockheaders on smart chains

## Type Parameters

| Type Parameter                                                                                                                        | Default type                                                                                                     |
| ------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------- |
| `V` *extends* [`BtcStoredHeader`](https://docs.atomiq.exchange/sdk-reference/api/atomiq-sdk/src/interfaces/BtcStoredHeader.md)<`any`> | -                                                                                                                |
| `T`                                                                                                                                   | -                                                                                                                |
| `B` *extends* `BtcBlock`                                                                                                              | -                                                                                                                |
| `Signer` *extends* [`AbstractSigner`](https://docs.atomiq.exchange/sdk-reference/api/atomiq-sdk/src/type-aliases/AbstractSigner.md)   | [`AbstractSigner`](https://docs.atomiq.exchange/sdk-reference/api/atomiq-sdk/src/type-aliases/AbstractSigner.md) |

## Properties

### maxForkHeadersPerTx

```
maxForkHeadersPerTx: number;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:25](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L25)

Maximum amount of fork headers that fit in a single transactions

***

### maxHeadersPerTx

```
maxHeadersPerTx: number;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:21](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L21)

Maximum blockheaders that fit in a single transaction

***

### maxShortForkHeadersPerTx?

```
optional maxShortForkHeadersPerTx: number;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:29](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L29)

Maximum amount of fork headers that can be submitted at once using the short fork method

## Methods

### estimateSynchronizeFee()

```
estimateSynchronizeFee(requiredBlockheight, feeRate?): Promise<bigint>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:166](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L166)

Estimate required synchronization fee (worst case) to synchronize btc relay to the required blockheight

#### Parameters

| Parameter             | Type     | Description                                 |
| --------------------- | -------- | ------------------------------------------- |
| `requiredBlockheight` | `number` | Blockheight to which to synchronize         |
| `feeRate?`            | `string` | Optional fee rate to use for the estimation |

#### Returns

`Promise`<`bigint`>

***

### getFeePerBlock()

```
getFeePerBlock(feeRate?): Promise<bigint>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:173](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L173)

Returns required fee in native token to synchronize a single block to btc relay

#### Parameters

| Parameter  | Type  | Description                                 |
| ---------- | ----- | ------------------------------------------- |
| `feeRate?` | `any` | Optional fee rate to use for the estimation |

#### Returns

`Promise`<`bigint`>

***

### getForkFeeRate()

```
getForkFeeRate(signer, forkId): Promise<string>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:158](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L158)

Gets fee rate required for submitting blockheaders to the specific fork

#### Parameters

| Parameter | Type     | Description                                  |
| --------- | -------- | -------------------------------------------- |
| `signer`  | `string` | A signer's address to use for the estimation |
| `forkId`  | `number` | A fork ID to use for estimation              |

#### Returns

`Promise`<`string`>

***

### getMainFeeRate()

```
getMainFeeRate(signer): Promise<string>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:150](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L150)

Gets fee rate required for submitting blockheaders to the main chain

#### Parameters

| Parameter | Type     | Description                                  |
| --------- | -------- | -------------------------------------------- |
| `signer`  | `string` | A signer's address to use for the estimation |

#### Returns

`Promise`<`string`>

***

### getTipData()

```
getTipData(): Promise<{

  blockhash: string;

  blockheight: number;

  chainWork: Buffer;

  commitHash: string;

}>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:34](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L34)

Returns data about current main chain tip stored in the btc relay

#### Returns

`Promise`<{ `blockhash`: `string`; `blockheight`: `number`; `chainWork`: `Buffer`; `commitHash`: `string`; }>

***

### retrieveLatestKnownBlockLog()

```
retrieveLatestKnownBlockLog(): Promise<{

  resultBitcoinHeader: B;

  resultStoredHeader: V;

}>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:65](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L65)

Retrieves latest known bitcoin blockheader stored in the BTC Relay and also known to the bitcoin RPC

#### Returns

`Promise`<{ `resultBitcoinHeader`: `B`; `resultStoredHeader`: `V`; }>

***

### retrieveLogAndBlockheight()

```
retrieveLogAndBlockheight(blockData, requiredBlockheight?): Promise<{

  header: V;

  height: number;

}>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:48](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L48)

Retrieves blockheader with a specific blockhash, returns null if `requiredBlockheight` is provided and btc relay contract is not synced up to the desired blockheight

#### Parameters

| Parameter              | Type                                           | Description |
| ---------------------- | ---------------------------------------------- | ----------- |
| `blockData`            | { `blockhash`: `string`; `height`: `number`; } |             |
| `blockData.blockhash`  | `string`                                       | -           |
| `blockData.height?`    | `number`                                       | -           |
| `requiredBlockheight?` | `number`                                       |             |

#### Returns

`Promise`<{ `header`: `V`; `height`: `number`; }>

***

### retrieveLogByCommitHash()

```
retrieveLogByCommitHash(commitHash, blockData): Promise<V>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:60](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L60)

Retrieves stored bitcoin blockheader data by blockheader's commit hash and provided blockhash from `blockData`

#### Parameters

| Parameter             | Type                                           | Description |
| --------------------- | ---------------------------------------------- | ----------- |
| `commitHash`          | `string`                                       |             |
| `blockData`           | { `blockhash`: `string`; `height`: `number`; } |             |
| `blockData.blockhash` | `string`                                       | -           |
| `blockData.height`    | `number`                                       | -           |

#### Returns

`Promise`<`V`>

***

### saveForkHeaders()

```
saveForkHeaders(

   signer, 

   forkHeaders, 

   storedHeader, 

   forkId, 

   tipWork, 

   feeRate?): Promise<{

  computedCommitedHeaders: V[];

  forkId: number;

  lastStoredHeader: V;

  tx: T;

}>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:122](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L122)

Returns a transaction that continues submitting blockheaders to an existing long fork

#### Parameters

| Parameter      | Type     | Description                                                                  |
| -------------- | -------- | ---------------------------------------------------------------------------- |
| `signer`       | `string` | A signer's address for the transaction                                       |
| `forkHeaders`  | `B`\[]   | New fork bitcoin blockheaders to submit                                      |
| `storedHeader` | `V`      | Committed and stored bitcoin blockheader in the BTC relay from which to fork |
| `forkId`       | `number` | Fork ID to submit the blockheaders to                                        |
| `tipWork`      | `Buffer` | Chainwork of the current BTC Relay main chain tip                            |
| `feeRate?`     | `string` | Optional fee rate for the transaction                                        |

#### Returns

`Promise`<{ `computedCommitedHeaders`: `V`\[]; `forkId`: `number`; `lastStoredHeader`: `V`; `tx`: `T`; }>

***

### saveInitialHeader()

```
saveInitialHeader(

   signer, 

   header, 

   epochStart, 

   pastBlocksTimestamps, 

feeRate?): Promise<T>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:79](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L79)

Initializes the underlying BTC Relay contract

#### Parameters

| Parameter              | Type        | Description                                                        |
| ---------------------- | ----------- | ------------------------------------------------------------------ |
| `signer`               | `string`    | A signer's address to use for the transaction                      |
| `header`               | `B`         | Main chain blockheader to use as a genesis                         |
| `epochStart`           | `number`    | Timestamp of the first block in this difficulty epoch              |
| `pastBlocksTimestamps` | `number`\[] | Timestamps of the last 11 blockheaders, for median block time rule |
| `feeRate?`             | `string`    | Optional fee rate for the transaction                              |

#### Returns

`Promise`<`T`>

***

### saveMainHeaders()

```
saveMainHeaders(

   signer, 

   mainHeaders, 

   storedHeader, 

   feeRate?): Promise<{

  computedCommitedHeaders: V[];

  forkId: number;

  lastStoredHeader: V;

  tx: T;

}>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:89](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L89)

Returns a transaction that submits bitcoin blockheaders as a bitcoin main chain to the btc relay

#### Parameters

| Parameter      | Type     | Description                                                      |
| -------------- | -------- | ---------------------------------------------------------------- |
| `signer`       | `string` | A signer's address for the transaction                           |
| `mainHeaders`  | `B`\[]   | New bitcoin blockheaders to submit                               |
| `storedHeader` | `V`      | Latest committed and stored bitcoin blockheader in the BTC relay |
| `feeRate?`     | `string` | Optional fee rate for the transaction                            |

#### Returns

`Promise`<{ `computedCommitedHeaders`: `V`\[]; `forkId`: `number`; `lastStoredHeader`: `V`; `tx`: `T`; }>

***

### saveNewForkHeaders()

```
saveNewForkHeaders(

   signer, 

   forkHeaders, 

   storedHeader, 

   tipWork, 

   feeRate?): Promise<{

  computedCommitedHeaders: V[];

  forkId: number;

  lastStoredHeader: V;

  tx: T;

}>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:105](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L105)

Returns a transaction that submits a new long fork and submits the first headers to it

#### Parameters

| Parameter      | Type     | Description                                                                  |
| -------------- | -------- | ---------------------------------------------------------------------------- |
| `signer`       | `string` | A signer's address for the transaction                                       |
| `forkHeaders`  | `B`\[]   | New fork bitcoin blockheaders to submit                                      |
| `storedHeader` | `V`      | Committed and stored bitcoin blockheader in the BTC relay from which to fork |
| `tipWork`      | `Buffer` | Chainwork of the current BTC Relay main chain tip                            |
| `feeRate?`     | `string` | Optional fee rate for the transaction                                        |

#### Returns

`Promise`<{ `computedCommitedHeaders`: `V`\[]; `forkId`: `number`; `lastStoredHeader`: `V`; `tx`: `T`; }>

***

### saveShortForkHeaders()?

```
optional saveShortForkHeaders(

   signer, 

   forkHeaders, 

   storedHeader, 

   tipWork, 

   feeRate?): Promise<{

  computedCommitedHeaders: V[];

  forkId: number;

  lastStoredHeader: V;

  tx: T;

}>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:138](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L138)

Returns a transaction that submits a short fork with the provided blockheaders

#### Parameters

| Parameter      | Type     | Description                                                                  |
| -------------- | -------- | ---------------------------------------------------------------------------- |
| `signer`       | `string` | A signer's address for the transaction                                       |
| `forkHeaders`  | `B`\[]   | New fork bitcoin blockheaders to submit                                      |
| `storedHeader` | `V`      | Committed and stored bitcoin blockheader in the BTC relay from which to fork |
| `tipWork`      | `Buffer` | Chainwork of the current BTC Relay main chain tip                            |
| `feeRate?`     | `string` | Optional fee rate for the transaction                                        |

#### Returns

`Promise`<{ `computedCommitedHeaders`: `V`\[]; `forkId`: `number`; `lastStoredHeader`: `V`; `tx`: `T`; }>

***

### sweepForkData()?

```
optional sweepForkData(signer, lastSweepTimestamp?): Promise<number>;
```

Defined in: [atomiq-base/src/btcrelay/BtcRelay.ts:183](https://github.com/atomiqlabs/atomiq-base/blob/df344bedbab9ab3de863e3c2d9246e90bd861d04/src/btcrelay/BtcRelay.ts#L183)

Checks and sweeps data accounts which contain yet unused fork data (use for Solana's PDAs)

#### Parameters

| Parameter             | Type     | Description                             |
| --------------------- | -------- | --------------------------------------- |
| `signer`              | `Signer` | A signer's address to check account for |
| `lastSweepTimestamp?` | `number` | Timestamp of the last sweep             |

#### Returns

`Promise`<`number`>

A number of data accounts swept