synapsecns/sanguine

package watcher

import (
    "context"
    "fmt"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/synapsecns/sanguine/ethergo/chain/chainwatcher"
    "math/big"
)

// EthHeadClient defines a method for getting a subscription to the chain-tip height on geth based rpc clients.
type EthHeadClient interface {
    // HeaderByNumber gets a block by its number, If nil is passed for number, the most recent
    // block is returned.
    HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error)
}

// blockHeightWatcher wraps EthHeadClient to return chain agnostic heads.
type blockHeightWatcher struct {
    subscriberClient EthHeadClient
}

func newBlockSubscriber(underlyingClient EthHeadClient) chainwatcher.BlockSubscriberClient {
    return blockHeightWatcher{subscriberClient: underlyingClient}
}

func (l blockHeightWatcher) LatestHeight(ctx context.Context) (uint64, error) {
    latestBlock, err := l.subscriberClient.HeaderByNumber(ctx, nil)
    if err != nil {
        return 0, fmt.Errorf("could not get latest height: %w", err)
    }
    return latestBlock.Number.Uint64(), nil
}

var _ chainwatcher.BlockSubscriberClient = &blockHeightWatcher{}

// NewBlockHeightWatcher creates a new height watcher.
func NewBlockHeightWatcher(ctx context.Context, chainID uint64, reader EthHeadClient) chainwatcher.BlockHeightWatcher {
    return chainwatcher.NewBlockHeightWatcher(ctx, chainID, newBlockSubscriber(reader))
}