package eth

import (
	"context"
	"errors"

	"github.com/ethereum/go-ethereum/consensus/bor"
	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/event"
)

// GetRootHash returns root hash for given start and end block
func (b *EthAPIBackend) GetRootHash(ctx context.Context, starBlockNr uint64, endBlockNr uint64) (string, error) {
	var api *bor.API
	for _, _api := range b.eth.Engine().APIs(b.eth.BlockChain()) {
		if _api.Namespace == "bor" {
			api = _api.Service.(*bor.API)
		}
	}

	if api == nil {
		return "", errors.New("Only available in Bor engine")
	}

	root, err := api.GetRootHash(starBlockNr, endBlockNr)
	if err != nil {
		return "", err
	}
	return root, nil
}

// SubscribeStateSyncEvent subscribes to state sync event
func (b *EthAPIBackend) SubscribeStateSyncEvent(ch chan<- core.StateSyncEvent) event.Subscription {
	return b.eth.BlockChain().SubscribeStateSyncEvent(ch)
}