package filcns

import (
	"context"

	"golang.org/x/xerrors"

	"github.com/filecoin-project/lotus/api"
	"github.com/filecoin-project/lotus/chain/consensus"
	"github.com/filecoin-project/lotus/chain/stmgr"
	"github.com/filecoin-project/lotus/chain/types"
)

func (filec *FilecoinEC) CreateBlock(ctx context.Context, w api.Wallet, bt *api.BlockTemplate) (*types.FullBlock, error) {
	pts, err := filec.sm.ChainStore().LoadTipSet(ctx, bt.Parents)
	if err != nil {
		return nil, xerrors.Errorf("failed to load parent tipset: %w", err)
	}

	st, recpts, err := filec.sm.TipSetState(ctx, pts)
	if err != nil {
		return nil, xerrors.Errorf("failed to load tipset state: %w", err)
	}

	_, lbst, err := stmgr.GetLookbackTipSetForRound(ctx, filec.sm, pts, bt.Epoch)
	if err != nil {
		return nil, xerrors.Errorf("getting lookback miner actor state: %w", err)
	}

	worker, err := stmgr.GetMinerWorkerRaw(ctx, filec.sm, lbst, bt.Miner)
	if err != nil {
		return nil, xerrors.Errorf("failed to get miner worker: %w", err)
	}

	next := &types.BlockHeader{
		Miner:         bt.Miner,
		Parents:       bt.Parents.Cids(),
		Ticket:        bt.Ticket,
		ElectionProof: bt.Eproof,

		BeaconEntries:         bt.BeaconValues,
		Height:                bt.Epoch,
		Timestamp:             bt.Timestamp,
		WinPoStProof:          bt.WinningPoStProof,
		ParentStateRoot:       st,
		ParentMessageReceipts: recpts,
	}

	blsMessages, secpkMessages, err := consensus.MsgsFromBlockTemplate(ctx, filec.sm, next, pts, bt)
	if err != nil {
		return nil, xerrors.Errorf("failed to process messages from block template: %w", err)
	}

	filec.SignBlock(ctx, w, worker, next)
	if err != nil {
		return nil, xerrors.Errorf("failed to sign new block: %w", err)
	}

	fullBlock := &types.FullBlock{
		Header:        next,
		BlsMessages:   blsMessages,
		SecpkMessages: secpkMessages,
	}

	return fullBlock, nil
}