package sealing

import (
	"context"

	"github.com/filecoin-project/go-sectorbuilder/fs"
	"github.com/filecoin-project/specs-actors/actors/abi"
	"golang.org/x/xerrors"

	"github.com/filecoin-project/lotus/build"
	"github.com/filecoin-project/lotus/chain/actors"
	"github.com/filecoin-project/lotus/chain/types"
	"github.com/filecoin-project/lotus/lib/statemachine"
)

func (m *Sealing) handlePacking(ctx statemachine.Context, sector SectorInfo) error {
	log.Infow("performing filling up rest of the sector...", "sector", sector.SectorID)

	var allocated abi.UnpaddedPieceSize
	for _, piece := range sector.Pieces {
		allocated += piece.Size
	}

	ubytes := abi.PaddedPieceSize(m.sb.SectorSize()).Unpadded()

	if allocated > ubytes {
		return xerrors.Errorf("too much data in sector: %d > %d", allocated, ubytes)
	}

	fillerSizes, err := fillersFromRem(ubytes - allocated)
	if err != nil {
		return err
	}

	if len(fillerSizes) > 0 {
		log.Warnf("Creating %d filler pieces for sector %d", len(fillerSizes), sector.SectorID)
	}

	pieces, err := m.pledgeSector(ctx.Context(), sector.SectorID, sector.existingPieces(), fillerSizes...)
	if err != nil {
		return xerrors.Errorf("filling up the sector (%v): %w", fillerSizes, err)
	}

	return ctx.Send(SectorPacked{pieces: pieces})
}

func (m *Sealing) handleUnsealed(ctx statemachine.Context, sector SectorInfo) error {
	if err := checkPieces(ctx.Context(), sector, m.api); err != nil { // Sanity check state
		switch err.(type) {
		case *ErrApi:
			log.Errorf("handleUnsealed: api error, not proceeding: %+v", err)
			return nil
		case *ErrInvalidDeals:
			return ctx.Send(SectorPackingFailed{xerrors.Errorf("invalid deals in sector: %w", err)})
		case *ErrExpiredDeals: // Probably not much we can do here, maybe re-pack the sector?
			return ctx.Send(SectorPackingFailed{xerrors.Errorf("expired deals in sector: %w", err)})
		default:
			return xerrors.Errorf("checkPieces sanity check error: %w", err)
		}
	}

	log.Infow("performing sector replication...", "sector", sector.SectorID)
	ticket, err := m.tktFn(ctx.Context())
	if err != nil {
		return ctx.Send(SectorSealFailed{xerrors.Errorf("getting ticket failed: %w", err)})
	}

	rspco, err := m.sb.SealPreCommit(ctx.Context(), sector.SectorID, *ticket, sector.pieceInfos())
	if err != nil {
		return ctx.Send(SectorSealFailed{xerrors.Errorf("seal pre commit failed: %w", err)})
	}

	return ctx.Send(SectorSealed{
		commD: rspco.CommD[:],
		commR: rspco.CommR[:],
		ticket: SealTicket{
			BlockHeight: ticket.BlockHeight,
			TicketBytes: ticket.TicketBytes[:],
		},
	})
}

func (m *Sealing) handlePreCommitting(ctx statemachine.Context, sector SectorInfo) error {
	if err := checkSeal(ctx.Context(), m.maddr, sector, m.api); err != nil {
		switch err.(type) {
		case *ErrApi:
			log.Errorf("handlePreCommitting: api error, not proceeding: %+v", err)
			return nil
		case *ErrBadCommD: // TODO: Should this just back to packing? (not really needed since handleUnsealed will do that too)
			return ctx.Send(SectorSealFailed{xerrors.Errorf("bad CommD error: %w", err)})
		case *ErrExpiredTicket:
			return ctx.Send(SectorSealFailed{xerrors.Errorf("bad CommD error: %w", err)})
		default:
			return xerrors.Errorf("checkSeal sanity check error: %w", err)
		}
	}

	params := &actors.SectorPreCommitInfo{
		SectorNumber: sector.SectorID,

		CommR:     sector.CommR,
		SealEpoch: sector.Ticket.BlockHeight,
		DealIDs:   nil, // sector.deals(), // TODO: REFACTOR
	}
	enc, aerr := actors.SerializeParams(params)
	if aerr != nil {
		return ctx.Send(SectorPreCommitFailed{xerrors.Errorf("could not serialize commit sector parameters: %w", aerr)})
	}

	msg := &types.Message{
		To:       m.maddr,
		From:     m.worker,
		Method:   actors.MAMethods.PreCommitSector,
		Params:   enc,
		Value:    types.NewInt(0), // TODO: need to ensure sufficient collateral
		GasLimit: types.NewInt(1000000 /* i dont know help */),
		GasPrice: types.NewInt(1),
	}

	log.Info("submitting precommit for sector: ", sector.SectorID)
	smsg, err := m.api.MpoolPushMessage(ctx.Context(), msg)
	if err != nil {
		return ctx.Send(SectorPreCommitFailed{xerrors.Errorf("pushing message to mpool: %w", err)})
	}

	return ctx.Send(SectorPreCommitted{message: smsg.Cid()})
}

func (m *Sealing) handleWaitSeed(ctx statemachine.Context, sector SectorInfo) error {
	// would be ideal to just use the events.Called handler, but it wouldnt be able to handle individual message timeouts
	log.Info("Sector precommitted: ", sector.SectorID)
	mw, err := m.api.StateWaitMsg(ctx.Context(), *sector.PreCommitMessage)
	if err != nil {
		return ctx.Send(SectorPreCommitFailed{err})
	}

	if mw.Receipt.ExitCode != 0 {
		log.Error("sector precommit failed: ", mw.Receipt.ExitCode)
		err := xerrors.Errorf("sector precommit failed: %d", mw.Receipt.ExitCode)
		return ctx.Send(SectorPreCommitFailed{err})
	}
	log.Info("precommit message landed on chain: ", sector.SectorID)

	randHeight := mw.TipSet.Height() + build.InteractivePoRepDelay - 1 // -1 because of how the messages are applied
	log.Infof("precommit for sector %d made it on chain, will start proof computation at height %d", sector.SectorID, randHeight)

	err = m.events.ChainAt(func(ectx context.Context, ts *types.TipSet, curH abi.ChainEpoch) error {
		rand, err := m.api.ChainGetRandomness(ectx, ts.Key(), int64(randHeight))
		if err != nil {
			err = xerrors.Errorf("failed to get randomness for computing seal proof: %w", err)

			ctx.Send(SectorFatalError{error: err})
			return err
		}

		ctx.Send(SectorSeedReady{seed: SealSeed{
			BlockHeight: randHeight,
			TicketBytes: rand,
		}})

		return nil
	}, func(ctx context.Context, ts *types.TipSet) error {
		log.Warn("revert in interactive commit sector step")
		// TODO: need to cancel running process and restart...
		return nil
	}, build.InteractivePoRepConfidence, mw.TipSet.Height()+build.InteractivePoRepDelay)
	if err != nil {
		log.Warn("waitForPreCommitMessage ChainAt errored: ", err)
	}

	return nil
}

func (m *Sealing) handleCommitting(ctx statemachine.Context, sector SectorInfo) error {
	log.Info("scheduling seal proof computation...")

	proof, err := m.sb.SealCommit(ctx.Context(), sector.SectorID, sector.Ticket.SB(), sector.Seed.SB(), sector.pieceInfos(), sector.rspco())
	if err != nil {
		return ctx.Send(SectorComputeProofFailed{xerrors.Errorf("computing seal proof failed: %w", err)})
	}

	// TODO: Consider splitting states and persist proof for faster recovery

	/*params := &actors.SectorProveCommitInfo{
		Proof:    proof,
		SectorID: sector.SectorID,
		DealIDs:  sector.deals(),
	}*/

	enc, aerr := actors.SerializeParams(nil) // TODO: REFACTOR: Fix
	if aerr != nil {
		return ctx.Send(SectorCommitFailed{xerrors.Errorf("could not serialize commit sector parameters: %w", aerr)})
	}

	msg := &types.Message{
		To:       m.maddr,
		From:     m.worker,
		Method:   actors.MAMethods.ProveCommitSector,
		Params:   enc,
		Value:    types.NewInt(0), // TODO: need to ensure sufficient collateral
		GasLimit: types.NewInt(1000000 /* i dont know help */),
		GasPrice: types.NewInt(1),
	}

	// TODO: check seed / ticket are up to date

	smsg, err := m.api.MpoolPushMessage(ctx.Context(), msg)
	if err != nil {
		return ctx.Send(SectorCommitFailed{xerrors.Errorf("pushing message to mpool: %w", err)})
	}

	return ctx.Send(SectorCommitted{
		proof:   proof,
		message: smsg.Cid(),
	})
}

func (m *Sealing) handleCommitWait(ctx statemachine.Context, sector SectorInfo) error {
	if sector.CommitMessage == nil {
		log.Errorf("sector %d entered commit wait state without a message cid", sector.SectorID)
		return ctx.Send(SectorCommitFailed{xerrors.Errorf("entered commit wait with no commit cid")})
	}

	mw, err := m.api.StateWaitMsg(ctx.Context(), *sector.CommitMessage)
	if err != nil {
		return ctx.Send(SectorCommitFailed{xerrors.Errorf("failed to wait for porep inclusion: %w", err)})
	}

	if mw.Receipt.ExitCode != 0 {
		return ctx.Send(SectorCommitFailed{xerrors.Errorf("submitting sector proof failed (exit=%d, msg=%s) (t:%x; s:%x(%d); p:%x)", mw.Receipt.ExitCode, sector.CommitMessage, sector.Ticket.TicketBytes, sector.Seed.TicketBytes, sector.Seed.BlockHeight, sector.Proof)})
	}

	return ctx.Send(SectorProving{})
}

func (m *Sealing) handleFinalizeSector(ctx statemachine.Context, sector SectorInfo) error {
	// TODO: Maybe wait for some finality

	if err := m.sb.FinalizeSector(ctx.Context(), sector.SectorID); err != nil {
		if !xerrors.Is(err, fs.ErrNoSuitablePath) {
			return ctx.Send(SectorFinalizeFailed{xerrors.Errorf("finalize sector: %w", err)})
		}
		log.Warnf("finalize sector: %v", err)
	}

	if err := m.sb.DropStaged(ctx.Context(), sector.SectorID); err != nil {
		return ctx.Send(SectorFinalizeFailed{xerrors.Errorf("drop staged: %w", err)})
	}

	return ctx.Send(SectorFinalized{})
}

func (m *Sealing) handleFaulty(ctx statemachine.Context, sector SectorInfo) error {
	// TODO: check if the fault has already been reported, and that this sector is even valid

	// TODO: coalesce faulty sector reporting
	bf := types.NewBitField()
	bf.Set(uint64(sector.SectorID))

	enc, aerr := actors.SerializeParams(&actors.DeclareFaultsParams{bf})
	if aerr != nil {
		return xerrors.Errorf("failed to serialize declare fault params: %w", aerr)
	}

	msg := &types.Message{
		To:       m.maddr,
		From:     m.worker,
		Method:   actors.MAMethods.DeclareFaults,
		Params:   enc,
		Value:    types.NewInt(0), // TODO: need to ensure sufficient collateral
		GasLimit: types.NewInt(1000000 /* i dont know help */),
		GasPrice: types.NewInt(1),
	}

	smsg, err := m.api.MpoolPushMessage(ctx.Context(), msg)
	if err != nil {
		return xerrors.Errorf("failed to push declare faults message to network: %w", err)
	}

	return ctx.Send(SectorFaultReported{reportMsg: smsg.Cid()})
}

func (m *Sealing) handleFaultReported(ctx statemachine.Context, sector SectorInfo) error {
	if sector.FaultReportMsg == nil {
		return xerrors.Errorf("entered fault reported state without a FaultReportMsg cid")
	}

	mw, err := m.api.StateWaitMsg(ctx.Context(), *sector.FaultReportMsg)
	if err != nil {
		return xerrors.Errorf("failed to wait for fault declaration: %w", err)
	}

	if mw.Receipt.ExitCode != 0 {
		log.Errorf("UNHANDLED: declaring sector fault failed (exit=%d, msg=%s) (id: %d)", mw.Receipt.ExitCode, *sector.FaultReportMsg, sector.SectorID)
		return xerrors.Errorf("UNHANDLED: submitting fault declaration failed (exit %d)", mw.Receipt.ExitCode)
	}

	return ctx.Send(SectorFaultedFinal{})
}