package retrievaladapter

import (
	"context"

	"github.com/filecoin-project/go-address"
	"github.com/filecoin-project/go-fil-markets/retrievalmarket"
	"github.com/filecoin-project/go-fil-markets/shared"
	"github.com/filecoin-project/go-state-types/abi"
	"github.com/ipfs/go-cid"
	"github.com/multiformats/go-multiaddr"
	mh "github.com/multiformats/go-multihash"
	"golang.org/x/xerrors"

	"github.com/filecoin-project/lotus/api"
	"github.com/filecoin-project/lotus/chain/actors/builtin/paych"
	"github.com/filecoin-project/lotus/chain/types"
	"github.com/filecoin-project/lotus/node/impl/full"
	payapi "github.com/filecoin-project/lotus/node/impl/paych"
)

func mkPaychReusedCid(addr address.Address) cid.Cid {
	c, err := cid.V1Builder{Codec: cid.Raw, MhType: mh.IDENTITY}.Sum(addr.Bytes())
	if err != nil {
		panic(err)
	}
	return c
}

func extractPaychReusedCid(c cid.Cid) (address.Address, error) {
	if c.Prefix().Codec != cid.Raw {
		return address.Undef, nil
	}

	h, err := mh.Decode(c.Hash())
	if err != nil {
		return address.Address{}, err
	}

	return address.NewFromBytes(h.Digest)
}

type retrievalClientNode struct {
	forceOffChain bool

	chainAPI full.ChainAPI
	payAPI   payapi.PaychAPI
	stateAPI full.StateAPI
}

// NewRetrievalClientNode returns a new node adapter for a retrieval client that talks to the
// Lotus Node
func NewRetrievalClientNode(forceOffChain bool, payAPI payapi.PaychAPI, chainAPI full.ChainAPI, stateAPI full.StateAPI) retrievalmarket.RetrievalClientNode {
	return &retrievalClientNode{
		forceOffChain: forceOffChain,
		chainAPI:      chainAPI,
		payAPI:        payAPI,
		stateAPI:      stateAPI,
	}
}

// GetOrCreatePaymentChannel sets up a new payment channel if one does not exist
// between a client and a miner and ensures the client has the given amount of
// funds available in the channel.
func (rcn *retrievalClientNode) GetOrCreatePaymentChannel(ctx context.Context, clientAddress address.Address, minerAddress address.Address, clientFundsAvailable abi.TokenAmount, tok shared.TipSetToken) (address.Address, cid.Cid, error) {
	// TODO: respect the provided TipSetToken (a serialized TipSetKey) when
	// querying the chain
	ci, err := rcn.payAPI.PaychGet(ctx, clientAddress, minerAddress, clientFundsAvailable, api.PaychGetOpts{
		OffChain: rcn.forceOffChain,
	})
	if err != nil {
		log.Errorw("paych get failed", "error", err)
		return address.Undef, cid.Undef, err
	}
	if ci.WaitSentinel == cid.Undef {
		return ci.Channel, mkPaychReusedCid(ci.Channel), nil
	}

	return ci.Channel, ci.WaitSentinel, nil
}

// Allocate late creates a lane within a payment channel so that calls to
// CreatePaymentVoucher will automatically make vouchers only for the difference
// in total
func (rcn *retrievalClientNode) AllocateLane(ctx context.Context, paymentChannel address.Address) (uint64, error) {
	return rcn.payAPI.PaychAllocateLane(ctx, paymentChannel)
}

// CreatePaymentVoucher creates a new payment voucher in the given lane for a
// given payment channel so that all the payment vouchers in the lane add up
// to the given amount (so the payment voucher will be for the difference)
func (rcn *retrievalClientNode) CreatePaymentVoucher(ctx context.Context, paymentChannel address.Address, amount abi.TokenAmount, lane uint64, tok shared.TipSetToken) (*paych.SignedVoucher, error) {
	// TODO: respect the provided TipSetToken (a serialized TipSetKey) when
	// querying the chain
	voucher, err := rcn.payAPI.PaychVoucherCreate(ctx, paymentChannel, amount, lane)
	if err != nil {
		return nil, err
	}
	if voucher.Voucher == nil {
		return nil, retrievalmarket.NewShortfallError(voucher.Shortfall)
	}
	return voucher.Voucher, nil
}

func (rcn *retrievalClientNode) GetChainHead(ctx context.Context) (shared.TipSetToken, abi.ChainEpoch, error) {
	head, err := rcn.chainAPI.ChainHead(ctx)
	if err != nil {
		return nil, 0, err
	}

	return head.Key().Bytes(), head.Height(), nil
}

func (rcn *retrievalClientNode) WaitForPaymentChannelReady(ctx context.Context, messageCID cid.Cid) (address.Address, error) {
	maybeAddr, err := extractPaychReusedCid(messageCID)
	if err != nil {
		return address.Address{}, xerrors.Errorf("extract paych reused CID: %w", err)
	}
	if maybeAddr != address.Undef {
		return maybeAddr, nil
	}
	return rcn.payAPI.PaychGetWaitReady(ctx, messageCID)
}

func (rcn *retrievalClientNode) CheckAvailableFunds(ctx context.Context, paymentChannel address.Address) (retrievalmarket.ChannelAvailableFunds, error) {

	channelAvailableFunds, err := rcn.payAPI.PaychAvailableFunds(ctx, paymentChannel)
	if err != nil {
		return retrievalmarket.ChannelAvailableFunds{}, err
	}
	return retrievalmarket.ChannelAvailableFunds{
		ConfirmedAmt:        channelAvailableFunds.ConfirmedAmt,
		PendingAmt:          channelAvailableFunds.PendingAmt,
		PendingWaitSentinel: channelAvailableFunds.PendingWaitSentinel,
		QueuedAmt:           channelAvailableFunds.QueuedAmt,
		VoucherReedeemedAmt: channelAvailableFunds.VoucherReedeemedAmt,
	}, nil
}

func (rcn *retrievalClientNode) GetKnownAddresses(ctx context.Context, p retrievalmarket.RetrievalPeer, encodedTs shared.TipSetToken) ([]multiaddr.Multiaddr, error) {
	tsk, err := types.TipSetKeyFromBytes(encodedTs)
	if err != nil {
		return nil, err
	}
	mi, err := rcn.stateAPI.StateMinerInfo(ctx, p.Address, tsk)
	if err != nil {
		return nil, err
	}
	multiaddrs := make([]multiaddr.Multiaddr, 0, len(mi.Multiaddrs))
	for _, a := range mi.Multiaddrs {
		maddr, err := multiaddr.NewMultiaddrBytes(a)
		if err != nil {
			return nil, err
		}
		multiaddrs = append(multiaddrs, maddr)
	}

	return multiaddrs, nil
}