package deals

import (
	"bytes"
	"errors"

	"github.com/filecoin-project/go-address"
	"github.com/filecoin-project/go-cbor-util"
	"github.com/filecoin-project/lotus/api"
	"github.com/filecoin-project/lotus/chain/actors"
	"github.com/filecoin-project/lotus/chain/types"
	"github.com/ipfs/go-cid"
)

var (
	// ErrWrongVoucherType means the voucher was not the correct type can validate against
	ErrWrongVoucherType = errors.New("cannot validate voucher type.")

	// ErrNoPushAccepted just means clients do not accept pushes for storage deals
	ErrNoPushAccepted = errors.New("client should not receive data for a storage deal.")

	// ErrNoPullAccepted just means providers do not accept pulls for storage deals
	ErrNoPullAccepted = errors.New("provider should not send data for a storage deal.")

	// ErrNoDeal means no active deal was found for this vouchers proposal cid
	ErrNoDeal = errors.New("no deal found for this proposal.")

	// ErrWrongPeer means that the other peer for this data transfer request does not match
	// the other peer for the deal
	ErrWrongPeer = errors.New("data Transfer peer id and Deal peer id do not match.")

	// ErrWrongPiece means that the pieceref for this data transfer request does not match
	// the one specified in the deal
	ErrWrongPiece = errors.New("base CID for deal does not match CID for piece.")

	// ErrInacceptableDealState means the deal for this transfer is not in a deal state
	// where transfer can be performed
	ErrInacceptableDealState = errors.New("deal is not a in a state where deals are accepted.")

	// DataTransferStates are the states in which it would make sense to actually start a data transfer
	DataTransferStates = []api.DealState{api.DealAccepted, api.DealUnknown}
)

const DealProtocolID = "/fil/storage/mk/1.0.1"
const AskProtocolID = "/fil/storage/ask/1.0.1"

type Proposal struct {
	DealProposal *actors.StorageDealProposal

	Piece cid.Cid // Used for retrieving from the client
}

type Response struct {
	State api.DealState

	// DealProposalRejected
	Message  string
	Proposal cid.Cid

	// DealAccepted
	StorageDealSubmission *types.SignedMessage
}

// TODO: Do we actually need this to be signed?
type SignedResponse struct {
	Response Response

	Signature *types.Signature
}

func (r *SignedResponse) Verify(addr address.Address) error {
	b, err := cborutil.Dump(&r.Response)
	if err != nil {
		return err
	}

	return r.Signature.Verify(addr, b)
}

type AskRequest struct {
	Miner address.Address
}

type AskResponse struct {
	Ask *types.SignedStorageAsk
}

// StorageDataTransferVoucher is the voucher type for data transfers
// used by the storage market
type StorageDataTransferVoucher struct {
	Proposal cid.Cid
	DealID   uint64
}

// ToBytes converts the StorageDataTransferVoucher to raw bytes
func (dv *StorageDataTransferVoucher) ToBytes() ([]byte, error) {
	var buf bytes.Buffer
	err := dv.MarshalCBOR(&buf)
	if err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

// FromBytes converts the StorageDataTransferVoucher to raw bytes
func (dv *StorageDataTransferVoucher) FromBytes(raw []byte) error {
	r := bytes.NewReader(raw)
	return dv.UnmarshalCBOR(r)
}

// Type is the unique string identifier for a StorageDataTransferVoucher
func (dv *StorageDataTransferVoucher) Type() string {
	return "StorageDataTransferVoucher"
}