nip60: fixes, actual Cashu stuff and a wallet.Receive() method.

nip60/receive.go

@@ -0,0 +1,143 @@
+package nip60
+
+import (
+	"context"
+	"fmt"
+	"slices"
+
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/elnosh/gonuts/cashu"
+	"github.com/elnosh/gonuts/cashu/nuts/nut02"
+	"github.com/elnosh/gonuts/cashu/nuts/nut03"
+	"github.com/elnosh/gonuts/cashu/nuts/nut10"
+	"github.com/nbd-wtf/go-nostr"
+	"github.com/nbd-wtf/go-nostr/nip60/client"
+)
+
+func (w *Wallet) ReceiveToken(ctx context.Context, serializedToken string) error {
+	token, err := cashu.DecodeToken(serializedToken)
+	if err != nil {
+		return err
+	}
+
+	source := "http" + nostr.NormalizeURL(token.Mint())[2:]
+	swap := slices.Contains(w.Mints, source)
+	proofs := token.Proofs()
+	isp2pk := false
+
+	for i, proof := range proofs {
+		if proof.Secret != "" {
+			nut10Secret, err := nut10.DeserializeSecret(proof.Secret)
+			if err != nil {
+				return fmt.Errorf("invalid nip10 secret at %d: %w", i, err)
+			}
+			switch nut10Secret.Kind {
+			case nut10.P2PK:
+				isp2pk = true
+				proofs[i].Witness, err = signInput(w.PrivateKey, w.PublicKey, proof, nut10Secret)
+				if err != nil {
+					return fmt.Errorf("failed to sign locked proof %d: %w", i, err)
+				}
+			case nut10.HTLC:
+				return fmt.Errorf("HTLC token not supported yet")
+			case nut10.AnyoneCanSpend:
+				// ok
+			}
+		}
+	}
+
+	sourceKeysets, err := client.GetAllKeysets(ctx, source)
+	if err != nil {
+		return fmt.Errorf("failed to get %s keysets: %w", source, err)
+	}
+	var sourceActiveKeyset nut02.Keyset
+	var sourceActiveKeys map[uint64]*btcec.PublicKey
+	for _, keyset := range sourceKeysets {
+		if keyset.Unit == cashu.Sat.String() && keyset.Active {
+			sourceActiveKeyset = keyset
+			sourceActiveKeysHex, err := client.GetKeysetById(ctx, source, keyset.Id)
+			if err != nil {
+				return fmt.Errorf("failed to get keyset keys for %s: %w", keyset.Id, err)
+			}
+			sourceActiveKeys, err = parseKeysetKeys(sourceActiveKeysHex)
+		}
+	}
+
+	// get new proofs
+	splits := make([]uint64, len(proofs))
+	for i, p := range proofs { // TODO: do the fee stuff here because it won't always be free
+		splits[i] = p.Amount
+	}
+
+	outputs, secrets, rs, err := createBlindedMessages(splits, sourceActiveKeyset.Id)
+	if err != nil {
+		return fmt.Errorf("failed to create blinded message: %w", err)
+	}
+
+	if isp2pk {
+		for i, output := range outputs {
+			outputs[i].Witness, err = signOutput(w.PrivateKey, output)
+			if err != nil {
+				return fmt.Errorf("failed to sign output message %d: %w", i, err)
+			}
+		}
+	}
+
+	req := nut03.PostSwapRequest{
+		Inputs:  proofs,
+		Outputs: outputs,
+	}
+
+	res, err := client.PostSwap(ctx, source, req)
+	if err != nil {
+		return fmt.Errorf("failed to swap %s->%s: %w", source, w.Mints[0], err)
+	}
+
+	newProofs, err := constructProofs(res.Signatures, req.Outputs, secrets, rs, sourceActiveKeys)
+	if err != nil {
+		return fmt.Errorf("failed to construct proofs: %w", err)
+	}
+	newMint := source
+
+	// if we have to swap to our own mint we do it now by getting a bolt11 invoice from our mint
+	// and telling the current mint to pay it
+	if swap {
+		for _, targetMint := range w.Mints {
+			swappedProofs, err, tryAnother, needsManualAction := lightningMeltMint(
+				ctx,
+				newProofs,
+				source,
+				sourceKeysets,
+				targetMint,
+			)
+			if err != nil {
+				if tryAnother {
+					continue
+				}
+				if needsManualAction {
+					return fmt.Errorf("failed to swap (needs manual action): %w", err)
+				}
+
+				// if we get here that means we still have our proofs from the untrusted mint, so save those
+				goto saveproofs
+			} else {
+				// everything went well
+				newProofs = swappedProofs
+				newMint = targetMint
+				goto saveproofs
+			}
+		}
+
+		// if we got here that means we ran out of our trusted mints to swap to, so save the untrusted proofs
+		goto saveproofs
+	}
+
+saveproofs:
+	w.Tokens = append(w.Tokens, Token{
+		Mint:     newMint,
+		Proofs:   newProofs,
+		mintedAt: nostr.Now(),
+	})
+
+	return nil
+}