implement nip60 events.

nip60/history.go

@@ -0,0 +1,153 @@
+package nip60
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strconv"
+
+	"github.com/nbd-wtf/go-nostr"
+)
+
+type HistoryEntry struct {
+	In     bool // in = received, out = sent
+	Amount uint32
+
+	tokenEventIDs []string
+	nutZaps       []bool
+
+	createdAt nostr.Timestamp
+	event     *nostr.Event
+}
+
+func (h HistoryEntry) toEvent(ctx context.Context, kr nostr.Keyer, walletId string, evt *nostr.Event) error {
+	pk, err := kr.GetPublicKey(ctx)
+	if err != nil {
+		return err
+	}
+
+	dir := "in"
+	if !h.In {
+		dir = "out"
+	}
+
+	evt.CreatedAt = h.createdAt
+	evt.Kind = 7376
+	evt.Tags = nostr.Tags{{"a", fmt.Sprintf("37375:%s:%s", pk, walletId)}}
+
+	encryptedTags := nostr.Tags{
+		nostr.Tag{"direction", dir},
+		nostr.Tag{"amount", strconv.FormatUint(uint64(h.Amount), 10), "sat"},
+	}
+
+	for i, tid := range h.tokenEventIDs {
+		isNutZap := h.nutZaps[i]
+
+		if h.In && isNutZap {
+			evt.Tags = append(evt.Tags, nostr.Tag{"e", tid, "", "redeemed"})
+			continue
+		}
+
+		marker := "created"
+		if !h.In {
+			marker = "destroyed"
+		}
+
+		encryptedTags = append(encryptedTags, nostr.Tag{"e", tid, "", marker})
+	}
+
+	jsonb, _ := json.Marshal(encryptedTags)
+	evt.Content, err = kr.Encrypt(
+		ctx,
+		string(jsonb),
+		pk,
+	)
+	if err != nil {
+		return err
+	}
+
+	err = kr.SignEvent(ctx, evt)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (h *HistoryEntry) parse(ctx context.Context, kr nostr.Keyer, evt *nostr.Event) error {
+	h.event = evt
+	h.createdAt = evt.CreatedAt
+
+	pk, err := kr.GetPublicKey(ctx)
+	if err != nil {
+		return err
+	}
+
+	// event tags and encrypted tags are mixed together
+	jsonb, err := kr.Decrypt(ctx, evt.Content, pk)
+	if err != nil {
+		return err
+	}
+	var tags nostr.Tags
+	if len(jsonb) > 0 {
+		tags = make(nostr.Tags, 0, 7)
+		if err := json.Unmarshal([]byte(jsonb), &tags); err != nil {
+			return err
+		}
+		tags = append(tags, evt.Tags...)
+	}
+
+	essential := 0
+	for _, tag := range tags {
+		if len(tag) < 2 {
+			continue
+		}
+		switch tag[0] {
+		case "direction":
+			essential++
+			if tag[1] == "in" {
+				h.In = true
+			} else if tag[1] == "out" {
+				h.In = false
+			} else {
+				return fmt.Errorf("unexpected 'direction' tag %s", tag[1])
+			}
+		case "amount":
+			essential++
+			if len(tag) < 3 {
+				return fmt.Errorf("'amount' tag must have at least 3 items")
+			}
+			if tag[2] != "sat" {
+				return fmt.Errorf("only 'sat' wallets are supported")
+			}
+			v, err := strconv.ParseUint(tag[1], 10, 32)
+			if err != nil {
+				return fmt.Errorf("invalid 'amount' %s: %w", tag[1], err)
+			}
+			h.Amount = uint32(v)
+		case "e":
+			essential++
+			if len(tag) < 4 {
+				return fmt.Errorf("'e' tag must have at least 4 items")
+			}
+			if !nostr.IsValid32ByteHex(tag[1]) {
+				return fmt.Errorf("'e' tag has invalid event id %s", tag[1])
+			}
+			h.tokenEventIDs = append(h.tokenEventIDs, tag[1])
+			switch tag[3] {
+			case "created":
+				h.nutZaps = append(h.nutZaps, false)
+			case "destroyed":
+				h.nutZaps = append(h.nutZaps, false)
+			case "redeemed":
+				h.nutZaps = append(h.nutZaps, true)
+			}
+		}
+	}
+
+	if essential < 3 {
+		return fmt.Errorf("missing essential tags")
+	}
+
+	return nil
+}