event.go

package main

import (
	"context"
	"fmt"
	"os"
	"slices"
	"strings"
	"time"

	"github.com/fiatjaf/cli/v3"
	"github.com/mailru/easyjson"
	"github.com/nbd-wtf/go-nostr"
	"github.com/nbd-wtf/go-nostr/nip13"
	"github.com/nbd-wtf/go-nostr/nip19"
)

const (
	CATEGORY_EVENT_FIELDS = "EVENT FIELDS"
	CATEGORY_SIGNER       = "SIGNER OPTIONS"
	CATEGORY_EXTRAS       = "EXTRAS"
)

var event = &cli.Command{
	Name:  "event",
	Usage: "generates an encoded event and either prints it or sends it to a set of relays",
	Description: `outputs an event built with the flags. if one or more relays are given as arguments, an attempt is also made to publish the event to these relays.

example:
		nak event -c hello wss://nos.lol
		nak event -k 3 -p 3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d

if an event -- or a partial event -- is given on stdin, the flags can be used to optionally modify it. if it is modified it is rehashed and resigned, otherwise it is just returned as given, but that can be used to just publish to relays.

example:
		echo '{"id":"a889df6a387419ff204305f4c2d296ee328c3cd4f8b62f205648a541b4554dfb","pubkey":"c6047f9441ed7d6d3045406e95c07cd85c778e4b8cef3ca7abac09b95c709ee5","created_at":1698623783,"kind":1,"tags":[],"content":"hello from the nostr army knife","sig":"84876e1ee3e726da84e5d195eb79358b2b3eaa4d9bd38456fde3e8a2af3f1cd4cda23f23fda454869975b3688797d4c66e12f4c51c1b43c6d2997c5e61865661"}' | nak event wss://offchain.pub
		echo '{"tags": [["t", "spam"]]}' | nak event -c 'this is spam'`,
	DisableSliceFlagSeparator: true,
	Flags: append(defaultKeyFlags,
		// ~ these args are only for the convoluted musig2 signing process
		// they will be generally copy-shared-pasted across some manual coordination method between participants
		&cli.UintFlag{
			Name:        "musig",
			Usage:       "number of signers to use for musig2",
			Value:       1,
			DefaultText: "1 -- i.e. do not use musig2 at all",
			Category:    CATEGORY_SIGNER,
		},
		&cli.StringSliceFlag{
			Name:   "musig-pubkey",
			Hidden: true,
		},
		&cli.StringFlag{
			Name:   "musig-nonce-secret",
			Hidden: true,
		},
		&cli.StringSliceFlag{
			Name:   "musig-nonce",
			Hidden: true,
		},
		&cli.StringSliceFlag{
			Name:   "musig-partial",
			Hidden: true,
		},
		// ~~~
		&cli.UintFlag{
			Name:     "pow",
			Usage:    "NIP-13 difficulty to target when doing hash work on the event id",
			Category: CATEGORY_EXTRAS,
		},
		&cli.BoolFlag{
			Name:     "envelope",
			Usage:    "print the event enveloped in a [\"EVENT\", ...] message ready to be sent to a relay",
			Category: CATEGORY_EXTRAS,
		},
		&cli.BoolFlag{
			Name:     "auth",
			Usage:    "always perform NIP-42 \"AUTH\" when facing an \"auth-required: \" rejection and try again",
			Category: CATEGORY_EXTRAS,
		},
		&cli.BoolFlag{
			Name:     "nevent",
			Usage:    "print the nevent code (to stderr) after the event is published",
			Category: CATEGORY_EXTRAS,
		},
		&cli.UintFlag{
			Name:        "kind",
			Aliases:     []string{"k"},
			Usage:       "event kind",
			DefaultText: "1",
			Value:       0,
			Category:    CATEGORY_EVENT_FIELDS,
		},
		&cli.StringFlag{
			Name:        "content",
			Aliases:     []string{"c"},
			Usage:       "event content",
			DefaultText: "hello from the nostr army knife",
			Value:       "",
			Category:    CATEGORY_EVENT_FIELDS,
		},
		&cli.StringSliceFlag{
			Name:     "tag",
			Aliases:  []string{"t"},
			Usage:    "sets a tag field on the event, takes a value like -t e=<id> or -t sometag=\"value one;value two;value three\"",
			Category: CATEGORY_EVENT_FIELDS,
		},
		&cli.StringSliceFlag{
			Name:     "e",
			Usage:    "shortcut for --tag e=<value>",
			Category: CATEGORY_EVENT_FIELDS,
		},
		&cli.StringSliceFlag{
			Name:     "p",
			Usage:    "shortcut for --tag p=<value>",
			Category: CATEGORY_EVENT_FIELDS,
		},
		&cli.StringSliceFlag{
			Name:     "d",
			Usage:    "shortcut for --tag d=<value>",
			Category: CATEGORY_EVENT_FIELDS,
		},
		&NaturalTimeFlag{
			Name:        "created-at",
			Aliases:     []string{"time", "ts"},
			Usage:       "unix timestamp value for the created_at field",
			DefaultText: "now",
			Value:       nostr.Now(),
			Category:    CATEGORY_EVENT_FIELDS,
		},
	),
	ArgsUsage: "[relay...]",
	Action: func(ctx context.Context, c *cli.Command) error {
		// try to connect to the relays here
		var relays []*nostr.Relay
		if relayUrls := c.Args().Slice(); len(relayUrls) > 0 {
			relays = connectToAllRelays(ctx, relayUrls, false)
			if len(relays) == 0 {
				log("failed to connect to any of the given relays.\n")
				os.Exit(3)
			}
		}

		defer func() {
			for _, relay := range relays {
				relay.Close()
			}
		}()

		kr, sec, err := gatherKeyerFromArguments(ctx, c)
		if err != nil {
			return err
		}

		doAuth := c.Bool("auth")

		// then process input and generate events
		for stdinEvent := range getStdinLinesOrBlank() {
			evt := nostr.Event{
				Tags: make(nostr.Tags, 0, 3),
			}

			kindWasSupplied := false
			mustRehashAndResign := false

			if stdinEvent != "" {
				if err := easyjson.Unmarshal([]byte(stdinEvent), &evt); err != nil {
					ctx = lineProcessingError(ctx, "invalid event received from stdin: %s", err)
					continue
				}
				kindWasSupplied = strings.Contains(stdinEvent, `"kind"`)
			}

			if kind := c.Uint("kind"); slices.Contains(c.FlagNames(), "kind") {
				evt.Kind = int(kind)
				mustRehashAndResign = true
			} else if !kindWasSupplied {
				evt.Kind = 1
				mustRehashAndResign = true
			}

			if c.IsSet("content") {
				evt.Content = c.String("content")
				mustRehashAndResign = true
			} else if evt.Content == "" && evt.Kind == 1 {
				evt.Content = "hello from the nostr army knife"
				mustRehashAndResign = true
			}

			tagFlags := c.StringSlice("tag")
			tags := make(nostr.Tags, 0, len(tagFlags)+2)
			for _, tagFlag := range tagFlags {
				// tags are in the format key=value
				tagName, tagValue, found := strings.Cut(tagFlag, "=")
				tag := []string{tagName}
				if found {
					// tags may also contain extra elements separated with a ";"
					tagValues := strings.Split(tagValue, ";")
					tag = append(tag, tagValues...)
				}
				tags = append(tags, tag)
			}

			for _, etag := range c.StringSlice("e") {
				tags = tags.AppendUnique([]string{"e", etag})
			}
			for _, ptag := range c.StringSlice("p") {
				tags = tags.AppendUnique([]string{"p", ptag})
			}
			for _, dtag := range c.StringSlice("d") {
				tags = tags.AppendUnique([]string{"d", dtag})
			}
			if len(tags) > 0 {
				for _, tag := range tags {
					evt.Tags = append(evt.Tags, tag)
				}
				mustRehashAndResign = true
			}

			if c.IsSet("created-at") {
				evt.CreatedAt = getNaturalDate(c, "created-at")
				mustRehashAndResign = true
			} else if evt.CreatedAt == 0 {
				evt.CreatedAt = nostr.Now()
				mustRehashAndResign = true
			}

			if c.IsSet("musig") || c.IsSet("sec") || c.IsSet("prompt-sec") {
				mustRehashAndResign = true
			}

			if difficulty := c.Uint("pow"); difficulty > 0 {
				// before doing pow we need the pubkey
				if numSigners := c.Uint("musig"); numSigners > 1 {
					pubkeys := c.StringSlice("musig-pubkey")
					if int(numSigners) != len(pubkeys) {
						return fmt.Errorf("when doing a pow with musig we must know all signer pubkeys upfront")
					}
					evt.PubKey, err = getMusigAggregatedKey(ctx, pubkeys)
					if err != nil {
						return err
					}
				} else {
					evt.PubKey, _ = kr.GetPublicKey(ctx)
				}

				// try to generate work with this difficulty -- runs forever
				nonceTag, _ := nip13.DoWork(ctx, evt, int(difficulty))
				evt.Tags = append(evt.Tags, nonceTag)

				mustRehashAndResign = true
			}

			if evt.Sig == "" || mustRehashAndResign {
				if numSigners := c.Uint("musig"); numSigners > 1 {
					// must do musig
					pubkeys := c.StringSlice("musig-pubkey")
					secNonce := c.String("musig-nonce-secret")
					pubNonces := c.StringSlice("musig-nonce")
					partialSigs := c.StringSlice("musig-partial")
					signed, err := performMusig(ctx,
						sec, &evt, int(numSigners), pubkeys, pubNonces, secNonce, partialSigs)
					if err != nil {
						return fmt.Errorf("musig error: %w", err)
					}
					if !signed {
						// we haven't finished signing the event, so the users still have to do more steps
						// instructions for what to do should have been printed by the performMusig() function
						return nil
					}
				} else if err := kr.SignEvent(ctx, &evt); err != nil {
					return fmt.Errorf("error signing with provided key: %w", err)
				}
			}

			// print event as json
			var result string
			if c.Bool("envelope") {
				j, _ := json.Marshal(nostr.EventEnvelope{Event: evt})
				result = string(j)
			} else {
				j, _ := easyjson.Marshal(&evt)
				result = string(j)
			}
			stdout(result)

			// publish to relays
			successRelays := make([]string, 0, len(relays))
			if len(relays) > 0 {
				os.Stdout.Sync()
				for _, relay := range relays {
				publish:
					log("publishing to %s... ", relay.URL)
					ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
					defer cancel()

					err := relay.Publish(ctx, evt)
					if err == nil {
						// published fine
						log("success.\n")
						successRelays = append(successRelays, relay.URL)
						continue // continue to next relay
					}

					// error publishing
					if strings.HasPrefix(err.Error(), "msg: auth-required:") && kr != nil && doAuth {
						// if the relay is requesting auth and we can auth, let's do it
						pk, _ := kr.GetPublicKey(ctx)
						log("performing auth as %s... ", pk)
						if err := relay.Auth(ctx, func(authEvent *nostr.Event) error {
							return kr.SignEvent(ctx, authEvent)
						}); err == nil {
							// try to publish again, but this time don't try to auth again
							doAuth = false
							goto publish
						} else {
							log("auth error: %s. ", err)
						}
					}
					log("failed: %s\n", err)
				}
				if len(successRelays) > 0 && c.Bool("nevent") {
					nevent, _ := nip19.EncodeEvent(evt.ID, successRelays, evt.PubKey)
					log(nevent + "\n")
				}
			}
		}

		exitIfLineProcessingError(ctx)
		return nil
	},
}