nostr-poster/internal/nostr/events/events.go

// internal/nostr/events/events.go
package events

import (
	"encoding/json"
	"fmt"
	"time"

	"github.com/nbd-wtf/go-nostr"
	"git.sovbit.dev/Enki/nostr-poster/internal/models"
)

// EventManager handles creation and signing of Nostr events
type EventManager struct {
	// The private key getter function returns a private key for the given pubkey
	getPrivateKey func(pubkey string) (string, error)
}

// NewEventManager creates a new EventManager
func NewEventManager(getPrivateKey func(pubkey string) (string, error)) *EventManager {
	return &EventManager{
		getPrivateKey: getPrivateKey,
	}
}

// CreateAndSignMetadataEvent creates and signs a kind 0 metadata event for the bot
func (em *EventManager) CreateAndSignMetadataEvent(bot *models.Bot) (*nostr.Event, error) {
	// Create the metadata structure
	metadata := map[string]interface{}{
		"name":     bot.Name,
		"display_name": bot.DisplayName,
		"about":    bot.Bio,
	}

	// Add optional fields if they exist
	if bot.Nip05 != "" {
		metadata["nip05"] = bot.Nip05
	}
	
	if bot.ProfilePicture != "" {
		metadata["picture"] = bot.ProfilePicture
	}
	
	if bot.Banner != "" {
		metadata["banner"] = bot.Banner
	}

	// Convert metadata to JSON
	content, err := json.Marshal(metadata)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal metadata: %w", err)
	}

	// Create the event
	ev := nostr.Event{
		Kind:      0,
		CreatedAt: nostr.Timestamp(time.Now().Unix()),
		Tags:      []nostr.Tag{},
		Content:   string(content),
	}

	// Sign the event
	if err := em.SignEvent(&ev, bot.Pubkey); err != nil {
		return nil, err
	}

	return &ev, nil
}

// CreateAndSignTextNoteEvent creates and signs a kind 1 text note event
func (em *EventManager) CreateAndSignTextNoteEvent(
	pubkey string,
	content string,
	tags []nostr.Tag,
) (*nostr.Event, error) {
	// Create the event
	ev := nostr.Event{
		Kind:      1,
		CreatedAt: nostr.Timestamp(time.Now().Unix()),
		Tags:      tags,
		Content:   content,
	}

	// Sign the event
	if err := em.SignEvent(&ev, pubkey); err != nil {
		return nil, err
	}

	return &ev, nil
}

// CreateAndSignMediaEvent creates and signs a kind 1 event with media attachment
func (em *EventManager) CreateAndSignMediaEvent(
	pubkey string,
	content string,
	mediaURL string,
	mediaType string,
	mediaHash string,
	altText string,
	hashtags []string,
) (*nostr.Event, error) {
	// Create the imeta tag for the media
	imeta := []string{"imeta", "url " + mediaURL, "m " + mediaType}
	
	// Add hash if available
	if mediaHash != "" {
		imeta = append(imeta, "x "+mediaHash)
	}
	
	// Add alt text if available
	if altText != "" {
		imeta = append(imeta, "alt "+altText)
	}
	
	// Create tags
	tags := []nostr.Tag{imeta}
	
	// Add hashtags
	for _, tag := range hashtags {
		tags = append(tags, nostr.Tag{"t", tag})
	}
	
	// Create the event
	ev := nostr.Event{
		Kind:      1,
		CreatedAt: nostr.Timestamp(time.Now().Unix()),
		Tags:      tags,
		Content:   content,
	}
	
	// Sign the event
	if err := em.SignEvent(&ev, pubkey); err != nil {
		return nil, err
	}
	
	return &ev, nil
}

// CreateAndSignPictureEvent creates and signs a kind 20 picture event (NIP-68)
func (em *EventManager) CreateAndSignPictureEvent(
	pubkey string,
	title string,
	description string,
	mediaURL string,
	mediaType string,
	mediaHash string,
	altText string,
	hashtags []string,
) (*nostr.Event, error) {
	// Create the imeta tag for the media
	imeta := []string{"imeta", "url " + mediaURL, "m " + mediaType}
	
	// Add hash if available
	if mediaHash != "" {
		imeta = append(imeta, "x "+mediaHash)
	}
	
	// Add alt text if available
	if altText != "" {
		imeta = append(imeta, "alt "+altText)
	}
	
	// Create tags
	tags := []nostr.Tag{
		{"title", title},
		imeta,
	}
	
	// Add media type tag
	tags = append(tags, nostr.Tag{"m", mediaType})
	
	// Add media hash tag
	if mediaHash != "" {
		tags = append(tags, nostr.Tag{"x", mediaHash})
	}
	
	// Add hashtags
	for _, tag := range hashtags {
		tags = append(tags, nostr.Tag{"t", tag})
	}
	
	// Create the event
	ev := nostr.Event{
		Kind:      20, // NIP-68 Picture Event
		CreatedAt: nostr.Timestamp(time.Now().Unix()),
		Tags:      tags,
		Content:   description,
	}
	
	// Sign the event
	if err := em.SignEvent(&ev, pubkey); err != nil {
		return nil, err
	}
	
	return &ev, nil
}

// CreateAndSignVideoEvent creates and signs a kind 21/22 video event (NIP-71)
func (em *EventManager) CreateAndSignVideoEvent(
	pubkey string,
	title string,
	description string,
	mediaURL string,
	mediaType string,
	mediaHash string,
	previewImageURL string,
	duration int,
	altText string,
	hashtags []string,
	isShortVideo bool,
) (*nostr.Event, error) {
	// Create the imeta tag for the media
	imeta := []string{
		"imeta",
		"url " + mediaURL,
		"m " + mediaType,
	}
	
	// Add hash if available
	if mediaHash != "" {
		imeta = append(imeta, "x "+mediaHash)
	}
	
	// Add preview image if available
	if previewImageURL != "" {
		imeta = append(imeta, "image "+previewImageURL)
	}
	
	// Create tags
	tags := []nostr.Tag{
		{"title", title},
		imeta,
	}
	
	// Add duration if available
	if duration > 0 {
		tags = append(tags, nostr.Tag{"duration", fmt.Sprintf("%d", duration)})
	}
	
	// Add alt text if available
	if altText != "" {
		tags = append(tags, nostr.Tag{"alt", altText})
	}
	
	// Add hashtags
	for _, tag := range hashtags {
		tags = append(tags, nostr.Tag{"t", tag})
	}
	
	// Choose the right kind based on video type
	kind := 21 // Regular video
	if isShortVideo {
		kind = 22 // Short video
	}
	
	// Create the event
	ev := nostr.Event{
		Kind:      kind,
		CreatedAt: nostr.Timestamp(time.Now().Unix()),
		Tags:      tags,
		Content:   description,
	}
	
	// Sign the event
	if err := em.SignEvent(&ev, pubkey); err != nil {
		return nil, err
	}
	
	return &ev, nil
}

// SignEvent signs a Nostr event using the private key for the given pubkey
func (em *EventManager) SignEvent(ev *nostr.Event, pubkey string) error {
	// Set the public key
	ev.PubKey = pubkey
	
	// Get the private key
	privkey, err := em.getPrivateKey(pubkey)
	if err != nil {
		return fmt.Errorf("failed to get private key: %w", err)
	}
	
	// Sign the event
	return ev.Sign(privkey)
}