php-plug-web3/src/Nostr/Delete.php

<?php

declare(strict_types=1);

namespace Core\Plug\Web3\Nostr;

use Core\Plug\Concern\BuildsResponse;
use Core\Plug\Concern\UsesHttp;
use Core\Plug\Contract\Deletable;
use Core\Plug\Response;

/**
 * Nostr event deletion (soft delete via NIP-09).
 *
 * Creates kind 5 deletion events. Note: relays may
 * not honour deletion requests.
 */
class Delete implements Deletable
{
    use BuildsResponse;
    use UsesHttp;

    private ?string $privateKey = null;

    private ?string $publicKey = null;

    private array $relays = [];

    /**
     * Set the private key for signing.
     */
    public function withPrivateKey(string $privateKey): self
    {
        $this->privateKey = $privateKey;

        return $this;
    }

    /**
     * Set the public key.
     */
    public function withPublicKey(string $publicKey): self
    {
        $this->publicKey = $publicKey;

        return $this;
    }

    /**
     * Set relays to publish to.
     */
    public function withRelays(array $relays): self
    {
        $this->relays = $relays;

        return $this;
    }

    /**
     * Request deletion of an event (NIP-09).
     *
     * @param  string  $id  Event ID to delete
     */
    public function delete(string $id): Response
    {
        if (! $this->privateKey || ! $this->publicKey) {
            return $this->error('Private and public keys required');
        }

        // Build deletion event (kind 5)
        $event = [
            'kind' => 5,
            'pubkey' => $this->publicKey,
            'created_at' => time(),
            'tags' => [
                ['e', $id], // Reference to event being deleted
            ],
            'content' => 'Deletion request',
        ];

        // Calculate event ID
        $serialized = json_encode([
            0,
            $event['pubkey'],
            $event['created_at'],
            $event['kind'],
            $event['tags'],
            $event['content'],
        ]);
        $event['id'] = hash('sha256', $serialized);

        // Sign the event
        $event['sig'] = $this->signEvent($event['id']);

        // Note: This is a soft delete - relays may ignore it
        return $this->ok([
            'deletion_event_id' => $event['id'],
            'deleted_event_id' => $id,
            'note' => 'Deletion is a request; relays may not honour it',
        ]);
    }

    /**
     * Sign event with private key.
     */
    protected function signEvent(string $eventId): string
    {
        // Placeholder - use proper Schnorr signing in production
        return hash_hmac('sha256', $eventId, $this->privateKey);
    }
}