Add NSpec and SoapboxSigner

src/features/nostr/SoapboxSigner.ts

@@ -0,0 +1,44 @@
+import { hexToBytes } from '@noble/hashes/utils';
+import { type NostrSigner, type NostrEvent, NSecSigner } from 'nspec';
+
+/** Use key from `localStorage` if available, falling back to NIP-07. */
+export class SoapboxSigner implements NostrSigner {
+
+  #signer: NostrSigner;
+
+  constructor() {
+    const privateKey = localStorage.getItem('soapbox:nostr:privateKey');
+    const signer = privateKey ? new NSecSigner(hexToBytes(privateKey)) : window.nostr;
+
+    if (!signer) {
+      throw new Error('No Nostr signer available');
+    }
+
+    this.#signer = signer;
+  }
+
+  async getPublicKey(): Promise<string> {
+    return this.#signer.getPublicKey();
+  }
+
+  async signEvent(event: Omit<NostrEvent, 'id' | 'pubkey' | 'sig'>): Promise<NostrEvent> {
+    return this.#signer.signEvent(event);
+  }
+
+  nip04 = {
+    encrypt: (pubkey: string, plaintext: string): Promise<string> => {
+      if (!this.#signer.nip04) {
+        throw new Error('NIP-04 not supported by signer');
+      }
+      return this.#signer.nip04.encrypt(pubkey, plaintext);
+    },
+
+    decrypt: (pubkey: string, ciphertext: string): Promise<string> => {
+      if (!this.#signer.nip04) {
+        throw new Error('NIP-04 not supported by signer');
+      }
+      return this.#signer.nip04.decrypt(pubkey, ciphertext);
+    },
+  };
+
+}

src/features/nostr/sign.ts

@@ -6,6 +6,7 @@ import {
   finishEvent,
   nip04 as _nip04,
 } from 'nostr-tools';
+import { type  NostrSigner } from 'nspec';
 
 import { powWorker } from 'soapbox/workers';
 
@@ -60,4 +61,10 @@ const nip04 = {
   },
 };
 
-export { getPublicKey, signEvent, nip04 };
+const signer: NostrSigner = {
+  getPublicKey,
+  signEvent,
+  nip04,
+};
+
+export { signer };