Add pomade signer

packages/signer/src/index.ts

@@ -4,3 +4,4 @@ export * from "./signers/nip01.js"
 export * from "./signers/nip07.js"
 export * from "./signers/nip46.js"
 export * from "./signers/nip55.js"
+export * from "./signers/pomade.js"

packages/signer/src/signers/pomade.ts

@@ -0,0 +1,68 @@
+import * as nt44 from "nostr-tools/nip44"
+import type {Client} from "@pomade/core"
+import type {StampedEvent} from "@welshman/util"
+import {thrower, hexToBytes} from "@welshman/lib"
+import {ISigner, SignOptions, signWithOptions} from "../util.js"
+
+export class PomadeSigner implements ISigner {
+  #pubkey: string
+  #sharedSecretCache = new Map<string, Uint8Array<ArrayBuffer>>()
+
+  constructor(readonly client: Client) {
+    this.#pubkey = client.userPubkey
+  }
+
+  private getSharedSecret = async (pubkey: string) => {
+    let sharedSecret = this.#sharedSecretCache.get(pubkey)
+    if (!sharedSecret) {
+      const hexSharedSecret = await this.client.getConversationKey(pubkey)
+
+      if (hexSharedSecret) {
+        sharedSecret = hexToBytes(hexSharedSecret)
+        this.#sharedSecretCache.set(pubkey, sharedSecret)
+      }
+    }
+
+    return sharedSecret
+  }
+
+  getPubkey = async () => this.#pubkey
+
+  sign = (event: StampedEvent, options: SignOptions = {}) => {
+    const promise = this.client.sign(event).then(r => {
+      if (!r.event) {
+        throw new Error(r.messages[0]?.payload.message || "Failed to sign event")
+      }
+
+      return r.event
+    })
+
+    return signWithOptions(promise, options)
+  }
+
+  nip04 = {
+    encrypt: thrower("PomadeSigner does not support nip44"),
+    decrypt: thrower("PomadeSigner does not support nip44"),
+  }
+
+  nip44 = {
+    encrypt: async (pubkey: string, message: string) => {
+      const sharedSecret = await this.getSharedSecret(pubkey)
+
+      if (!sharedSecret) {
+        throw new Error("Failed to get shared secret")
+      }
+
+      return nt44.v2.encrypt(message, sharedSecret)
+    },
+    decrypt: async (pubkey: string, message: string) => {
+      const sharedSecret = await this.getSharedSecret(pubkey)
+
+      if (!sharedSecret) {
+        throw new Error("Failed to get shared secret")
+      }
+
+      return nt44.v2.decrypt(message, sharedSecret)
+    },
+  }
+}