Name signers after nips

packages/signer/src/signers/nip07.ts

@@ -0,0 +1,53 @@
+import {EventTemplate} from '@welshman/util'
+import {hash, own, Sign, ISigner, EncryptionImplementation} from '../util'
+
+export type Nip07 = {
+  signEvent: Sign
+  nip04: EncryptionImplementation
+  nip44: EncryptionImplementation
+  getPublicKey: () => string | undefined
+}
+
+export const getNip07 = () => (window as {nostr?: Nip07}).nostr
+
+export class Nip07Signer implements ISigner {
+  #lock = Promise.resolve()
+
+  #then = async <T>(f: (ext: Nip07) => T | Promise<T>) => {
+    const promise = this.#lock.then(() => {
+      const ext = getNip07()
+
+      if (!ext) throw new Error("Nip07 is not enabled")
+
+      return f(ext)
+    })
+
+    // Recover from errors
+    this.#lock = promise.then(() => undefined, () => undefined)
+
+    return promise
+  }
+
+  getPubkey = async () => getNip07()!.getPublicKey()!
+
+  sign = async (template: EventTemplate) => {
+    const event = hash(own(await this.getPubkey(), template))
+
+    return this.#then(ext => ext.signEvent(event))
+  }
+
+  nip04 = {
+    encrypt: (pubkey: string, message: string) =>
+      this.#then(ext => ext.nip04.encrypt(pubkey, message)),
+    decrypt: (pubkey: string, message: string) =>
+      this.#then(ext => ext.nip04.decrypt(pubkey, message)),
+  }
+
+  nip44 = {
+    encrypt: (pubkey: string, message: string) =>
+      this.#then(ext => ext.nip44.encrypt(pubkey, message)),
+    decrypt: (pubkey: string, message: string) =>
+      this.#then(ext => ext.nip44.decrypt(pubkey, message)),
+  }
+}
+