Support Aegis URL scheme for NIP-46 login

src/app/util/nip46.ts

@@ -1,4 +1,4 @@
-import {writable} from "svelte/store"
+import {get, writable} from "svelte/store"
 import type {Nip46ResponseWithResult} from "@welshman/signer"
 import {Nip46Broker} from "@welshman/signer"
 import {makeSecret} from "@welshman/util"
@@ -11,8 +11,28 @@ import {
 } from "@app/core/state"
 import {pushToast} from "@app/util/toast"
 
+const APP_SCHEME = "social.flotilla"
+
+type NostrSignerScheme = "aegis" | "nostrsigner"
+
+const makeSignerCallbackUrl = (path: string, sourceAppScheme: string) =>
+  `${sourceAppScheme}://x-callback-url/${path}`
+
+const makeSignerLaunchUrl = (scheme: NostrSignerScheme, nostrconnectUrl: string) => {
+  const params = new URLSearchParams({
+    method: "connect",
+    nostrconnect: nostrconnectUrl,
+    "x-source": APP_SCHEME,
+    "x-success": makeSignerCallbackUrl("authSuccess", APP_SCHEME),
+    "x-error": makeSignerCallbackUrl("authError", APP_SCHEME),
+  })
+
+  return `${scheme}://x-callback-url/auth/nip46?${params.toString()}`
+}
+
 export class Nip46Controller {
   url = writable("")
+  signerUrls = writable<{aegis: string; nostrsigner: string} | undefined>(undefined)
   bunker = writable("")
   loading = writable(false)
   clientSecret = makeSecret()
@@ -33,6 +53,10 @@ export class Nip46Controller {
     })
 
     this.url.set(url)
+    this.signerUrls.set({
+      aegis: makeSignerLaunchUrl("aegis", url),
+      nostrsigner: makeSignerLaunchUrl("nostrsigner", url),
+    })
 
     let response
     try {
@@ -54,6 +78,21 @@ export class Nip46Controller {
     }
   }
 
+  launchSigner(scheme: NostrSignerScheme) {
+    const signerUrl = get(this.signerUrls)?.[scheme]
+
+    if (!signerUrl) {
+      pushToast({
+        theme: "error",
+        message: "Unable to open signer app right now. Please try again.",
+      })
+
+      return
+    }
+
+    window.location.href = signerUrl
+  }
+
   stop() {
     this.broker.cleanup()
     this.abortController.abort()