Support Aegis URL scheme for NIP-46 login

src/app/components/BunkerConnect.svelte

@@ -1,4 +1,6 @@
 <script lang="ts">
+  import {Capacitor} from "@capacitor/core"
+  import Button from "@lib/components/Button.svelte"
   import Spinner from "@lib/components/Spinner.svelte"
   import QRCode from "@app/components/QRCode.svelte"
   import type {Nip46Controller} from "@app/util/nip46"
@@ -9,6 +11,14 @@
 
   const {controller}: Props = $props()
   const {url, loading} = controller
+
+  const openAegis = () => {
+    controller.launchSigner("aegis")
+  }
+
+  const openNostrSigner = () => {
+    controller.launchSigner("nostrsigner")
+  }
 </script>
 
 {#if $url}
@@ -20,6 +30,12 @@
     <div class="flex flex-col items-center gap-2">
       <QRCode code={$url} />
       <p class="text-sm opacity-75">Scan with your signer to log in, or click to copy.</p>
+      {#if Capacitor.isNativePlatform()}
+        <div class="flex w-full flex-col gap-2">
+          <Button class="btn btn-primary" onclick={openAegis}>Open in Aegis</Button>
+          <Button class="btn" onclick={openNostrSigner}>Open in Nostr Signer</Button>
+        </div>
+      {/if}
     </div>
   {/if}
 {/if}

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()

src/routes/+layout.svelte

@@ -78,6 +78,21 @@
       return
     }
 
+    if (url.host === "x-callback-url") {
+      if (url.pathname === "/authError") {
+        const errorMessage = url.searchParams.get("errorMessage")
+
+        pushToast({
+          theme: "error",
+          message: errorMessage || "Signer authorization failed.",
+        })
+      }
+
+      if (["/authSuccess", "/authError"].includes(url.pathname)) {
+        return
+      }
+    }
+
     const target = `${url.pathname}${url.search}${url.hash}`
     goto(target, {replaceState: false, noScroll: false})
   })