reworked admin auth to use form and cookie + adjusted oauth to support API and cookie-based auth

app/src/core/server/flash.ts

@@ -0,0 +1,40 @@
+import type { Context } from "hono";
+import { setCookie } from "hono/cookie";
+
+const flash_key = "__bknd_flash";
+export type FlashMessageType = "error" | "warning" | "success" | "info";
+
+export async function addFlashMessage(
+   c: Context,
+   message: string,
+   type: FlashMessageType = "info"
+) {
+   setCookie(c, flash_key, JSON.stringify({ type, message }), {
+      path: "/"
+   });
+}
+
+function getCookieValue(name) {
+   const cookies = document.cookie.split("; ");
+   for (const cookie of cookies) {
+      const [key, value] = cookie.split("=");
+      if (key === name) {
+         try {
+            return decodeURIComponent(value as any);
+         } catch (e) {
+            return null;
+         }
+      }
+   }
+   return null; // Return null if the cookie is not found
+}
+
+export function getFlashMessage(
+   clear = true
+): { type: FlashMessageType; message: string } | undefined {
+   const flash = getCookieValue(flash_key);
+   if (flash && clear) {
+      document.cookie = `${flash_key}=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/;`;
+   }
+   return flash ? JSON.parse(flash) : undefined;
+}