Add openid discovery endpoint

It has a few fake fields, that I will implement later.

lib/comfycamp_web/controllers/oauth_controller.ex

@@ -108,6 +108,10 @@ defmodule ComfycampWeb.OauthController do
     )
   end
 
+  def openid_discovery(conn, _params) do
+    render(conn, :openid_discovery)
+  end
+
   defp build_redirect_uri(redirect_uri, code, state) do
     parsed_uri = URI.parse(redirect_uri)
 

lib/comfycamp_web/controllers/oauth_json.ex

@@ -7,4 +7,18 @@ defmodule ComfycampWeb.OauthJSON do
       id_token: id_token
     }
   end
+
+  def openid_discovery(_assigns) do
+    %{
+      issuer: "https://comfycamp.space",
+      authorization_endpoint: "https://comfycamp.space/oauth/authorize",
+      token_endpoint: "https://comfycamp.space/oauth/token",
+      userinfo_endpoint: "https://comfycamp.space/oauth/userinfo",
+      jwks_uri: "https://comfycamp.space/.well-known/jwks.json",
+      response_types_supported: ["code"],
+      id_token_signing_alg_values_supported: ["HS256"],
+      scopes_supported: ["openid", "profile", "email"],
+      claims_supported: ["sub", "email", "preferred_username"]
+    }
+  end
 end

lib/comfycamp_web/router.ex

@@ -32,6 +32,7 @@ defmodule ComfycampWeb.Router do
     pipe_through :api
 
     post "/oauth/token", OauthController, :token
+    get "/oauth/discovery", OauthController, :openid_discovery
   end
 
   # Enable LiveDashboard and Swoosh mailbox preview in development