fix: correct rate limit refresh

src/storage.gleam

@@ -1,12 +1,19 @@
 import gleam/dict.{type Dict}
+import gleam/erlang
 import gleam/erlang/process
 import gleam/option.{type Option}
 import gleam/otp/actor
+import gleam/result
 
 const max_requests_per_minute = 10
 
+const rate_limit_window_seconds = 60
+
 pub type StorageState {
-  StorageState(pastes: Dict(String, String), rate_limits: Dict(String, Int))
+  StorageState(
+    pastes: Dict(String, String),
+    rate_limits: Dict(String, #(Int, Int)),
+  )
 }
 
 pub type StorageMsg {
@@ -39,16 +46,20 @@ pub fn handle_message(state: StorageState, msg: StorageMsg) {
       actor.continue(StorageState(new_pastes, state.rate_limits))
     }
     CheckRateLimit(ip, reply) -> {
-      let count =
+      let now = erlang.system_time(erlang.Second)
+      let #(count, window_start) =
         state.rate_limits
         |> dict.get(ip)
-        |> option.from_result
+        |> result.unwrap(#(0, now))
-        |> option.unwrap(0)
+      let #(count, window_start) = case now - window_start >= rate_limit_window_seconds {
+        True -> #(0, now)
+        False -> #(count, window_start)
+      }
       let allowed = count < max_requests_per_minute
       let new_limits = case allowed {
         True ->
           state.rate_limits
-          |> dict.insert(ip, count + 1)
+          |> dict.insert(ip, #(count + 1, window_start))
         False -> state.rate_limits
       }
       process.send(reply, allowed)