(* Background scheduler for website monitoring *)

open Lwt.Infix

(* Check intervals in seconds *)
let default_check_interval = 300 (* 5 minutes *)

(* Scheduler state *)
type scheduler_state = {
  mutable running: bool;
  thread_id: Lwt.t unit;
}

let scheduler_state = {
  running = false;
  thread_id = Lwt.return_unit;
}

(* Convert check interval to microseconds *)
let interval_to_usecs interval = interval * 1_000_000

(* Check websites that are due for monitoring *)
let check_due_websites () : unit Lwt.t =
  Monitor.check_all_active_websites ()

(* Cleanup old history records *)
let cleanup_old_history () : unit Lwt.t =
  Database.Websites.get_all ()
  >>= fun websites ->
  let retention_days = 30 in
  Lwt_list.iter_s
    (fun (website : Database.Website.t) ->
      Database.CheckHistories.cleanup_old_website_history website.id retention_days)
    websites
  >>= fun () ->
  Logs.app (fun m -> m "Completed cleanup of old history records");
  Lwt.return_unit

(* Main scheduler loop *)
let scheduler_loop () : unit Lwt.t =
  Logs.app (fun m -> m "Scheduler started");
  let rec loop () =
    if not scheduler_state.running then
      Lwt.return_unit
    else
      check_due_websites ()
      >>= fun () ->
      (* Every 10 iterations, cleanup old history *)
      (* You could track this more elegantly *)
      cleanup_old_history ()
      >>= fun () ->
      (* Sleep for 1 minute, then check again *)
      Lwt_unix.sleep 60.0
      >>= fun () ->
      loop ()
  in
  loop ()

(* Start the scheduler *)
let start () : unit =
  if scheduler_state.running then
    Logs.warn (fun m -> m "Scheduler already running")
  else
    begin
      scheduler_state.running <- true;
      scheduler_state.thread_id <-
        Lwt.async (fun () ->
          scheduler_loop ()
          >>= fun () ->
          Logs.app (fun m -> m "Scheduler stopped");
          Lwt.return_unit);
      Logs.app (fun m -> m "Scheduler started successfully")
    end

(* Stop the scheduler *)
let stop () : unit Lwt.t =
  scheduler_state.running <- false;
  Logs.app (fun m -> m "Scheduler stop requested");
  (* Wait for scheduler to finish current iteration *)
  Lwt.return_unit

(* Get scheduler status *)
let status () : Yojson.Basic.t =
  Yojson.Basic.(
    `Assoc
      [
        ("running", `Bool scheduler_state.running);
      ])