import { api, getToken } from "@/lib/api";
import type { UserPreferences } from "@/lib/types";
import { useUi } from "@/store/ui";

/** Seed the local browse settings from the signed-in user's saved preferences. */
export function applyPreferences(
  preferences: UserPreferences | null | undefined,
): void {
  if (!preferences) return;
  const ui = useUi.getState();
  if (Array.isArray(preferences.ratings)) ui.setRatings(preferences.ratings);
  if (typeof preferences.ordering === "string") ui.setOrdering(preferences.ordering);
  if (typeof preferences.per_page === "number") ui.setPerPage(preferences.per_page);
  if (typeof preferences.zoom === "number") ui.setZoom(preferences.zoom);
  if (typeof preferences.e621_per_page === "number") {
    ui.setE621PerPage(preferences.e621_per_page);
  }
}

/** The browse settings currently in effect, as a preferences payload. */
export function preferencesPayload(extra?: UserPreferences): UserPreferences {
  const ui = useUi.getState();
  return {
    ratings: ui.ratings,
    ordering: ui.ordering,
    per_page: ui.perPage,
    zoom: ui.zoom,
    e621_per_page: ui.e621PerPage,
    ...extra,
  };
}

export function savePreferences(
  patch: UserPreferences,
): Promise<UserPreferences> {
  return api<UserPreferences>("/api/auth/preferences/", {
    method: "POST",
    json: patch,
  });
}

let pending: number | null = null;
let pendingPatch: UserPreferences = {};

/**
 * Persist browse settings for the signed-in user, debounced so slider drags
 * do not spam the API. Guests keep using localStorage only.
 */
export function schedulePreferenceSave(patch: UserPreferences): void {
  if (!getToken()) return;
  pendingPatch = { ...pendingPatch, ...patch };
  if (pending !== null) window.clearTimeout(pending);
  pending = window.setTimeout(() => {
    pending = null;
    const body = preferencesPayload(pendingPatch);
    pendingPatch = {};
    void savePreferences(body).catch(() => undefined);
  }, 700);
}