import type { PetState } from "../types.ts";
import { petEngine } from "./engine.ts";
import { fresh, parseSave } from "./save-format.ts";
import { store } from "./store.ts";
import { errorMessage } from "./utils.ts";
export { fresh, parseSave } from "./save-format.ts";

export function load(): PetState {
  let raw = null;
  try {
    raw = localStorage.getItem(KEY);
  } catch {
    return fresh();
  } // storage unavailable
  if (raw == null) return fresh();
  try {
    return parseSave(raw);
  } catch (e) {
    store.badEgg = {
      raw,
      why: errorMessage(e),
      newer: e instanceof Error && "newer" in e && !!e.newer,
    };
    return fresh();
  }
}
let saveTimer = 0;
export function save() {
  // Never write while a hard reset reloads the page, over a save this page
  // could not read, or from a tab that no longer holds the pet.
  if (store.resetting || store.badEgg || !store.tabOwned) return;
  clearTimeout(saveTimer);
  saveTimer = setTimeout(() => {
    if (store.resetting || store.badEgg || !store.tabOwned) return;
    try {
      localStorage.setItem(KEY, petEngine().stateJson());
    } catch {
      /* quota or private mode */
    }
  }, 200);
}

export const KEY = "tokenling.v1";
export const BAD_KEY = "tokenling.bad";
export function cancelSave() {
  clearTimeout(saveTimer);
}
// Ownership changes need a confirmed write, not a best-effort debounce.
export function saveNow() {
  if (store.resetting || store.badEgg || !store.tabOwned)
    throw new Error("This tab cannot save the pet right now.");
  cancelSave();
  localStorage.setItem(KEY, petEngine().stateJson());
}