import type { ShoppingListItem, PriceAlert, PriceSnapshot } from "./types";

const KEYS = {
  list: "pc_list",
  alerts: "pc_alerts",
  priceSnapshot: "pc_price_snapshot",
  lastVisit: "pc_lastVisit",
} as const;

function safeGet<T>(key: string, fallback: T): T {
  try {
    const raw = localStorage.getItem(key);
    if (!raw) return fallback;
    return JSON.parse(raw) as T;
  } catch {
    return fallback;
  }
}

export function getShoppingList(): ShoppingListItem[] {
  return safeGet<ShoppingListItem[]>(KEYS.list, []);
}

export function saveShoppingList(list: ShoppingListItem[]): void {
  localStorage.setItem(KEYS.list, JSON.stringify(list));
}

export function getAlerts(): PriceAlert[] {
  return safeGet<PriceAlert[]>(KEYS.alerts, []);
}

export function saveAlerts(alerts: PriceAlert[]): void {
  localStorage.setItem(KEYS.alerts, JSON.stringify(alerts));
}

export function getPriceSnapshot(): PriceSnapshot {
  return safeGet<PriceSnapshot>(KEYS.priceSnapshot, {});
}

export function savePriceSnapshot(snapshot: PriceSnapshot): void {
  localStorage.setItem(KEYS.priceSnapshot, JSON.stringify(snapshot));
}

export function getLastVisit(): number | null {
  const raw = localStorage.getItem(KEYS.lastVisit);
  return raw ? parseInt(raw, 10) : null;
}

export function setLastVisit(): void {
  localStorage.setItem(KEYS.lastVisit, Date.now().toString());
}