"use client";

// Survives navigating away from /checkout and back (e.g. to double-check
// something in /cart) — same localStorage approach as lib/cart.ts/
// lib/discount.ts, but plain read/write functions rather than
// useSyncExternalStore: CheckoutContent is this draft's only reader, so
// there's no cross-component subscription to keep in sync the way the cart
// needs (Navbar + CartContent + CheckoutContent all read it at once).
// Deliberately excludes `password` — that field stays a plain uncontrolled
// input, never persisted.
const DRAFT_KEY = "ep_checkout_draft";

export type CheckoutDraft = {
  firstName: string;
  lastName: string;
  email: string;
  // Optional B2B fields — see CheckoutContent.tsx's own comment on why
  // they sit here (right next to the Rechnungsadresse fields, not a
  // separate persisted concept).
  companyName: string;
  vatId: string;
  // Rechnungsadresse is always a plain street address now — no
  // deliveryMethod/packstationNumber/postNumber here, only on the
  // shipping* override fields below (see CheckoutContent.tsx).
  street: string;
  zip: string;
  city: string;
  country: string;
  hasDifferentShippingAddress: boolean;
  shippingFirstName: string;
  shippingLastName: string;
  shippingDeliveryMethod: "address" | "packstation";
  shippingStreet: string;
  shippingPackstationNumber: string;
  shippingPostNumber: string;
  shippingZip: string;
  shippingCity: string;
  shippingCountry: string;
  shippingCompanyName: string;
  shippingContactEmail: string;
  shippingContactPhone: string;
  newsletterOptIn: boolean;
  shippingMethodId: number | null;
  paymentMethodId: number | null;
};

export function readCheckoutDraft(): Partial<CheckoutDraft> | null {
  if (typeof window === "undefined") return null;
  try {
    const raw = window.localStorage.getItem(DRAFT_KEY);
    return raw ? JSON.parse(raw) : null;
  } catch {
    return null;
  }
}

export function writeCheckoutDraft(draft: CheckoutDraft) {
  try {
    window.localStorage.setItem(DRAFT_KEY, JSON.stringify(draft));
  } catch {
    // localStorage unavailable (private browsing etc.) — the draft just
    // doesn't persist this time, same best-effort fallback as
    // lib/order.ts's sessionStorage write.
  }
}

// Called once an order actually completes (handleSubmit) — a leftover
// draft from a finished purchase would otherwise pre-fill the next one.
export function clearCheckoutDraft() {
  try {
    window.localStorage.removeItem(DRAFT_KEY);
  } catch {
    // ignore
  }
}