import { ref } from 'vue';

/**
 * Wallet store (module-level singleton so the header, shop, and composer all
 * share one balance). Credits are CENTI-CREDITS server-side; `displayBalance`
 * converts to a human "crédits" number. Live updates arrive via the WS `wallet`
 * frame, routed here through useMessages' realtime hook (applyWalletFrame).
 */

export interface WalletView {
  ip: string;
  balance: number; // centi-credits, or a huge sentinel in free mode
  freeMode: boolean;
}

const API_URL = import.meta.env.VITE_API_URL ?? 'http://localhost:3000';

const ip = ref<string>('');
const balanceRaw = ref<number>(0); // centi-credits
const freeMode = ref<boolean>(false);
const loaded = ref<boolean>(false);

function apply(view: WalletView): void {
  ip.value = view.ip;
  balanceRaw.value = view.balance;
  freeMode.value = view.freeMode;
  loaded.value = true;
}

/** Called by the realtime `wallet` frame handler. */
export function applyWalletFrame(data: WalletView): void {
  apply(data);
}

async function fetchWallet(): Promise<void> {
  try {
    const res = await fetch(`${API_URL}/api/wallet`);
    if (res.ok) apply((await res.json()) as WalletView);
  } catch {
    /* offline — keep last known */
  }
}

async function topUp(): Promise<void> {
  try {
    const res = await fetch(`${API_URL}/api/wallet/topup`, { method: 'POST' });
    if (res.ok) apply((await res.json()) as WalletView);
  } catch {
    /* ignore */
  }
}

/** Human-readable balance ("∞" in free mode, else credits with 2 decimals). */
function displayBalance(): string {
  if (freeMode.value) return '∞';
  return (balanceRaw.value / 100).toLocaleString('fr-FR', {
    minimumFractionDigits: 2,
    maximumFractionDigits: 2,
  });
}

export function useWallet() {
  return {
    ip,
    balanceRaw,
    freeMode,
    loaded,
    fetchWallet,
    topUp,
    displayBalance,
  };
}