/*!
 * Nuva Checkout Foundation — Phase 6B
 * ---------------------------------------------------------------------------
 * Builds the checkout STRUCTURE only: field validation, an order summary
 * derived from the cart + catalog (never from a remembered cart price),
 * a payment-method architecture with two seams (online, cash/pay-on-
 * delivery) that are both explicitly marked NOT LIVE, and the Part 21 order
 * data model. No real payment is processed by this file, ever.
 *
 * ORDERS is an in-memory array used only so this foundation can be tested
 * end-to-end. It is not a real persistence layer — Part 43 requires a real
 * backend to validate price/stock server-side and persist orders before
 * this can go live. clearOrders() exists so test/dev runs never leave
 * residual data behind (Part 40).
 */
(function (root) {
  'use strict';

  var CHECKOUT_VERSION = '1.0';

  var PAYMENT_METHODS = [
    { id: 'online-payment', label: 'Online Payment', live: false, note: 'Online payment provider integration is not yet configured. Selecting this option does not process a real payment in this phase.' },
    { id: 'cash-on-delivery', label: 'Cash on Delivery / Pay on Delivery', live: false, note: 'COD/POD logistics integration is not yet configured. Selecting this option does not trigger real fulfillment in this phase.' }
  ];

  var ORDERS = [];

  function str(v) { return typeof v === 'string' ? v.trim() : ''; }

  /* ===========================================================================
   * PART 19 — customer field validation
   * ===========================================================================
   */
  function validatePhone(phone) {
    var cleaned = str(phone).replace(/[\s-]/g, '');
    // Nigeria-friendly: 0XXXXXXXXXX or +234XXXXXXXXXX / 234XXXXXXXXXX, local
    // subscriber number starting 7/8/9.
    return /^(\+?234|0)[789]\d{9}$/.test(cleaned);
  }

  function validateEmail(email) {
    return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(str(email));
  }

  function validateCustomerInfo(customer, delivery) {
    customer = customer || {};
    delivery = delivery || {};
    var errors = {};

    if (!str(customer.name)) errors.name = 'Full name is required.';
    if (!str(customer.phone)) errors.phone = 'Phone number is required.';
    else if (!validatePhone(customer.phone)) errors.phone = 'Enter a valid Nigerian phone number (e.g. 080XXXXXXXX or +234XXXXXXXXXX).';
    if (!str(customer.email)) errors.email = 'Email is required.';
    else if (!validateEmail(customer.email)) errors.email = 'Enter a valid email address.';

    if (!str(delivery.address)) errors.address = 'Delivery address is required.';
    if (!str(delivery.city)) errors.city = 'City is required.';
    if (!str(delivery.state)) errors.state = 'State is required.';
    // delivery.notes is optional

    return { valid: Object.keys(errors).length === 0, errors: errors };
  }

  /* ===========================================================================
   * PART 19 — order summary (built from the CART's own re-resolved items,
   * never from a value the client remembered on its own)
   * ===========================================================================
   */
  function buildOrderSummary(deliveryFee) {
    var cart = root.NuvaCart;
    if (!cart) throw new Error('NuvaCheckout requires window.NuvaCart (Phase 6B) to be loaded first.');
    var items = cart.getItems().filter(function (i) { return i.available; });
    var subtotal = items.reduce(function (sum, i) { return sum + i.lineTotal; }, 0);
    var fee = typeof deliveryFee === 'number' ? deliveryFee : null;
    return {
      items: items.map(function (i) {
        return { productId: i.productId, name: i.name, quantity: i.quantity, unitPrice: i.unitPrice, currency: i.currency, lineTotal: i.lineTotal };
      }),
      subtotal: subtotal,
      deliveryFee: fee,
      total: subtotal + (fee || 0)
    };
  }

  function getPaymentMethods() {
    return PAYMENT_METHODS.slice();
  }

  function isPaymentMethodValid(id) {
    return PAYMENT_METHODS.some(function (m) { return m.id === id; });
  }

  function generateOrderId() {
    // Development-only scheme. A real deployment must generate this
    // server-side alongside server-side price/stock validation (Part 43).
    return 'DEV-ORDER-' + Date.now() + '-' + Math.random().toString(36).slice(2, 8).toUpperCase();
  }

  /* ===========================================================================
   * PART 21/22 — order creation
   * ===========================================================================
   */
  function createOrder(input) {
    input = input || {};
    var customer = input.customer || {};
    var delivery = input.delivery || {};
    var paymentMethod = input.paymentMethod;
    var source = input.source || {};

    var fieldCheck = validateCustomerInfo(customer, delivery);
    if (!fieldCheck.valid) {
      return { ok: false, order: null, errors: fieldCheck.errors };
    }

    if (!isPaymentMethodValid(paymentMethod)) {
      return { ok: false, order: null, errors: { paymentMethod: 'Select a valid payment method.' } };
    }

    var summary = buildOrderSummary(input.deliveryFee);
    if (!summary.items.length) {
      return { ok: false, order: null, errors: { cart: 'Your cart has no available items to order.' } };
    }

    var order = {
      orderId: generateOrderId(),
      customer: { name: str(customer.name), phone: str(customer.phone), email: str(customer.email) },
      delivery: { address: str(delivery.address), city: str(delivery.city), state: str(delivery.state), notes: str(delivery.notes) },
      items: summary.items,
      subtotal: summary.subtotal,
      deliveryFee: summary.deliveryFee,
      total: summary.total,
      paymentMethod: paymentMethod,
      paymentStatus: 'pending',
      orderStatus: 'pending',
      source: {
        // PART 22 — non-sensitive traceability only. No photos, no full
        // assessment payload, nothing transmitted externally.
        consultationType: str(source.consultationType),
        assessmentId: str(source.assessmentId),
        recommendationId: str(source.recommendationId)
      },
      createdAt: new Date().toISOString()
    };

    ORDERS.push(order);
    return { ok: true, order: order, errors: {} };
  }

  function getOrders() {
    return JSON.parse(JSON.stringify(ORDERS));
  }

  function clearOrders() {
    ORDERS.length = 0; // mutate in place so _internals.ORDERS (a live reference) stays accurate
  }

  var api = {
    version: CHECKOUT_VERSION,
    getPaymentMethods: getPaymentMethods,
    isPaymentMethodValid: isPaymentMethodValid,
    validateCustomerInfo: validateCustomerInfo,
    validatePhone: validatePhone,
    validateEmail: validateEmail,
    buildOrderSummary: buildOrderSummary,
    createOrder: createOrder,
    getOrders: getOrders,
    clearOrders: clearOrders,
    _internals: { ORDERS: ORDERS, PAYMENT_METHODS: PAYMENT_METHODS }
  };

  root.NuvaCheckout = api;

  if (typeof module !== 'undefined' && module.exports) {
    module.exports = api;
  }
})(typeof window !== 'undefined' ? window : this);