/**
 * cuentas.js — Accounts receivable logic for Nexus Autoparts
 */
(function () {
    'use strict';

    var API = '';
    var currentCustomerId = null;
    var customerPage = 1;

    // ================================================================
    // Utility
    // ================================================================

    function toast(msg, type) {
        var el = document.createElement('div');
        el.className = 'toast ' + (type || 'success');
        el.textContent = msg;
        document.body.appendChild(el);
        setTimeout(function () { el.remove(); }, 3000);
    }

    function api(path, opts) {
        opts = opts || {};
        return fetch(API + path, opts).then(function (r) {
            if (!r.ok) return r.json().then(function (d) { throw new Error(d.error || 'Error'); });
            return r.json();
        });
    }

    function esc(s) {
        if (!s) return '';
        var d = document.createElement('div');
        d.textContent = s;
        return d.innerHTML;
    }

    function fmt(n) {
        return '$' + (parseFloat(n) || 0).toFixed(2).replace(/\B(?=(\d{3})+(?!\d))/g, ',');
    }

    function fmtDate(d) {
        if (!d) return '';
        var dt = new Date(d);
        return dt.toLocaleDateString('es-MX', { day: '2-digit', month: 'short', year: 'numeric' });
    }

    // ================================================================
    // Customer List
    // ================================================================

    var searchTimer = null;
    document.getElementById('customer-search').addEventListener('input', function () {
        clearTimeout(searchTimer);
        searchTimer = setTimeout(function () {
            customerPage = 1;
            loadCustomers();
        }, 400);
    });

    function loadCustomers() {
        var search = document.getElementById('customer-search').value;
        var grid = document.getElementById('customer-grid');
        grid.innerHTML = '<div class="empty-state">Cargando...</div>';

        var params = '?page=' + customerPage + '&per_page=30';
        if (search) params += '&search=' + encodeURIComponent(search);

        api('/api/pos/customers' + params).then(function (res) {
            var data = res.data || [];
            if (data.length === 0) {
                grid.innerHTML = '<div class="empty-state">No se encontraron clientes</div>';
                document.getElementById('customer-pagination').innerHTML = '';
                return;
            }

            grid.innerHTML = data.map(function (c) {
                return '<div class="customer-card-item" data-id="' + c.id_customer + '">' +
                    '<div class="cci-name">' + esc(c.name) + '</div>' +
                    '<div class="cci-rfc">' + esc(c.rfc || 'Sin RFC') + '</div>' +
                    '<div class="cci-balance-row">' +
                    '<span class="cci-balance ' + (c.balance > 0 ? 'positive' : 'zero') + '">' + fmt(c.balance) + '</span>' +
                    '<span class="cci-limit">Limite: ' + fmt(c.credit_limit) + '</span></div></div>';
            }).join('');

            grid.querySelectorAll('.customer-card-item').forEach(function (card) {
                card.addEventListener('click', function () {
                    showCustomerDetail(parseInt(card.getAttribute('data-id')));
                });
            });

            // Pagination
            var pag = res.pagination;
            var pagEl = document.getElementById('customer-pagination');
            if (pag.total_pages <= 1) { pagEl.innerHTML = ''; return; }
            pagEl.innerHTML = '<button ' + (pag.page <= 1 ? 'disabled' : '') + ' data-p="' + (pag.page - 1) + '">&laquo;</button>' +
                '<span class="page-info">Pag ' + pag.page + '/' + pag.total_pages + '</span>' +
                '<button ' + (pag.page >= pag.total_pages ? 'disabled' : '') + ' data-p="' + (pag.page + 1) + '">&raquo;</button>';
            pagEl.querySelectorAll('button').forEach(function (btn) {
                btn.addEventListener('click', function () {
                    customerPage = parseInt(btn.getAttribute('data-p'));
                    loadCustomers();
                });
            });
        }).catch(function (err) {
            console.error('Error loading customers:', err);
            grid.innerHTML = '<div class="empty-state">Error al cargar clientes</div>';
        });
    }

    // ================================================================
    // Customer Detail
    // ================================================================

    function showCustomerDetail(customerId) {
        currentCustomerId = customerId;
        document.getElementById('list-view').style.display = 'none';
        document.getElementById('detail-view').style.display = 'block';

        api('/api/pos/customers/' + customerId + '/statement').then(function (res) {
            var c = res.customer;
            document.getElementById('dh-name').textContent = c.name;
            document.getElementById('dh-rfc').textContent = c.rfc || 'Sin RFC';

            var balEl = document.getElementById('dh-balance');
            balEl.textContent = fmt(c.balance);
            balEl.className = 'dh-value ' + (c.balance > 0 ? 'danger' : 'success');

            document.getElementById('dh-limit').textContent = fmt(c.credit_limit);
            document.getElementById('dh-terms').textContent = c.payment_terms + ' dias';

            // Invoices
            var invBody = document.getElementById('invoice-list');
            if (res.invoices.length === 0) {
                invBody.innerHTML = '<tr><td colspan="5" class="empty-state">Sin facturas</td></tr>';
            } else {
                invBody.innerHTML = res.invoices.map(function (i) {
                    return '<tr>' +
                        '<td style="font-family:monospace;font-weight:600">' + esc(i.folio) + '</td>' +
                        '<td>' + fmtDate(i.date_issued) + '</td>' +
                        '<td>' + fmt(i.total) + '</td>' +
                        '<td>' + fmt(i.amount_paid) + '</td>' +
                        '<td><span class="status-badge ' + i.status + '">' + i.status + '</span></td></tr>';
                }).join('');
            }

            // Payments
            var payBody = document.getElementById('payment-list');
            if (res.payments.length === 0) {
                payBody.innerHTML = '<tr><td colspan="5" class="empty-state">Sin pagos</td></tr>';
            } else {
                payBody.innerHTML = res.payments.map(function (p) {
                    return '<tr>' +
                        '<td>' + fmtDate(p.date_payment) + '</td>' +
                        '<td style="font-weight:600;color:var(--success)">' + fmt(p.amount) + '</td>' +
                        '<td>' + esc(p.payment_method) + '</td>' +
                        '<td>' + esc(p.reference || '') + '</td>' +
                        '<td>' + esc(p.invoice_folio || 'General') + '</td></tr>';
                }).join('');
            }

            // Populate invoice dropdown for payment form
            var invSelect = document.getElementById('pay-invoice');
            invSelect.innerHTML = '<option value="">Abono general</option>';
            res.invoices.filter(function (i) { return i.status !== 'paid' && i.status !== 'cancelled'; })
                .forEach(function (i) {
                    invSelect.innerHTML += '<option value="' + i.id_invoice + '">' +
                        i.folio + ' — ' + fmt(i.total - i.amount_paid) + ' pendiente</option>';
                });
        });
    }

    document.getElementById('btn-back-list').addEventListener('click', function () {
        document.getElementById('detail-view').style.display = 'none';
        document.getElementById('list-view').style.display = 'block';
        currentCustomerId = null;
        loadCustomers();
    });

    // ================================================================
    // Register Payment
    // ================================================================

    document.getElementById('btn-pay').addEventListener('click', function () {
        var amount = parseFloat(document.getElementById('pay-amount').value);
        if (!amount || amount <= 0) {
            toast('Ingresa un monto valido', 'error');
            return;
        }

        var invoiceId = document.getElementById('pay-invoice').value;

        api('/api/pos/payments', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
                customer_id: currentCustomerId,
                amount: amount,
                payment_method: document.getElementById('pay-method').value,
                reference: document.getElementById('pay-reference').value.trim() || null,
                invoice_id: invoiceId ? parseInt(invoiceId) : null,
                notes: document.getElementById('pay-notes').value.trim() || null
            })
        }).then(function () {
            toast('Pago de ' + fmt(amount) + ' registrado');
            // Clear form
            document.getElementById('pay-amount').value = '';
            document.getElementById('pay-reference').value = '';
            document.getElementById('pay-notes').value = '';
            // Refresh detail
            showCustomerDetail(currentCustomerId);
        }).catch(function (err) {
            toast(err.message, 'error');
        });
    });

    // ================================================================
    // Init
    // ================================================================

    loadCustomers();
})();