document.addEventListener('DOMContentLoaded', () => {
    const body = document.body;
    const savedTheme = localStorage.getItem('store-theme');
    if (savedTheme === 'dark' || savedTheme === 'light') {
        body.dataset.theme = savedTheme;
    }

    const themeToggle = document.querySelector('[data-theme-toggle]');
    const helpToggle = document.querySelector('[data-help-toggle]');
    const helpClose = document.querySelector('[data-help-close]');
    const helpDrawer = document.querySelector('[data-help-drawer]');

    themeToggle?.addEventListener('click', () => {
        const nextTheme = body.dataset.theme === 'dark' ? 'light' : 'dark';
        body.dataset.theme = nextTheme;
        localStorage.setItem('store-theme', nextTheme);
    });

    const toggleHelp = (open) => {
        if (!helpDrawer) return;
        helpDrawer.classList.toggle('is-open', open);
        helpDrawer.setAttribute('aria-hidden', open ? 'false' : 'true');
    };

    helpToggle?.addEventListener('click', () => toggleHelp(true));
    helpClose?.addEventListener('click', () => toggleHelp(false));
    helpDrawer?.addEventListener('click', (event) => {
        if (event.target === helpDrawer) {
            toggleHelp(false);
        }
    });

    document.querySelectorAll('[data-auto-hide]').forEach((alert) => {
        setTimeout(() => {
            alert.style.transition = 'opacity .3s ease';
            alert.style.opacity = '0';
            setTimeout(() => alert.remove(), 320);
        }, 3200);
    });

    const formatSyp = (value) => `${new Intl.NumberFormat('en-US', { maximumFractionDigits: 0 }).format(value || 0)} ل.س`;
    const rateInput = document.querySelector('[data-rate-input]');
    const ratePreview = document.querySelector('[data-rate-preview]');
    const equipmentUsd = document.querySelector('[data-equipment-usd]');
    const equipmentPreview = document.querySelector('[data-equipment-preview]');
    const invoiceEquipment = document.querySelector('[data-invoice-equipment]');
    const invoiceQty = document.querySelector('[data-invoice-qty]');
    const invoiceStock = document.querySelector('[data-invoice-stock]');
    const invoiceTotal = document.querySelector('[data-invoice-total]');

    const currentRate = () => {
        const parsed = parseFloat(rateInput?.value || body.dataset.currentRate || '0');
        return Number.isFinite(parsed) ? parsed : 0;
    };

    const updateRatePreview = () => {
        if (ratePreview) ratePreview.textContent = formatSyp(currentRate());
    };

    const updateEquipmentPreview = () => {
        if (!equipmentPreview) return;
        const usd = parseFloat(equipmentUsd?.value || '0');
        equipmentPreview.textContent = usd > 0 && currentRate() > 0 ? formatSyp(usd * currentRate()) : '—';
    };

    const updateInvoicePreview = () => {
        if (!invoiceTotal) return;
        const option = invoiceEquipment?.selectedOptions?.[0];
        const price = parseFloat(option?.dataset.price || '0');
        const stock = parseInt(option?.dataset.stock || '0', 10);
        const qty = parseInt(invoiceQty?.value || '0', 10);
        if (invoiceStock) {
            invoiceStock.textContent = option && option.value ? `${stock} قطعة` : '—';
        }
        if (!option || !option.value || price <= 0 || qty <= 0 || currentRate() <= 0) {
            invoiceTotal.textContent = '—';
            return;
        }
        invoiceTotal.textContent = formatSyp(price * qty * currentRate());
    };

    rateInput?.addEventListener('input', () => {
        body.dataset.currentRate = rateInput.value;
        updateRatePreview();
        updateEquipmentPreview();
        updateInvoicePreview();
    });
    equipmentUsd?.addEventListener('input', updateEquipmentPreview);
    invoiceEquipment?.addEventListener('change', updateInvoicePreview);
    invoiceQty?.addEventListener('input', updateInvoicePreview);
    updateRatePreview();
    updateEquipmentPreview();
    updateInvoicePreview();

    const printableInvoice = document.querySelector('[data-printable-invoice]');
    const printButton = document.querySelector('[data-print-invoice]');
    const exportSelectedButton = document.querySelector('[data-export-selected-pdf]');
    const exportInvoicesButton = document.querySelector('[data-export-invoices]');
    const invoicesTable = document.querySelector('[data-invoices-table]');

    const openPrintWindow = (title, html) => {
        const win = window.open('', '_blank', 'width=900,height=700');
        if (!win) return;
        win.document.write(`<!doctype html><html lang="ar" dir="rtl"><head><meta charset="utf-8"><title>${title}</title><style>
            body{font-family:Segoe UI,Tahoma,Arial,sans-serif;padding:24px;background:#fff;color:#111827}
            .sheet{max-width:720px;margin:0 auto;border:1px solid #d7dfeb;border-radius:24px;padding:24px}
            .sheet *{direction:rtl;text-align:right}
            .invoice-row,.invoice-item,.invoice-note{margin-bottom:10px;padding:12px 14px;border:1px solid #d7dfeb;border-radius:14px;background:#f8fafc}
        </style></head><body><div class="sheet">${html}</div><script>window.onload=function(){window.print();setTimeout(function(){window.close();},150);};</script></body></html>`);
        win.document.close();
    };

    printButton?.addEventListener('click', () => {
        if (!printableInvoice) return;
        openPrintWindow('فاتورة', printableInvoice.innerHTML);
    });

    const hasPdf = () => window.jspdf && window.jspdf.jsPDF;

    exportSelectedButton?.addEventListener('click', () => {
        if (!hasPdf() || !printableInvoice) return;
        const { jsPDF } = window.jspdf;
        const doc = new jsPDF({ unit: 'pt', format: 'a4' });
        doc.setFontSize(18);
        doc.text('Selected Invoice', 40, 50);
        const lines = printableInvoice.innerText.split('\n').map((line) => line.trim()).filter(Boolean);
        let y = 90;
        lines.forEach((line) => {
            const chunks = doc.splitTextToSize(line, 500);
            doc.text(chunks, 40, y);
            y += chunks.length * 18 + 8;
        });
        doc.save('selected-invoice.pdf');
    });

    exportInvoicesButton?.addEventListener('click', () => {
        if (!hasPdf() || !invoicesTable) return;
        const { jsPDF } = window.jspdf;
        const doc = new jsPDF({ orientation: 'landscape', unit: 'pt', format: 'a4' });
        doc.setFontSize(16);
        doc.text('Invoices Register', 40, 40);
        const rows = Array.from(invoicesTable.querySelectorAll('tbody tr')).map((tr) =>
            Array.from(tr.querySelectorAll('td')).map((td) => td.innerText.replace(/\s+/g, ' ').trim())
        ).filter((row) => row.length === 5);
        doc.autoTable({
            head: [['Invoice', 'Customer', 'Total USD', 'Total SYP', 'Created At']],
            body: rows,
            startY: 60,
            styles: { fontSize: 10 },
            headStyles: { fillColor: [15, 118, 110] }
        });
        doc.save('invoices-register.pdf');
    });
});