// helper: convert number to Indian-notation words (Crore, Lakh, Thousand, Hundred)
function numberToWords(num) {
  const small = ['', 'One', 'Two', 'Three', 'Four', 'Five', 'Six', 'Seven', 'Eight', 'Nine',
    'Ten', 'Eleven', 'Twelve', 'Thirteen', 'Fourteen', 'Fifteen', 'Sixteen', 'Seventeen', 'Eighteen', 'Nineteen'];
  const tens = ['', '', 'Twenty', 'Thirty', 'Forty', 'Fifty', 'Sixty', 'Seventy', 'Eighty', 'Ninety'];
  function twoDigit(n) {
    if (n < 20) return small[n];
    return tens[Math.floor(n / 10)] + (n % 10 ? ' ' + small[n % 10] : '');
  }
  let words = '';
  const crore = Math.floor(num / 10000000); num %= 10000000;
  if (crore) words += twoDigit(crore) + ' Crore ';
  const lakh = Math.floor(num / 100000); num %= 100000;
  if (lakh) words += twoDigit(lakh) + ' Lakh ';
  const thousand = Math.floor(num / 1000); num %= 1000;
  if (thousand) words += twoDigit(thousand) + ' Thousand ';
  const hundred = Math.floor(num / 100); num %= 100;
  if (hundred) words += small[hundred] + ' Hundred ';
  if (num) words += (words ? 'and ' : '') + twoDigit(num) + ' ';
  return words.trim() || 'Zero';
}

if (typeof document !== 'undefined') {
  document.addEventListener('DOMContentLoaded', function () {
    const addItemBtn = document.getElementById('add-item');
    const itemsTableBody = document.querySelector('#items-table tbody');
    const form = document.getElementById('quotation-form');
    const output = document.getElementById('quotation-output');
    const previewContent = document.getElementById('preview-content');

    // Add initial empty row
    addItemRow();

    function generateQuotationHTML(form) {
      const data = new FormData(form);
      const company = {
        name: data.get('company-name'),
        address: data.get('company-address'),
        phone: data.get('company-phone'),
        email: data.get('company-email'),
        gstin: data.get('company-gstin')
      };
      const customer = {
        name: data.get('customer-name'),
        address: data.get('customer-address'),
        phone: data.get('customer-phone'),
        email: data.get('customer-email'),
        gstin: data.get('customer-gstin')
      };
      const quotationNumber = data.get('quotation-number');
      const quotationDate = data.get('quotation-date');
      const igstRate = parseFloat(data.get('igst-rate')) || 0;
      const freightCharges = parseFloat(data.get('freight-charges')) || 0;
      const bank = {
        name: data.get('bank-name'),
        account: data.get('bank-account'),
        ifsc: data.get('bank-ifsc'),
        branch: data.get('bank-branch')
      };
      const items = [];
      itemsTableBody.querySelectorAll('tr').forEach(row => {
        const desc = row.querySelector('.item-desc').value.trim();
        if (desc) { // Only include rows with description
          items.push({
            description: desc,
            hsn: row.querySelector('.item-hsn').value,
            qty: parseFloat(row.querySelector('.item-qty').value) || 0,
            price: parseFloat(row.querySelector('.item-price').value) || 0,
            discount: parseFloat(row.querySelector('.item-discount').value) || 0,
            amount: parseFloat(row.querySelector('.item-amount').textContent) || 0
          });
        }
      });

      if (items.length === 0) {
        return '<div class="text-center text-gray-500 p-8">Please add items to generate quotation</div>';
      }

      const { subtotal, igstAmount, _total, rOff, finalTotal } = calculateQuotation(items, igstRate, freightCharges);

      // convert total to words (Rupees and Paise)
      const rupeePart = Math.floor(finalTotal);
      const paisePart = Math.round((finalTotal - rupeePart) * 100);
      const rupeeWords = numberToWords(rupeePart);
      const paiseWords = paisePart > 0 ? numberToWords(paisePart) : '';

      let html = `
        <div class="quotation-print">
          <div class="header">
            <div class="company-details">
              <h1>${company.name}</h1>
              {{address}}<br>
              GST NO. : ${company.gstin || ''}<br>
              CONTACT NO : ${company.phone} ${company.email}
            </div>
            <div class="quotation-title">
              <h1>QUOTATION</h1>
              <table class="quote-meta">
                <tr>
                  <td>QUO. NO</td>
                  <td>${quotationNumber}</td>
                </tr>
                <tr>
                  <td>DATE</td>
                  <td>${quotationDate}</td>
                </tr>
              </table>
            </div>
          </div>

          <div class="customer-info">
            <strong>CUSTOMER INFO</strong><br>
            ${customer.name}<br>
            {{cutomer_address}}<br>
            GST NO. : ${customer.gstin || ''}<br>
            CONTACT NO : ${customer.phone} ${customer.email}
          </div>

          <table class="items-table-print">
            <thead>
              <tr>
                <th>SL NO</th>
                <th>DESCRIPTION</th>
                <th>HSN CODE</th>
                <th>QTY</th>
                <th>UNIT PRICE</th>
                <th>DISCOUNT</th>
                <th>AMOUNT</th>
              </tr>
            </thead>
            <tbody>
      `;
      items.forEach((item, idx) => {
        html += `
              <tr>
                <td>${idx + 1}</td>
                <td>${item.description}</td>
                <td>${item.hsn}</td>
                <td>${item.qty}</td>
                <td>${item.price.toFixed(2)}</td>
                <td>${item.discount.toFixed(2)}%</td>
                <td>${item.amount.toFixed(2)}</td>
              </tr>
        `;
      });
      // Add empty rows to fill the page
      for (let i = items.length; i < 7; i++) {
        html += '<tr><td>&nbsp;</td><td></td><td></td><td></td><td></td><td></td><td></td></tr>';
      }

      html += `
            </tbody>
          </table>

          <div class="footer">
            <div class="notes-and-total">
              <div class="notes">
                SPECIAL NOTES:<br><br>
                AMOUNT IN WORDS:<br>
                <strong>Rupees ${rupeeWords}${paiseWords ? ' and ' + paiseWords + ' Paise' : ''} only</strong><br><br>
                Delivery : 7 to 10 working days after receiving PO<br><br>
                BANK DETAILS FOR RTGS/ NEFT<br>
                BANK:${bank.name}<br>
                BRANCH: ${bank.branch}<br>
                A/C NO: ${bank.account}<br>
                IFSC CODE: ${bank.ifsc}
              </div>
              <div class="totals">
                <table>
                  <tr>
                    <td>SUB TOTAL</td>
                    <td>${subtotal.toFixed(2)}</td>
                  </tr>
                  <tr>
                    <td>FREIGHT CHARGES</td>
                    <td>${freightCharges.toFixed(2)}</td>
                  </tr>
                  <tr>
                    <td>IGST</td>
                    <td>${igstAmount.toFixed(2)}</td>
                  </tr>
                  <tr>
                    <td>R/OFF</td>
                    <td>${rOff.toFixed(2)}</td>
                  </tr>
                  <tr>
                    <td><strong>TOTAL</strong></td>
                    <td><strong>${finalTotal.toFixed(2)}</strong></td>
                  </tr>
                </table>
              </div>
            </div>
            <div class="disclaimer">
              This quotation is not a contract or a bill. It is our best guess at the total price for the service and goods described above. The customer will be billed after indicating acceptance of this quote. Payment will be due prior to the delivery of service and goods. Please fax or mail the signed quote to the address listed above.
            </div>
            <div class="thank-you">
              Thank you for your business!
            </div>
          </div>
          <button onclick="window.print()">Print / Save as PDF</button>
        </div>
      `;
      html = html.replace('{{address}}', company.address.replace(/\n/g, '<br>'));
      html = html.replace('{{cutomer_address}}', customer.address.replace(/\n/g, '<br>'));
      return html;
    }

    function updatePreview() {
      const html = generateQuotationHTML(form);
      previewContent.innerHTML = html;
    }

    function updateSerialNumbers() {
      itemsTableBody.querySelectorAll('tr').forEach((row, i) => {
        row.querySelector('.item-slno').textContent = i + 1;
      });
    }

    function validateItemInput(input) {
      const value = input.value;
      const type = input.type;

      input.classList.remove('input-error', 'input-success');

      if (type === 'number' && value !== '') {
        const num = parseFloat(value);
        if (isNaN(num) || num < 0) {
          input.classList.add('input-error');
          return false;
        } else {
          input.classList.add('input-success');
        }
      } else if (type === 'text' && input.hasAttribute('required') && value.trim() === '') {
        input.classList.add('input-error');
        return false;
      }

      return true;
    }

    function handleKeyNavigation(event) {
      if (event.key === 'Tab' || event.key === 'Enter') {
        const currentRow = event.target.closest('tr');
        const inputs = Array.from(currentRow.querySelectorAll('input'));
        const currentIndex = inputs.indexOf(event.target);

        if (event.key === 'Enter') {
          event.preventDefault();

          // If we're at the last input in the row and it's the last row, add a new row
          if (currentIndex === inputs.length - 1) {
            const allRows = Array.from(itemsTableBody.querySelectorAll('tr'));
            const currentRowIndex = allRows.indexOf(currentRow);

            if (currentRowIndex === allRows.length - 1) {
              // Last row - add new row and focus first input
              addItemRow();
              setTimeout(() => {
                const newRow = itemsTableBody.lastElementChild;
                newRow.querySelector('.item-desc').focus();
              }, 50);
            } else {
              // Not last row - focus next row's first input
              const nextRow = allRows[currentRowIndex + 1];
              nextRow.querySelector('.item-desc').focus();
            }
          } else {
            // Move to next input in same row
            inputs[currentIndex + 1].focus();
          }
        }
      }
    }

    function addItemRow() {
      const row = document.createElement('tr');
      row.innerHTML = `
        <td class="item-slno" data-label="S.No"></td>
        <td data-label="Description">
          <div class="tooltip">
            <input type="text" class="item-desc" placeholder="Enter item description" required>
            <span class="tooltiptext">Describe the item or service being quoted</span>
          </div>
        </td>
        <td data-label="HSN Code">
          <div class="tooltip">
            <input type="text" class="item-hsn" placeholder="HSN Code">
            <span class="tooltiptext">Harmonized System of Nomenclature code for tax purposes</span>
          </div>
        </td>
        <td data-label="Qty">
          <div class="tooltip">
            <input type="number" class="item-qty" value="1" min="0" step="0.01" required>
            <span class="tooltiptext">Quantity of items</span>
          </div>
        </td>
        <td data-label="Unit Price">
          <div class="tooltip">
            <input type="number" class="item-price" value="0" min="0" step="0.01" required>
            <span class="tooltiptext">Price per unit before discount</span>
          </div>
        </td>
        <td data-label="Discount (%)">
          <div class="tooltip">
            <input type="number" class="item-discount" value="0" min="0" max="100" step="0.01" placeholder="0">
            <span class="tooltiptext">Discount percentage (0-100)</span>
          </div>
        </td>
        <td class="item-amount" data-label="Amount">0.00</td>
        <td data-label="Action">
          <button type="button" class="remove-item" title="Remove this item">
            <span>×</span> Remove
          </button>
        </td>
      `;

      itemsTableBody.appendChild(row);
      updateSerialNumbers();

      // Add event listeners to inputs
      const inputs = row.querySelectorAll('input');
      inputs.forEach(input => {
        input.addEventListener('input', (event) => {
          validateItemInput(event.target);
          updateItemAmount(event);
          updatePreview();
        });

        input.addEventListener('keydown', handleKeyNavigation);

        input.addEventListener('blur', (event) => {
          validateItemInput(event.target);
        });
      });

      // Add remove button listener
      row.querySelector('.remove-item').addEventListener('click', (_event) => {
        if (itemsTableBody.children.length > 1) {
          row.remove();
          updateSerialNumbers();
          updatePreview();
        } else {
          // If it's the last row, just clear it instead of removing
          inputs.forEach(input => {
            if (input.type === 'number') {
              input.value = input.classList.contains('item-qty') ? '1' : '0';
            } else {
              input.value = '';
            }
            input.classList.remove('input-error', 'input-success');
          });
          row.querySelector('.item-amount').textContent = '0.00';
          updatePreview();
        }
      });

      // Auto-calculate initial amount
      updateItemAmount({ target: row.querySelector('.item-qty') });
    }

    function updateItemAmount(event) {
      const row = event.target.closest('tr');
      if (!row) return;

      const qty = parseFloat(row.querySelector('.item-qty').value) || 0;
      const price = parseFloat(row.querySelector('.item-price').value) || 0;
      const discountRate = parseFloat(row.querySelector('.item-discount').value) || 0;

      const discountAmount = qty * price * discountRate / 100;
      const amount = qty * price - discountAmount;

      row.querySelector('.item-amount').textContent = amount.toFixed(2);

      // Add visual feedback for calculated amount
      const amountCell = row.querySelector('.item-amount');
      amountCell.style.backgroundColor = amount > 0 ? '#f0fdf4' : '#fef2f2';
    }

    // Enhanced Add Item button
    addItemBtn.addEventListener('click', () => {
      addItemRow();
      updatePreview();

      // Focus the new row's first input
      setTimeout(() => {
        const newRow = itemsTableBody.lastElementChild;
        newRow.querySelector('.item-desc').focus();
      }, 50);
    });

    // Add keyboard shortcut for adding items (Ctrl+I)
    document.addEventListener('keydown', (event) => {
      if (event.ctrlKey && event.key === 'i') {
        event.preventDefault();
        addItemBtn.click();
      }
    });

    form.addEventListener('input', updatePreview);

    form.addEventListener('submit', function (event) {
      event.preventDefault();

      // Validate that we have at least one item with description
      const hasValidItems = Array.from(itemsTableBody.querySelectorAll('tr')).some(row => {
        return row.querySelector('.item-desc').value.trim() !== '';
      });

      if (!hasValidItems) {
        alert('Please add at least one item with a description before generating the quotation.');
        return;
      }

      const html = generateQuotationHTML(form);
      output.innerHTML = html;
      output.style.display = 'block';
      document.getElementById('form-container').style.display = 'none';
      document.getElementById('preview-container').style.display = 'none';
      document.getElementById('top-header').style.display = 'none';
    });

    // Initial preview
    updatePreview();
  });
}

function calculateQuotation(items, igstRate, freightCharges) {
  const subtotal = items.reduce((sum, i) => sum + i.amount, 0);
  const igstAmount = (subtotal * igstRate) / 100;
  const total = subtotal + igstAmount + freightCharges;
  const totalBeforeRoundOff = total;
  const finalTotal = Math.round(totalBeforeRoundOff);
  const rOff = totalBeforeRoundOff - finalTotal;

  return {
    subtotal,
    igstAmount,
    total,
    rOff,
    finalTotal
  };
}

// Export for testing (Node.js)
if (typeof module !== 'undefined' && module.exports) {
  module.exports = { numberToWords, calculateQuotation };
}