import { getInvoiceById, updateInvoice, validateInvoice, addInvoiceLine } from '../services/invoices.js';

export function InvoiceModal(invoiceId, onClose, onUpdate) {
    const modal = document.createElement('div');
    modal.className = 'modal-overlay';

    let invoice = null;
    let isLoading = true;

    // Formatear fecha para input type="date"
    const formatDateForInput = (dateString) => {
        if (!dateString) return '';
        const date = new Date(dateString);
        return date.toISOString().split('T')[0];
    };

    // Formatear fecha para mostrar
    const formatDate = (dateString) => {
        if (!dateString) return '-';
        const date = new Date(dateString);
        return date.toLocaleDateString('es-ES');
    };

    // Formatear moneda
    const formatCurrency = (amount) => {
        return new Intl.NumberFormat('es-ES', {
            style: 'currency',
            currency: 'EUR'
        }).format(amount || 0);
    };

    // Obtener texto de estado
    const getStatusText = (status) => {
        const statusTextMap = {
            'draft': 'Borrador',
            'validated': 'Validada',
            'paid': 'Pagada',
            'unpaid': 'Impagada',
            'canceled': 'Cancelada'
        };
        return statusTextMap[status] || status;
    };

    // Renderizar contenido del modal
    const renderContent = () => {
        const modalContent = modal.querySelector('.modal-content');

        if (isLoading) {
            modalContent.innerHTML = `
        <div class="modal-header">
          <h2>Cargando...</h2>
          <button class="btn-close">×</button>
        </div>
        <div class="modal-body">
          <div class="loading">Cargando detalles de la factura...</div>
        </div>
      `;
            return;
        }

        if (!invoice) {
            modalContent.innerHTML = `
        <div class="modal-header">
          <h2>Error</h2>
          <button class="btn-close">×</button>
        </div>
        <div class="modal-body">
          <div class="error">No se pudo cargar la factura</div>
        </div>
      `;
            return;
        }

        const isDraft = invoice.status === 'draft';
        const canEdit = isDraft || invoice.status === 'validated' || invoice.status === 'unpaid';

        modalContent.innerHTML = `
      <div class="modal-header">
        <div class="modal-title">
          <h2>${invoice.number || 'Nueva Factura'}</h2>
          <span class="status-badge status-${invoice.status}">
            ${getStatusText(invoice.status)}
          </span>
        </div>
        <button class="btn-close">×</button>
      </div>

      <div class="modal-body">
        <form id="invoice-form">
          <!-- Información básica -->
          <div class="form-section">
            <h3>Información de la Factura</h3>
            
            <div class="form-row">
              <div class="form-group">
                <label>Número de Factura</label>
                <input 
                  type="text" 
                  name="number" 
                  value="${invoice.number || ''}"
                  disabled
                />
              </div>
              
              <div class="form-group">
                <label>Fecha</label>
                <input 
                  type="date" 
                  name="date" 
                  value="${formatDateForInput(invoice.date)}"
                  disabled
                />
              </div>
            </div>

            <div class="form-row">
              <div class="form-group">
                <label>Fecha de Vencimiento</label>
                <input 
                  type="date" 
                  name="expireDate" 
                  value="${formatDateForInput(invoice.expireDate)}"
                  ${!canEdit ? 'disabled' : ''}
                />
              </div>
              
              <div class="form-group">
                <label>Cliente ID</label>
                <input 
                  type="text" 
                  name="clientId" 
                  value="${invoice.clientId || ''}"
                  disabled
                />
              </div>
            </div>

            <div class="form-row">
              <div class="form-group full-width">
                <label>Nota Pública</label>
                <textarea name="note_public" rows="3">${invoice.note_public || ''}</textarea>
              </div>
            </div>

            <div class="form-row">
              <div class="form-group full-width">
                <label>Nota Privada</label>
                <textarea name="note_private" rows="3">${invoice.note_private || ''}</textarea>
              </div>
            </div>
          </div>

          <!-- Líneas de factura -->
          <div class="form-section">
            <div class="section-header">
              <h3>Líneas de Factura</h3>
              ${isDraft ? '<button type="button" class="btn-add-line btn-small">+ Añadir Línea</button>' : ''}
            </div>

            ${isDraft ? `
            <div class="add-line-form" style="display: none;">
              <div class="form-row">
                <div class="form-group full-width">
                  <label>Descripción</label>
                  <input type="text" id="line-description" placeholder="Descripción del producto/servicio" />
                </div>
              </div>
              <div class="form-row">
                <div class="form-group">
                  <label>Cantidad</label>
                  <input type="number" id="line-quantity" value="1" min="0.01" step="0.01" />
                </div>
                <div class="form-group">
                  <label>Precio Unitario (€)</label>
                  <input type="number" id="line-price" value="0" min="0" step="0.01" />
                </div>
              </div>
              <div class="form-row">
                <div class="form-group">
                  <label>IVA (%)</label>
                  <input type="number" id="line-tax" value="21" min="0" max="100" step="0.01" />
                </div>
                <div class="form-group" style="display: flex; align-items: flex-end; gap: 0.5rem;">
                  <button type="button" class="btn-save-line btn-small btn-success">Guardar Línea</button>
                  <button type="button" class="btn-cancel-line btn-small btn-cancel">Cancelar</button>
                </div>
              </div>
            </div>
            ` : ''}

            <div class="invoice-lines">
              <table class="lines-table">
                <thead>
                  <tr>
                    <th>Descripción</th>
                    <th>Cantidad</th>
                    <th>Precio Unitario</th>
                    <th>IVA %</th>
                    <th>Total</th>
                  </tr>
                </thead>
                <tbody>
                  ${invoice.lines && invoice.lines.length > 0
                ? invoice.lines.map(line => `
                      <tr>
                        <td>${line.description || ''}</td>
                        <td>${line.quantity || 0}</td>
                        <td>${formatCurrency(line.unitPrice)}</td>
                        <td>${line.taxRate || 0}%</td>
                        <td>${formatCurrency(line.total)}</td>
                      </tr>
                    `).join('')
                : '<tr><td colspan="5" class="no-lines">No hay líneas en esta factura</td></tr>'
            }
                </tbody>
              </table>
            </div>

            <!-- Totales -->
            <div class="invoice-totals">
              <div class="total-row">
                <span>Total:</span>
                <strong>${formatCurrency(invoice.total)}</strong>
              </div>
              <div class="total-row pending">
                <span>Pendiente:</span>
                <strong>${formatCurrency(invoice.remainToPay)}</strong>
              </div>
            </div>
          </div>
        </form>
      </div>

      <div class="modal-footer">
        <div class="footer-actions-left">
          ${isDraft ? '<button type="button" class="btn-validate btn-success"><svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" style="vertical-align: middle; margin-right: 4px;"><polyline points="20 6 9 17 4 12"/></svg>Validar Factura</button>' : ''}
        </div>
        <div class="footer-actions-right">
          <button type="button" class="btn-cancel-modal">Cancelar</button>
          ${canEdit ? '<button type="button" class="btn-save btn-primary">Guardar Cambios</button>' : ''}
        </div>
      </div>
    `;

        attachEventListeners();
    };

    // Adjuntar event listeners
    const attachEventListeners = () => {
        // Botón cerrar
        const closeBtn = modal.querySelector('.btn-close');
        closeBtn?.addEventListener('click', handleClose);

        // Botón cancelar modal
        const cancelBtn = modal.querySelector('.btn-cancel-modal');
        cancelBtn?.addEventListener('click', handleClose);

        // Botón guardar
        const saveBtn = modal.querySelector('.btn-save');
        saveBtn?.addEventListener('click', handleSave);

        // Botón validar
        const validateBtn = modal.querySelector('.btn-validate');
        validateBtn?.addEventListener('click', handleValidate);

        // Botón añadir línea
        const addLineBtn = modal.querySelector('.btn-add-line');
        addLineBtn?.addEventListener('click', toggleAddLineForm);

        // Botón guardar línea
        const saveLineBtn = modal.querySelector('.btn-save-line');
        saveLineBtn?.addEventListener('click', handleSaveLine);

        // Botón cancelar línea
        const cancelLineBtn = modal.querySelector('.btn-cancel-line');
        cancelLineBtn?.addEventListener('click', () => {
            const form = modal.querySelector('.add-line-form');
            if (form) form.style.display = 'none';
        });

        // Click fuera del modal
        modal.addEventListener('click', (e) => {
            if (e.target === modal) {
                handleClose();
            }
        });
    };

    // Manejar cierre
    const handleClose = () => {
        modal.remove();
        if (onClose) onClose();
    };

    // Manejar guardado
    const handleSave = async () => {
        const form = modal.querySelector('#invoice-form');
        const formData = new FormData(form);

        // La API espera camelCase en el PUT (notePublic/notePrivate)
        const data = {
            number: formData.get('number') || undefined,
            expireDate: formData.get('expireDate') || undefined,
            notePublic: formData.get('note_public') || undefined,
            notePrivate: formData.get('note_private') || undefined
        };

        // Filtrar valores undefined
        Object.keys(data).forEach(key => {
            if (data[key] === undefined || data[key] === '') {
                delete data[key];
            }
        });

        try {
            const saveBtn = modal.querySelector('.btn-save');
            saveBtn.disabled = true;
            saveBtn.textContent = 'Guardando...';

            await updateInvoice(invoiceId, data);

            alert('Factura actualizada correctamente');
            if (onUpdate) onUpdate();
            handleClose();
        } catch (error) {
            console.error('Error al guardar:', error);
            alert('Error al guardar la factura: ' + error.message);
        } finally {
            const saveBtn = modal.querySelector('.btn-save');
            if (saveBtn) {
                saveBtn.disabled = false;
                saveBtn.textContent = 'Guardar Cambios';
            }
        }
    };

    // Manejar validación
    const handleValidate = async () => {
        if (!confirm('¿Estás seguro de que quieres validar esta factura? No podrás editarla completamente después.')) {
            return;
        }

        try {
            const validateBtn = modal.querySelector('.btn-validate');
            validateBtn.disabled = true;
            validateBtn.textContent = 'Validando...';

            await validateInvoice(invoiceId);

            alert('Factura validada correctamente');
            if (onUpdate) onUpdate();

            // Recargar la factura para mostrar el nuevo estado
            await loadInvoice();
        } catch (error) {
            console.error('Error al validar:', error);
            alert('Error al validar la factura: ' + error.message);

            const validateBtn = modal.querySelector('.btn-validate');
            if (validateBtn) {
                validateBtn.disabled = false;
                validateBtn.innerHTML = '<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" style="vertical-align: middle; margin-right: 4px;"><polyline points="20 6 9 17 4 12"/></svg>Validar Factura';
            }
        }
    };

    // Mostrar/ocultar formulario de añadir línea
    const toggleAddLineForm = () => {
        const form = modal.querySelector('.add-line-form');
        if (form) {
            const isVisible = form.style.display !== 'none';
            form.style.display = isVisible ? 'none' : 'block';

            if (!isVisible) {
                // Limpiar campos
                modal.querySelector('#line-description').value = '';
                modal.querySelector('#line-quantity').value = '1';
                modal.querySelector('#line-price').value = '0';
                modal.querySelector('#line-tax').value = '21';
            }
        }
    };

    // Guardar nueva línea
    const handleSaveLine = async () => {
        const description = modal.querySelector('#line-description').value.trim();
        const quantity = parseFloat(modal.querySelector('#line-quantity').value);
        const unitPrice = parseFloat(modal.querySelector('#line-price').value);
        const taxRate = parseFloat(modal.querySelector('#line-tax').value);

        if (!description) {
            alert('La descripción es obligatoria');
            return;
        }

        if (!quantity || quantity <= 0) {
            alert('La cantidad debe ser mayor que 0');
            return;
        }

        if (unitPrice < 0) {
            alert('El precio no puede ser negativo');
            return;
        }

        if (taxRate < 0 || taxRate > 100) {
            alert('El IVA debe estar entre 0 y 100');
            return;
        }

        try {
            const saveBtn = modal.querySelector('.btn-save-line');
            saveBtn.disabled = true;
            saveBtn.textContent = 'Guardando...';

            await addInvoiceLine(invoiceId, {
                description,
                quantity,
                unitPrice,
                taxRate
            });

            alert('Línea añadida correctamente');
            toggleAddLineForm();
            await loadInvoice();
        } catch (error) {
            console.error('Error al añadir línea:', error);
            alert('Error al añadir línea: ' + error.message);
        } finally {
            const saveBtn = modal.querySelector('.btn-save-line');
            if (saveBtn) {
                saveBtn.disabled = false;
                saveBtn.textContent = 'Guardar Línea';
            }
        }
    };

    // Cargar factura
    const loadInvoice = async () => {
        try {
            isLoading = true;
            renderContent();

            invoice = await getInvoiceById(invoiceId);
            isLoading = false;
            renderContent();
        } catch (error) {
            console.error('Error al cargar factura:', error);
            isLoading = false;
            invoice = null;
            renderContent();
        }
    };

    // Inicializar modal
    modal.innerHTML = `
    <div class="modal-content invoice-modal">
    </div>
  `;

    // Cargar factura
    loadInvoice();

    return modal;
}