import 'dart:typed_data';
import 'package:flutter/services.dart' show rootBundle;
import 'package:intl/intl.dart';
import 'package:pdf/pdf.dart';
import 'package:pdf/widgets.dart' as pw;
import 'package:printing/printing.dart';

class DepartmentReferralPdfService {
  /// Genera el documento PDF de Referimiento a Departamento en formato Media Carta Vertical
  /// (5.5 x 8.5 pulgadas / 396 x 612 pt).
  static Future<Uint8List> buildDepartmentReferralPdf({
    required String doctorName,
    required String specialty,
    required String subspecialty,
    required String generalContact,
    required String referralText,
    DateTime? date,
    pw.Font? fontRegular,
    pw.Font? fontBold,
    pw.Font? fontTitle,
    String? logoSvg,
  }) async {
    final pdf = pw.Document(title: 'Referir a Departamento');
    final formattedDate = DateFormat('dd/MM/yyyy').format(date ?? DateTime.now());

    // Formato Carta Vertical (8.5 x 11.0 pulgadas / 612 x 792 pt):
    // Todo el contenido abarca estrictamente la mitad superior de la hoja (5.5 pulgadas / 396 pt),
    // dejando la mitad inferior libre para corte o papel pre-cortado.
    const pageFormat = PdfPageFormat(
      8.5 * PdfPageFormat.inch,
      11.0 * PdfPageFormat.inch,
      marginLeft: 54,
      marginRight: 54,
      marginTop: 20,
      marginBottom: 20,
    );

    // Tipografías estándar con fallback a fuentes base PDF si no hay conexión a internet
    pw.Font regular = fontRegular ?? pw.Font.helvetica();
    pw.Font bold = fontBold ?? pw.Font.helveticaBold();
    pw.Font titleFont = fontTitle ?? pw.Font.timesBoldItalic();

    if (fontRegular == null || fontBold == null || fontTitle == null) {
      try {
        regular = await PdfGoogleFonts.robotoRegular();
        bold = await PdfGoogleFonts.robotoBold();
        titleFont = await PdfGoogleFonts.playfairDisplayItalic();
      } catch (_) {
        regular = pw.Font.helvetica();
        bold = pw.Font.helveticaBold();
        titleFont = pw.Font.timesBoldItalic();
      }
    }

    String? svgContent = logoSvg;
    if (svgContent == null) {
      try {
        svgContent = await rootBundle.loadString('assets/images/hidalyx_logo_blue.svg');
      } catch (_) {
        svgContent = null;
      }
    }

    pdf.addPage(
      pw.Page(
        pageFormat: pageFormat,
        build: (pw.Context context) {
          return pw.Column(
            crossAxisAlignment: pw.CrossAxisAlignment.stretch,
            children: [
              // Mitad superior de la hoja (máximo 5.5 pulgadas / 396 pt)
              pw.Container(
                height: 5.5 * PdfPageFormat.inch - 36,
                child: pw.Column(
                  crossAxisAlignment: pw.CrossAxisAlignment.stretch,
                  children: [
                    // 1. Cabecera con Nombre del Doctor y Badge Sutil de Hidalyx Med
                    pw.Stack(
                children: [
                  pw.Align(
                    alignment: pw.Alignment.center,
                    child: pw.Column(
                      children: [
                        pw.Text(
                          doctorName.isNotEmpty ? doctorName : 'Dr. Luis A. Castro Sosa',
                          style: pw.TextStyle(
                            font: titleFont,
                            fontSize: 22,
                            fontWeight: pw.FontWeight.bold,
                            color: PdfColor.fromHex('1E293B'),
                          ),
                        ),
                        pw.SizedBox(height: 3),
                        if (specialty.isNotEmpty)
                          pw.Text(
                            specialty.toUpperCase(),
                            style: pw.TextStyle(
                              font: bold,
                              fontSize: 10.5,
                              letterSpacing: 0.5,
                              color: PdfColor.fromHex('0F172A'),
                            ),
                          ),
                        if (subspecialty.isNotEmpty) ...[
                          pw.SizedBox(height: 2),
                          pw.Text(
                            subspecialty.toUpperCase(),
                            textAlign: pw.TextAlign.center,
                            style: pw.TextStyle(
                              font: regular,
                              fontSize: 8.5,
                              color: PdfColor.fromHex('475569'),
                            ),
                          ),
                        ],
                        pw.SizedBox(height: 3),
                        pw.Text(
                          'Fecha: $formattedDate',
                          style: pw.TextStyle(
                            font: regular,
                            fontSize: 9.5,
                            color: PdfColor.fromHex('334155'),
                          ),
                        ),
                      ],
                    ),
                  ),

                  // Badge sutil de Hidalyx Med en la esquina superior derecha
                  pw.Positioned(
                    top: 0,
                    right: 0,
                    child: pw.Row(
                      mainAxisSize: pw.MainAxisSize.min,
                      crossAxisAlignment: pw.CrossAxisAlignment.center,
                      children: [
                        if (svgContent != null && svgContent.isNotEmpty) ...[
                          pw.Opacity(
                            opacity: 0.6,
                            child: pw.SvgImage(
                              svg: svgContent,
                              width: 7.5,
                              height: 7.5,
                            ),
                          ),
                          pw.SizedBox(width: 3),
                        ],
                        pw.Text(
                          'hidalyx.com',
                          style: pw.TextStyle(
                            font: regular,
                            fontSize: 6.0,
                            color: PdfColor.fromHex('94A3B8'),
                          ),
                        ),
                      ],
                    ),
                  ),
                ],
              ),
              pw.SizedBox(height: 6),

              // Línea divisoria decorativa del membrete
              pw.Container(
                height: 1,
                color: PdfColor.fromHex('CBD5E1'),
              ),
              pw.SizedBox(height: 8),

              // 2. Contenido del Referimiento (Idéntico a AlfaMedical)
              pw.Expanded(
                child: pw.Container(
                  padding: const pw.EdgeInsets.symmetric(vertical: 4),
                  child: pw.Text(
                    referralText.trim().isNotEmpty
                        ? referralText.trim()
                        : 'Sin detalles de referimiento.',
                    style: pw.TextStyle(
                      font: regular,
                      fontSize: 10.5,
                      lineSpacing: 3.5,
                      color: PdfColor.fromHex('1E293B'),
                    ),
                  ),
                ),
              ),
              pw.SizedBox(height: 6),

              // 3. Pie de página con Contacto del Consultorio
              if (generalContact.isNotEmpty) ...[
                pw.Container(
                  padding: const pw.EdgeInsets.only(top: 4),
                  child: pw.Text(
                    generalContact.toUpperCase(),
                    textAlign: pw.TextAlign.center,
                    style: pw.TextStyle(
                      font: regular,
                      fontSize: 6.8,
                      color: PdfColor.fromHex('64748B'),
                      lineSpacing: 1.5,
                    ),
                  ),
                ),
              ],

              pw.SizedBox(height: 3),

              // Confirmación institucional
              pw.Center(
                child: pw.Text(
                  'Documento médico emitido electrónicamente',
                  style: pw.TextStyle(
                    font: regular,
                    fontSize: 6.0,
                    color: PdfColor.fromHex('94A3B8'),
                  ),
                ),
              ),
            ],
          ),
        ),
      ],
    );
        },
      ),
    );

    return pdf.save();
  }

  /// Envía a imprimir directamente o abre el diálogo nativo de impresión/PDF.
  static Future<void> printDepartmentReferral({
    required String doctorName,
    required String specialty,
    required String subspecialty,
    required String generalContact,
    required String referralText,
    DateTime? date,
  }) async {
    final pdfBytes = await buildDepartmentReferralPdf(
      doctorName: doctorName,
      specialty: specialty,
      subspecialty: subspecialty,
      generalContact: generalContact,
      referralText: referralText,
      date: date,
    );

    await Printing.layoutPdf(
      onLayout: (PdfPageFormat format) async => pdfBytes,
      name: 'Referimiento_Departamento',
    );
  }
}