certificate.dart

///Package imports
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
// ignore: depend_on_referenced_packages
import 'package:intl/intl.dart';

///Pdf import
import 'package:syncfusion_flutter_pdf/pdf.dart';

///Local imports
import '../../model/sample_view.dart';
import 'helper/save_file_mobile.dart'
    if (dart.library.js_interop) 'helper/save_file_web.dart';

/// Render pdf of course completion certificate
class CourseCompletionCertificatePdf extends SampleView {
  /// Creates pdf of course completion certificate
  const CourseCompletionCertificatePdf(Key key) : super(key: key);
  @override
  _CertificatePdfState createState() => _CertificatePdfState();
}

class _CertificatePdfState extends SampleViewState {
  _CertificatePdfState();

  @override
  void dispose() {
    _dateController.dispose();
    _nameController.dispose();
    _courceNameController.dispose();
    super.dispose();
  }

  final TextEditingController _dateController = TextEditingController(
    text: DateFormat('MMMM d, yyyy').format(DateTime.now()),
  );
  final TextEditingController _nameController = TextEditingController(
    text: 'John Milton',
  );
  final TextEditingController _courceNameController = TextEditingController(
    text: 'Getting Started with PDF Development',
  );
  DateTime selectedDate = DateTime.now();
  Future<void> _selectDate(BuildContext context) async {
    final DateTime? picked = await showDatePicker(
      context: context,
      initialDate: selectedDate,
      firstDate: DateTime(2000),
      lastDate: DateTime(2100),
    );
    if (picked != null && picked != selectedDate) {
      setState(() {
        selectedDate = picked;
        _dateController.text = DateFormat('MMMM d, yyyy').format(selectedDate);
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: model.sampleOutputCardColor,
      body: SingleChildScrollView(
        child: Center(
          child: Padding(
            padding: const EdgeInsets.all(8.0),
            child: Column(
              children: <Widget>[
                Text(
                  'This sample showcase how to dynamically generates the course completion certificate for online learning portal with participant name, course name and date of completion.',
                  style: TextStyle(fontSize: 16, color: model.textColor),
                ),
                TextFormField(
                  decoration: InputDecoration(
                    labelText: 'Recipient Name',
                    labelStyle: TextStyle(
                      color:
                          model.themeData.colorScheme.brightness ==
                                  Brightness.light
                              ? Colors.grey
                              : Colors.lightBlue,
                    ),
                  ),
                  controller: _nameController,
                  style: TextStyle(color: model.textColor),
                ),
                TextFormField(
                  decoration: InputDecoration(
                    labelText: 'Course Name',
                    labelStyle: TextStyle(
                      color:
                          model.themeData.colorScheme.brightness ==
                                  Brightness.light
                              ? Colors.grey
                              : Colors.lightBlue,
                    ),
                  ),
                  controller: _courceNameController,
                  style: TextStyle(color: model.textColor),
                ),
                TextFormField(
                  decoration: InputDecoration(
                    labelText: 'Date',
                    labelStyle: TextStyle(
                      color:
                          model.themeData.colorScheme.brightness ==
                                  Brightness.light
                              ? Colors.grey
                              : Colors.lightBlue,
                    ),
                  ),
                  controller: _dateController,
                  style: TextStyle(color: model.textColor),
                  onTap: () {
                    _selectDate(context);
                  },
                ),
                const SizedBox(height: 20, width: 30),
                TextButton(
                  onPressed: _createCertificate,
                  style: ButtonStyle(
                    backgroundColor: WidgetStateProperty.all<Color>(
                      model.primaryColor,
                    ),
                    padding:
                        model.isMobile
                            ? null
                            : WidgetStateProperty.all(
                              const EdgeInsets.symmetric(
                                vertical: 15,
                                horizontal: 15,
                              ),
                            ),
                  ),
                  child: const Text(
                    'Generate PDF',
                    style: TextStyle(color: Colors.white),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  Future<void> _createCertificate() async {
    //Create a PDF document.
    final PdfDocument document = PdfDocument();
    document.pageSettings.orientation = PdfPageOrientation.landscape;
    document.pageSettings.margins.all = 0;
    //Add page to the PDF
    final PdfPage page = document.pages.add();
    //Get the page size
    final Size pageSize = page.getClientSize();
    //Draw image
    page.graphics.drawImage(
      PdfBitmap(await _readImageData('certificate.jpg')),
      Rect.fromLTWH(0, 0, pageSize.width, pageSize.height),
    );
    //Create font
    final PdfFont nameFont = PdfStandardFont(PdfFontFamily.helvetica, 22);
    final PdfFont controlFont = PdfStandardFont(PdfFontFamily.helvetica, 19);
    final PdfFont dateFont = PdfStandardFont(PdfFontFamily.helvetica, 16);
    double x = _calculateXPosition(
      _nameController.text,
      nameFont,
      pageSize.width,
    );
    page.graphics.drawString(
      _nameController.text,
      nameFont,
      bounds: Rect.fromLTWH(x, 253, 0, 0),
      brush: PdfSolidBrush(PdfColor(20, 58, 86)),
    );
    x = _calculateXPosition(
      _courceNameController.text,
      controlFont,
      pageSize.width,
    );
    page.graphics.drawString(
      _courceNameController.text,
      controlFont,
      bounds: Rect.fromLTWH(x, 340, 0, 0),
      brush: PdfSolidBrush(PdfColor(20, 58, 86)),
    );
    final String dateText = 'on ' + _dateController.text;
    x = _calculateXPosition(dateText, dateFont, pageSize.width);
    page.graphics.drawString(
      dateText,
      dateFont,
      bounds: Rect.fromLTWH(x, 385, 0, 0),
      brush: PdfSolidBrush(PdfColor(20, 58, 86)),
    );
    //Save and launch the document
    final List<int> bytes = await document.save();
    //Dispose the document.
    document.dispose();
    //Save and launch file.
    await FileSaveHelper.saveAndLaunchFile(bytes, 'Certificate.pdf');
  }

  double _calculateXPosition(String text, PdfFont font, double pageWidth) {
    final Size textSize = font.measureString(
      text,
      layoutArea: Size(pageWidth, 0),
    );
    return (pageWidth - textSize.width) / 2;
  }

  Future<List<int>> _readImageData(String name) async {
    final ByteData data = await rootBundle.load('images/pdf/$name');
    return data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
  }
}