Download PDF files; implement opening and sharing

When downloading a language, download the PDF files (available in the
newly created PDF repositories for each language).
Implement opening and sharing of these PDF files in our share menu.
This should be fully functional but tests are still missing

lib/data/globals.dart

@@ -145,20 +145,33 @@ class Globals {
   static const String githubUser = '4training';
   static const String branch = 'main';
   static const String htmlPath = 'html';
+  static const String pdfPath = 'pdf';
   static const String remoteZipUrl = '/archive/refs/heads/$branch.zip';
 
   /// Url of the zip file for the HTML resources of a language
-  static String getRemoteUrl(String languageCode) {
+  static String getRemoteUrlHtml(String languageCode) {
     return 'https://github.com/$githubUser/$htmlPath-$languageCode$remoteZipUrl';
   }
 
+  /// Url of the zip file for the HTML resources of a language
+  static String getRemoteUrlPdf(String languageCode) {
+    return 'https://github.com/$githubUser/$pdfPath-$languageCode$remoteZipUrl';
+  }
+
   /// Folder name of the resources of a language. Example: html-en-main
   ///
   /// Must be the main folder name that is inside the zip file we download.
   static String getResourcesDir(String languageCode) {
     return '$htmlPath-$languageCode-$branch';
   }
 
+  /// Folder name of the PDF files of a language. Example: pdf-en-main
+  ///
+  /// Must be the main folder name that is inside the zip file we download.
+  static String getPdfDir(String languageCode) {
+    return '$pdfPath-$languageCode-$branch';
+  }
+
   /// Folder name of the assets dir of a language
   static String getAssetsDir(String languageCode) {
     return 'assets-$languageCode';

lib/data/languages.dart

@@ -155,7 +155,7 @@ class LanguageController extends FamilyNotifier<Language, String> {
   Future<bool> lazyInit() async {
     await _initController();
     String path =
-        '${_controller.assetsDir}/${Globals.getResourcesDir(languageCode)}';
+        join(_controller.assetsDir!, Globals.getResourcesDir(languageCode));
     final stat = await ref
         .watch(fileSystemProvider)
         .stat(join(path, 'structure', 'contents.json'));
@@ -182,16 +182,16 @@ class LanguageController extends FamilyNotifier<Language, String> {
     try {
       // Now we store the full path to the language
       String path =
-          '${_controller.assetsDir}/${Globals.getResourcesDir(languageCode)}';
+          join(_controller.assetsDir!, Globals.getResourcesDir(languageCode));
       debugPrint("Path: $path");
-      Directory dir = fileSystem.directory(path);
 
       bool downloaded = await _controller.assetsDirAlreadyExists();
       debugPrint("Trying to load '$languageCode', downloaded: $downloaded");
       if (!downloaded) return false;
 
-      // Store the size of the downloaded directory
-      int sizeInKB = await _calculateMemoryUsage(dir);
+      // Store the size of the downloaded files (HTML + PDF)
+      int sizeInKB = await _calculateMemoryUsage(
+          fileSystem.directory(_controller.assetsDir!));
 
       // Get the timestamp: When were our contents stored on the device?
       FileStat stat =
@@ -207,22 +207,49 @@ class LanguageController extends FamilyNotifier<Language, String> {
       final Map<String, Page> pages = {};
       final List<String> pageIndex = [];
       final Map<String, Image> images = {};
+      final Set<String> pdfFiles = {};
 
+      // Go through existing PDF files
+      var pdfPath =
+          join(_controller.assetsDir!, Globals.getPdfDir(languageCode));
+      var pdfDir = fileSystem.directory(pdfPath);
+      if (await pdfDir.exists()) {
+        await for (var file
+            in pdfDir.list(recursive: false, followLinks: false)) {
+          if (file is File) {
+            pdfFiles.add(file.basename);
+          } else {
+            debugPrint("Found unexpected element $file in the PDF directory");
+          }
+        }
+      }
+
+      // Store everything in our data structures
       for (var element in structure["worksheets"]) {
         // TODO add error handling
         pageIndex.add(element['page']);
+        String? pdfName; // Stores PDF file name if it is available
+        if (element.containsKey('pdf') && pdfFiles.contains(element['pdf'])) {
+          pdfName = join(pdfPath, element['pdf']);
+          pdfFiles.remove(element['pdf']);
+        }
         pages[element['page']] = Page(element['page'], element['title'],
-            element['filename'], element['version']);
+            element['filename'], element['version'], pdfName);
+      }
+
+      // Consistency checking...
+      if (pdfFiles.isNotEmpty) {
+        debugPrint("Found unexpected PDF file(s): $pdfFiles");
       }
-      await _checkConsistency(dir, pages);
+      await _checkConsistency(fileSystem.directory(path), pages);
 
       // Register available images
       var filesDir = fileSystem.directory(join(path, 'files'));
       if (await filesDir.exists()) {
         await for (var file
             in filesDir.list(recursive: false, followLinks: false)) {
           if (file is File) {
-            images[basename(file.path)] = Image(basename(file.path));
+            images[file.basename] = Image(file.basename);
           } else {
             debugPrint("Found unexpected element $file in files/ directory");
           }
@@ -251,36 +278,25 @@ class LanguageController extends FamilyNotifier<Language, String> {
   }
 
   /// Download all files for one language via DownloadAssetsController
-  /// Returns whether we were successful and shouldn't throw
+  /// Returns whether we were successful. Shouldn't throw
   Future<bool> _download() async {
     await _initController();
     debugPrint("Starting to download language '$languageCode' ...");
-    // URL of the zip file to be downloaded
-    String remoteUrl = Globals.getRemoteUrl(languageCode);
 
     try {
-      await _controller.startDownload(
-        assetsUrls: [remoteUrl],
-        onProgress: (progressValue) {
-          if (progressValue < 20) {
-            // The value goes for some reason only up to 18.7 or so ...
-            String progress = "Downloading $languageCode: ";
-
-            for (int i = 0; i < 20; i++) {
-              progress += (i <= progressValue) ? "|" : ".";
-            }
-            debugPrint("$progress ${progressValue.round()}");
-          } else {
-            debugPrint("Download completed");
-          }
-        },
-      );
+      // assetUrls takes an array, but we can't specify both URLs in one call:
+      // DownloadAssets throws when both files have the same name (main.zip) :-/
+      await _controller
+          .startDownload(assetsUrls: [Globals.getRemoteUrlHtml(languageCode)]);
+      await _controller
+          .startDownload(assetsUrls: [Globals.getRemoteUrlPdf(languageCode)]);
     } catch (e) {
       debugPrint("Error while downloading language '$languageCode': $e");
       // delete the empty folder left behind by startDownload()
       await _controller.clearAssets();
       return false;
     }
+    debugPrint("Downloading language '$languageCode' finished.");
     return true;
   }
 
@@ -303,7 +319,7 @@ class LanguageController extends FamilyNotifier<Language, String> {
     Set<String> files = {};
     await for (var file in dir.list(recursive: false, followLinks: false)) {
       if (file is File) {
-        files.add(basename(file.path));
+        files.add(file.basename);
       }
     }
     pages.forEach((key, page) {
@@ -331,7 +347,10 @@ class Page {
 
   final String version;
 
-  const Page(this.name, this.title, this.fileName, this.version);
+  /// Full path of the associated PDF file if it exists on the device
+  final String? pdfName;
+
+  const Page(this.name, this.title, this.fileName, this.version, this.pdfName);
 }
 
 /// Holds properties of an image.

lib/design/theme.dart

@@ -41,3 +41,6 @@ ThemeData lightTheme = _defaultLightTheme.copyWith(
 ThemeData darkTheme =
     FlexThemeData.dark(scheme: FlexScheme.red, useMaterial3: true)
         .copyWith(appBarTheme: darkAppBarTheme);
+
+/// Size of smileys (used on "sorry, not yet available" dialogs)
+const double smileySize = 50;

lib/l10n/locales/app_de.arb

@@ -338,5 +338,6 @@
     "sharePdf": "PDF teilen",
     "openPdf": "PDF öffnen",
     "openInBrowser": "Im Browser öffnen",
-    "shareLink": "Link teilen"
+    "shareLink": "Link teilen",
+    "pdfNotAvailable": "Für dieses Arbeitsblatt ist leider noch kein PDF verfügbar. Wenn du mithelfen möchtest, damit sich das bald ändert, dann melde dich bitte!"
 }

lib/l10n/locales/app_en.arb

@@ -338,5 +338,6 @@
     "sharePdf": "Share PDF",
     "openPdf": "Open PDF",
     "openInBrowser": "Open in browser",
-    "shareLink": "Share link"
+    "shareLink": "Share link",
+    "pdfNotAvailable": "Unfortunately there is no PDF available yet for this worksheet. If you want to help make this change soon, please contact us!"
 }

lib/widgets/main_drawer.dart

@@ -5,12 +5,11 @@ import 'package:app4training/data/app_language.dart';
 import 'package:app4training/data/categories.dart';
 import 'package:app4training/data/globals.dart';
 import 'package:app4training/data/languages.dart';
+import 'package:app4training/design/theme.dart';
 import 'package:app4training/l10n/l10n.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
-const double smileySize = 50;
-
 /// Our main menu with the list of pages, organized into categories.
 /// The currently shown page is highlighted and the category it belongs to
 /// is expanded.

lib/widgets/share_button.dart

@@ -1,9 +1,12 @@
 import 'dart:async';
 
+import 'package:app4training/data/languages.dart';
+import 'package:app4training/design/theme.dart';
 import 'package:app4training/l10n/l10n.dart';
 import 'package:app4training/routes/view_page.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:open_filex/open_filex.dart';
 import 'package:share_plus/share_plus.dart';
 import 'package:url_launcher/url_launcher.dart';
 
@@ -20,6 +23,12 @@ class ShareButton extends ConsumerWidget {
     final viewPage = context.findAncestorWidgetOfExactType<ViewPage>()!;
     String currentPage = viewPage.page;
     String currentLang = viewPage.langCode;
+    String? pdfFile =
+        ref.watch(languageProvider(currentLang)).pages[currentPage]?.pdfName;
+    // Color for the PDF-related entries (greyed out if PDF is not available)
+    Color pdfColor = (pdfFile != null)
+        ? Theme.of(context).colorScheme.onSurface
+        : Theme.of(context).disabledColor;
 
     return MenuAnchor(
         controller: menuController,
@@ -44,21 +53,48 @@ class ShareButton extends ConsumerWidget {
                 children: [
                   Column(children: [
                     ListTile(
-                      dense: true,
-                      title: Text(context.l10n.openPdf),
-                      leading: const ImageIcon(
-                          AssetImage("assets/file-document-outline.png")),
-                      onTap: () {
-                        menuController.close();
-                      },
-                    ),
+                        dense: true,
+                        title: Text(context.l10n.openPdf,
+                            style: TextStyle(color: pdfColor)),
+                        leading: ImageIcon(
+                            const AssetImage(
+                                "assets/file-document-outline.png"),
+                            color: pdfColor),
+                        onTap: () async {
+                          if (pdfFile != null) {
+                            menuController.close();
+                            var result = await OpenFilex.open(pdfFile);
+                            debugPrint(
+                                'OpenResult: ${result.message}; ${result.type}');
+                          } else {
+                            await showDialog(
+                                context: context,
+                                builder: (context) {
+                                  return const PdfNotAvailableDialog();
+                                });
+                            menuController.close();
+                          }
+                        }),
                     ListTile(
                       dense: true,
-                      title: Text(context.l10n.sharePdf),
-                      leading: const ImageIcon(AssetImage(
-                          "assets/file-document-arrow-right-outline.png")),
-                      onTap: () {
-                        menuController.close();
+                      title: Text(context.l10n.sharePdf,
+                          style: TextStyle(color: pdfColor)),
+                      leading: ImageIcon(
+                          const AssetImage(
+                              "assets/file-document-arrow-right-outline.png"),
+                          color: pdfColor),
+                      onTap: () async {
+                        if (pdfFile != null) {
+                          menuController.close();
+                          await Share.shareXFiles([XFile(pdfFile)]);
+                        } else {
+                          await showDialog(
+                              context: context,
+                              builder: (context) {
+                                return const PdfNotAvailableDialog();
+                              });
+                          menuController.close();
+                        }
                       },
                     ),
                     ListTile(
@@ -86,3 +122,28 @@ class ShareButton extends ConsumerWidget {
         ]);
   }
 }
+
+class PdfNotAvailableDialog extends StatelessWidget {
+  const PdfNotAvailableDialog({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+        title: Text(context.l10n.sorry),
+        content: Column(mainAxisSize: MainAxisSize.min, children: [
+          Icon(Icons.sentiment_dissatisfied,
+              size: smileySize,
+              // For unknown reasons smiley is invisible otherwise
+              color: Theme.of(context).colorScheme.onSurface),
+          const SizedBox(height: 10),
+          Text(context.l10n.pdfNotAvailable),
+        ]),
+        actions: <Widget>[
+          TextButton(
+              onPressed: () {
+                Navigator.of(context).pop();
+              },
+              child: Text(context.l10n.okay))
+        ]);
+  }
+}

pubspec.lock

@@ -540,6 +540,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.0.2"
+  open_filex:
+    dependency: "direct main"
+    description:
+      name: open_filex
+      sha256: "74e2280754cf8161e860746c3181db2c996d6c1909c7057b738ede4a469816b8"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.4.0"
   package_config:
     dependency: transitive
     description:

pubspec.yaml

@@ -53,6 +53,7 @@ dependencies:
   package_info_plus: ^5.0.1
   workmanager: ^0.5.2
   share_plus: ^7.2.2
+  open_filex: ^4.4.0
 
 
 dev_dependencies:

test/globals_test.dart

@@ -4,9 +4,13 @@ import 'package:flutter_test/flutter_test.dart';
 void main() {
   test('Test remote URLs and local path', () {
     expect(
-        Globals.getRemoteUrl('de'),
+        Globals.getRemoteUrlHtml('de'),
         equals(
             'https://github.com/4training/html-de/archive/refs/heads/main.zip'));
+    expect(
+        Globals.getRemoteUrlPdf('de'),
+        equals(
+            'https://github.com/4training/pdf-de/archive/refs/heads/main.zip'));
     expect(Globals.getAssetsDir('de'), equals('assets-de'));
     expect(Globals.getResourcesDir('de'), equals('html-de-main'));
     expect(

test/language_selection_button_test.dart

@@ -34,7 +34,7 @@ void main() {
       appLanguageProvider.overrideWith(() => TestAppLanguage('en')),
       languageProvider.overrideWith(() => TestLanguageController(
           downloadedLanguages: ['de'],
-          pages: {'Healing': const Page('test', 'test', 'test', '1.0')}))
+          pages: {'Healing': const Page('test', 'test', 'test', '1.0', null)}))
     ], child: const TestLanguagesButton()));
 
     expect(find.byIcon(Icons.translate), findsOneWidget);
@@ -57,7 +57,7 @@ void main() {
       appLanguageProvider.overrideWith(() => TestAppLanguage('de')),
       languageProvider.overrideWith(() => TestLanguageController(
           downloadedLanguages: ['de', 'en', 'fr', 'es', 'ar'],
-          pages: {'Healing': const Page('test', 'test', 'test', '1.0')}))
+          pages: {'Healing': const Page('test', 'test', 'test', '1.0', null)}))
     ], child: const TestLanguagesButton()));
 
     expect(find.byIcon(Icons.translate), findsOneWidget);