fix #90: export comic as epub

lib/components/message.dart

@@ -46,21 +46,28 @@ class _ToastOverlay extends StatelessWidget {
           child: IconTheme(
             data: IconThemeData(
                 color: Theme.of(context).colorScheme.onInverseSurface),
-            child: Container(
-              padding: const EdgeInsets.symmetric(vertical: 6, horizontal: 16),
-              child: Row(
-                mainAxisSize: MainAxisSize.min,
-                children: [
-                  if (icon != null) icon!.paddingRight(8),
-                  Text(
-                    message,
-                    style: const TextStyle(
-                        fontSize: 16, fontWeight: FontWeight.w500),
-                    maxLines: 3,
-                    overflow: TextOverflow.ellipsis,
-                  ),
-                  if (trailing != null) trailing!.paddingLeft(8)
-                ],
+            child: IntrinsicWidth(
+              child: Container(
+                padding: const EdgeInsets.symmetric(vertical: 6, horizontal: 16),
+                constraints: BoxConstraints(
+                  maxWidth: context.width - 32,
+                ),
+                child: Row(
+                  mainAxisSize: MainAxisSize.min,
+                  children: [
+                    if (icon != null) icon!.paddingRight(8),
+                    Expanded(
+                      child: Text(
+                        message,
+                        style: const TextStyle(
+                            fontSize: 16, fontWeight: FontWeight.w500),
+                        maxLines: 3,
+                        overflow: TextOverflow.ellipsis,
+                      ),
+                    ),
+                    if (trailing != null) trailing!.paddingLeft(8)
+                  ],
+                ),
               ),
             ),
           ),
@@ -220,7 +227,7 @@ LoadingDialogController showLoadingDialog(BuildContext context,
         );
       });
 
-  var navigator = Navigator.of(context);
+  var navigator = Navigator.of(context, rootNavigator: true);
 
   navigator.push(loadingDialogRoute).then((value) => controller.closed = true);
 

lib/pages/favorites/favorite_actions.dart

@@ -1,5 +1,3 @@
-import 'package:venera/foundation/appdata.dart';
-
 part of 'favorites_page.dart';
 
 /// Open a dialog to create a new favorite folder.

lib/pages/local_comics_page.dart

@@ -7,6 +7,7 @@ import 'package:venera/foundation/local.dart';
 import 'package:venera/foundation/log.dart';
 import 'package:venera/pages/downloading_page.dart';
 import 'package:venera/utils/cbz.dart';
+import 'package:venera/utils/epub.dart';
 import 'package:venera/utils/io.dart';
 import 'package:venera/utils/pdf.dart';
 import 'package:venera/utils/translations.dart';
@@ -389,6 +390,33 @@ class _LocalComicsPageState extends State<LocalComicsPage> {
                         File(cache).deleteIgnoreError();
                       }
                     },
+                  ),
+                if (!multiSelectMode)
+                  MenuEntry(
+                    icon: Icons.import_contacts_outlined,
+                    text: "Export as epub".tl,
+                    onClick: () async {
+                      var controller = showLoadingDialog(
+                        context,
+                        allowCancel: false,
+                      );
+                      File? file;
+                      try {
+                        file = await createEpubWithLocalComic(
+                          c as LocalComic,
+                        );
+                        await saveFile(
+                          file: file,
+                          filename: "${c.title}.epub",
+                        );
+                      } catch (e, s) {
+                        Log.error("EPUB Export", e, s);
+                        context.showMessage(message: e.toString());
+                      } finally {
+                        controller.close();
+                        file?.deleteIgnoreError();
+                      }
+                    },
                   )
               ];
             },

lib/utils/epub.dart

@@ -0,0 +1,208 @@
+import 'dart:isolate';
+
+import 'package:uuid/uuid.dart';
+import 'package:venera/foundation/app.dart';
+import 'package:venera/foundation/local.dart';
+import 'package:venera/utils/file_type.dart';
+import 'package:venera/utils/io.dart';
+import 'package:zip_flutter/zip_flutter.dart';
+
+class EpubData {
+  final String title;
+
+  final String author;
+
+  final File cover;
+
+  final Map<String, List<File>> chapters;
+
+  const EpubData({
+    required this.title,
+    required this.author,
+    required this.cover,
+    required this.chapters,
+  });
+}
+
+Future<File> createEpubComic(EpubData data, String cacheDir) async {
+  final workingDir = Directory(FilePath.join(cacheDir, 'epub'));
+  if (workingDir.existsSync()) {
+    workingDir.deleteSync(recursive: true);
+  }
+  workingDir.createSync(recursive: true);
+
+  // mimetype
+  workingDir.joinFile('mimetype').writeAsStringSync('application/epub+zip');
+
+  // META-INF
+  Directory(FilePath.join(workingDir.path, 'META-INF')).createSync();
+  File(FilePath.join(workingDir.path, 'META-INF', 'container.xml'))
+      .writeAsStringSync('''
+<?xml version="1.0"?>
+<container version="1.0" xmlns="urn:oasis:names:tc:opendocument:xmlns:container">
+  <rootfiles>
+    <rootfile full-path="content.opf" media-type="application/oebps-package+xml"/>
+  </rootfiles>
+</container>
+  ''');
+
+  Directory(FilePath.join(workingDir.path, 'OEBPS')).createSync();
+
+  // copy images, create html files
+  final imageDir = Directory(FilePath.join(workingDir.path, 'OEBPS', 'images'));
+  imageDir.createSync();
+  final coverExt = data.cover.extension;
+  final coverMime = FileType.fromExtension(coverExt).mime;
+  imageDir
+      .joinFile('cover.$coverExt')
+      .writeAsBytesSync(data.cover.readAsBytesSync());
+  int imgIndex = 0;
+  int chapterIndex = 0;
+  var manifestStrBuilder = StringBuffer();
+  manifestStrBuilder.writeln(
+      '        <item id="cover_image" href="OEBPS/images/cover.$coverExt" media-type="$coverMime"/>');
+  manifestStrBuilder.writeln(
+      '        <item id="toc" href="toc.ncx" media-type="application/x-dtbncx+xml"/>');
+  for (final chapter in data.chapters.keys) {
+    var images = <String>[];
+    for (final image in data.chapters[chapter]!) {
+      final ext = image.extension;
+      imageDir
+          .joinFile('img$imgIndex.$ext')
+          .writeAsBytesSync(image.readAsBytesSync());
+      images.add('images/img$imgIndex.$ext');
+      var mime = FileType.fromExtension(ext).mime;
+      manifestStrBuilder.writeln(
+          '        <item id="img$imgIndex" href="OEBPS/images/img$imgIndex$ext" media-type="$mime"/>');
+      imgIndex++;
+    }
+    var html =
+        File(FilePath.join(workingDir.path, 'OEBPS', '$chapterIndex.html'));
+    html.writeAsStringSync('''
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" 
+    "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+    <title>$chapter</title>
+    <style type="text/css">
+        img { 
+            max-width: 100%;
+            height: auto;
+        }
+        body {
+            margin: 0;
+            padding: 0;
+        }
+    </style>
+</head>
+<body>
+    <h1>$chapter</h1>
+    <div>
+${images.map((e) => '        <img src="$e" alt="$e"/>').join('\n')}
+    </div>
+</body>
+</html>
+    ''');
+    manifestStrBuilder.writeln(
+        '        <item id="chapter$chapterIndex" href="OEBPS/$chapterIndex.html" media-type="application/xhtml+xml"/>');
+    chapterIndex++;
+  }
+
+  // content.opf
+  final contentOpf =
+      File(FilePath.join(workingDir.path, 'content.opf'));
+  final uuid = const Uuid().v4();
+  var spineStrBuilder = StringBuffer();
+  for (var i = 0; i < chapterIndex; i++) {
+    var idRef = 'idref="chapter$i"';
+    spineStrBuilder.writeln('        <itemref $idRef/>');
+  }
+  contentOpf.writeAsStringSync('''
+<?xml version="1.0" encoding="UTF-8"?>
+<package version="3.0" 
+    xmlns="http://www.idpf.org/2007/opf"
+    xmlns:dc="http://purl.org/dc/elements/1.1/">
+    <metadata>
+        <dc:title>${data.title}</dc:title>
+        <dc:creator>${data.author}</dc:creator>
+        <dc:identifier id="book_id">urn:uuid:$uuid</dc:identifier>
+        <meta name="cover" content="cover_image"/>
+    </metadata>
+    <manifest>
+${manifestStrBuilder.toString()}       
+    </manifest>
+    <spine toc="toc">
+${spineStrBuilder.toString()}
+    </spine>
+</package>
+  ''');
+
+  // toc.ncx
+  final tocNcx = File(FilePath.join(workingDir.path, 'toc.ncx'));
+  var navMapStrBuilder = StringBuffer();
+  var playOrder = 2;
+  final chapterNames = data.chapters.keys.toList();
+  for (var i = 0; i < chapterIndex; i++) {
+    navMapStrBuilder
+        .writeln('        <navPoint id="chapter$i" playOrder="$playOrder">');
+    navMapStrBuilder.writeln(
+        '            <navLabel><text>${chapterNames[i]}</text></navLabel>');
+    navMapStrBuilder.writeln('            <content src="OEBPS/$i.html"/>');
+    navMapStrBuilder.writeln('        </navPoint>');
+    playOrder++;
+  }
+
+  tocNcx.writeAsStringSync('''
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE ncx PUBLIC "-//NISO//DTD ncx 2005-1//EN" "http://www.daisy.org/z3986/2005/ncx-2005-1.dtd">
+<ncx xmlns="http://www.daisy.org/z3986/2005/ncx" version="2005-1">
+    <head>
+        <meta name="dtb:uid" content="urn:uuid:$uuid"/>
+        <meta name="dtb:depth" content="1"/>
+        <meta name="dtb:totalPageCount" content="0"/>
+        <meta name="dtb:maxPageNumber" content="0"/>
+    </head>
+    <docTitle>
+        <text>${data.title}</text>
+    </docTitle>
+    <navMap>
+${navMapStrBuilder.toString()}
+    </navMap>
+</ncx>
+  ''');
+
+  // zip
+  final zipPath = FilePath.join(cacheDir, '${data.title}.epub');
+  ZipFile.compressFolder(workingDir.path, zipPath);
+
+  return File(zipPath);
+}
+
+Future<File> createEpubWithLocalComic(LocalComic comic) async {
+  var chapters = <String, List<File>>{};
+  if (comic.chapters == null) {
+    chapters[comic.title] =
+        (await LocalManager().getImages(comic.id, comic.comicType, 0))
+            .map((e) => File(e))
+            .toList();
+  } else {
+    for (var chapter in comic.chapters!.keys) {
+      chapters[comic.chapters![chapter]!] = (await LocalManager()
+              .getImages(comic.id, comic.comicType, chapter))
+          .map((e) => File(e))
+          .toList();
+    }
+  }
+  var data = EpubData(
+    title: comic.title,
+    author: comic.subtitle,
+    cover: comic.coverFile,
+    chapters: chapters,
+  );
+
+  final cacheDir = App.cachePath;
+
+  return Isolate.run(() => overrideIO(() async {
+        return createEpubComic(data, cacheDir);
+      }));
+}