edit

BookReader/MauiProgram.cs

@@ -1,4 +1,5 @@
-using BookReader.Services;
+using BookReader.Platforms.Android.Services;
+using BookReader.Services;
 using BookReader.ViewModels;
 using BookReader.Views;
 using CommunityToolkit.Maui;
@@ -26,24 +27,21 @@ public static class MauiProgram
         builder.Logging.AddDebug();
 #endif
 
-        // Register Services (Singleton for shared state)
         builder.Services.AddSingleton<IDatabaseService, DatabaseService>();
         builder.Services.AddSingleton<IBookParserService, BookParserService>();
         builder.Services.AddSingleton<ISettingsService, SettingsService>();
         builder.Services.AddSingleton<INavigationService, NavigationService>();
         builder.Services.AddSingleton<ICoverCacheService, LruCoverCacheService>();
         builder.Services.AddSingleton<ICachedImageLoadingService, CachedImageLoadingService>();
+        builder.Services.AddSingleton<IBookImportPickerService, AndroidBookImportPickerService>();
 
-        // HTTP Client for Calibre
         builder.Services.AddHttpClient<ICalibreWebService, CalibreWebService>();
 
-        // Register ViewModels
         builder.Services.AddTransient<BookshelfViewModel>();
         builder.Services.AddTransient<ReaderViewModel>();
         builder.Services.AddTransient<SettingsViewModel>();
         builder.Services.AddTransient<CalibreLibraryViewModel>();
 
-        // Register Pages
         builder.Services.AddTransient<BookshelfPage>();
         builder.Services.AddTransient<ReaderPage>();
         builder.Services.AddTransient<SettingsPage>();
@@ -51,4 +49,4 @@ public static class MauiProgram
 
         return builder.Build();
     }
-}
+}

BookReader/Platforms/Android/MainActivity.cs

@@ -1,6 +1,8 @@
 using Android.App;
+using Android.Content;
 using Android.Content.PM;
 using Android.OS;
+using BookReader.Platforms.Android.Services;
 
 namespace BookReader;
 
@@ -16,7 +18,12 @@ public class MainActivity : MauiAppCompatActivity
     {
         base.OnCreate(savedInstanceState);
 
-        // Keep screen on while reading
         Window?.AddFlags(Android.Views.WindowManagerFlags.KeepScreenOn);
     }
-}
+
+    protected override void OnActivityResult(int requestCode, Result resultCode, Intent? data)
+    {
+        base.OnActivityResult(requestCode, resultCode, data);
+        AndroidActivityResultRegistry.Dispatch(requestCode, resultCode, data);
+    }
+}

BookReader/Platforms/Android/Services/AndroidBookImportPickerService.cs

@@ -0,0 +1,214 @@
+using Android.App;
+using Android.Content;
+using Android.Database;
+using Android.Provider;
+using Android.Webkit;
+using BookReader.Services;
+using Microsoft.Maui.ApplicationModel;
+using ActivityResult = Android.App.Result;
+using AndroidUri = global::Android.Net.Uri;
+
+namespace BookReader.Platforms.Android.Services;
+
+internal sealed class AndroidActivityResultEventArgs : EventArgs
+{
+    public AndroidActivityResultEventArgs(int requestCode, ActivityResult resultCode, Intent? data)
+    {
+        RequestCode = requestCode;
+        ResultCode = resultCode;
+        Data = data;
+    }
+
+    public int RequestCode { get; }
+    public ActivityResult ResultCode { get; }
+    public Intent? Data { get; }
+}
+
+internal static class AndroidActivityResultRegistry
+{
+    public static event EventHandler<AndroidActivityResultEventArgs>? ActivityResultReceived;
+
+    public static void Dispatch(int requestCode, ActivityResult resultCode, Intent? data)
+    {
+        ActivityResultReceived?.Invoke(null, new AndroidActivityResultEventArgs(requestCode, resultCode, data));
+    }
+}
+
+public sealed class AndroidBookImportPickerService : IBookImportPickerService
+{
+    private const int PickBookRequestCode = 41071;
+
+    private static readonly string[] SupportedMimeTypes =
+    {
+        "application/epub+zip",
+        "application/x-fictionbook+xml",
+        "application/xml",
+        "text/xml",
+        "application/octet-stream"
+    };
+
+    private readonly SemaphoreSlim _pickLock = new(1, 1);
+    private TaskCompletionSource<(ActivityResult ResultCode, Intent? Data)>? _pendingPick;
+
+    public AndroidBookImportPickerService()
+    {
+        AndroidActivityResultRegistry.ActivityResultReceived += OnActivityResultReceived;
+    }
+
+    public async Task<SelectedBookFile?> PickBookFileAsync(CancellationToken cancellationToken = default)
+    {
+        await _pickLock.WaitAsync(cancellationToken);
+
+        try
+        {
+            var activity = Platform.CurrentActivity
+                ?? throw new InvalidOperationException("Текущая Android activity недоступна.");
+
+            var pickCompletionSource = new TaskCompletionSource<(ActivityResult ResultCode, Intent? Data)>(TaskCreationOptions.RunContinuationsAsynchronously);
+            _pendingPick = pickCompletionSource;
+
+            using var registration = cancellationToken.Register(() => pickCompletionSource.TrySetCanceled(cancellationToken));
+
+            await MainThread.InvokeOnMainThreadAsync(() =>
+            {
+                var intent = new Intent(Intent.ActionOpenDocument);
+                intent.AddCategory(Intent.CategoryOpenable);
+                intent.SetType("*/*");
+                intent.PutExtra(Intent.ExtraMimeTypes, SupportedMimeTypes);
+                intent.AddFlags(ActivityFlags.GrantReadUriPermission | ActivityFlags.GrantPersistableUriPermission);
+
+#pragma warning disable CS0618
+                activity.StartActivityForResult(Intent.CreateChooser(intent, "Выберите книгу"), PickBookRequestCode);
+#pragma warning restore CS0618
+            });
+
+            var (resultCode, data) = await pickCompletionSource.Task;
+            if (resultCode != ActivityResult.Ok || data?.Data == null)
+            {
+                return null;
+            }
+
+            var documentUri = data.Data;
+            TryTakePersistablePermission(activity, documentUri, data.Flags);
+
+            return await CopyDocumentToCacheAsync(activity, documentUri, cancellationToken);
+        }
+        finally
+        {
+            Interlocked.Exchange(ref _pendingPick, null);
+            _pickLock.Release();
+        }
+    }
+
+    private void OnActivityResultReceived(object? sender, AndroidActivityResultEventArgs args)
+    {
+        if (args.RequestCode != PickBookRequestCode)
+        {
+            return;
+        }
+
+        _pendingPick?.TrySetResult((args.ResultCode, args.Data));
+    }
+
+    private static void TryTakePersistablePermission(Activity activity, AndroidUri documentUri, ActivityFlags grantedFlags)
+    {
+        var persistableFlags = grantedFlags & (ActivityFlags.GrantReadUriPermission | ActivityFlags.GrantWriteUriPermission);
+        if ((persistableFlags & ActivityFlags.GrantReadUriPermission) == 0)
+        {
+            persistableFlags |= ActivityFlags.GrantReadUriPermission;
+        }
+
+        try
+        {
+            activity.ContentResolver?.TakePersistableUriPermission(documentUri, persistableFlags);
+        }
+        catch (Java.Lang.SecurityException)
+        {
+        }
+        catch (Java.Lang.UnsupportedOperationException)
+        {
+        }
+    }
+
+    private static async Task<SelectedBookFile> CopyDocumentToCacheAsync(Activity activity, AndroidUri documentUri, CancellationToken cancellationToken)
+    {
+        var contentResolver = activity.ContentResolver
+            ?? throw new InvalidOperationException("ContentResolver недоступен.");
+
+        var originalFileName = ResolveFileName(contentResolver, documentUri);
+        var extension = Path.GetExtension(originalFileName);
+        if (string.IsNullOrWhiteSpace(extension))
+        {
+            var mimeType = contentResolver.GetType(documentUri);
+            var inferredExtension = MimeTypeMap.Singleton?.GetExtensionFromMimeType(mimeType);
+            if (!string.IsNullOrWhiteSpace(inferredExtension))
+            {
+                extension = $".{inferredExtension}";
+                originalFileName = $"{originalFileName}{extension}";
+            }
+        }
+
+        var tempPath = Path.Combine(FileSystem.CacheDirectory, $"{Guid.NewGuid()}{extension}");
+
+        try
+        {
+            await using var destinationStream = File.Create(tempPath);
+            await using var sourceStream = await OpenReadStreamAsync(contentResolver, documentUri, cancellationToken);
+            await sourceStream.CopyToAsync(destinationStream, cancellationToken);
+            await destinationStream.FlushAsync(cancellationToken);
+
+            return new SelectedBookFile(originalFileName, tempPath);
+        }
+        catch
+        {
+            try
+            {
+                if (File.Exists(tempPath))
+                {
+                    File.Delete(tempPath);
+                }
+            }
+            catch
+            {
+            }
+
+            throw;
+        }
+    }
+
+    private static Task<Stream> OpenReadStreamAsync(ContentResolver contentResolver, AndroidUri documentUri, CancellationToken cancellationToken)
+    {
+        return Task.Run(() =>
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+
+            return contentResolver.OpenInputStream(documentUri)
+                ?? throw new InvalidOperationException("Не удалось открыть выбранный документ.");
+        }, cancellationToken);
+    }
+
+    private static string ResolveFileName(ContentResolver contentResolver, AndroidUri documentUri)
+    {
+        try
+        {
+            using ICursor? cursor = contentResolver.Query(documentUri, new[] { IOpenableColumns.DisplayName }, null, null, null);
+            if (cursor != null && cursor.MoveToFirst())
+            {
+                var displayNameIndex = cursor.GetColumnIndex(IOpenableColumns.DisplayName);
+                if (displayNameIndex >= 0)
+                {
+                    var displayName = cursor.GetString(displayNameIndex);
+                    if (!string.IsNullOrWhiteSpace(displayName))
+                    {
+                        return displayName;
+                    }
+                }
+            }
+        }
+        catch
+        {
+        }
+
+        return documentUri.LastPathSegment?.Split('/').LastOrDefault() ?? "book";
+    }
+}

BookReader/Services/CalibreWebService.cs

@@ -1,15 +1,31 @@
 using BookReader.Models;
 using Newtonsoft.Json.Linq;
+using System.Net;
 using System.Net.Http.Headers;
 using System.Text;
+using System.Text.RegularExpressions;
+using System.Xml.Linq;
 
 namespace BookReader.Services;
 
 public class CalibreWebService : ICalibreWebService
 {
+    private static readonly XNamespace AtomNamespace = "http://www.w3.org/2005/Atom";
+    private const string OpdsAcquisitionRel = "http://opds-spec.org/acquisition";
+    private const string OpdsImageRel = "http://opds-spec.org/image";
+    private const string OpdsThumbnailRel = "http://opds-spec.org/image/thumbnail";
+
     private readonly HttpClient _httpClient;
     private readonly ICoverCacheService _coverCacheService;
     private string _baseUrl = string.Empty;
+    private CalibreBackendKind _backendKind = CalibreBackendKind.Unknown;
+
+    private enum CalibreBackendKind
+    {
+        Unknown,
+        ContentServerAjax,
+        Opds
+    }
 
     public CalibreWebService(HttpClient httpClient, ICoverCacheService coverCacheService)
     {
@@ -20,7 +36,13 @@ public class CalibreWebService : ICalibreWebService
 
     public void Configure(string url, string username, string password)
     {
-        _baseUrl = url.Trim().TrimEnd('/');
+        if (!TryCreateSupportedRemoteUri(url, out var serverUri))
+        {
+            throw new ArgumentException("Адрес сервера Calibre должен начинаться с http:// или https://.");
+        }
+
+        _baseUrl = serverUri.ToString().TrimEnd('/');
+        _backendKind = CalibreBackendKind.Unknown;
 
         if (!string.IsNullOrWhiteSpace(username))
         {
@@ -39,8 +61,8 @@ public class CalibreWebService : ICalibreWebService
         try
         {
             Configure(url, username, password);
-            var response = await _httpClient.GetAsync($"{_baseUrl}/ajax/search?query=&num=1");
+            var backendKind = await DetectBackendAsync(forceRefresh: true);
-            return response.IsSuccessStatusCode;
+            return backendKind != CalibreBackendKind.Unknown;
         }
         catch
         {
@@ -55,52 +77,209 @@ public class CalibreWebService : ICalibreWebService
             return Result<List<CalibreBook>>.Failure("Сначала укажите адрес сервера Calibre в настройках.");
         }
 
-        var books = new List<CalibreBook>();
-
         try
         {
-            var offset = page * pageSize;
+            var backendKind = await DetectBackendAsync();
-            var query = string.IsNullOrWhiteSpace(searchQuery) ? string.Empty : Uri.EscapeDataString(searchQuery.Trim());
+            return backendKind switch
-            var url = $"{_baseUrl}/ajax/search?query={query}&num={pageSize}&offset={offset}&sort=timestamp&sort_order=desc";
-
-            var response = await _httpClient.GetStringAsync(url);
-            var json = JObject.Parse(response);
-            var bookIds = json["book_ids"]?.ToObject<List<int>>() ?? new List<int>();
-
-            var semaphore = new SemaphoreSlim(4);
-            var tasks = bookIds.Select(async bookId =>
             {
-                await semaphore.WaitAsync();
+                CalibreBackendKind.ContentServerAjax => await GetBooksFromAjaxAsync(searchQuery, page, pageSize),
-                try
+                CalibreBackendKind.Opds => await GetBooksFromOpdsAsync(searchQuery, page, pageSize),
-                {
+                _ => Result<List<CalibreBook>>.Failure("Не удалось определить API сервера Calibre. Для calibre-web нужен доступный OPDS, для calibre-server — API /ajax.")
-                    return await LoadBookDataAsync(bookId);
+            };
-                }
-                finally
-                {
-                    semaphore.Release();
-                }
-            });
-
-            var results = await Task.WhenAll(tasks);
-            books.AddRange(results.Where(book => book != null)!);
-
-            return Result<List<CalibreBook>>.Success(books);
         }
         catch (TaskCanceledException ex)
         {
             return Result<List<CalibreBook>>.Failure(new TimeoutException("Сервер Calibre отвечает слишком долго.", ex));
         }
+        catch (HttpRequestException ex) when (ex.StatusCode == HttpStatusCode.Unauthorized || ex.StatusCode == HttpStatusCode.Forbidden)
+        {
+            return Result<List<CalibreBook>>.Failure("Сервер Calibre отклонил авторизацию. Проверьте логин и пароль.");
+        }
         catch (HttpRequestException ex)
         {
-            return Result<List<CalibreBook>>.Failure(new HttpRequestException("Не удалось подключиться к серверу Calibre.", ex));
+            return Result<List<CalibreBook>>.Failure($"Не удалось загрузить каталог Calibre: {ex.Message}");
+        }
+        catch (ArgumentException ex)
+        {
+            return Result<List<CalibreBook>>.Failure(ex.Message);
+        }
+        catch (InvalidOperationException ex)
+        {
+            return Result<List<CalibreBook>>.Failure(ex.Message);
         }
         catch (Exception ex)
         {
-            return Result<List<CalibreBook>>.Failure(new Exception("Не удалось загрузить каталог Calibre.", ex));
+            return Result<List<CalibreBook>>.Failure($"Не удалось загрузить каталог Calibre: {ex.GetBaseException().Message}");
         }
     }
 
-    private async Task<CalibreBook?> LoadBookDataAsync(int bookId)
+    public async Task<string> DownloadBookAsync(CalibreBook book, IProgress<double>? progress = null)
+    {
+        if (string.IsNullOrWhiteSpace(book.DownloadUrl))
+        {
+            throw new InvalidOperationException("У книги нет ссылки на скачивание.");
+        }
+
+        if (!TryCreateSupportedRemoteUri(book.DownloadUrl, out var downloadUri))
+        {
+            throw new InvalidOperationException("Сервер Calibre вернул неподдерживаемую ссылку на скачивание. Поддерживаются только http:// и https://.");
+        }
+
+        var booksDir = Path.Combine(FileSystem.AppDataDirectory, Constants.Files.BooksFolder);
+        Directory.CreateDirectory(booksDir);
+
+        var fileName = $"{Guid.NewGuid()}.{book.Format}";
+        var filePath = Path.Combine(booksDir, fileName);
+
+        using var response = await _httpClient.GetAsync(downloadUri, HttpCompletionOption.ResponseHeadersRead);
+        var hasAuthorizationHeader = _httpClient.DefaultRequestHeaders.Authorization != null;
+
+        if (response.StatusCode == HttpStatusCode.Unauthorized || response.StatusCode == HttpStatusCode.Forbidden)
+        {
+            var message = hasAuthorizationHeader
+                ? $"Сервер Calibre отклонил авторизацию при скачивании книги. Проверьте логин и пароль в настройках. URL: {downloadUri}"
+                : $"Сервер Calibre требует авторизацию для скачивания книги. Укажите логин и пароль в настройках. URL: {downloadUri}";
+
+            throw new UnauthorizedAccessException(message);
+        }
+
+        if (!response.IsSuccessStatusCode)
+        {
+            var errorSnippet = await ReadErrorSnippetAsync(response);
+            var authHint = !hasAuthorizationHeader && IsOpdsDownloadUri(downloadUri)
+                ? " Каталог OPDS может быть публичным, а скачивание требовать логин и пароль."
+                : string.Empty;
+            var responseHint = string.IsNullOrWhiteSpace(errorSnippet)
+                ? string.Empty
+                : $" Ответ сервера: {errorSnippet}";
+
+            throw new HttpRequestException(
+                $"Сервер Calibre вернул {(int)response.StatusCode} {response.ReasonPhrase} при скачивании книги. URL: {downloadUri}.{authHint}{responseHint}",
+                null,
+                response.StatusCode);
+        }
+
+        var totalBytes = response.Content.Headers.ContentLength ?? -1;
+        var bytesRead = 0L;
+
+        using var contentStream = await response.Content.ReadAsStreamAsync();
+        using var fileStream = File.Create(filePath);
+
+        var buffer = new byte[Constants.Network.DownloadBufferSize];
+        int read;
+
+        while ((read = await contentStream.ReadAsync(buffer, 0, buffer.Length)) > 0)
+        {
+            await fileStream.WriteAsync(buffer, 0, read);
+            bytesRead += read;
+
+            if (totalBytes > 0)
+            {
+                progress?.Report((double)bytesRead / totalBytes);
+            }
+        }
+
+        return filePath;
+    }
+
+    private async Task<CalibreBackendKind> DetectBackendAsync(bool forceRefresh = false)
+    {
+        if (!forceRefresh && _backendKind != CalibreBackendKind.Unknown)
+        {
+            return _backendKind;
+        }
+
+        if (string.IsNullOrWhiteSpace(_baseUrl))
+        {
+            return CalibreBackendKind.Unknown;
+        }
+
+        using var ajaxResponse = await _httpClient.GetAsync($"{_baseUrl}/ajax/search?query=&num=1");
+        if (ajaxResponse.IsSuccessStatusCode)
+        {
+            _backendKind = CalibreBackendKind.ContentServerAjax;
+            return _backendKind;
+        }
+
+        using var opdsResponse = await _httpClient.GetAsync($"{_baseUrl}/opds");
+        if (opdsResponse.IsSuccessStatusCode)
+        {
+            var responseBody = await opdsResponse.Content.ReadAsStringAsync();
+            if (IsOpdsFeed(responseBody))
+            {
+                _backendKind = CalibreBackendKind.Opds;
+                return _backendKind;
+            }
+        }
+
+        _backendKind = CalibreBackendKind.Unknown;
+        return _backendKind;
+    }
+
+    private async Task<Result<List<CalibreBook>>> GetBooksFromAjaxAsync(string? searchQuery, int page, int pageSize)
+    {
+        var books = new List<CalibreBook>();
+        var offset = page * pageSize;
+        var query = string.IsNullOrWhiteSpace(searchQuery) ? string.Empty : Uri.EscapeDataString(searchQuery.Trim());
+        var url = $"{_baseUrl}/ajax/search?query={query}&num={pageSize}&offset={offset}&sort=timestamp&sort_order=desc";
+
+        var response = await _httpClient.GetStringAsync(url);
+        var json = JObject.Parse(response);
+        var bookIds = json["book_ids"]?.ToObject<List<int>>() ?? new List<int>();
+
+        var semaphore = new SemaphoreSlim(4);
+        var tasks = bookIds.Select(async bookId =>
+        {
+            await semaphore.WaitAsync();
+            try
+            {
+                return await LoadBookDataFromAjaxAsync(bookId);
+            }
+            finally
+            {
+                semaphore.Release();
+            }
+        });
+
+        var results = await Task.WhenAll(tasks);
+        books.AddRange(results.Where(book => book != null)!);
+
+        return Result<List<CalibreBook>>.Success(books);
+    }
+
+    private async Task<Result<List<CalibreBook>>> GetBooksFromOpdsAsync(string? searchQuery, int page, int pageSize)
+    {
+        var requestUrl = string.IsNullOrWhiteSpace(searchQuery)
+            ? ToAbsoluteUrl("/opds/books/letter/00")
+            : ToAbsoluteUrl($"/opds/search/{Uri.EscapeDataString(searchQuery.Trim())}");
+
+        using var response = await _httpClient.GetAsync(requestUrl);
+        if (response.StatusCode == HttpStatusCode.NotFound)
+        {
+            return Result<List<CalibreBook>>.Failure("На сервере calibre-web не найден каталог OPDS.");
+        }
+
+        response.EnsureSuccessStatusCode();
+
+        var xml = await response.Content.ReadAsStringAsync();
+        var document = XDocument.Parse(xml);
+        var allBooks = document.Root?
+            .Elements(AtomNamespace + "entry")
+            .Select(ParseOpdsBook)
+            .Where(book => book != null)
+            .Cast<CalibreBook>()
+            .ToList() ?? new List<CalibreBook>();
+
+        var pagedBooks = allBooks
+            .Skip(page * pageSize)
+            .Take(pageSize)
+            .ToList();
+
+        await PopulateCoverImagesAsync(pagedBooks);
+        return Result<List<CalibreBook>>.Success(pagedBooks);
+    }
+
+    private async Task<CalibreBook?> LoadBookDataFromAjaxAsync(int bookId)
     {
         try
         {
@@ -130,21 +309,7 @@ public class CalibreWebService : ICalibreWebService
                 DownloadUrl = $"{_baseUrl}/get/{supportedFormat}/{bookId}"
             };
 
-            var cacheKey = $"cover_{bookId}";
+            await PopulateCoverImageAsync(calibreBook);
-            calibreBook.CoverImage = await _coverCacheService.GetCoverAsync(cacheKey);
-
-            if (calibreBook.CoverImage == null)
-            {
-                try
-                {
-                    calibreBook.CoverImage = await _httpClient.GetByteArrayAsync(calibreBook.CoverUrl);
-                    await _coverCacheService.SetCoverAsync(cacheKey, calibreBook.CoverImage);
-                }
-                catch
-                {
-                }
-            }
-
             return calibreBook;
         }
         catch
@@ -153,37 +318,243 @@ public class CalibreWebService : ICalibreWebService
         }
     }
 
-    public async Task<string> DownloadBookAsync(CalibreBook book, IProgress<double>? progress = null)
+    private CalibreBook? ParseOpdsBook(XElement entry)
     {
-        var booksDir = Path.Combine(FileSystem.AppDataDirectory, Constants.Files.BooksFolder);
+        try
-        Directory.CreateDirectory(booksDir);
-
-        var fileName = $"{Guid.NewGuid()}.{book.Format}";
-        var filePath = Path.Combine(booksDir, fileName);
-
-        using var response = await _httpClient.GetAsync(book.DownloadUrl, HttpCompletionOption.ResponseHeadersRead);
-        response.EnsureSuccessStatusCode();
-
-        var totalBytes = response.Content.Headers.ContentLength ?? -1;
-        var bytesRead = 0L;
-
-        using var contentStream = await response.Content.ReadAsStreamAsync();
-        using var fileStream = File.Create(filePath);
-
-        var buffer = new byte[Constants.Network.DownloadBufferSize];
-        int read;
-
-        while ((read = await contentStream.ReadAsync(buffer, 0, buffer.Length)) > 0)
         {
-            await fileStream.WriteAsync(buffer, 0, read);
+            var links = entry.Elements(AtomNamespace + "link").ToList();
-            bytesRead += read;
+            var acquisitionLink = links.FirstOrDefault(link =>
-
-            if (totalBytes > 0)
             {
-                progress?.Report((double)bytesRead / totalBytes);
+                var rel = (string?)link.Attribute("rel") ?? string.Empty;
+                return rel.Contains(OpdsAcquisitionRel, StringComparison.OrdinalIgnoreCase) &&
+                       DetermineSupportedFormat(link) != null;
+            });
+
+            if (acquisitionLink == null)
+            {
+                return null;
             }
+
+            var downloadHref = (string?)acquisitionLink.Attribute("href");
+            var format = DetermineSupportedFormat(acquisitionLink);
+            if (string.IsNullOrWhiteSpace(downloadHref) || string.IsNullOrWhiteSpace(format))
+            {
+                return null;
+            }
+
+            var title = entry.Element(AtomNamespace + "title")?.Value?.Trim();
+            var authors = entry.Elements(AtomNamespace + "author")
+                .Select(author => author.Element(AtomNamespace + "name")?.Value?.Trim())
+                .Where(name => !string.IsNullOrWhiteSpace(name))
+                .Cast<string>()
+                .ToList();
+
+            var coverHref = links
+                .FirstOrDefault(link => string.Equals((string?)link.Attribute("rel"), OpdsImageRel, StringComparison.OrdinalIgnoreCase))?
+                .Attribute("href")?.Value
+                ?? links.FirstOrDefault(link => string.Equals((string?)link.Attribute("rel"), OpdsThumbnailRel, StringComparison.OrdinalIgnoreCase))?
+                    .Attribute("href")?.Value;
+
+            string? coverUrl = null;
+            if (!string.IsNullOrWhiteSpace(coverHref))
+            {
+                coverUrl = TryToAbsoluteHttpUrl(coverHref);
+            }
+
+            var downloadUrl = TryToAbsoluteHttpUrl(downloadHref);
+            if (string.IsNullOrWhiteSpace(downloadUrl))
+            {
+                return null;
+            }
+
+            return new CalibreBook
+            {
+                Id = ExtractBookId(downloadHref) ?? ExtractBookId(coverHref) ?? Guid.NewGuid().ToString("N"),
+                Title = string.IsNullOrWhiteSpace(title) ? "Без названия" : title,
+                Author = authors.Count > 0 ? string.Join(", ", authors) : "Неизвестный автор",
+                Format = format,
+                CoverUrl = coverUrl,
+                DownloadUrl = downloadUrl
+            };
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    private async Task PopulateCoverImagesAsync(IEnumerable<CalibreBook> books)
+    {
+        var semaphore = new SemaphoreSlim(4);
+        var tasks = books.Select(async book =>
+        {
+            await semaphore.WaitAsync();
+            try
+            {
+                await PopulateCoverImageAsync(book);
+            }
+            finally
+            {
+                semaphore.Release();
+            }
+        });
+
+        await Task.WhenAll(tasks);
+    }
+
+    private async Task PopulateCoverImageAsync(CalibreBook book)
+    {
+        if (string.IsNullOrWhiteSpace(book.CoverUrl))
+        {
+            return;
         }
 
-        return filePath;
+        if (!TryCreateSupportedRemoteUri(book.CoverUrl, out var coverUri))
+        {
+            return;
+        }
+
+        book.CoverImage = await _coverCacheService.GetCoverAsync(book.CoverCacheKey);
+        if (book.CoverImage != null)
+        {
+            return;
+        }
+
+        try
+        {
+            book.CoverImage = await _httpClient.GetByteArrayAsync(coverUri);
+            if (book.CoverImage != null && book.CoverImage.Length > 0)
+            {
+                await _coverCacheService.SetCoverAsync(book.CoverCacheKey, book.CoverImage);
+            }
+        }
+        catch
+        {
+        }
+    }
+
+    private static bool IsOpdsFeed(string responseBody)
+    {
+        try
+        {
+            var document = XDocument.Parse(responseBody);
+            return document.Root?.Name == AtomNamespace + "feed";
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private static string? DetermineSupportedFormat(XElement link)
+    {
+        var type = (string?)link.Attribute("type");
+        var title = (string?)link.Attribute("title");
+        var href = (string?)link.Attribute("href");
+        var candidates = new[] { type, title, href };
+
+        if (candidates.Any(candidate => candidate?.Contains("epub", StringComparison.OrdinalIgnoreCase) == true))
+        {
+            return "epub";
+        }
+
+        if (candidates.Any(candidate =>
+                candidate?.Contains("fb2", StringComparison.OrdinalIgnoreCase) == true ||
+                candidate?.Contains("fictionbook", StringComparison.OrdinalIgnoreCase) == true))
+        {
+            return "fb2";
+        }
+
+        return null;
+    }
+
+    private string ToAbsoluteUrl(string relativeOrAbsoluteUrl)
+    {
+        var absoluteUrl = TryToAbsoluteHttpUrl(relativeOrAbsoluteUrl);
+        if (string.IsNullOrWhiteSpace(absoluteUrl))
+        {
+            throw new InvalidOperationException($"Сервер Calibre вернул ссылку с неподдерживаемой схемой. BaseUrl: {_baseUrl}; Link: {relativeOrAbsoluteUrl}");
+        }
+
+        return absoluteUrl;
+    }
+
+    private string? TryToAbsoluteHttpUrl(string relativeOrAbsoluteUrl)
+    {
+        if (string.IsNullOrWhiteSpace(relativeOrAbsoluteUrl) || string.IsNullOrWhiteSpace(_baseUrl))
+        {
+            return null;
+        }
+
+        if (HasExplicitUriScheme(relativeOrAbsoluteUrl))
+        {
+            return TryCreateSupportedRemoteUri(relativeOrAbsoluteUrl, out var absoluteUri)
+                ? absoluteUri.ToString()
+                : null;
+        }
+
+        var baseUri = new Uri($"{_baseUrl.TrimEnd('/')}/");
+        var combinedUri = new Uri(baseUri, relativeOrAbsoluteUrl.TrimStart('/'));
+        return IsSupportedRemoteScheme(combinedUri) ? combinedUri.ToString() : null;
+    }
+
+    private static bool HasExplicitUriScheme(string value)
+    {
+        return Regex.IsMatch(value, @"^[a-zA-Z][a-zA-Z0-9+.-]*:");
+    }
+
+    private static bool TryCreateSupportedRemoteUri(string? value, out Uri uri)
+    {
+        if (Uri.TryCreate(value, UriKind.Absolute, out uri!))
+        {
+            return IsSupportedRemoteScheme(uri);
+        }
+
+        uri = null!;
+        return false;
+    }
+
+    private static bool IsSupportedRemoteScheme(Uri uri)
+    {
+        return uri.Scheme == Uri.UriSchemeHttp || uri.Scheme == Uri.UriSchemeHttps;
+    }
+
+    private static bool IsOpdsDownloadUri(Uri uri)
+    {
+        return uri.AbsolutePath.Contains("/opds/download/", StringComparison.OrdinalIgnoreCase);
+    }
+
+    private static async Task<string?> ReadErrorSnippetAsync(HttpResponseMessage response)
+    {
+        try
+        {
+            var body = await response.Content.ReadAsStringAsync();
+            if (string.IsNullOrWhiteSpace(body))
+            {
+                return null;
+            }
+
+            var normalized = Regex.Replace(body, @"\s+", " ").Trim();
+            return normalized.Length <= 180 ? normalized : normalized[..180];
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    private static string? ExtractBookId(string? href)
+    {
+        if (string.IsNullOrWhiteSpace(href))
+        {
+            return null;
+        }
+
+        var match = Regex.Match(href, @"/(?:opds/)?(?:download|cover)/(\d+)", RegexOptions.IgnoreCase);
+        return match.Success ? match.Groups[1].Value : null;
     }
 }
+
+
+
+

BookReader/Services/IBookImportPickerService.cs

@@ -0,0 +1,8 @@
+namespace BookReader.Services;
+
+public sealed record SelectedBookFile(string OriginalFileName, string TempFilePath);
+
+public interface IBookImportPickerService
+{
+    Task<SelectedBookFile?> PickBookFileAsync(CancellationToken cancellationToken = default);
+}

BookReader/ViewModels/BookshelfViewModel.cs

@@ -11,6 +11,7 @@ public partial class BookshelfViewModel : BaseViewModel
     private readonly IDatabaseService _databaseService;
     private readonly IBookParserService _bookParserService;
     private readonly INavigationService _navigationService;
+    private readonly IBookImportPickerService _bookImportPickerService;
 
     public ObservableCollection<Book> Books { get; } = new();
 
@@ -48,11 +49,13 @@ public partial class BookshelfViewModel : BaseViewModel
     public BookshelfViewModel(
         IDatabaseService databaseService,
         IBookParserService bookParserService,
-        INavigationService navigationService)
+        INavigationService navigationService,
+        IBookImportPickerService bookImportPickerService)
     {
         _databaseService = databaseService;
         _bookParserService = bookParserService;
         _navigationService = navigationService;
+        _bookImportPickerService = bookImportPickerService;
         Title = "Библиотека";
     }
 
@@ -103,25 +106,17 @@ public partial class BookshelfViewModel : BaseViewModel
     [RelayCommand]
     public async Task AddBookFromFileAsync()
     {
+        SelectedBookFile? selectedBookFile = null;
+
         try
         {
-            var customFileTypes = new FilePickerFileType(new Dictionary<DevicePlatform, IEnumerable<string>>
+            selectedBookFile = await _bookImportPickerService.PickBookFileAsync();
-            {
+            if (selectedBookFile == null)
-                { DevicePlatform.Android, new[] { "application/epub+zip", "application/x-fictionbook+xml", "application/octet-stream", "*/*" } }
-            });
-
-            var result = await FilePicker.Default.PickAsync(new PickOptions
-            {
-                PickerTitle = "Выберите книгу",
-                FileTypes = customFileTypes
-            });
-
-            if (result == null)
             {
                 return;
             }
 
-            var extension = Path.GetExtension(result.FileName).ToLowerInvariant();
+            var extension = Path.GetExtension(selectedBookFile.OriginalFileName).ToLowerInvariant();
             if (extension != Constants.Files.EpubExtension && extension != Constants.Files.Fb2Extension)
             {
                 await _navigationService.DisplayAlertAsync("Формат не поддерживается", "Сейчас можно добавить только EPUB и FB2.", "OK");
@@ -131,24 +126,9 @@ public partial class BookshelfViewModel : BaseViewModel
             IsBusy = true;
             StatusMessage = "Добавляю книгу...";
 
-            using var sourceStream = await result.OpenReadAsync();
+            var book = await _bookParserService.ParseAndStoreBookAsync(selectedBookFile.TempFilePath, selectedBookFile.OriginalFileName);
-            var tempPath = Path.Combine(FileSystem.CacheDirectory, result.FileName);
-            using (var tempFileStream = File.Create(tempPath))
-            {
-                await sourceStream.CopyToAsync(tempFileStream);
-            }
-
-            var book = await _bookParserService.ParseAndStoreBookAsync(tempPath, result.FileName);
             Books.Insert(0, book);
             RefreshLibraryState();
-
-            try
-            {
-                File.Delete(tempPath);
-            }
-            catch
-            {
-            }
         }
         catch (Exception ex)
         {
@@ -156,6 +136,7 @@ public partial class BookshelfViewModel : BaseViewModel
         }
         finally
         {
+            TryDeleteTempFile(selectedBookFile?.TempFilePath);
             IsBusy = false;
             StatusMessage = string.Empty;
         }
@@ -214,6 +195,25 @@ public partial class BookshelfViewModel : BaseViewModel
     [RelayCommand]
     public Task OpenCalibreLibraryAsync() => _navigationService.GoToAsync("//calibre");
 
+    private static void TryDeleteTempFile(string? tempFilePath)
+    {
+        if (string.IsNullOrWhiteSpace(tempFilePath))
+        {
+            return;
+        }
+
+        try
+        {
+            if (File.Exists(tempFilePath))
+            {
+                File.Delete(tempFilePath);
+            }
+        }
+        catch
+        {
+        }
+    }
+
     private void RefreshLibraryState()
     {
         IsEmpty = Books.Count == 0;

BookReader/ViewModels/CalibreLibraryViewModel.cs

@@ -68,7 +68,15 @@ public partial class CalibreLibraryViewModel : BaseViewModel
 
         if (IsConfigured)
         {
-            _calibreWebService.Configure(url, username, password);
+            if (!Uri.TryCreate(url, UriKind.Absolute, out var uri) ||
+                (uri.Scheme != Uri.UriSchemeHttp && uri.Scheme != Uri.UriSchemeHttps))
+            {
+                Books.Clear();
+                ConnectionErrorMessage = $"Сохранён некорректный адрес Calibre: {url}";
+                return;
+            }
+
+            _calibreWebService.Configure(uri.ToString(), username, password);
             await LoadBooksAsync();
         }
         else
@@ -226,3 +234,4 @@ public partial class CalibreLibraryViewModel : BaseViewModel
         OnPropertyChanged(nameof(HasBooks));
     }
 }
+

BookReader/ViewModels/SettingsViewModel.cs

@@ -129,8 +129,17 @@ public partial class SettingsViewModel : BaseViewModel
         try
         {
             var success = await _calibreWebService.TestConnectionAsync(CalibreUrl, CalibreUsername, CalibrePassword);
-            ConnectionStatus = success ? "Соединение установлено." : "Сервер ответил ошибкой или недоступен.";
+            if (success)
-            ConnectionStatusColor = success ? SuccessTone : DangerTone;
+            {
+                await PersistSettingsAsync(showNotification: false);
+                ConnectionStatus = "Соединение установлено. Настройки сохранены.";
+                ConnectionStatusColor = SuccessTone;
+            }
+            else
+            {
+                ConnectionStatus = "Сервер ответил ошибкой или недоступен.";
+                ConnectionStatusColor = DangerTone;
+            }
         }
         catch (Exception ex)
         {
@@ -236,3 +245,4 @@ public partial class SettingsViewModel : BaseViewModel
         _ => Constants.Reader.DefaultTheme
     };
 }
+

BookReader/Views/CalibreLibraryPage.xaml

@@ -76,6 +76,7 @@
                          IsRefreshing="{Binding IsRefreshing}"
                          Margin="0,0,0,24">
                 <CollectionView ItemsSource="{Binding Books}"
+                                IsVisible="{Binding HasConnectionError, Converter={StaticResource InvertedBoolConverter}}"
                                 SelectionMode="None"
                                 RemainingItemsThreshold="5"
                                 RemainingItemsThresholdReachedCommand="{Binding LoadMoreBooksCommand}">
@@ -167,3 +168,4 @@
         </Grid>
     </Grid>
 </ContentPage>
+