feat: ios mobil arayüz tasarımı

ios/Bookibra/ViewModels/BookDetailViewModel.swift

@@ -0,0 +1,55 @@
+import Foundation
+import SwiftData
+import UIKit
+
+@MainActor
+final class BookDetailViewModel: ObservableObject {
+    @Published var book: BookRemote
+    @Published var isInLibrary = false
+
+    init(book: BookRemote) {
+        self.book = book
+    }
+
+    func refresh(context: ModelContext) {
+        let all = (try? context.fetch(FetchDescriptor<LibraryBook>())) ?? []
+        isInLibrary = all.contains(where: { local in
+            match(local: local, remote: book)
+        })
+    }
+
+    func toggleLibrary(context: ModelContext) {
+        let all = (try? context.fetch(FetchDescriptor<LibraryBook>())) ?? []
+
+        if let existing = all.first(where: { match(local: $0, remote: book) }) {
+            context.delete(existing)
+            isInLibrary = false
+            UINotificationFeedbackGenerator().notificationOccurred(.warning)
+        } else {
+            let local = LibraryBook(
+                title: book.title,
+                authorsString: book.authors.joined(separator: ", "),
+                coverUrlString: book.coverImageUrl?.absoluteString,
+                isbn10: book.isbn10,
+                isbn13: book.isbn13,
+                publishedYear: book.publishedYear,
+                categoriesString: book.categories.joined(separator: ", "),
+                summary: book.description,
+                language: book.language,
+                sourceLocale: book.sourceLocale,
+                remotePayloadJson: nil
+            )
+            context.insert(local)
+            isInLibrary = true
+            UINotificationFeedbackGenerator().notificationOccurred(.success)
+        }
+
+        try? context.save()
+    }
+
+    private func match(local: LibraryBook, remote: BookRemote) -> Bool {
+        if let lhs = local.isbn13, let rhs = remote.isbn13 { return lhs == rhs }
+        if let lhs = local.isbn10, let rhs = remote.isbn10 { return lhs == rhs }
+        return local.title == remote.title
+    }
+}