Fix loading initial pdf page if not yet synced (#1233)

Author: michalrentka

Zotero/Controllers/Database/Requests/ReadDocumentDataDbRequest.swift

@@ -15,11 +15,12 @@ struct ReadDocumentDataDbRequest: DbResponseRequest {
 
     let attachmentKey: String
     let libraryId: LibraryIdentifier
+    let defaultPageValue: String
 
     var needsWrite: Bool { return false }
 
     func process(in database: Realm) throws -> String {
-        guard let pageIndex = database.objects(RPageIndex.self).uniqueObject(key: attachmentKey, libraryId: libraryId) else { return "" }
+        guard let pageIndex = database.objects(RPageIndex.self).uniqueObject(key: attachmentKey, libraryId: libraryId) else { return defaultPageValue }
         return pageIndex.index
     }
 }

Zotero/Scenes/Detail/HTML:EPUB/Models/HtmlEpubReaderState.swift

@@ -91,6 +91,10 @@ struct HtmlEpubReaderState: ViewModelState {
                 return L10n.Errors.unknown
             }
         }
+        
+        var documentShouldClose: Bool {
+            return false
+        }
     }
 
     let readerURL: URL?

Zotero/Scenes/Detail/HTML:EPUB/ViewModels/HtmlEpubReaderActionHandler.swift

@@ -788,9 +788,10 @@ final class HtmlEpubReaderActionHandler: ViewModelActionHandler, BackgroundDbPro
 
         func loadItemAnnotationsAndPage(in viewModel: ViewModel<HtmlEpubReaderActionHandler>) -> (RItem, Results<RItem>, String)? {
             do {
+                let defaultPageValue = defaultPageValue(forExt: viewModel.state.documentFile.ext.lowercased())
                 let itemRequest = ReadItemDbRequest(libraryId: viewModel.state.library.identifier, key: viewModel.state.key)
                 let item = try dbStorage.perform(request: itemRequest, on: .main)
-                let pageIndexRequest = ReadDocumentDataDbRequest(attachmentKey: viewModel.state.key, libraryId: viewModel.state.library.identifier)
+                let pageIndexRequest = ReadDocumentDataDbRequest(attachmentKey: viewModel.state.key, libraryId: viewModel.state.library.identifier, defaultPageValue: defaultPageValue)
                 let pageIndex = try dbStorage.perform(request: pageIndexRequest, on: .main)
                 let annotationsRequest = ReadAnnotationsDbRequest(attachmentKey: viewModel.state.key, libraryId: viewModel.state.library.identifier)
                 let items = try dbStorage.perform(request: annotationsRequest, on: .main)
@@ -799,6 +800,19 @@ final class HtmlEpubReaderActionHandler: ViewModelActionHandler, BackgroundDbPro
                 DDLogError("HtmlEpubReaderActionHandler: can't load annotations - \(error)")
                 return nil
             }
+            
+            func defaultPageValue(forExt ext: String) -> String {
+                switch ext {
+                case "epub":
+                    return "_start"
+
+                case "html", "htm":
+                    return "0"
+
+                default:
+                    return ""
+                }
+            }
         }
 
         func processAnnotations(items: Results<RItem>) -> ([String], [String: HtmlEpubAnnotation], String) {
@@ -818,11 +832,10 @@ final class HtmlEpubReaderActionHandler: ViewModelActionHandler, BackgroundDbPro
         func loadTypeAndPage(from file: File, rawPage: String) throws -> (String, HtmlEpubReaderState.DocumentData.Page?) {
             switch viewModel.state.documentFile.ext.lowercased() {
             case "epub":
-                let cfi = rawPage.isEmpty ? "_start" : rawPage
-                return ("epub", .epub(cfi: cfi))
+                return ("epub", .epub(cfi: rawPage))
 
             case "html", "htm":
-                if let scrollYPercent = Double(rawPage.isEmpty ? "0" : rawPage) {
+                if let scrollYPercent = Double(rawPage) {
                     return ("snapshot", .html(scrollYPercent: scrollYPercent))
                 } else {
                     DDLogError("HtmlEPubReaderActionHandler: incompatible lastIndexPage stored for \(viewModel.state.key) - \(rawPage)")

Zotero/Scenes/Detail/PDF/Models/PDFReaderState.swift

@@ -62,10 +62,11 @@ struct PDFReaderState: ViewModelState {
         case pageNotInt
         case unknown
         case documentEmpty
+        case unknownLoading
 
         var title: String {
             switch self {
-            case .cantDeleteAnnotation, .cantAddAnnotations, .cantUpdateAnnotation, .pageNotInt, .unknown, .documentEmpty:
+            case .cantDeleteAnnotation, .cantAddAnnotations, .cantUpdateAnnotation, .pageNotInt, .unknown, .documentEmpty, .unknownLoading:
                 return L10n.error
 
             case .mergeTooBig:
@@ -90,13 +91,23 @@ struct PDFReaderState: ViewModelState {
             case .pageNotInt:
                 return L10n.Errors.Pdf.pageIndexNotInt
 
-            case .unknown:
+            case .unknown, .unknownLoading:
                 return L10n.Errors.unknown
 
             case .documentEmpty:
                 return L10n.Errors.Pdf.emptyDocument
             }
         }
+        
+        var documentShouldClose: Bool {
+            switch self {
+            case .documentEmpty, .pageNotInt, .unknownLoading:
+                return true
+                
+            case .cantDeleteAnnotation, .cantAddAnnotations, .cantUpdateAnnotation, .mergeTooBig, .unknown:
+                return false
+            }
+        }
     }
 
     enum DefaultAnnotationPageLabel {

Zotero/Scenes/Detail/PDF/ViewModels/PDFReaderActionHandler.swift

@@ -1875,8 +1875,10 @@ final class PDFReaderActionHandler: ViewModelActionHandler, BackgroundDbProcessi
 
             observeDocument(in: viewModel)
         } catch let error {
-            // TODO: - Show error
             DDLogError("PDFReaderActionHandler: failed to load PDF: \(error)")
+            update(viewModel: viewModel) { state in
+                state.error = (error as? PDFReaderState.Error) ?? .unknownLoading
+            }
         }
 
         func observe(library: Library, viewModel: ViewModel<PDFReaderActionHandler>, handler: PDFReaderActionHandler) {
@@ -1935,7 +1937,7 @@ final class PDFReaderActionHandler: ViewModelActionHandler, BackgroundDbProcessi
 
             try dbStorage.perform(on: .main, with: { coordinator in
                 item = try coordinator.perform(request: ReadItemDbRequest(libraryId: libraryId, key: key))
-                pageStr = try coordinator.perform(request: ReadDocumentDataDbRequest(attachmentKey: key, libraryId: libraryId))
+                pageStr = try coordinator.perform(request: ReadDocumentDataDbRequest(attachmentKey: key, libraryId: libraryId, defaultPageValue: "0"))
                 results = try coordinator.perform(request: ReadAnnotationsDbRequest(attachmentKey: key, libraryId: libraryId))
             })
 

Zotero/Scenes/Detail/ReaderCoordinator.swift

@@ -13,6 +13,8 @@ import RxSwift
 protocol ReaderError: Error {
     var title: String { get }
     var message: String { get }
+    
+    var documentShouldClose: Bool { get }
 }
 
 protocol ReaderState {
@@ -100,7 +102,13 @@ protocol ReaderCoordinator: Coordinator, ReaderCoordinatorDelegate, ReaderSideba
 extension ReaderCoordinator {
     func show(error: ReaderError) {
         let controller = UIAlertController(title: error.title, message: error.message, preferredStyle: .alert)
-        controller.addAction(UIAlertAction(title: L10n.ok, style: .default))
+        if error.documentShouldClose {
+            controller.addAction(UIAlertAction(title: L10n.close, style: .default, handler: { [weak self] _ in
+                self?.navigationController?.dismiss(animated: true)
+            }))
+        } else {
+            controller.addAction(UIAlertAction(title: L10n.ok, style: .default))
+        }
         navigationController?.present(controller, animated: true)
     }