make pdf preview open pattern reading mode

Localizable.xcstrings

@@ -883,6 +883,22 @@
         }
       }
     },
+    "Open PDF instructions" : {
+      "localizations" : {
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "PDF-Anleitung öffnen"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Open PDF instructions"
+          }
+        }
+      }
+    },
     "Open Reading Mode" : {
       "comment" : "A button that opens a reading mode.",
       "isCommentAutoGenerated" : true,
@@ -1493,4 +1509,4 @@
     }
   },
   "version" : "1.3"
-}
+}

LoopLine/Services/ImportedPDFStorage.swift

@@ -1,6 +1,14 @@
 import Foundation
 
 enum ImportedPDFStorage {
+    static func fileURL(for project: Project) -> URL? {
+        guard project.sourceType == .pdf, let storedReference = project.sourceFilePath else {
+            return nil
+        }
+
+        return fileURL(for: storedReference)
+    }
+
     static func directoryURL() throws -> URL {
         let applicationSupportDirectory = try FileManager.default.url(
             for: .applicationSupportDirectory,

LoopLine/ViewModels/PDFReadingViewModel.swift

@@ -10,11 +10,7 @@ final class PDFReadingViewModel {
     var markupError: PDFMarkupError?
 
     func pdfURL(for project: Project) -> URL? {
-        guard project.sourceType == .pdf, let sourceFilePath = project.sourceFilePath else {
-            return nil
-        }
-
-        return ImportedPDFStorage.fileURL(for: sourceFilePath)
+        ImportedPDFStorage.fileURL(for: project)
     }
 
     func selectedMetricValue(for project: Project) -> Int {

LoopLine/Views/ProjectDetailView.swift

@@ -62,12 +62,19 @@ struct ProjectDetailView: View {
     private var mediaHeader: some View {
         Group {
             if project.sourceType == .pdf, let sourceFilePath = project.sourceFilePath {
-                StoredPDFPreview(storedReference: sourceFilePath, height: 190)
-                    .clipShape(RoundedRectangle(cornerRadius: LoopLineTheme.cornerRadius, style: .continuous))
-                    .overlay {
-                        RoundedRectangle(cornerRadius: LoopLineTheme.cornerRadius, style: .continuous)
-                            .stroke(LoopLineTheme.subtleStroke, lineWidth: 1)
+                if ImportedPDFStorage.fileURL(for: project) != nil {
+                    NavigationLink {
+                        PDFReadingView(project: project)
+                    } label: {
+                        pdfPreview(storedReference: sourceFilePath)
+                            .contentShape(Rectangle())
                     }
+                    .buttonStyle(.plain)
+                    .accessibilityLabel("Open PDF instructions")
+                    .accessibilityIdentifier("openPDFPreview")
+                } else {
+                    pdfPreview(storedReference: sourceFilePath)
+                }
             } else if project.sourceType == .image, let sourceFilePath = project.sourceFilePath {
                 StoredImagePreview(storedReference: sourceFilePath, height: 190)
                     .clipShape(RoundedRectangle(cornerRadius: LoopLineTheme.cornerRadius, style: .continuous))
@@ -82,6 +89,15 @@ struct ProjectDetailView: View {
         }
     }
 
+    private func pdfPreview(storedReference: String) -> some View {
+        StoredPDFPreview(storedReference: storedReference, height: 190)
+            .clipShape(RoundedRectangle(cornerRadius: LoopLineTheme.cornerRadius, style: .continuous))
+            .overlay {
+                RoundedRectangle(cornerRadius: LoopLineTheme.cornerRadius, style: .continuous)
+                    .stroke(LoopLineTheme.subtleStroke, lineWidth: 1)
+            }
+    }
+
     private var titleBlock: some View {
         VStack(alignment: .leading, spacing: 10) {
             Text(project.name)

LoopLineTests/ProjectPersistenceTests.swift

@@ -10,6 +10,23 @@ import XCTest
 @testable import LoopLine
 
 final class ProjectPersistenceTests: XCTestCase {
+    @MainActor
+    func testPDFURLRequiresPDFSourceAndExistingFile() throws {
+        let fileURL = FileManager.default.temporaryDirectory
+            .appendingPathComponent("LoopLine-PDF-Resolver-\(UUID().uuidString).pdf")
+        try Data().write(to: fileURL)
+        defer { try? FileManager.default.removeItem(at: fileURL) }
+
+        let pdfProject = Project(name: "PDF", sourceType: .pdf, sourceFilePath: fileURL.path)
+        XCTAssertEqual(ImportedPDFStorage.fileURL(for: pdfProject), fileURL)
+
+        let textProject = Project(name: "Text", sourceType: .text, sourceFilePath: fileURL.path)
+        XCTAssertNil(ImportedPDFStorage.fileURL(for: textProject))
+
+        let missingPDFProject = Project(name: "Missing PDF", sourceType: .pdf)
+        XCTAssertNil(ImportedPDFStorage.fileURL(for: missingPDFProject))
+    }
+
     @MainActor
     func testProjectPreservesTrackingValuesAfterSaveAndFetch() throws {
         let container = try ModelContainer(

LoopLineUITests/ReadingModeUITests.swift

@@ -22,4 +22,22 @@ final class ReadingModeUITests: XCTestCase {
         let pdfReadingMode = app.descendants(matching: .any)["pdfReadingMode"]
         XCTAssertTrue(pdfReadingMode.waitForExistence(timeout: 5))
     }
+
+    @MainActor
+    func testUserCanOpenReadingModeFromPDFPreview() throws {
+        let app = XCUIApplication()
+        app.launchArguments.append("-uiTesting")
+        app.launch()
+
+        let project = app.buttons["uiTestPDFProject"]
+        XCTAssertTrue(project.waitForExistence(timeout: 5))
+        project.tap()
+
+        let pdfPreview = app.buttons["openPDFPreview"]
+        XCTAssertTrue(pdfPreview.waitForExistence(timeout: 5))
+        pdfPreview.tap()
+
+        let pdfReadingMode = app.descendants(matching: .any)["pdfReadingMode"]
+        XCTAssertTrue(pdfReadingMode.waitForExistence(timeout: 5))
+    }
 }