fix crash because currentPage and currentChapter were yet to be set

ImageViewer/ViewController.swift

@@ -251,11 +251,11 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                 try String(
                     contentsOfFile: currentPath.appendingPathComponent("state.json").path
                 ).utf8)
-            let l = try JSONDecoder().decode(LocalState.self, from: json)
-            currentPage = l.page
-            currentChapter = l.chapter
-            mode = l.turnMode
-            readerView.backgroundColor = convertStringToColor(str: l.backgroundColor)
+            let local = try JSONDecoder().decode(LocalState.self, from: json)
+            currentPage = local.page
+            currentChapter = local.chapter
+            mode = local.turnMode
+            readerView.backgroundColor = convertStringToColor(str: local.backgroundColor)
         } catch {
             print("failed to load local state")
         }
@@ -693,8 +693,8 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         info.text = """
             \(metadata.title)
             \(metadata.chapters[currentChapter - 1].title)
-            Volume \(Int(metadata.chapters[currentChapter - 1].volume)) of \(Int(metadata.chapters.last!.volume))
-            Chapter \(currentChapter!) of \(Int(metadata.chapters.last!.chapter))
+            Volume \(Int(metadata.chapters[currentChapter - 1].volume)) of \(Int(metadata.last_volume))
+            Chapter \(currentChapter!) of \(Int(metadata.last_chapter))
             Page \(currentPage!) of \(metadata.chapters[currentChapter - 1].pages)
             Image size: \(Int(imageView.image!.size.width))x\(Int(imageView.image!.size.height))
             """
@@ -814,7 +814,6 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
             let ps: [String] = try fileManager.contentsOfDirectory(atPath: dir.path).sorted()
             let current = dir.appendingPathComponent(ps[0])
             imageView.image = UIImage(contentsOfFile: current.path)
-            updateInfo()
 
             let path_meta = current.lastPathComponent.components(separatedBy: "_")
             assert(path_meta[0] == "chapter")
@@ -829,6 +828,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                 assert(path_meta[2] == "image")
                 currentPage = Int(path_meta[3].components(separatedBy: ".")[0])! + 1
             }
+            updateInfo()
         } catch {
             print("failed to set images")
         }