ImageViewer/ViewController.swift

@@ -59,6 +59,8 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
     var scrollPos: CGPoint!
     var hasSetContentOffset = false
 
+    var pendingAlert: UIAlertController?
+
     var imageView = UIImageView()
     var mode = PageTurnMode.leftToRight
     var metadataList: [URL: Metadata] = [:]
@@ -105,6 +107,13 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         setup()
     }
 
+    override func viewDidAppear(_ animated: Bool) {
+        super.viewDidAppear(animated)
+        if let alert = pendingAlert {
+            present(alert, animated: false, completion: nil)
+        }
+    }
+
     func setup() {
         do {
             if try fileManager.contentsOfDirectory(atPath: documentsURL.path).isEmpty {
@@ -140,8 +149,6 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         setupHomeView()
         if let name = globalState.comicName {
             readComic(name: name)
-        } else {
-            print("no comic?")
         }
     }
 
@@ -163,14 +170,21 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
     }
 
     func loadComics() {
+        let alert = UIAlertController(title: "Failed to load comics.", message: "This is an alert.", preferredStyle: .alert) 
+        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
         do {
             var directories: [URL] = []
 
-            let contents = try fileManager.contentsOfDirectory(
+            guard let contents = try? fileManager.contentsOfDirectory(
                 at: documentsURL,
                 includingPropertiesForKeys: [.isDirectoryKey],
                 options: [.skipsHiddenFiles]
             )
+            else {
+                alert.message = String(format: "Failed to read contents of directory: \(documentsURL)")
+                pendingAlert = alert
+                return
+            }
 
             directories = contents.filter { url in
                 var isDirectory: ObjCBool = false
@@ -181,33 +195,63 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
             for dir in directories {
                 if !fileManager.fileExists(atPath: dir.appendingPathComponent(metadataFilename).path) {
                     getMetadataFromFilename(path: dir)
+                    if pendingAlert != nil {
+                        return
+                    }
                 }
 
                 currentPath = dir
 
-                let data = try! Data(contentsOf: dir.appendingPathComponent(metadataFilename))
+                guard let data = try? Data(contentsOf: dir.appendingPathComponent(metadataFilename))
+                else {
+                    alert.message = String(format: "Failed to read contents of metadata: \(dir.appendingPathComponent(metadataFilename))")
+                    pendingAlert = alert
+                    return
+                }
                 var byteBuffer = ByteBuffer(data: data)
-                metadata = try! getCheckedRoot(byteBuffer: &byteBuffer)
+                metadata = try? getCheckedRoot(byteBuffer: &byteBuffer)
+                if metadata == nil {
+                    alert.message = String(format: "Failed to read contents of metadata flatbuffer file: \(dir.appendingPathComponent(metadataFilename))")
+                    pendingAlert = alert
+                    return
+                }
                 metadataList[dir] = metadata
                 loadLocalState()
                 let volCovP = ProgressIndices(v: progress.v, c: 0, i: 0)
                 let archivePath = getArchiveURL(volCovP.v)
-                let archive = try! Archive(url: archivePath, accessMode: .read)
+                let archive = try Archive(url: archivePath, accessMode: .read)
                 let filename = metadata.volumes[volCovP.v].chapters[volCovP.c].images[volCovP.i].filename!
-                let targetEntry = archive[filename]!
+                guard let targetEntry = archive[filename] else {
+                    alert.message = String(format: "Archive entry does not exist: \(filename)")
+                    pendingAlert = alert
+                    return
+                }
                 var extractedData = Data()
-                _ = try archive.extract(targetEntry) { data in
+                do {
-                    extractedData.append(data)
+                    _ = try archive.extract(targetEntry) { data in
+                        extractedData.append(data)
+                    }
+                } catch {
+                    alert.message = String(format: "Failed to extract data from entry: \(targetEntry.path)")
+                    pendingAlert = alert
+                    return
+                }
+                guard let coverImage = UIImage(data: extractedData) else {
+                    alert.message = String(format: "Cover image is nil: \(filename)")
+                    pendingAlert = alert
+                    return
                 }
                 comics.append(
                     Comic(
-                        cover: UIImage(data: extractedData)!,
+                        cover: coverImage,
                         metadata: metadata,
                         path: dir
                     )
                 )
             }
         } catch {
+            pendingAlert = alert
+            alert.message = String(format: "Generic failure.")
             print("Failed to read directories")
         }
     }
@@ -263,9 +307,9 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
 
     func getMetadataFromFilename(path: URL) {
         // Beautiful, is it not?
-        let patterns: [(NSRegularExpression, NSRegularExpression, Int, Int, Int)] = [
+        let patterns: [(NSRegularExpression?, NSRegularExpression?, Int, Int, Int)] = [
-            (try! NSRegularExpression(pattern: #"c([0-9]+(?:x[0-9]+)?) \(v([0-9]+)\) - p([0-9]+(?:-p?[0-9]+)?)"#), try! NSRegularExpression(pattern: #"^(.*) - c([0-9]+(?:x[0-9]+)?) \(v([0-9]+)\) - p([0-9]+(?:-p?[0-9]+)?)"#), 3, 1, 2),
+            (try? NSRegularExpression(pattern: #"c([0-9]+(?:x[0-9]+)?) \(v([0-9]+)\) - p([0-9]+(?:-p?[0-9]+)?)"#), try? NSRegularExpression(pattern: #"^(.*) - c([0-9]+(?:x[0-9]+)?) \(v([0-9]+)\) - p([0-9]+(?:-p?[0-9]+)?)"#), 3, 1, 2),
-            (try! NSRegularExpression(pattern: "v([0-9]+) p([0-9]+(?:-[0-9]+)?) - c([0-9]+(?:x[0-9]+)?)"), try! NSRegularExpression(pattern: "^(.*) - v([0-9]+) p([0-9]+(?:-[0-9]+)?) - c([0-9]+(?:x[0-9]+)?)"), 2, 3, 1),
+            (try? NSRegularExpression(pattern: "v([0-9]+) p([0-9]+(?:-[0-9]+)?) - c([0-9]+(?:x[0-9]+)?)"), try? NSRegularExpression(pattern: "^(.*) - v([0-9]+) p([0-9]+(?:-[0-9]+)?) - c([0-9]+(?:x[0-9]+)?)"), 2, 3, 1),
         ]
         var pattern: NSRegularExpression! = nil
         var titlePattern: NSRegularExpression! = nil
@@ -293,6 +337,9 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
 
         var titleValue: String = ""
 
+        let alert = UIAlertController(title: "Failed to get metadata from filename.", message: "This is an alert.", preferredStyle: .alert) 
+        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
+
         let volumeDir = path.appendingPathComponent("volumes")
 
         var isDir: ObjCBool = false
@@ -300,25 +347,42 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
             print("Subdirectory volumes not found in \"\(path)\", returning")
             return
         }
-        let volumeURLs = try! fileManager.contentsOfDirectory(
+        let volumeURLs = try? fileManager.contentsOfDirectory(
             at: volumeDir,
             includingPropertiesForKeys: [.isRegularFileKey],
             options: [.skipsHiddenFiles]
         ).filter { $0.pathExtension == "cbz" }
          .sorted { $0.lastPathComponent < $1.lastPathComponent }
+         if volumeURLs == nil {
+            alert.message = String(format: "failed to read dir: \(volumeDir)")
+            pendingAlert = alert
+            return
+        }
 
-        if volumeURLs.isEmpty {
+        if volumeURLs!.isEmpty {
             print("found no volumes in volume dir: \(volumeDir)")
             return
         }
 
         var filenames: [(String, String)] = []
-        for volumeURL in volumeURLs {
+        for volumeURL in volumeURLs! {
             do {
                 let volumeArchive = try Archive(url: volumeURL, accessMode: .read)
-                volumeArchive.map { URL(string: $0.path)!.lastPathComponent }.sorted().forEach{ filenames.append((volumeURL.lastPathComponent, $0)) }
+                var volumeArchiveFiles: [String] = []
+                for entry in volumeArchive {
+                    // guard let url = URL(string: entry.path) else {
+                    //     alert.message = String(format: "failed to create URL from string: \(entry.path)")
+                    //     pendingAlert = alert
+                    //     return
+                    // }
+                    volumeArchiveFiles.append(entry.path)
+                }
+                for filename in volumeArchiveFiles.sorted() {
+                    filenames.append((volumeURL.lastPathComponent, filename))
+                }
             } catch {
-                print("Failed to read archive \(volumeURL)")
+                alert.message = String(format: "failed to read archive: \(volumeURL)")
+                pendingAlert = alert
                 continue
             }
         }
@@ -330,6 +394,16 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
 
         do {
             for (currentPattern, currentTitlePattern, currentPageRegexPosition, currentChapterRegexPosition, currentVolumeRegexPosition) in patterns {
+                guard let currentPattern = currentPattern else {
+                    alert.message = String(format: "failed to get currentPattern")
+                    pendingAlert = alert
+                    continue
+                }
+                guard let currentTitlePattern = currentTitlePattern else {
+                    alert.message = String(format: "failed to get currentTitlePattern")
+                    pendingAlert = alert
+                    continue
+                }
                 let filename = filenames[0].1
                 let range = NSRange(filename.startIndex..., in: filename)
                 if let match = currentTitlePattern.firstMatch(in: filename, range: range) {
@@ -390,25 +464,51 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                 if let match = regex.firstMatch(in: filename, range: range) {
                     let chapterStr = (filename as NSString).substring(with: match.range(at: chapterRegexPosition))
                     let chapterParts = chapterStr.split(separator: "x", maxSplits: 1)
+                    if chapterParts.count < 1 {
+                        alert.message = String(format: "Did not find chapter number in filename: \(filename)")
+                        pendingAlert = alert
+                        return
+                    }
+                    guard let nChapter0 = UInt32(chapterParts[0]) else {
+                        alert.message = String(format: "Failed to convert chapter number to an int: \(filename)")
+                        pendingAlert = alert
+                        return
+                    }
                     let chapter: (UInt32, UInt32?) = (
-                        UInt32(chapterParts[0])!, chapterParts.count > 1 ? UInt32(chapterParts[1])! : nil
+                        nChapter0, chapterParts.count > 1 ? UInt32(chapterParts[1]) : nil
                     )
 
-                    let volume: UInt32 = UInt32((filename as NSString).substring(with: match.range(at: volumeRegexPosition)))!
+
+                    guard let volume: UInt32 = UInt32((filename as NSString).substring(with: match.range(at: volumeRegexPosition))) else {
+                        alert.message = String(format: "failed to get match for volume in filename: \(filename)")
+                        pendingAlert = alert
+                        return
+                    }
+
 
                     let pageStr = (filename as NSString).substring(with: match.range(at: pageRegexPosition))
                     let pageParts = pageStr.split(separator: "-", maxSplits: 1)
+                    guard let nPage = UInt32(pageParts[0]) else {
+                        alert.message = String(format: "failed to read archive: \(filename)")
+                        pendingAlert = alert
+                        return
+                    }
                     let (page, doublePage) = (
-                        UInt32(pageParts[0])!, pageParts.count > 1
+                        nPage, pageParts.count > 1
                     )
 
                     let archive = try Archive(url: volumeDir.appendingPathComponent(volumeURL), accessMode: .read)
-                    let entry = archive[filename]!
+                    guard let entry = archive[filename] else {
+                        alert.message = String(format: "failed to read archive: \(filename)")
+                        pendingAlert = alert
+                        return
+                    }
                     var size = ImageDimensions(width: 0, height: 0)
                     do {
                         size = try imageDimensions(of: entry, in: archive)
                     } catch {
-                        print("Failed to get image dimensions of filename: \(filename)")
+                        alert.message = String(format: "Failed to get image dimensions of filename: \(filename)")
+                        pendingAlert = alert
                         return
                     }
                     let m_filename = builder.create(string: filename)
@@ -452,8 +552,23 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                             currentChapters = []
                         } else if chapter != currentChapter {
                             if chapter.0 == currentChapter.0 {
+                                if chapter.1 == nil {
+                                    alert.message = String(format: "chapter.1 is nil")
+                                    pendingAlert = alert
+                                    return
+                                }
+                                if chapter.1! != currentChapter.1 ?? 1 {
+                                    alert.message = String(format: "chapter != currentChapter")
+                                    pendingAlert = alert
+                                    return
+                                }
                                 assert(chapter.1! == currentChapter.1 ?? 1)
                             } else {
+                                if chapter.0 != currentChapter.0 + 1 {
+                                    alert.message = String(format: "chapter.0 != currentChapter.0 + 1")
+                                    pendingAlert = alert
+                                    return
+                                }
                                 assert(chapter.0 == currentChapter.0 + 1)
                             }
 
@@ -547,7 +662,12 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         )
 
         builder.finish(offset: metadata)
-        try! builder.data.write(to: path.appendingPathComponent(metadataFilename))
+        do {
+            try builder.data.write(to: path.appendingPathComponent(metadataFilename))
+        } catch {
+            alert.message = String(format: "Failed to write metadata file at: \(metadataFilename)")
+            pendingAlert = alert
+        }
     }
 
     func saveLocalState() {