Move source code into "Source" folder

Source/LibationFileManager/AudibleFileStorage.cs

@@ -0,0 +1,106 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text.RegularExpressions;
+using FileManager;
+
+namespace LibationFileManager
+{
+    public abstract class AudibleFileStorage
+    {
+        protected abstract string GetFilePathCustom(string productId);
+
+        #region static
+        public static string DownloadsInProgressDirectory => Directory.CreateDirectory(Path.Combine(Configuration.Instance.InProgress, "DownloadsInProgress")).FullName;
+        public static string DecryptInProgressDirectory => Directory.CreateDirectory(Path.Combine(Configuration.Instance.InProgress, "DecryptInProgress")).FullName;
+
+        private static AaxcFileStorage AAXC { get; } = new AaxcFileStorage();
+        public static bool AaxcExists(string productId) => AAXC.Exists(productId);
+
+        public static AudioFileStorage Audio { get; } = new AudioFileStorage();
+
+        public static string BooksDirectory
+        {
+            get
+            {
+                if (string.IsNullOrWhiteSpace(Configuration.Instance.Books))
+                    Configuration.Instance.Books = Path.Combine(Configuration.UserProfile, "Books");
+                return Directory.CreateDirectory(Configuration.Instance.Books).FullName;
+            }
+        }
+        #endregion
+
+        #region instance
+        private FileType FileType { get; }
+        private string regexTemplate { get; }
+
+        protected AudibleFileStorage(FileType fileType)
+        {
+            FileType = fileType;
+
+            var extAggr = FileTypes.GetExtensions(FileType).Aggregate((a, b) => $"{a}|{b}");
+            regexTemplate = $@"{{0}}.*?\.({extAggr})$";
+        }
+
+        protected string GetFilePath(string productId)
+        {
+            // primary lookup
+            var cachedFile = FilePathCache.GetFirstPath(productId, FileType);
+            if (cachedFile is not null && File.Exists(cachedFile))
+                return cachedFile;
+
+            // secondary lookup attempt
+            var firstOrNull = GetFilePathCustom(productId);
+            if (firstOrNull is not null)
+                FilePathCache.Insert(productId, firstOrNull);
+
+            return firstOrNull;
+        }
+
+        protected Regex GetBookSearchRegex(string productId)
+        {
+            var pattern = string.Format(regexTemplate, productId);
+            return new Regex(pattern, RegexOptions.IgnoreCase);
+        }
+        #endregion
+    }
+
+    internal class AaxcFileStorage : AudibleFileStorage
+    {
+        internal AaxcFileStorage() : base(FileType.AAXC) { }
+
+        protected override string GetFilePathCustom(string productId)
+        {
+            var regex = GetBookSearchRegex(productId);
+            return FileUtility
+                .SaferEnumerateFiles(DownloadsInProgressDirectory, "*.*", SearchOption.AllDirectories)
+                .FirstOrDefault(s => regex.IsMatch(s));
+        }
+
+        public bool Exists(string productId) => GetFilePath(productId) is not null;
+    }
+
+    public class AudioFileStorage : AudibleFileStorage
+    {
+        internal AudioFileStorage() : base(FileType.Audio)
+            => BookDirectoryFiles ??= new BackgroundFileSystem(BooksDirectory, "*.*", SearchOption.AllDirectories);
+
+        private static BackgroundFileSystem BookDirectoryFiles { get; set; }
+        private static object bookDirectoryFilesLocker { get; } = new();
+        protected override string GetFilePathCustom(string productId)
+        {
+            // If user changed the BooksDirectory: reinitialize
+            lock (bookDirectoryFilesLocker)
+                if (BooksDirectory != BookDirectoryFiles.RootDirectory)
+                    BookDirectoryFiles = new BackgroundFileSystem(BooksDirectory, "*.*", SearchOption.AllDirectories);
+
+            var regex = GetBookSearchRegex(productId);
+            return BookDirectoryFiles.FindFile(regex);
+        }
+
+        public void Refresh() => BookDirectoryFiles.RefreshFiles();
+
+        public string GetPath(string productId) => GetFilePath(productId);
+    }
+}