Refactor and enhance Download Manager application

- Added new services: IContentDialogService, ISnackbarService
- Replaced DashboardPage and DashboardViewModel with DownloadingPage, DownloadingPageViewModel, WaitingPage, and WaitingPageViewModel
- Introduced AddNewTaskPage and AddNewTaskViewModel
- Replaced DownloadServiceManger with DownloadManagerService
- Updated WPF-UI package to 3.0.4 and added HtmlAgilityPack 1.11.61
- Refactored DownloadWorker to use async methods and added retry logic
- Converted DownloadItemData to partial class with ObservableProperty attributes
- Changed initial navigation page to DownloadingPage
- Updated MainWindow navigation items and title
- Added new utility classes: DoubleUtilities, MD5Utilities, StringExtension
- Added new XAML pages and ViewModels for task management and display
- Removed obsolete DashboardPage and related files

Models/UrlGetter/DirectUrlGetter.cs

@@ -0,0 +1,13 @@
+using DownloadManager.Utilities;
+
+namespace DownloadManager.Models.UrlGetter
+{
+    class DirectUrlGetter : IUrlGetter
+    {
+        public async Task<FileUrl> GetFileUrl(string taskUrl)
+        {
+            var fileName = System.IO.Path.GetFileName(taskUrl).ToUnescapedString();
+            return new FileUrl(taskUrl, fileName, null);
+        }
+    }
+}

Models/UrlGetter/IUrlGetter.cs

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+namespace DownloadManager.Models.UrlGetter;
+public struct FileUrl(string? url, string? name, string? md5)
+{
+    public string? Url { get; } = url;
+    public string? Name { get; } = name;
+    public string? MD5 { get; } = md5;
+}
+
+public interface IUrlGetter
+{
+    public Task<FileUrl> GetFileUrl(string taskUrl);
+}

Models/UrlGetter/UrlGetterFactory.cs

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+namespace DownloadManager.Models.UrlGetter
+{
+    public class UrlGetterFactory
+    {
+        public static IUrlGetter CreateUrlGetter(UrlGetterType type)
+        {
+            return type switch
+            {
+                UrlGetterType.Direct => new DirectUrlGetter(),
+                UrlGetterType.Yande => new YandeUrlGetter(),
+                _ => throw new ArgumentException("Invalid UrlGetterType"),
+            };
+        }
+    }
+}

Models/UrlGetter/UrlGetterType.cs

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+using System.ComponentModel;
+
+namespace DownloadManager.Models.UrlGetter
+{
+    public enum UrlGetterType
+    {
+        [Description("Direct")]
+        Direct,
+        [Description("Yande post URL")]
+        Yande,
+    }
+}

Models/UrlGetter/YandeUrlGetter.cs

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+using DownloadManager.Utilities;
+using System.IO;
+using System.Net.Http;
+using System.Net.Http.Json;
+using System.Text.Json;
+
+namespace DownloadManager.Models.UrlGetter;
+public class YandeUrlGetter : IUrlGetter
+{
+    readonly HttpClient client = new ();
+    const int maxRetries = 3;
+    const int delayMilliseconds = 1000;
+
+    public async Task<FileUrl> GetFileUrl(string taskUrl)
+    {
+        // Get the ID of the post from the URL
+        var id = taskUrl.Split("https://yande.re/post/show/").Last();
+
+        for (int attempt = 0; attempt < maxRetries; attempt++)
+        {
+            try
+            {
+                var response = await client.GetAsync($"https://yande.re/post.json?tags=id:{id}");
+
+                if (response.IsSuccessStatusCode)
+                {
+                    var data = await response.Content.ReadFromJsonAsync<JsonElement[]>();
+                    if (data == null || data.Length == 0)
+                    {
+                        return new FileUrl(null, null, null);
+                    }
+
+                    var firstElement = data.FirstOrDefault();
+                    if (firstElement.ValueKind != JsonValueKind.Object || !firstElement.TryGetProperty("file_url", out var fileUrlElement))
+                    {
+                        return new FileUrl(null, null, null);
+                    }
+
+                    if (!firstElement.TryGetProperty("md5", out var md5Element))
+                    {
+                        return new FileUrl(null, null, null);
+                    }
+
+                    var fileUrl = fileUrlElement.GetString();
+                    var fileName = Path.GetFileName(fileUrl)?.ToUnescapedString();
+                    var md5 = md5Element.GetString();
+
+                    return new FileUrl(fileUrl, fileName, md5);
+                }
+            }
+            catch (HttpRequestException)
+            {
+                // Log the exception if needed
+            }
+
+            // Wait before retrying
+            await Task.Delay(delayMilliseconds);
+        }
+
+        // If all retries fail, return a FileUrl with null values
+        return new FileUrl(null, null, null);
+    }
+}