Implement NotifyOnStatusChange feature for nodes and enhance Telegram notifications

- Added `NotifyOnStatusChange` property to the `Node` class and related DTOs to allow individual node configuration for status change notifications.
- Updated `NodeHealthCheckService` to send Telegram notifications to admins when a node's status changes, based on the new property.
- Enhanced the `ITelegramNotifier` interface with a method for notifying admins about node status changes.
- Modified the frontend to include a checkbox for `NotifyOnStatusChange` in the node editing dialog, allowing admins to easily configure this setting.
- Updated API documentation to reflect the new `notifyOnStatusChange` parameter in the node update endpoint.
- Added tests to ensure the correct behavior of the new feature and its integration with existing functionality.

backend/src/PnvPanel.Api/Endpoints/NodeEndpoints.cs

@@ -55,6 +55,7 @@ public static class NodeEndpoints
             body.BaseAddress,
             body.Location,
             body.IsEnabled,
+            body.NotifyOnStatusChange,
             body.Username,
             body.Password
         );
@@ -98,6 +99,7 @@ public sealed record UpdateNodeBody(
     string BaseAddress,
     string? Location,
     bool IsEnabled,
+    bool NotifyOnStatusChange,
     string? Username,
     string? Password
 );

backend/src/PnvPanel.Api/Telegram/TelegramNotifier.cs

@@ -1,6 +1,7 @@
 using Microsoft.Extensions.Options;
 using PnvPanel.Application.Common.Interfaces;
 using PnvPanel.Domain.Billing;
+using PnvPanel.Domain.Nodes;
 using PnvPanel.Domain.Support;
 using PnvPanel.Infrastructure.Telegram;
 using Telegram.Bot;
@@ -358,6 +359,48 @@ internal sealed class TelegramNotifier(
         }
     }
 
+    public async Task NotifyAdminsNodeStatusChangedAsync(
+        Guid nodeId,
+        string nodeName,
+        NodeStatus status,
+        CancellationToken cancellationToken
+    )
+    {
+        if (string.IsNullOrWhiteSpace(options.Value.BotToken))
+            return;
+
+        var emoji = status == NodeStatus.Online ? "✅" : "🔴";
+        var statusLabel = status == NodeStatus.Online ? "снова в сети" : "недоступна";
+        var text = $"{emoji} Нода <b>{Escape(nodeName)}</b> {statusLabel}.";
+
+        InlineKeyboardMarkup? keyboard = null;
+        if (!string.IsNullOrWhiteSpace(options.Value.PublicSiteUrl))
+        {
+            var url = $"{options.Value.PublicSiteUrl.TrimEnd('/')}/admin/nodes";
+            keyboard = new InlineKeyboardMarkup(
+                new[] { InlineKeyboardButton.WithUrl("🌐 Открыть на сайте", url) }
+            );
+        }
+
+        foreach (var adminId in options.Value.ParseAdminTelegramUserIds())
+        {
+            try
+            {
+                await botClient.SendMessage(
+                    adminId,
+                    text,
+                    parseMode: ParseMode.Html,
+                    replyMarkup: keyboard,
+                    cancellationToken: cancellationToken
+                );
+            }
+            catch
+            {
+                // Админ мог не запускать бота (нет чата с ботом) — пропускаем, не валим команду.
+            }
+        }
+    }
+
     private static string Escape(string text) =>
         text.Replace("&", "&amp;").Replace("<", "&lt;").Replace(">", "&gt;");
 }

backend/src/PnvPanel.Application/Admin/Nodes/NodeDto.cs

@@ -11,6 +11,7 @@ public sealed record NodeDto(
     string? Location,
     NodeStatus Status,
     bool IsEnabled,
+    bool NotifyOnStatusChange,
     DateTimeOffset? LastSyncAt
 )
 {
@@ -23,6 +24,7 @@ public sealed record NodeDto(
             node.Location,
             node.Status,
             node.IsEnabled,
+            node.NotifyOnStatusChange,
             node.LastSyncAt
         );
 }

backend/src/PnvPanel.Application/Admin/Nodes/UpdateNodeCommand.cs

@@ -9,6 +9,7 @@ public sealed record UpdateNodeCommand(
     string BaseAddress,
     string? Location,
     bool IsEnabled,
+    bool NotifyOnStatusChange,
     string? Username,
     string? Password
 ) : ICommand<Result<NodeDto>>;

backend/src/PnvPanel.Application/Admin/Nodes/UpdateNodeCommandHandler.cs

@@ -47,6 +47,8 @@ public sealed class UpdateNodeCommandHandler(
         else
             node.Disable();
 
+        node.SetNotifyOnStatusChange(command.NotifyOnStatusChange);
+
         var credentialsChanged =
             !string.IsNullOrWhiteSpace(command.Username)
             && !string.IsNullOrWhiteSpace(command.Password);

backend/src/PnvPanel.Application/Common/Interfaces/ITelegramNotifier.cs

@@ -1,4 +1,5 @@
 using PnvPanel.Domain.Billing;
+using PnvPanel.Domain.Nodes;
 using PnvPanel.Domain.Support;
 
 namespace PnvPanel.Application.Common.Interfaces;
@@ -74,4 +75,13 @@ public interface ITelegramNotifier
         string justification,
         CancellationToken cancellationToken
     );
+
+    /// <summary>Нода с включённым Node.NotifyOnStatusChange перешла Online↔Offline (см.
+    /// NodeHealthCheckService) — только информационное сообщение, без инлайн-действий.</summary>
+    Task NotifyAdminsNodeStatusChangedAsync(
+        Guid nodeId,
+        string nodeName,
+        NodeStatus status,
+        CancellationToken cancellationToken
+    );
 }

backend/src/PnvPanel.Domain/Nodes/Node.cs

@@ -15,6 +15,7 @@ public sealed class Node : Entity
     public string? Location { get; private set; }
     public NodeStatus Status { get; private set; }
     public bool IsEnabled { get; private set; }
+    public bool NotifyOnStatusChange { get; private set; }
     public DateTimeOffset? LastSyncAt { get; private set; }
     public DateTimeOffset CreatedAt { get; private set; }
 
@@ -68,6 +69,11 @@ public sealed class Node : Entity
 
     public void UpdateCredentials(NodeCredentials credentials) => Credentials = credentials;
 
+    /// <summary>Слать админам в Telegram уведомление при каждом переходе Online↔Offline (см.
+    /// NodeHealthCheckService) — по умолчанию выключено, чтобы не спамить теми, кому неинтересен
+    /// конкретный узел.</summary>
+    public void SetNotifyOnStatusChange(bool value) => NotifyOnStatusChange = value;
+
     public void Enable() => IsEnabled = true;
 
     public void Disable() => IsEnabled = false;

backend/src/PnvPanel.Infrastructure/BackgroundJobs/NodeHealthCheckService.cs

@@ -37,6 +37,7 @@ public sealed class NodeHealthCheckService(
         var dbContext = scope.ServiceProvider.GetRequiredService<AppDbContext>();
         var gateway = scope.ServiceProvider.GetRequiredService<IXuiPanelGateway>();
         var notifier = scope.ServiceProvider.GetRequiredService<IRealtimeNotifier>();
+        var telegramNotifier = scope.ServiceProvider.GetRequiredService<ITelegramNotifier>();
 
         var nodes = await dbContext.Nodes.Where(n => n.IsEnabled).ToListAsync(cancellationToken);
 
@@ -54,6 +55,16 @@ public sealed class NodeHealthCheckService(
                     node.LastSyncAt,
                     cancellationToken
                 );
+
+                if (node.NotifyOnStatusChange)
+                {
+                    await telegramNotifier.NotifyAdminsNodeStatusChangedAsync(
+                        node.Id,
+                        node.Name,
+                        newStatus,
+                        cancellationToken
+                    );
+                }
             }
         }
 

backend/src/PnvPanel.Infrastructure/Persistence/Migrations/20260723080059_AddNodeNotifyOnStatusChange.cs

@@ -0,0 +1,29 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace PnvPanel.Infrastructure.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddNodeNotifyOnStatusChange : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<bool>(
+                name: "NotifyOnStatusChange",
+                table: "Nodes",
+                type: "boolean",
+                nullable: false,
+                defaultValue: false);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "NotifyOnStatusChange",
+                table: "Nodes");
+        }
+    }
+}

backend/src/PnvPanel.Infrastructure/Persistence/Migrations/AppDbContextModelSnapshot.cs

@@ -17,7 +17,7 @@ namespace PnvPanel.Infrastructure.Persistence.Migrations
         {
 #pragma warning disable 612, 618
             modelBuilder
-                .HasAnnotation("ProductVersion", "10.0.9")
+                .HasAnnotation("ProductVersion", "10.0.10")
                 .HasAnnotation("Relational:MaxIdentifierLength", 63);
 
             NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
@@ -577,6 +577,9 @@ namespace PnvPanel.Infrastructure.Persistence.Migrations
                         .HasMaxLength(100)
                         .HasColumnType("character varying(100)");
 
+                    b.Property<bool>("NotifyOnStatusChange")
+                        .HasColumnType("boolean");
+
                     b.Property<string>("Status")
                         .IsRequired()
                         .HasMaxLength(32)

backend/tests/PnvPanel.Application.Tests/Admin/Nodes/UpdateNodeCommandHandlerTests.cs

@@ -38,6 +38,7 @@ public class UpdateNodeCommandHandlerTests
             "https://node1-new.example.com",
             null,
             true,
+            false,
             null,
             null
         );
@@ -66,6 +67,7 @@ public class UpdateNodeCommandHandlerTests
             "https://node1.example.com",
             "eu",
             true,
+            false,
             null,
             null
         );
@@ -88,7 +90,7 @@ public class UpdateNodeCommandHandlerTests
 
         var handler = new UpdateNodeCommandHandler(dbContext, _gateway, _secretProtector, _currentUser);
 
-        var command = new UpdateNodeCommand(node.Id, "node-1", "not-a-uri", null, true, null, null);
+        var command = new UpdateNodeCommand(node.Id, "node-1", "not-a-uri", null, true, false, null, null);
 
         var result = await handler.Handle(command, CancellationToken.None);
 
@@ -117,6 +119,7 @@ public class UpdateNodeCommandHandlerTests
             "http://node1-new.example.com",
             null,
             true,
+            false,
             null,
             null
         );
@@ -147,6 +150,7 @@ public class UpdateNodeCommandHandlerTests
             "https://node1.example.com",
             null,
             true,
+            false,
             "new-admin",
             "new-password"
         );
@@ -175,6 +179,7 @@ public class UpdateNodeCommandHandlerTests
             "https://node1.example.com",
             null,
             true,
+            false,
             "new-admin",
             null
         );
@@ -187,6 +192,34 @@ public class UpdateNodeCommandHandlerTests
         _gateway.DidNotReceive().InvalidateClient(Arg.Any<Guid>());
     }
 
+    [Fact]
+    public async Task Handle_SetsNotifyOnStatusChange()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var node = SeedNode();
+        dbContext.Nodes.Add(node);
+        await dbContext.SaveChangesAsync(CancellationToken.None);
+        Assert.False(node.NotifyOnStatusChange);
+
+        var handler = new UpdateNodeCommandHandler(dbContext, _gateway, _secretProtector, _currentUser);
+
+        var command = new UpdateNodeCommand(
+            node.Id,
+            "node-1",
+            "https://node1.example.com",
+            null,
+            true,
+            true,
+            null,
+            null
+        );
+
+        var result = await handler.Handle(command, CancellationToken.None);
+
+        Assert.True(result.IsSuccess);
+        Assert.True(node.NotifyOnStatusChange);
+    }
+
     [Fact]
     public async Task Handle_WhenNodeNotFound_ReturnsNotFound()
     {
@@ -200,6 +233,7 @@ public class UpdateNodeCommandHandlerTests
             "https://node1.example.com",
             null,
             true,
+            false,
             null,
             null
         );

backend/tests/PnvPanel.Domain.Tests/Nodes/NodeTests.cs

@@ -97,6 +97,19 @@ public class NodeTests
         Assert.True(node.IsEnabled);
     }
 
+    [Fact]
+    public void SetNotifyOnStatusChange_DefaultsFalse_AndCanBeToggled()
+    {
+        var node = Node.Register("Node", new Uri("https://example.com"), Credentials, null);
+        Assert.False(node.NotifyOnStatusChange);
+
+        node.SetNotifyOnStatusChange(true);
+        Assert.True(node.NotifyOnStatusChange);
+
+        node.SetNotifyOnStatusChange(false);
+        Assert.False(node.NotifyOnStatusChange);
+    }
+
     [Fact]
     public void UpdateStatus_SetsStatus()
     {