feat: add backoffice projections status

src/StreetNameRegistry.Projector/BackOffice/BackOfficeController.cs

@@ -0,0 +1,56 @@
+namespace StreetNameRegistry.Projector.BackOffice
+{
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Be.Vlaanderen.Basisregisters.Api;
+    using Be.Vlaanderen.Basisregisters.ProjectionHandling.Runner.ProjectionStates;
+    using Dapper;
+    using Microsoft.AspNetCore.Mvc;
+    using Microsoft.Data.SqlClient;
+    using Microsoft.Extensions.Configuration;
+    using SqlStreamStore;
+
+    [ApiVersion("1.0")]
+    [ApiRoute("backoffice")]
+    public class BackOfficeController : ApiController
+    {
+        private const string? BackOfficeConnectionStringKey = "Events";
+
+        [HttpGet]
+        public async Task<IActionResult> Get(
+            [FromServices] IConfiguration configuration,
+            [FromServices] IStreamStore streamStore,
+            CancellationToken cancellationToken)
+        {
+            var streamPosition = await streamStore.ReadHeadPosition(cancellationToken);
+
+            List<BackOfficeStatusResponse> response;
+            await using (var sqlConnection = new SqlConnection(configuration.GetConnectionString(BackOfficeConnectionStringKey)))
+            {
+                var result =
+                    await sqlConnection.QueryAsync<ProjectionStateItem>(
+                        "SELECT * FROM [StreetNameRegistryBackOfficeProjections].[ProjectionStates]", cancellationToken);
+
+                response = result.Select(x => new BackOfficeStatusResponse(x, streamPosition)).ToList();
+            }
+
+            return Ok(response);
+        }
+    }
+
+    public class BackOfficeStatusResponse
+    {
+        public long MaxPosition { get; set; }
+        public string ProjectionName { get; set; }
+        public long Position { get; set; }
+
+        public BackOfficeStatusResponse(ProjectionStateItem projectionStateItem, long maxPosition)
+        {
+            MaxPosition = maxPosition;
+            ProjectionName = projectionStateItem.Name;
+            Position = projectionStateItem.Position;
+        }
+    }
+}