Added take-a-number implementation

AccessQueueService/Data/TakeANumberAccessQueueRepo.cs

@@ -0,0 +1,102 @@
+using AccessQueueService.Models;
+using Microsoft.Extensions.Configuration;
+
+namespace AccessQueueService.Data
+{
+    public class TakeANumberAccessQueueRepo : IAccessQueueRepo
+    {
+        private readonly Dictionary<Guid, AccessTicket> _accessTickets = [];
+        private readonly Dictionary<Guid, ulong> _queueNumbers = [];
+        private readonly Dictionary<ulong, AccessTicket> _accessQueue = [];
+
+        private ulong _nowServing = 0;
+        private ulong _nextUnusedTicket = 0; 
+
+        public int GetUnexpiredTicketsCount() => _accessTickets.Count(t => t.Value.ExpiresOn > DateTime.UtcNow);
+        public int GetActiveTicketsCount(DateTime activeCutoff) => _accessTickets
+            .Count(t => t.Value.ExpiresOn > DateTime.UtcNow && t.Value.LastActive > activeCutoff);
+        public int GetQueueCount() => (int)(_nextUnusedTicket - _nowServing);
+        public int GetRequestsAhead(Guid userId)
+        {
+            if(_queueNumbers.TryGetValue(userId, out var queueNumber))
+            {
+                return queueNumber >= _nowServing ? (int)(queueNumber - _nowServing) : -1;
+            }
+            return -1;
+            
+        }
+
+        public void Enqueue(AccessTicket ticket)
+        {
+            _queueNumbers[ticket.UserId] = _nextUnusedTicket;
+            _accessQueue[_nextUnusedTicket] = ticket;
+            _nextUnusedTicket++;
+        }
+
+        public int DeleteExpiredTickets()
+        {
+            var cutoff = DateTime.UtcNow;
+            var expiredTickets = _accessTickets.Where(t => t.Value.ExpiresOn < cutoff);
+            int count = 0;
+            foreach (var ticket in expiredTickets)
+            {
+                count++;
+                _accessTickets.Remove(ticket.Key);
+            }
+            return count;
+        }
+
+        public void RemoveUser(Guid userId)
+        {
+            _accessTickets.Remove(userId);
+        }
+
+        public bool DidDequeueUntilFull(int activeSeconds, int expirationSeconds, int capacityLimit)
+        {
+            var now = DateTime.UtcNow;
+            var activeCutoff = now.AddSeconds(-activeSeconds);
+            var numberOfActiveUsers = _accessTickets.Count(t => t.Value.ExpiresOn > now && t.Value.LastActive > activeCutoff);
+            var openSpots = capacityLimit - numberOfActiveUsers;
+            int filledSpots = 0;
+            while (filledSpots < openSpots && _nowServing < _nextUnusedTicket)
+            {
+                if (_accessQueue.TryGetValue(_nowServing, out var nextUser))
+                {
+                    _nowServing++;
+                    if (nextUser.LastActive < activeCutoff)
+                    {
+                        // User is inactive, throw away their ticket
+                        continue;
+                    }
+                    _accessTickets[nextUser.UserId] = new AccessTicket
+                    {
+                        UserId = nextUser.UserId,
+                        ExpiresOn = now.AddSeconds(expirationSeconds),
+                        LastActive = now
+                    };
+                    filledSpots++;
+                }
+                else
+                {
+                    break;
+                }
+            }
+            return filledSpots == openSpots;
+        }
+
+        public AccessTicket? GetTicket(Guid userId)
+        {
+            return _accessTickets.TryGetValue(userId, out var ticket) ? ticket : null;
+        }
+
+        public void UpsertTicket(AccessTicket ticket)
+        {
+            _accessTickets[ticket.UserId] = ticket;
+        }
+
+        bool IAccessQueueRepo.RemoveUser(Guid userId)
+        {
+            return _accessTickets.Remove(userId);
+        }
+    }
+}

AccessQueueServiceTests/AccessServiceTests.cs

@@ -18,9 +18,14 @@ namespace AccessQueueServiceTests
             const int ACT_MILLIS = 1000 * ACT_SECONDS;
             const int CAP_LIMIT = 5;
             const int BULK_COUNT = 50000;
-            private readonly AccessService _accessService;
+            private AccessService _accessService;
+            public static IEnumerable<object[]> RepoImplementations()
+            {
+                yield return new object[] { new DictionaryAccessQueueRepo() };
+                yield return new object[] { new TakeANumberAccessQueueRepo() };
+            }
 
-            public AccessServiceTests()
+            private void CreateService(IAccessQueueRepo repo)
             {
                 var inMemorySettings = new Dictionary<string, string?>
                 {
@@ -33,14 +38,16 @@ namespace AccessQueueServiceTests
                 var configuration = new ConfigurationBuilder()
                     .AddInMemoryCollection(inMemorySettings)
                     .Build();
-                var accessQueueRepo = new DictionaryAccessQueueRepo();
 
-                _accessService = new AccessService(configuration, accessQueueRepo);
+
+                _accessService = new AccessService(configuration, repo);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldGrantAccess_WhenCapacityIsAvailable()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldGrantAccess_WhenCapacityIsAvailable(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 var userId = Guid.NewGuid();
 
                 var response = await _accessService.RequestAccess(userId);
@@ -53,9 +60,11 @@ namespace AccessQueueServiceTests
                 Assert.Equal(0, _accessService.QueueCount);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldReturnAccessResponse_WhenUserAlreadyHasTicket()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldReturnAccessResponse_WhenUserAlreadyHasTicket(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 var userId = Guid.NewGuid();
                 await _accessService.RequestAccess(userId);
 
@@ -69,9 +78,11 @@ namespace AccessQueueServiceTests
                 Assert.Equal(0, _accessService.QueueCount);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldQueueUser_WhenCapacityIsFull()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldQueueUser_WhenCapacityIsFull(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 for (int i = 0; i < CAP_LIMIT * 2; i++) // Fill double capacity
                 {
                     await _accessService.RequestAccess(Guid.NewGuid());
@@ -89,9 +100,11 @@ namespace AccessQueueServiceTests
             }
 
 
-            [Fact]
+            [Theory]
-            public async Task RevokeAccess_ShouldReturnTrue_WhenUserHasAccess()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RevokeAccess_ShouldReturnTrue_WhenUserHasAccess(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 var userId = Guid.NewGuid();
                 await _accessService.RequestAccess(userId);
 
@@ -100,9 +113,11 @@ namespace AccessQueueServiceTests
                 Assert.True(result);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RevokeAccess_ShouldReturnFalse_WhenUserDoesNotHaveAccess()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RevokeAccess_ShouldReturnFalse_WhenUserDoesNotHaveAccess(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 var userId = Guid.NewGuid();
 
                 var result = await _accessService.RevokeAccess(userId);
@@ -110,9 +125,11 @@ namespace AccessQueueServiceTests
                 Assert.False(result);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldQueueUser_AfterAccessRevoked()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldQueueUser_AfterAccessRevoked(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 var userId = Guid.NewGuid();
                 await _accessService.RequestAccess(userId);
 
@@ -131,9 +148,11 @@ namespace AccessQueueServiceTests
                 Assert.False(responseAfterRevoke.HasAccess);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldNotQueueUser_WhenMultipleRequestsForOtherUsersMade()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldNotQueueUser_WhenMultipleRequestsForOtherUsersMade(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 for (int i = 0; i < CAP_LIMIT; i++) // Fill slots without awaiting
                 {
                     _ = _accessService.RequestAccess(Guid.NewGuid());
@@ -143,9 +162,11 @@ namespace AccessQueueServiceTests
                 Assert.False(response.HasAccess);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldUpdateExpirationTime_WhenRollingExpirationTrue()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldUpdateExpirationTime_WhenRollingExpirationTrue(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 var userId = Guid.NewGuid();
                 var initialResponse = await _accessService.RequestAccess(userId);
                 await Task.Delay(ACT_MILLIS);
@@ -153,9 +174,11 @@ namespace AccessQueueServiceTests
                 Assert.True(updatedResponse.ExpiresOn > initialResponse.ExpiresOn);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldGrantAccess_WhenUsersWithAccessInactive()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldGrantAccess_WhenUsersWithAccessInactive(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 for (int i = 0; i < CAP_LIMIT; i++)
                 {
                     await _accessService.RequestAccess(Guid.NewGuid());
@@ -168,9 +191,11 @@ namespace AccessQueueServiceTests
                 Assert.True(response.HasAccess);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldRevokeAccess_WhenExpired()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldRevokeAccess_WhenExpired(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 var userId = Guid.NewGuid();
                 var response = await _accessService.RequestAccess(userId);
                 Assert.True(response.HasAccess);
@@ -183,9 +208,11 @@ namespace AccessQueueServiceTests
                 Assert.False(response.HasAccess);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldRetailAccess_WhenNotExpired()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldRetailAccess_WhenNotExpired(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 var userId = Guid.NewGuid();
                 var response = await _accessService.RequestAccess(userId);
                 Assert.True(response.HasAccess);
@@ -199,9 +226,11 @@ namespace AccessQueueServiceTests
                 Assert.True(response.HasAccess);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldProcessBulkRequests()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldProcessBulkRequests(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 var userId = Guid.NewGuid();
                 await _accessService.RequestAccess(userId);
                 for (int i = 0; i < BULK_COUNT; i++)
@@ -213,9 +242,11 @@ namespace AccessQueueServiceTests
                 Assert.True(response.HasAccess);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldReportLessInQueue_AsTicketsInactivate()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldReportLessInQueue_AsTicketsInactivate(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 var start = DateTime.UtcNow;
                 for (int i = 0; i < CAP_LIMIT; i++)
                 {
@@ -245,9 +276,11 @@ namespace AccessQueueServiceTests
                 Assert.Equal(0, response.RequestsAhead);
             }
 
-            [Fact]
+            [Theory]
-            public async Task RequestAccess_ShouldShowCorrectRequestsAhead_WhenAccessRerequested()
+            [MemberData(nameof(RepoImplementations))]
+            public async Task RequestAccess_ShouldShowCorrectRequestsAhead_WhenAccessRerequested(IAccessQueueRepo repo)
             {
+                CreateService(repo);
                 for (int i = 0; i < CAP_LIMIT + 3; i++)
                 {
                     await _accessService.RequestAccess(Guid.NewGuid());