feat: change mock logic

TimeMocker.Hook/InjectionEntryPoint.cs

@@ -14,7 +14,7 @@ namespace TimeMocker.Hook
     [StructLayout(LayoutKind.Sequential)]
     public struct MockTimeInfo
     {
-        public long FakeUtcTicks; // DateTime ticks (UTC)
+        public long DeltaTicks; // Offset to add to DateTime.UtcNow.Ticks (can be negative)
         public int Enabled; // 1 = mock active, 0 = passthrough
     }
 
@@ -108,9 +108,12 @@ namespace TimeMocker.Hook
         private DateTime GetFakeUtc()
         {
             var info = ReadMockInfo();
-            return info.Enabled == 1
-                ? new DateTime(info.FakeUtcTicks, DateTimeKind.Utc)
-                : DateTime.UtcNow;
+            if (info.Enabled == 1)
+            {
+                // Return real UTC time plus the stored delta offset
+                return new DateTime(DateTime.UtcNow.Ticks + info.DeltaTicks, DateTimeKind.Utc);
+            }
+            return DateTime.UtcNow;
         }
 
         private void InstallHooks()

TimeMocker.UI/Core/InjectionManager.cs

@@ -44,7 +44,7 @@ namespace TimeMocker.UI.Core
             try
             {
                 // Write disabled state initially so hook passes through
-                entry.Shm.Write(new MockTimeInfo { Enabled = 0, FakeUtcTicks = DateTime.UtcNow.Ticks });
+                entry.Shm.Write(new MockTimeInfo { Enabled = 0, DeltaTicks = 0 });
 
                 RemoteHooking.Inject(
                     process.Id,
@@ -74,9 +74,20 @@ namespace TimeMocker.UI.Core
         {
             if (!_injected.TryGetValue(processId, out var entry)) return;
 
+            long deltaTicks;
+            if (enabled)
+            {
+                // Calculate delta: (desired fake time) - (current real UTC time)
+                deltaTicks = fakeUtc.Ticks - DateTime.UtcNow.Ticks;
+            }
+            else
+            {
+                deltaTicks = 0;
+            }
+
             entry.Shm.Write(new MockTimeInfo
             {
-                FakeUtcTicks = fakeUtc.Ticks,
+                DeltaTicks = deltaTicks,
                 Enabled = enabled ? 1 : 0
             });
         }
@@ -100,7 +111,7 @@ namespace TimeMocker.UI.Core
         public void Eject(int processId)
         {
             if (!_injected.TryGetValue(processId, out var entry)) return;
-            entry.Shm.Write(new MockTimeInfo { Enabled = 0 }); // disable mock first
+            entry.Shm.Write(new MockTimeInfo { Enabled = 0, DeltaTicks = 0 }); // disable mock first
             entry.Shm.Dispose();
             _injected.Remove(processId);
             Log($"Ejected from [{processId}] {entry.ProcessName}");

TimeMocker.UI/Core/SharedMemoryManager.cs

@@ -46,7 +46,7 @@ namespace TimeMocker.UI.Core
     [StructLayout(LayoutKind.Sequential)]
     public struct MockTimeInfo
     {
-        public long FakeUtcTicks;
-        public int Enabled;
+        public long DeltaTicks; // Offset to add to DateTime.UtcNow.Ticks (can be negative)
+        public int Enabled; // 1 = mock active, 0 = passthrough
     }
 }

TimeMocker.UI/Forms/MainForm.cs

@@ -25,7 +25,6 @@ namespace TimeMocker.UI.Forms
             "timemocker-config.json");
 
         public bool AutoInjectEnabled { get; set; } = true;
-        public bool AutoAdvanceEnabled { get; set; } = true;
         public List<PatternRuleDto> Patterns { get; set; } = new List<PatternRuleDto>();
 
         public void Save()
@@ -70,7 +69,6 @@ namespace TimeMocker.UI.Forms
         private CheckBox chkMockEnabled;
         private Button btnApply;
         private Label lblPreview;
-        private CheckBox chkAutoAdvance;
 
         // -- Patterns tab
         private DataGridView dgvPatterns;
@@ -83,11 +81,6 @@ namespace TimeMocker.UI.Forms
         private RichTextBox rtbLog;
         private Button btnClearLog;
 
-        // Time advancing
-        private Timer _advanceTimer;
-        private DateTime _fakeTimeBase;
-        private DateTime _advanceStartReal;
-
         public MainForm()
         {
             _config = AppConfig.Load();
@@ -112,7 +105,6 @@ namespace TimeMocker.UI.Forms
 
             // Load config settings
             chkWatcherEnabled.Checked = _config.AutoInjectEnabled;
-            chkAutoAdvance.Checked = _config.AutoAdvanceEnabled;
             foreach (var pattern in _config.Patterns)
             {
                 _watcher.AddRule(new PatternRule
@@ -194,21 +186,10 @@ namespace TimeMocker.UI.Forms
                 ApplyTime();
             };
 
-            chkAutoAdvance = new CheckBox
-            {
-                Text = "Auto-advance time",
-                ForeColor = Color.FromArgb(220, 220, 220),
-                Width = 140,
-                Height = 30,
-                Margin = new Padding(8, 12, 4, 0),
-                Checked = true
-            };
-            chkAutoAdvance.CheckedChanged += ToggleAutoAdvance;
-
             lblPreview = new Label
             {
                 AutoSize = false,
-                Width = 260,
+                Width = 300,
                 Height = 20,
                 ForeColor = Color.FromArgb(180, 180, 180),
                 Font = new Font("Segoe UI", 8.5f, FontStyle.Italic),
@@ -217,8 +198,7 @@ namespace TimeMocker.UI.Forms
 
             timeFlow.Controls.AddRange(new Control[]
             {
-                chkMockEnabled, dtpDate, dtpTime, btnApply, btnSetNow,
-                chkAutoAdvance, lblPreview
+                chkMockEnabled, dtpDate, dtpTime, btnApply, btnSetNow, lblPreview
             });
             grpTime.Controls.Add(timeFlow);
 
@@ -247,10 +227,6 @@ namespace TimeMocker.UI.Forms
 
             Controls.Add(tabMain);
             Controls.Add(grpTime);
-
-            // advance timer
-            _advanceTimer = new Timer { Interval = 1000 };
-            _advanceTimer.Tick += AdvanceTick;
         }
 
         // =====================================================================
@@ -573,52 +549,28 @@ namespace TimeMocker.UI.Forms
             _watcher.FakeUtc = dt;
             _watcher.MockEnabled = chkMockEnabled.Checked;
 
-            if (chkAutoAdvance.Checked)
-            {
-                _fakeTimeBase = GetFakeTime();
-                _advanceStartReal = DateTime.Now;
-            }
-
             UpdateTimePreview();
         }
 
         private void UpdateTimePreview()
         {
             var dt = GetFakeTime();
-            lblPreview.Text = chkMockEnabled.Checked
-                ? $"Fake: {dt:yyyy-MM-dd HH:mm:ss} (local)"
-                : "Pass-through (real time)";
-        }
-
-        private void ToggleAutoAdvance(object sender, EventArgs e)
-        {
-            if (chkAutoAdvance.Checked)
+            if (chkMockEnabled.Checked)
             {
-                _fakeTimeBase = GetFakeTime();
-                _advanceStartReal = DateTime.Now;
-                _advanceTimer.Start();
+                // Calculate what the current offset is
+                var realNow = DateTime.Now;
+                var delta = dt - realNow;
+                var deltaStr = delta.TotalSeconds >= 0
+                    ? $"+{delta.TotalSeconds:F0}s"
+                    : $"{delta.TotalSeconds:F0}s";
+                lblPreview.Text = $"Fake: {dt:yyyy-MM-dd HH:mm:ss} (local, offset {deltaStr})";
             }
             else
             {
-                _advanceTimer.Stop();
+                lblPreview.Text = "Pass-through (real time)";
             }
         }
 
-        private void AdvanceTick(object sender, EventArgs e)
-        {
-            if (!chkMockEnabled.Checked) return;
-            var elapsed = DateTime.Now - _advanceStartReal;
-            var advanced = _fakeTimeBase + elapsed;
-            // Silently update dtpDate/dtpTime without triggering ValueChanged loop
-            dtpDate.ValueChanged -= (s, ev) => UpdateTimePreview();
-            dtpTime.ValueChanged -= (s, ev) => UpdateTimePreview();
-            dtpDate.Value = advanced;
-            dtpTime.Value = advanced;
-            dtpDate.ValueChanged += (s, ev) => UpdateTimePreview();
-            dtpTime.ValueChanged += (s, ev) => UpdateTimePreview();
-            ApplyTime();
-        }
-
         // =====================================================================
         // Helpers
         // =====================================================================
@@ -738,7 +690,6 @@ namespace TimeMocker.UI.Forms
         {
             // Save config
             _config.AutoInjectEnabled = chkWatcherEnabled.Checked;
-            _config.AutoAdvanceEnabled = chkAutoAdvance.Checked;
             _config.Patterns.Clear();
             foreach (DataGridViewRow row in dgvPatterns.Rows)
             {