Add bad habit slip alert feature with AI notifications

src/Orbit.Api/Controllers/HabitsController.cs

@@ -25,6 +25,7 @@ public record CreateHabitRequest(
         TimeOnly? DueTime = null,
         bool ReminderEnabled = false,
         int ReminderMinutesBefore = 15,
+        bool SlipAlertEnabled = false,
         IReadOnlyList<Guid>? TagIds = null);
 
     public record UpdateHabitRequest(
@@ -37,7 +38,8 @@ public record UpdateHabitRequest(
         DateOnly? DueDate = null,
         TimeOnly? DueTime = null,
         bool? ReminderEnabled = null,
-        int? ReminderMinutesBefore = null);
+        int? ReminderMinutesBefore = null,
+        bool? SlipAlertEnabled = null);
 
     public record LogHabitRequest(string? Note = null);
 
@@ -136,6 +138,7 @@ public async Task<IActionResult> CreateHabit(
             request.DueTime,
             request.ReminderEnabled,
             request.ReminderMinutesBefore,
+            request.SlipAlertEnabled,
             request.TagIds);
 
         var result = await mediator.Send(command, cancellationToken);
@@ -185,7 +188,8 @@ public async Task<IActionResult> UpdateHabit(
             request.DueDate,
             request.DueTime,
             request.ReminderEnabled,
-            request.ReminderMinutesBefore);
+            request.ReminderMinutesBefore,
+            request.SlipAlertEnabled);
 
         var result = await mediator.Send(command, cancellationToken);
 

src/Orbit.Api/Program.cs

@@ -63,6 +63,8 @@
     builder.Configuration.GetSection(VapidSettings.SectionName));
 builder.Services.AddScoped<IPushNotificationService, PushNotificationService>();
 builder.Services.AddHostedService<ReminderSchedulerService>();
+builder.Services.AddHostedService<SlipAlertSchedulerService>();
+builder.Services.AddHttpClient<ISlipAlertMessageService, GeminiSlipAlertMessageService>();
 
 // Initialize Firebase Admin SDK for FCM
 var firebaseCredJson = builder.Configuration["Firebase:CredentialsJson"];

src/Orbit.Application/Chat/Commands/ProcessUserChatCommand.cs

@@ -373,16 +373,20 @@ public async Task<Result<ChatResponse>> Handle(
 
         var dueDate = action.DueDate ?? await userDateService.GetUserTodayAsync(userId, ct);
 
+        var isBadHabit = action.IsBadHabit ?? false;
+        var slipAlertEnabled = action.SlipAlertEnabled ?? isBadHabit;
+
         var habitResult = Habit.Create(
             userId,
             action.Title,
             action.FrequencyUnit,
             action.FrequencyQuantity,
             action.Description,
             days: action.Days,
-            isBadHabit: action.IsBadHabit ?? false,
+            isBadHabit: isBadHabit,
             dueDate: dueDate,
-            dueTime: action.DueTime);
+            dueTime: action.DueTime,
+            slipAlertEnabled: slipAlertEnabled);
 
         if (habitResult.IsFailure)
             return Result.Failure<(Guid? Id, string? Name)>(habitResult.Error);

src/Orbit.Application/Habits/Commands/CreateHabitCommand.cs

@@ -21,6 +21,7 @@ public record CreateHabitCommand(
     TimeOnly? DueTime = null,
     bool ReminderEnabled = false,
     int ReminderMinutesBefore = 15,
+    bool SlipAlertEnabled = false,
     IReadOnlyList<Guid>? TagIds = null) : IRequest<Result<Guid>>;
 
 public class CreateHabitCommandHandler(
@@ -59,7 +60,8 @@ public async Task<Result<Guid>> Handle(CreateHabitCommand request, CancellationT
             dueDate,
             dueTime: request.DueTime,
             reminderEnabled: request.ReminderEnabled,
-            reminderMinutesBefore: request.ReminderMinutesBefore);
+            reminderMinutesBefore: request.ReminderMinutesBefore,
+            slipAlertEnabled: request.SlipAlertEnabled);
 
         if (habitResult.IsFailure)
             return Result.Failure<Guid>(habitResult.Error);

src/Orbit.Application/Habits/Commands/UpdateHabitCommand.cs

@@ -21,7 +21,8 @@ public record UpdateHabitCommand(
     DateOnly? DueDate = null,
     TimeOnly? DueTime = null,
     bool? ReminderEnabled = null,
-    int? ReminderMinutesBefore = null) : IRequest<Result>;
+    int? ReminderMinutesBefore = null,
+    bool? SlipAlertEnabled = null) : IRequest<Result>;
 
 public class UpdateHabitCommandHandler(
     IGenericRepository<Habit> habitRepository,
@@ -49,7 +50,8 @@ public async Task<Result> Handle(UpdateHabitCommand request, CancellationToken c
             request.DueDate,
             dueTime: request.DueTime,
             reminderEnabled: request.ReminderEnabled,
-            reminderMinutesBefore: request.ReminderMinutesBefore);
+            reminderMinutesBefore: request.ReminderMinutesBefore,
+            slipAlertEnabled: request.SlipAlertEnabled);
 
         if (result.IsFailure)
             return result;

src/Orbit.Application/Habits/Queries/GetHabitScheduleQuery.cs

@@ -27,6 +27,7 @@ public record HabitScheduleItem(
     bool IsOverdue,
     bool ReminderEnabled,
     int ReminderMinutesBefore,
+    bool SlipAlertEnabled,
     IReadOnlyList<HabitTagItem> Tags,
     IReadOnlyList<HabitScheduleChildItem> Children);
 
@@ -178,6 +179,7 @@ private static HabitScheduleItem MapToScheduleItem(
             isOverdue,
             h.ReminderEnabled,
             h.ReminderMinutesBefore,
+            h.SlipAlertEnabled,
             MapTags(h),
             MapChildren(h.Id, lookup, dateFrom, dateTo));
 

src/Orbit.Application/Habits/Services/SlipPatternDetectionService.cs

@@ -0,0 +1,72 @@
+using Orbit.Domain.Entities;
+using Orbit.Domain.Models;
+
+namespace Orbit.Application.Habits.Services;
+
+public static class SlipPatternDetectionService
+{
+    private const int LookbackDays = 60;
+    private const int MinOccurrencesPerDay = 3;
+    private const int MinBucketCountForTimePeak = 2;
+
+    public static SlipPattern? DetectPattern(
+        IReadOnlyList<HabitLog> logs,
+        Guid habitId,
+        TimeZoneInfo userTimeZone)
+    {
+        var cutoff = DateTime.UtcNow.AddDays(-LookbackDays);
+        var recentLogs = logs.Where(l => l.CreatedAtUtc >= cutoff).ToList();
+
+        if (recentLogs.Count < MinOccurrencesPerDay)
+            return null;
+
+        // Convert to user local time and extract (DayOfWeek, Hour)
+        var localEntries = recentLogs.Select(l =>
+        {
+            var localTime = TimeZoneInfo.ConvertTimeFromUtc(l.CreatedAtUtc, userTimeZone);
+            return (localTime.DayOfWeek, localTime.Hour);
+        }).ToList();
+
+        // Group by DayOfWeek, filter to days with 3+ occurrences
+        var dayGroups = localEntries
+            .GroupBy(e => e.DayOfWeek)
+            .Where(g => g.Count() >= MinOccurrencesPerDay)
+            .ToList();
+
+        if (dayGroups.Count == 0)
+            return null;
+
+        SlipPattern? strongest = null;
+
+        foreach (var dayGroup in dayGroups)
+        {
+            // Bucket hours into 2-hour windows, pick peak window
+            var hourBuckets = dayGroup
+                .GroupBy(e => e.Hour / 2)
+                .OrderByDescending(g => g.Count())
+                .ToList();
+
+            var topBucket = hourBuckets.First();
+
+            // Only assign a peak hour if the top bucket has meaningful concentration
+            int? peakHour = topBucket.Count() >= MinBucketCountForTimePeak
+                ? topBucket.Key * 2 + 1
+                : null;
+
+            var occurrenceCount = dayGroup.Count();
+            var confidence = (double)occurrenceCount / recentLogs.Count;
+
+            var pattern = new SlipPattern(
+                habitId,
+                dayGroup.Key,
+                peakHour,
+                occurrenceCount,
+                confidence);
+
+            if (strongest is null || confidence > strongest.Confidence)
+                strongest = pattern;
+        }
+
+        return strongest;
+    }
+}

src/Orbit.Domain/Entities/Habit.cs

@@ -17,6 +17,7 @@ public class Habit : Entity
     public TimeOnly? DueTime { get; private set; }
     public bool ReminderEnabled { get; private set; }
     public int ReminderMinutesBefore { get; private set; } = 15;
+    public bool SlipAlertEnabled { get; private set; }
     public int? Position { get; private set; }
     public DateTime CreatedAtUtc { get; private set; }
     public ICollection<System.DayOfWeek> Days { get; private set; } = [];
@@ -46,7 +47,8 @@ public static Result<Habit> Create(
         TimeOnly? dueTime = null,
         Guid? parentHabitId = null,
         bool reminderEnabled = false,
-        int reminderMinutesBefore = 15)
+        int reminderMinutesBefore = 15,
+        bool slipAlertEnabled = false)
     {
         if (userId == Guid.Empty)
             return Result.Failure<Habit>("User ID is required.");
@@ -74,6 +76,7 @@ public static Result<Habit> Create(
             ParentHabitId = parentHabitId,
             ReminderEnabled = reminderEnabled,
             ReminderMinutesBefore = reminderMinutesBefore,
+            SlipAlertEnabled = slipAlertEnabled,
             CreatedAtUtc = DateTime.UtcNow
         });
     }
@@ -166,7 +169,8 @@ public Result Update(
         DateOnly? dueDate,
         TimeOnly? dueTime = null,
         bool? reminderEnabled = null,
-        int? reminderMinutesBefore = null)
+        int? reminderMinutesBefore = null,
+        bool? slipAlertEnabled = null)
     {
         if (string.IsNullOrWhiteSpace(title))
             return Result.Failure("Title is required.");
@@ -193,6 +197,8 @@ public Result Update(
             ReminderEnabled = reminderEnabled.Value;
         if (reminderMinutesBefore.HasValue)
             ReminderMinutesBefore = reminderMinutesBefore.Value;
+        if (slipAlertEnabled.HasValue)
+            SlipAlertEnabled = slipAlertEnabled.Value;
 
         return Result.Success();
     }

src/Orbit.Domain/Entities/SentSlipAlert.cs

@@ -0,0 +1,22 @@
+using Orbit.Domain.Common;
+
+namespace Orbit.Domain.Entities;
+
+public class SentSlipAlert : Entity
+{
+    public Guid HabitId { get; private set; }
+    public DateOnly WeekStart { get; private set; }
+    public DateTime SentAtUtc { get; private set; }
+
+    private SentSlipAlert() { }
+
+    public static SentSlipAlert Create(Guid habitId, DateOnly weekStart)
+    {
+        return new SentSlipAlert
+        {
+            HabitId = habitId,
+            WeekStart = weekStart,
+            SentAtUtc = DateTime.UtcNow
+        };
+    }
+}

src/Orbit.Domain/Interfaces/ISlipAlertMessageService.cs

@@ -0,0 +1,13 @@
+using Orbit.Domain.Common;
+
+namespace Orbit.Domain.Interfaces;
+
+public interface ISlipAlertMessageService
+{
+    Task<Result<(string Title, string Body)>> GenerateMessageAsync(
+        string habitTitle,
+        DayOfWeek dayOfWeek,
+        int? peakHour,
+        string language,
+        CancellationToken cancellationToken = default);
+}

src/Orbit.Domain/Models/AiAction.cs

@@ -12,6 +12,7 @@ public record AiAction
     public int? FrequencyQuantity { get; init; }
     public List<System.DayOfWeek>? Days { get; init; }
     public bool? IsBadHabit { get; init; }
+    public bool? SlipAlertEnabled { get; init; }
     public DateOnly? DueDate { get; init; }
     public TimeOnly? DueTime { get; init; }
     public string? Note { get; init; }

src/Orbit.Domain/Models/SlipPattern.cs

@@ -0,0 +1,8 @@
+namespace Orbit.Domain.Models;
+
+public record SlipPattern(
+    Guid HabitId,
+    DayOfWeek DayOfWeek,
+    int? PeakHour,
+    int OccurrenceCount,
+    double Confidence);