Agent Skills: Streak Tracker Generator

Streak Tracker Generator

Generate a production streak tracking system that records consecutive days of user activity, calculates current and longest streaks, handles timezone-aware day boundaries, supports streak freeze/protection passes, and schedules streak-at-risk local notifications.

When This Skill Activates

Use this skill when the user:

• Asks to "add streaks" or "daily streak" tracking
• Wants "streak tracking" or "consecutive days" counting
• Mentions "engagement streaks" or "habit tracking"
• Asks about "streak freeze" or "streak protection"
• Wants "streak-at-risk" notifications or reminders
• Mentions "login streak" or "activity streak"

Pre-Generation Checks

1. Project Context Detection

• [ ] Check Swift version (requires Swift 5.9+)
• [ ] Check deployment target (iOS 17+ / macOS 14+ for @Observable and SwiftData)
• [ ] Check for SwiftData availability and existing model container setup
• [ ] Identify source file locations

2. Conflict Detection

Search for existing streak or habit tracking:

Glob: **/*Streak*.swift, **/*Habit*.swift, **/*DailyTrack*.swift
Grep: "streak" or "consecutiveDays" or "habitTrack" or "dailyStreak"

If existing streak/habit system found:

• Ask if user wants to replace or extend it
• If extending, generate only the missing components

3. Platform Detection

Determine if generating for iOS (UNUserNotificationCenter) or macOS (UNUserNotificationCenter available on macOS 11+) or both.

Configuration Questions

Ask user via AskUserQuestion:

1. Streak type?

   • Daily (consecutive calendar days) -- recommended
   • Weekly (at least one activity per calendar week)
   • Custom interval (every N hours/days)

2. Storage backend?

   • SwiftData (recommended for iOS 17+ / macOS 14+)
   • UserDefaults (lightweight, no model container needed)

3. Include streak freeze/protection?

   • Yes — users get limited freeze passes to preserve streaks on missed days
   • No — strict consecutive tracking only

4. Streak-at-risk notifications?

   • Yes — schedule a local notification (e.g., 8 PM) if no activity recorded today
   • No — no notifications

5. Additional features? (multi-select)

   • Calendar heat map view (visual grid of activity days)
   • Streak badge view (compact count with animation)
   • Milestone celebrations (7-day, 30-day, 100-day, etc.)

Generation Process

Step 1: Read Templates

Read templates.md for production Swift code.

Step 2: Create Core Files

Generate these files:

1. StreakRecord.swift — SwiftData @Model for activity records
2. StreakManager.swift — @Observable class: record activity, calculate streaks, manage freezes
3. StreakError.swift — Error types for streak operations

Step 3: Create UI Files

4. StreakCalendarView.swift — Grid showing days with/without activity
5. StreakBadgeView.swift — Compact badge with streak count and animation

Step 4: Create Optional Files

Based on configuration:

• StreakFreeze.swift — If streak freeze selected
• StreakNotificationScheduler.swift — If notifications selected

Step 5: Determine File Location

Check project structure:

• If Sources/ exists -> Sources/StreakTracking/
• If App/ exists -> App/StreakTracking/
• Otherwise -> StreakTracking/

Output Format

After generation, provide:

Files Created

StreakTracking/
├── StreakRecord.swift               # SwiftData model for activity records
├── StreakManager.swift              # Core streak calculation engine
├── StreakError.swift                # Error types
├── StreakCalendarView.swift         # Calendar heat map view
├── StreakBadgeView.swift            # Compact animated badge
├── StreakFreeze.swift               # Freeze/protection passes (optional)
└── StreakNotificationScheduler.swift # Streak-at-risk reminders (optional)

Integration Steps

Set up the model container (SwiftData):

@main
struct MyApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        .modelContainer(for: [StreakRecord.self, StreakFreeze.self])
    }
}

Record activity on user action:

struct LessonCompleteView: View {
    @Environment(\.modelContext) private var modelContext
    @State private var streakManager: StreakManager?

    var body: some View {
        Button("Complete Lesson") {
            Task {
                try await streakManager?.recordActivity(type: "lesson")
            }
        }
        .onAppear {
            streakManager = StreakManager(modelContext: modelContext)
        }
    }
}

Display the current streak:

struct ProfileView: View {
    @Environment(\.modelContext) private var modelContext
    @State private var streakManager: StreakManager?

    var body: some View {
        VStack {
            if let manager = streakManager {
                StreakBadgeView(streak: manager.currentStreak)
                Text("Longest: \(manager.longestStreak) days")
                    .foregroundStyle(.secondary)
            }
        }
        .onAppear {
            streakManager = StreakManager(modelContext: modelContext)
            Task { await streakManager?.refresh() }
        }
    }
}

Show the calendar heat map:

struct StatsView: View {
    @Environment(\.modelContext) private var modelContext
    @State private var streakManager: StreakManager?

    var body: some View {
        if let manager = streakManager {
            StreakCalendarView(manager: manager)
        }
    }
}

Use a streak freeze:

Button("Use Streak Freeze") {
    if streakManager.useStreakFreeze() {
        // Freeze applied — streak preserved
    } else {
        // No freezes available
    }
}

Testing

import Testing
import SwiftData

@Test
func recordingActivityIncrementsStreak() async throws {
    let container = try ModelContainer(
        for: StreakRecord.self, StreakFreeze.self,
        configurations: ModelConfiguration(isStoredInMemoryOnly: true)
    )
    let context = ModelContext(container)
    let manager = StreakManager(modelContext: context)

    // Record activity for today
    try await manager.recordActivity(type: "workout")
    await manager.refresh()

    #expect(manager.currentStreak == 1)
}

@Test
func consecutiveDaysBuildStreak() async throws {
    let container = try ModelContainer(
        for: StreakRecord.self, StreakFreeze.self,
        configurations: ModelConfiguration(isStoredInMemoryOnly: true)
    )
    let context = ModelContext(container)
    let manager = StreakManager(modelContext: context)

    // Simulate 3 consecutive days
    let calendar = Calendar.current
    for daysAgo in (0...2).reversed() {
        let date = calendar.date(byAdding: .day, value: -daysAgo, to: .now)!
        try await manager.recordActivity(type: "workout", date: date)
    }
    await manager.refresh()

    #expect(manager.currentStreak == 3)
    #expect(manager.longestStreak == 3)
}

@Test
func missedDayBreaksStreak() async throws {
    let container = try ModelContainer(
        for: StreakRecord.self, StreakFreeze.self,
        configurations: ModelConfiguration(isStoredInMemoryOnly: true)
    )
    let context = ModelContext(container)
    let manager = StreakManager(modelContext: context)

    let calendar = Calendar.current
    // Day 3 ago and Day 2 ago (streak of 2), then skip Day 1, record today
    let threeDaysAgo = calendar.date(byAdding: .day, value: -3, to: .now)!
    let twoDaysAgo = calendar.date(byAdding: .day, value: -2, to: .now)!
    try await manager.recordActivity(type: "workout", date: threeDaysAgo)
    try await manager.recordActivity(type: "workout", date: twoDaysAgo)
    try await manager.recordActivity(type: "workout", date: .now)
    await manager.refresh()

    #expect(manager.currentStreak == 1) // Gap broke the streak
    #expect(manager.longestStreak == 2) // Previous streak preserved
}

@Test
func streakFreezePreservesStreak() async throws {
    let container = try ModelContainer(
        for: StreakRecord.self, StreakFreeze.self,
        configurations: ModelConfiguration(isStoredInMemoryOnly: true)
    )
    let context = ModelContext(container)
    let manager = StreakManager(modelContext: context)

    let calendar = Calendar.current
    // Record 2 days ago and today — gap of 1 day
    let twoDaysAgo = calendar.date(byAdding: .day, value: -2, to: .now)!
    try await manager.recordActivity(type: "workout", date: twoDaysAgo)
    manager.addStreakFreeze(count: 1)
    let used = manager.useStreakFreeze()
    try await manager.recordActivity(type: "workout", date: .now)
    await manager.refresh()

    #expect(used == true)
    #expect(manager.currentStreak == 3) // 2 days ago + freeze + today
}

Common Patterns

Check In for Today

// Record a single check-in per day (idempotent)
try await streakManager.recordActivity(type: "daily-check-in")
// StreakManager deduplicates — calling twice on the same day is safe

Query Streak State

let current = streakManager.currentStreak    // Consecutive days up to today
let longest = streakManager.longestStreak    // All-time best
let atRisk = streakManager.isStreakAtRisk    // No activity today yet
let hasActivity = streakManager.hasActivityToday

Streak Freeze

// Grant freeze passes (e.g., as a reward or purchase)
streakManager.addStreakFreeze(count: 2)

// Use a freeze to cover a missed day
let success = streakManager.useStreakFreeze()
// Returns false if no freezes remaining or no gap to fill

Gotchas & Edge Cases

Timezone and Day Boundary Handling

Always use Calendar.current.startOfDay(for:) to normalize dates. Never compare raw Date values for "same day" checks — a user active at 11:59 PM and 12:01 AM has activity on two different calendar days but should not get a gap. The StreakManager uses the user's local calendar for all day boundary calculations.

Midnight Edge Cases

If a user completes an activity exactly at midnight, startOfDay(for:) may place it on the new day. The templates handle this by recording the timestamp as well as the normalized date, so the raw data is preserved for debugging.

Device Clock Manipulation

Users can change their device clock to fake streak activity. Mitigations:

• Store createdAt timestamps alongside activityDate and flag anomalies (e.g., createdAt is before a previously recorded createdAt)
• For server-synced apps, validate streaks server-side
• For local-only apps, accept that determined users can game it — focus on honest users

Calendar vs Gregorian Day Changes

Different calendars (Islamic, Hebrew, Japanese) have different day boundaries and week structures. The templates use Calendar.current which respects the user's locale. If your app requires a fixed calendar (e.g., Gregorian for global leaderboards), pass an explicit Calendar(identifier: .gregorian) to StreakManager.

Duplicate Activity on Same Day

StreakManager.recordActivity is idempotent per calendar day per activity type. Calling it multiple times on the same day creates only one StreakRecord. This prevents accidental double-counting.

App Reinstall / Data Loss

SwiftData stores persist across app updates but are lost on reinstall. For critical streak data, consider syncing to CloudKit or a backend. The templates include a lastSyncDate hook in StreakManager for this purpose.

References

• templates.md — All production Swift templates for streak tracking
• Related: generators/push-notifications — Push notification setup for streak reminders
• Related: generators/milestone-celebration — Celebrate streak milestones with animations