Imported from elchrysaki/offmap (.claude/skills/generators/milestone-celebration/SKILL.md). Install upstream with npx skills add elchrysaki/offmap --skill milestone-celebration. Copyright stays with the author.

Milestone Celebration Generator

Generate a production milestone celebration system with confetti particle animations via CAEmitterLayer, achievement badge views with locked/unlocked states, a celebration overlay with spring animations, haptic feedback, and optional shareable achievement cards — all triggered automatically when users hit key thresholds.

When This Skill Activates

Use this skill when the user:

• Asks to "add celebrations" or "celebrate achievements"
• Wants "confetti animation" or "particle effects for milestones"
• Mentions "achievement badges" or "badge unlock animation"
• Asks about "milestone rewards" or "progress milestones"
• Wants to "celebrate achievement" or "trigger celebration on threshold"
• Asks about "level-up animation" or "gamification celebrations"

Pre-Generation Checks

1. Project Context Detection

• Check Swift version (requires Swift 5.9+)
• Check deployment target (iOS 17+ / macOS 14+ for @Observable, spring animations, sensoryFeedback)
• Check for UIKit availability (iOS — CAEmitterLayer for confetti, haptics)
• Identify source file locations

2. Conflict Detection

Search for existing celebration/animation code:

Glob: **/*Confetti*.swift, **/*Celebration*.swift, **/*Achievement*.swift, **/*Milestone*.swift, **/*Badge*.swift
Grep: "CAEmitterLayer" or "CAEmitterCell" or "UINotificationFeedbackGenerator" or "confetti" or "celebration"

If existing celebration or gamification library found (e.g., custom confetti, third-party particle libraries):

• Ask if user wants to replace or integrate with it
• If keeping, advise on best practices instead of generating

3. Platform Detection

Determine if generating for iOS (UIKit-based confetti + haptics) or macOS (Core Animation confetti, no haptics) or both (cross-platform with feature gates).

Configuration Questions

Ask user via AskUserQuestion:

1. Celebration type? (multi-select)

   • Confetti burst (full-screen particle animation)
   • Badge unlock (icon reveal with glow animation)
   • Level-up (progress ring fill + title transition)
   • Custom (user defines their own celebration style)

2. Haptic feedback?

   • Yes — success haptic on celebration trigger (recommended)
   • No — silent celebrations only

3. Shareable achievement card?

   • Yes — render achievement as image for social sharing via ShareLink
   • No — in-app celebration only

4. Sound effects?

   • Yes — play system sound or bundled audio on celebration
   • No — visual only

Generation Process

Step 1: Read Templates

Read templates.md for production Swift code.

Step 2: Create Core Files

Generate these files:

1. Milestone.swift — Model with id, title, description, threshold, icon, unlock state. Codable + Sendable.
2. MilestoneTracker.swift — @Observable class tracking progress toward milestones, checking thresholds, triggering celebrations. Persists unlock state via UserDefaults or file storage.
3. ConfettiView.swift — UIViewRepresentable wrapping CAEmitterLayer for confetti particle animation. Configurable colors, duration, density. Respects Reduce Motion.

Step 3: Create UI Files

4. CelebrationOverlay.swift — Full-screen overlay combining confetti + badge reveal + congratulations message. Auto-dismisses after configurable duration. Uses withAnimation(.spring).
5. MilestoneBadgeView.swift — Individual badge view with locked/unlocked states, SF Symbol icon, progress ring for partial progress.
6. MilestoneCollectionView.swift — Grid layout of all milestones showing locked/unlocked state with progress indicators.

Step 4: Create Optional Files

Based on configuration:

• HapticManager.swift — If haptic feedback selected (thin wrapper around UINotificationFeedbackGenerator / UIImpactFeedbackGenerator)
• ShareableMilestoneCard.swift — If shareable selected (renders milestone as image via ImageRenderer + ShareLink)

Step 5: Determine File Location

Check project structure:

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

Output Format

After generation, provide:

Files Created

MilestoneCelebration/
├── Milestone.swift              # Model with threshold, icon, unlock state
├── MilestoneTracker.swift       # @Observable tracker with persistence
├── ConfettiView.swift           # CAEmitterLayer confetti animation
├── CelebrationOverlay.swift     # Full-screen celebration overlay
├── MilestoneBadgeView.swift     # Badge with locked/unlocked + progress ring
├── MilestoneCollectionView.swift # Grid of all milestones
├── HapticManager.swift          # Celebration haptics (optional)
└── ShareableMilestoneCard.swift # Achievement share card (optional)

Integration Steps

Trigger celebration on threshold:

struct WorkoutCompleteView: View {
    @State private var tracker = MilestoneTracker()
    @State private var celebratingMilestone: Milestone?

    var body: some View {
        VStack {
            // ... workout summary content ...

            Button("Save Workout") {
                saveWorkout()
                let newCount = totalWorkouts + 1
                if let milestone = tracker.checkThreshold(value: newCount, category: .workouts) {
                    celebratingMilestone = milestone
                }
            }
        }
        .overlay {
            if let milestone = celebratingMilestone {
                CelebrationOverlay(milestone: milestone) {
                    celebratingMilestone = nil
                }
            }
        }
    }
}

Badge collection screen:

struct ProfileView: View {
    @State private var tracker = MilestoneTracker()

    var body: some View {
        NavigationStack {
            ScrollView {
                MilestoneCollectionView(
                    milestones: tracker.allMilestones,
                    columns: 3
                )
            }
            .navigationTitle("Achievements")
        }
    }
}

Share an achievement:

struct MilestoneDetailView: View {
    let milestone: Milestone
    @State private var showShareCard = false

    var body: some View {
        VStack {
            MilestoneBadgeView(milestone: milestone, size: .large)
            Text(milestone.title).font(.title2.bold())
            Text(milestone.milestoneDescription).foregroundStyle(.secondary)

            if milestone.isUnlocked {
                Button("Share Achievement") {
                    showShareCard = true
                }
                .buttonStyle(.borderedProminent)
            }
        }
        .sheet(isPresented: $showShareCard) {
            ShareableMilestoneCard(milestone: milestone, brandName: "FitApp")
        }
    }
}

Testing

@Test
func milestoneUnlocksAtThreshold() {
    let tracker = MilestoneTracker(store: InMemoryMilestoneStore())
    let milestone = Milestone(
        id: "first-10",
        title: "First 10",
        milestoneDescription: "Complete 10 workouts",
        threshold: 10,
        iconName: "flame.fill"
    )
    tracker.register(milestone)

    let result = tracker.checkThreshold(value: 10, for: milestone.id)
    #expect(result != nil)
    #expect(result?.isUnlocked == true)
    #expect(result?.unlockedDate != nil)
}

@Test
func milestoneDoesNotUnlockBelowThreshold() {
    let tracker = MilestoneTracker(store: InMemoryMilestoneStore())
    let milestone = Milestone(
        id: "first-10",
        title: "First 10",
        milestoneDescription: "Complete 10 workouts",
        threshold: 10,
        iconName: "flame.fill"
    )
    tracker.register(milestone)

    let result = tracker.checkThreshold(value: 9, for: milestone.id)
    #expect(result == nil)
}

@Test
func confettiRespectsReduceMotion() {
    // When Reduce Motion is enabled, ConfettiView should not emit particles
    let config = ConfettiConfiguration(reduceMotionOverride: true)
    #expect(config.shouldAnimate == false)
}

@Test
func celebrationOverlayAutoDismisses() async throws {
    // Verify overlay dismisses after the configured duration
    let expectation = XCTestExpectation(description: "Dismissed")
    let duration: TimeInterval = 0.5
    // Test that the onDismiss callback fires after duration
}

Common Patterns

Trigger Celebration on Threshold

Best for: fitness, learning, productivity apps.

• Define milestones with numeric thresholds (10 workouts, 100 pages read, 7-day streak)
• MilestoneTracker checks values against registered milestones
• Celebration fires only on the first crossing — subsequent calls are no-ops
• Persist unlock state so celebrations do not repeat

Badge Collection View

Best for: gamification, loyalty, progression systems.

• Grid of all milestones: locked ones are dimmed/grayscale, unlocked ones are vibrant
• Progress ring shows how close user is to unlocking each badge
• Tapping a badge shows detail view with full description and share option
• Counter showing "12 of 20 unlocked" at the top

Share Achievement

Best for: social apps, fitness, competitions.

• Render the unlocked badge + title + metric as a shareable image
• Use ImageRenderer at @2x scale for Retina quality
• Include app branding and optional QR code for deep linking
• Integrate with ShareLink for native share sheet

Gotchas

CAEmitterLayer Performance on Older Devices

• Confetti with many particles (200+) can drop frames on A11 and older chips
• Cap birthRate at 50-80 for smooth 60fps on most devices
• Use emitterCells with only 3-5 distinct shapes to reduce GPU draw calls
• Stop emission after burst duration — do not leave the emitter running indefinitely
• Profile with Instruments (Core Animation template) if users report frame drops

Reduce Motion Accessibility

• Always check UIAccessibility.isReduceMotionEnabled before starting particle animations
• When Reduce Motion is on: skip confetti, show a static badge reveal or a simple fade-in instead
• Use @Environment(\.accessibilityReduceMotion) in SwiftUI for reactive updates
• Provide an equally rewarding experience without animation — the badge reveal and message still appear

Haptic Feedback on Non-Supporting Devices

• UINotificationFeedbackGenerator is a no-op on devices without a Taptic Engine (e.g., iPod touch, iPad)
• Always guard with CHHapticEngine.capabilitiesForHardware().supportsHaptics before preparing generators
• On macOS, haptics are not available — gate with #if canImport(UIKit) and #if os(iOS)
• Use .sensoryFeedback(.success, trigger:) modifier on iOS 17+ for a simpler SwiftUI-native approach

Sound Effect Considerations

• Use AudioServicesPlaySystemSound for lightweight celebration sounds (no audio session needed)
• Respect the device silent/mute switch — AudioServicesPlaySystemSound honors it automatically
• For custom sounds, keep files under 30 seconds and use CAF or WAV format
• Do not play sounds when Reduce Motion is enabled (some users enable it for sensory reasons)

Persistence Edge Cases

• If the app is terminated between unlocking a milestone and persisting it, the user may see the celebration again
• Use UserDefaults for simple unlock flags or a lightweight JSON file for full milestone state
• For SwiftData or CoreData apps, consider storing unlock state alongside the user's data model
• Sync unlock state via CloudKit if the app supports multiple devices

App Store Guidelines

• Guideline 4.5.4: Milestone-announcement pushes ("you're 1 away from a badge!") are promotional — explicit opt-in consent and an in-app opt-out are required.
• Guideline 2.3.1: Screenshots showing badges and achievements must reflect what the app actually awards — aspirational metadata is a rejection risk.
• Guideline 4.3 (Spam): Celebrations don't differentiate a thin app. If this is one of several similar apps on your account, run app-store/originality-check before submitting.

References

• templates.md — All production Swift templates
• Related: generators/streak-tracker — Streak tracking pairs naturally with milestone celebrations
• Related: generators/share-card — Shareable achievement card rendering and social sharing
• Related: generators/variable-rewards — Variable reward schedules for deeper engagement