# TheNoiseClock - Product Requirements Document

## Overview
TheNoiseClock is a SwiftUI-based iOS application that combines a customizable digital clock display with white noise playback and alarm functionality. The app is designed with a dark theme and focuses on providing a clean, distraction-free interface for time display and ambient sound management.

## Core Features

### 1. Digital Clock Display
- **Real-time clock** with automatic updates every second
- **Customizable time format**: 12-hour or 24-hour display
- **Optional seconds display** with toggle control
- **AM/PM badge** for 12-hour format (optional)
- **Segmented time display** with colon separators that adapt to orientation
- **Dynamic scaling** that maximizes available screen space usage
- **Portrait and landscape orientation support** with responsive font sizing
- **Optimal font sizing** that uses all available space efficiently
- **Immediate updates** on orientation changes and tab bar visibility changes
- **Fixed-width digit rendering** to prevent layout shifts and jumping
- **Individual digit views** with consistent spacing and alignment
- **Font customization** with family, weight, and design selection
- **Dynamic dot sizing** that matches selected font weight
- **Safe area handling** with proper Dynamic Island avoidance on iPhone and full-width layout on iPad
- **Full-screen mode** with status bar hiding and tab bar expansion
- **Orientation-aware spacing** for optimal layout in all orientations

### 2. Clock Customization
- **Color customization**: User-selectable digit colors with color picker
- **Background color**: Customizable background with color picker
- **Glow effects**: Adjustable glow intensity (0-100%)
- **Size control**: Manual scaling (0-100%) or auto-fit mode
- **Opacity controls**: Separate opacity for clock digits and overlays
- **Random color mode**: Automatically changes digit color every minute
- **Preset themes**: Quick "Night" (black/white) and "Day" (white/black) themes
- **Font family selection**: Choose from System, Helvetica, Arial, Times New Roman, Georgia, Verdana, Monaco, Courier fonts
- **Font weight options**: Ultra Light, Thin, Light, Regular, Medium, Semibold, Bold, Heavy, Black
- **Font design choices**: Default, Serif, Rounded, Monospaced designs
- **Live font preview**: Real-time preview of font changes in settings
- **Font persistence**: All font settings saved and restored automatically

### 3. Display Modes
- **Normal mode**: Standard interface with navigation and settings
- **Display mode**: Full-screen clock activated by long-press (0.6 seconds)
- **Automatic UI hiding**: Tab bar and navigation elements hide in display mode
- **iPad compatibility**: Uses SwiftUI's native `.toolbar(.hidden, for: .tabBar)` for proper iPad sidebar-style tab bar hiding
- **Cross-platform support**: Works correctly on both iPhone (bottom tab bar) and iPad (top sidebar tab bar)
- **Smooth transitions**: Animated transitions between modes
- **Status bar control**: Status bar hidden on the Clock tab (including full-screen mode)
- **Safe area expansion**: Clock expands into tab bar area when hidden
- **Dynamic Island awareness**: Proper spacing to avoid Dynamic Island overlap
- **Orientation handling**: Full-screen mode works in both portrait and landscape
- **Keep awake functionality**: Optional screen wake lock to prevent device sleep in display mode
- **Battery optimization**: Wake lock automatically disabled when exiting display mode

### 4. Information Overlays
- **Battery level display**: Real-time battery percentage with dynamic icon
- **Battery state awareness**: Shows charging state with lightning bolt icon
- **Battery color coding**: Green (50-100%), Yellow (20-49%), Orange (10-19%), Red (<10%)
- **Charging indicator**: Green lightning bolt icon when device is charging
- **Date display**: Current date in "d MMMM EEE" format (e.g., "7 September Mon")
- **Overlay opacity control**: Independent opacity for battery/date overlays
- **Automatic updates**: Battery and date update in real-time
- **Battery service integration**: Dedicated BatteryService for monitoring and state management

### 5. White Noise Player
- **Multiple sound options**:
  - White Noise (`white-noise.mp3`)
  - Heavy Rain White Noise (`heavy-rain-white-noise.mp3`)
  - Fan White Noise (`fan-white-noise-heater.mp3`)
- **Continuous playback**: Sounds loop indefinitely
- **Advanced sound selection**: Category-based grid with search and preview
- **Simple controls**: Play/Stop button with visual feedback
- **Auto-stop on selection**: Automatically stops current sound when selecting new one
- **Sound preview**: 3-second preview on long-press
- **JSON-based configuration**: Sound definitions loaded from external configuration
- **Bundle organization**: Sounds organized in category-based bundles
- **Shared audio player**: Singleton pattern prevents audio conflicts
- **Background audio support**: Continues playing when app is backgrounded
- **Audio interruption handling**: Automatically resumes after phone calls or route changes
- **Wake lock integration**: Prevents device sleep while audio is playing
- **Bluetooth audio support**: Works with AirPods and other Bluetooth audio devices
- **Responsive layout**: Optimized for both portrait and landscape orientations
- **AudioPlaybackKit integration**: Powered by reusable Swift package for audio functionality

### 6. Advanced Alarm System
- **Multiple alarms**: Create and manage unlimited alarms
- **Rich alarm editor**: Full-featured alarm creation and editing interface
- **Time selection**: Wheel-style date picker with optimized font sizing for maximum readability
- **Dynamic alarm sounds**: Configurable alarm sounds loaded from dedicated alarm-sounds.json configuration
- **Sound preview**: Play/stop functionality for testing alarm sounds before selection
- **Sound organization**: Alarm sounds organized in dedicated AlarmSounds.bundle with categories
- **Custom labels**: User-defined alarm names and descriptions
- **Repeat schedules**: Set alarms to repeat on specific weekdays or daily
- **Sound selection**: Choose from extensive alarm sounds with live preview
- **Volume control**: Adjustable alarm volume (0-100%)
- **Vibration settings**: Enable/disable vibration for each alarm
- **Snooze functionality**: Configurable snooze duration (5, 7, 8, 9, 10, 15, 20 minutes)
- **Smart notifications**: Automatic scheduling for one-time and repeating alarms
- **Enable/disable toggles**: Individual alarm control with instant feedback
- **Notification integration**: Uses iOS UserNotifications framework with proper scheduling
- **Persistent storage**: Alarms saved to UserDefaults with backward compatibility
- **Alarm management**: Add, edit, delete, and duplicate alarms
- **Next trigger preview**: Shows when the next alarm will fire
- **Responsive time picker**: Font sizes adapt to available space and orientation
- **AlarmSoundService integration**: Dedicated service for alarm-specific sound management

## Advanced Clock Display Features

### Fixed-Width Digit Rendering
- **Individual digit views**: Each digit (0-9) rendered in its own view component
- **Consistent spacing**: All digits use the width of the widest digit ("8") for uniform layout
- **Height consistency**: All digits use the height of the tallest digit ("8") to prevent vertical jumping
- **Layout stability**: No shifting or jumping when time changes (e.g., "11" to "12")
- **Perfect centering**: Each digit is centered within its fixed-width container

### Advanced Font Customization System
- **Type-safe font selection**: FontFamily enum with System, Helvetica, Arial, Times New Roman, Georgia, Verdana, Courier, Futura, Avenir, Roboto options
- **Weight variations**: Font.Weight enum with 9 weight options from Ultra Light to Black
- **Design choices**: Font.Design enum with Default, Serif, Rounded, Monospaced designs
- **Live preview**: Real-time font preview in settings interface with allCases picker integration
- **Binary search font sizing**: Advanced calculateOptimalFontSize with tight bounding box calculations
- **Dynamic font sizing**: Real-time font size optimization based on container geometry
- **UIFont integration**: Proper font measurement with createUIFont and tightBoundingBox utilities
- **Weight-based dot scaling**: Colon dots automatically scale with font weight using dotSizeMultiplier
- **Enum-based architecture**: Type-safe font selection eliminates string-based errors
- **Legacy compatibility**: Backward compatibility methods for existing code integration

### Dynamic Layout and Sizing
- **GeometryReader integration**: Real-time container size detection
- **Orientation-aware calculations**: Different sizing algorithms for portrait vs landscape
- **Safe area handling**: Proper Dynamic Island avoidance and tab bar expansion
- **Maximum space utilization**: Font sizes calculated to use all available space
- **Responsive updates**: Immediate recalculation on orientation or layout changes

### Advanced Spacing and Alignment
- **Unified colon component**: Single ColonView with isHorizontal parameter for both orientations
- **Orientation-aware spacing**: Different spacing values for portrait vs landscape
- **Consistent segment spacing**: Uniform spacing between hours, minutes, seconds
- **Dot weight matching**: Colon dots scale with selected font weight
- **Overflow prevention**: Spacing calculations prevent content clipping
- **Perfect centering**: All elements centered both horizontally and vertically
- **Component consolidation**: Eliminated redundant HorizontalColon and VerticalColon views

### Full-Screen Mode Enhancements
- **Status bar hiding**: Status bar remains hidden while on the Clock tab
- **Tab bar expansion**: Clock expands into tab bar area when hidden
- **Safe area management**: Proper handling of Dynamic Island and other safe areas
- **Smooth transitions**: Animated transitions between normal and full-screen modes
- **Orientation support**: Full-screen mode works seamlessly in all orientations

## Technical Architecture

### Swift Package Architecture

TheNoiseClock has been refactored to use a modular Swift Package architecture for improved code reusability and maintainability:

#### AudioPlaybackKit Package
- **Purpose**: Reusable audio playback functionality for iOS and tvOS applications
- **Platform Support**: iOS 17.0+ and tvOS 17.0+
- **Core Components**:
  - `Sound` model: Generic sound data structure with Codable support and GUID generation
  - `SoundConfiguration` models: Configuration structures for sound management
  - `SoundConfigurationService`: Generic sound configuration service with JSON loading
  - `NoisePlayer`: Audio playback service with background support
  - `WakeLockService`: Screen wake lock management
  - `NoiseViewModel`: Audio playback state management
  - `AudioConstants`: Audio-related constants and configuration
- **Key Features**:
  - Generic sound management (no alarm-specific functionality)
  - Fatal error handling for missing configuration files
  - Platform-conditional compilation for tvOS compatibility
  - Modern @Observable state management
  - Background audio support with interruption handling

#### Package Integration
- **Local Package**: AudioPlaybackKit is included as a local Swift package dependency
- **Xcode Integration**: Properly configured in project.pbxproj with XCLocalSwiftPackageReference
- **Import Usage**: Main app imports AudioPlaybackKit for audio functionality
- **Separation of Concerns**: Generic audio functionality in package, app-specific logic in main app

#### App-Specific Extensions
- **AlarmSoundService**: Dedicated service in main app for alarm-specific sound management
- **Configuration Separation**: Alarm sounds use separate alarm-sounds.json file
- **Category Constants**: Hardcoded alarm category ID to avoid magic strings
- **Service Pattern**: Extension pattern for app-specific functionality

### Code Organization Principles

**TOP PRIORITY:** The codebase must be built with the following architectural principles from the beginning:

- **True Separation of Concerns:** 
  - Many small files with focused responsibilities
  - Each module/class should have a single, well-defined purpose
  - Avoid monolithic files with mixed responsibilities

- **View Structure Requirements:**
  - **Single View Per File:** Each SwiftUI view must be in its own file
  - **No Nested Views:** Views should not contain other view structs/classes in the same file
  - **Component Extraction:** Complex views must be broken down into smaller, reusable components
  - **Clean Main Views:** Main view files should only contain the primary view logic and helper methods
  - **Component Organization:** Supporting views should be placed in appropriate `Components/` subdirectories

- **Constants and Enums:**
  - Create constants, enums, and configuration objects to avoid duplicate code or values
  - Centralize magic numbers, strings, and configuration values
  - Use enums for type safety and clarity

- **Readability and Maintainability:**
  - Code should be self-documenting with clear naming conventions
  - Easy to understand, extend, and refactor
  - Consistent patterns throughout the codebase

- **Extensibility:**
  - Design for future growth and feature additions
  - Modular architecture that allows easy integration of new components
  - Clear interfaces between modules

- **Refactorability:**
  - Code structure should make future refactoring straightforward
  - Minimize coupling between components
  - Use dependency injection and abstraction where appropriate

These principles are fundamental to the project's long-term success and must be applied consistently throughout development.

### App Structure
- **Main App**: `TheNoiseClockApp.swift` - Entry point with WindowGroup
- **Branded launch**: AppLaunchView wrapped in a Color.Branding.primary ZStack
- **Tab-based navigation**: Three main tabs (Clock, Alarms, Noise)
- **SwiftUI framework**: Modern declarative UI framework with iOS 18+ and iOS 26 features
- **Dark theme**: Preferred color scheme set to dark

### Data Models
- **ClockStyle**: @Observable class for clock customization settings
  - Time format preferences (24-hour, seconds, AM/PM)
  - Visual settings (colors, glow, scale, opacity)
  - Overlay settings (battery, date, opacity)
  - Background settings
  - Type-safe font customization (FontFamily, Font.Weight, Font.Design enums)
  - Color caching for performance optimization
  - Persistent storage with JSON encoding/decoding and enum-to-string conversion
  - Backward compatibility for legacy string-based font settings
- **Alarm**: Codable struct for comprehensive alarm data
  - UUID identifier
  - Time and enabled state
  - Custom label and description
  - Repeat schedule (weekdays)
  - Sound name with volume control
  - Vibration settings
  - Snooze duration configuration
- **Sound** (AudioPlaybackKit): Generic sound data model with Codable support
  - Unique GUID identifier (auto-generated)
  - Display name and file name
  - Category and description
  - Optional bundle name for organization
  - Optional isDefault flag for default sound selection
  - Custom Codable implementation with GUID generation
- **SoundConfiguration** (AudioPlaybackKit): Configuration structure for sound management
  - Array of Sound objects
  - Sound categories and audio settings
  - JSON-based configuration loading
- **LegacyAlarm**: Backward compatibility struct for old alarm data

### Data Persistence
- **AppStorage**: ClockStyle settings persisted as JSON
- **UserDefaults**: Alarm data persisted as JSON
- **Bundle resources**: Audio files stored in app bundle

### Audio System
- **AudioPlaybackKit Package**: Reusable audio functionality in Swift package
- **AVFoundation**: AVAudioPlayer for noise playback
- **@Observable NoisePlayer**: Modern state management with preloading
- **Looping playback**: Infinite loop for ambient sounds
- **Audio session management**: Proper audio session configuration with background support
- **Error handling**: Fatal error handling for missing configuration files
- **AlarmTonePlayer**: Dedicated player for alarm sound previews
- **Background audio**: Continues playback when app is backgrounded
- **Interruption handling**: Automatic resume after phone calls and route changes
- **Wake lock integration**: Prevents device sleep during audio playback
- **Focus mode awareness**: Monitors and respects Focus mode settings
- **Notification compatibility**: Ensures alarms work with Focus modes enabled
- **Configuration separation**: Separate JSON files for ambient sounds (sounds.json) and alarm sounds (alarm-sounds.json)
- **Generic sound management**: AudioPlaybackKit provides generic sound functionality
- **App-specific extensions**: AlarmSoundService handles alarm-specific sound management

### Battery System
- **@Observable BatteryService**: Modern state management for battery monitoring
- **Real-time monitoring**: Continuous battery level and charging state tracking
- **UIDevice integration**: Native iOS battery monitoring with proper lifecycle management
- **Charging state detection**: Automatic detection of charging/not charging states
- **Color-coded display**: Dynamic color coding based on battery level (green/yellow/orange/red)
- **Icon management**: Dynamic battery icons with charging state indicators
- **Lifecycle management**: Automatic start/stop monitoring based on view visibility
- **Pure view architecture**: BatteryOverlayView is purely presentational with no business logic

### Notification System
- **UserNotifications**: iOS notification framework
- **Permission handling**: Automatic permission requests
- **Smart scheduling**: One-time and repeating alarm support
- **Calendar triggers**: Precise alarm scheduling with weekday support
- **Sound customization**: System sound selection with volume control
- **Multiple notifications**: Support for repeating alarms with unique identifiers

### Wake Lock System
- **WakeLockService**: Singleton service for managing screen wake lock
- **Display mode integration**: Automatically enables wake lock in full-screen display mode
- **Audio integration**: Enables wake lock during audio playback to prevent device sleep
- **Battery optimization**: Automatic wake lock management with proper cleanup
- **Timer-based maintenance**: Periodic wake lock refresh to ensure continuous operation
- **State management**: Tracks wake lock status and provides toggle functionality

### Focus Mode Integration
- **FocusModeService**: Comprehensive service for handling Focus mode interactions
- **Notification compatibility**: Ensures alarms work properly with Focus modes
- **Audio awareness**: Monitors Focus mode status for audio playback decisions
- **Permission management**: Requests notification permissions compatible with Focus modes
- **Alarm scheduling**: Uses Focus mode-aware notification scheduling
- **User settings**: Toggle to respect or override Focus mode restrictions
- **Guidance system**: Provides user instructions for optimal Focus mode configuration

## User Interface Design

### Navigation
- **TabView**: Three-tab interface (Clock, Alarms, Noise)
- **NavigationStack**: Modern navigation with back button support
- **Navigation destinations**: Deep linking for alarm editing
- **Toolbar integration**: Settings and add buttons in navigation bars
- **Sheet presentations**: Modal settings and alarm creation
- **Title presentation**: Inline titles on iPhone; titles hidden on iPad tab screens

### Visual Design
- **Rounded corners**: Modern iOS design language
- **Modern animations**: iOS 18+ smooth and bouncy animations
- **Color consistency**: Bedrock theme with branded surfaces and accents
- **Branded launch**: AppLaunchView with matching launch screen background
- **Accessibility**: Proper labels and hidden decorative elements
- **Card-based layouts**: Bedrock settings cards for grouping controls
- **Interactive controls**: Bedrock toggles, sliders, pickers, and color pickers

### Settings Interface
- **Bedrock layout**: Section headers with card-based grouping
- **Interactive controls**: SettingsToggle, SettingsSlider, menu pickers, color pickers
- **Type-safe font selection**: FontFamily.allCases, Font.Weight.allCases, Font.Design.allCases pickers
- **Real-time updates**: Changes apply immediately with live preview
- **Sheet presentation**: Full-screen settings sheet for uninterrupted editing
- **Enum-based architecture**: Type-safe picker selections eliminate string-based errors

## File Structure and Organization

### Recommended File Organization
Following the separation of concerns principle, the codebase is organized into focused, single-responsibility files with Swift Package integration:

```
TheNoiseClock/
├── README.md                        # App Store copy + project overview
├── AudioPlaybackKit/                    # Swift Package for reusable audio functionality
│   ├── Package.swift                    # Package configuration (iOS 17.0+, tvOS 17.0+)
│   └── Sources/AudioPlaybackKit/
│       ├── Models/
│       │   ├── Sound.swift              # Generic sound data model with Codable support
│       │   └── SoundConfiguration.swift # Sound configuration models and service
│       ├── Services/
│       │   ├── NoisePlayer.swift        # Audio playback service
│       │   └── WakeLockService.swift    # Screen wake lock management
│       ├── ViewModels/
│       │   └── NoiseViewModel.swift     # Audio playback state management
│       └── Constants/
│           └── AudioConstants.swift     # Audio-related constants
├── TheNoiseClock/                       # Main application
│   ├── App/
│   │   ├── TheNoiseClockApp.swift       # App entry point and configuration
│   │   └── ContentView.swift            # Main tab navigation coordinator
│   ├── Configuration/
│   │   ├── AppIdentifiers.swift         # xcconfig-backed identifiers
│   │   ├── Base.xcconfig                # Company/app identifiers
│   │   ├── Debug.xcconfig               # Debug settings
│   │   └── Release.xcconfig             # Release settings
│   ├── Shared/
│   │   ├── Design/
│   │   │   ├── BrandingConfig.swift     # Bedrock branding + launch config
│   │   │   ├── AppConstants.swift       # App-wide constants and configuration
│   │   │   ├── NoiseClockTheme.swift    # Bedrock app color theme
│   │   │   ├── Design+NoiseClock.swift  # App-specific Design extensions
│   │   │   └── Fonts/
│   │   │       ├── Font.Design.swift
│   │   │       ├── Font.Weight.swift
│   │   │       ├── FontFamily.swift
│   │   │       └── FontUtils.swift
│   │   ├── Extensions/
│   │   │   ├── Color+Extensions.swift   # Color utilities and extensions
│   │   │   ├── Date+Extensions.swift    # Date formatting and utilities
│   │   │   └── View+Extensions.swift    # Common view modifiers and responsive utilities
│   │   ├── Models/
│   │   │   └── SoundCategory.swift      # Shared sound category definitions
│   │   └── Utilities/
│   │       ├── ColorUtils.swift         # Color manipulation utilities
│   │       └── NotificationUtils.swift  # Notification helper functions
│   ├── Features/
│   │   ├── Clock/
│   │   │   ├── Models/
│   │   │   │   └── ClockStyle.swift
│   │   │   ├── State/
│   │   │   │   └── ClockViewModel.swift
│   │   │   ├── Services/
│   │   │   │   ├── AmbientLightService.swift
│   │   │   │   └── BatteryService.swift
│   │   │   └── Views/
│   │   │       ├── ClockView.swift
│   │   │       ├── ClockSettingsView.swift
│   │   │       └── Components/
│   │   │           ├── TimeDisplayView.swift
│   │   │           ├── TimeSegment.swift
│   │   │           ├── DigitView.swift
│   │   │           ├── ColonView.swift
│   │   │           ├── DotCircle.swift
│   │   │           ├── BatteryOverlayView.swift
│   │   │           ├── DateOverlayView.swift
│   │   │           ├── TopOverlayView.swift
│   │   │           ├── ClockDisplayContainer.swift
│   │   │           ├── ClockOverlayContainer.swift
│   │   │           ├── ClockGestureHandler.swift
│   │   │           ├── ClockTabBarManager.swift
│   │   │           ├── ClockToolbar.swift
│   │   │           ├── FullScreenHintView.swift
│   │   │           └── Settings/
│   │   │               ├── BasicAppearanceSection.swift
│   │   │               ├── BasicDisplaySection.swift
│   │   │               ├── AdvancedAppearanceSection.swift
│   │   │               ├── AdvancedDisplaySection.swift
│   │   │               ├── FontSection.swift
│   │   │               ├── NightModeSection.swift
│   │   │               ├── OverlaySection.swift
│   │   │               └── TimePickerView.swift
│   │   ├── Alarms/
│   │   │   ├── Models/
│   │   │   │   └── Alarm.swift
│   │   │   ├── State/
│   │   │   │   └── AlarmViewModel.swift
│   │   │   ├── Services/
│   │   │   │   ├── AlarmService.swift
│   │   │   │   ├── AlarmSoundService.swift
│   │   │   │   ├── FocusModeService.swift
│   │   │   │   ├── NotificationService.swift
│   │   │   │   └── NotificationDelegate.swift
│   │   │   └── Views/
│   │   │       ├── AlarmView.swift
│   │   │       ├── AddAlarmView.swift
│   │   │       ├── EditAlarmView.swift
│   │   │       └── Components/
│   │   │           ├── AlarmRowView.swift
│   │   │           ├── EmptyAlarmsView.swift
│   │   │           ├── LabelEditView.swift
│   │   │           ├── NotificationMessageEditView.swift
│   │   │           ├── SnoozeSelectionView.swift
│   │   │           ├── SoundSelectionView.swift
│   │   │           ├── TimePickerSection.swift
│   │   │           └── TimeUntilAlarmSection.swift
│   │   └── Noise/
│   │       └── Views/
│   │           ├── NoiseView.swift
│   │           └── Components/
│   │               ├── SoundCategoryView.swift
│   │               └── SoundControlView.swift
│   └── Resources/
│       ├── LaunchScreen.storyboard      # Branded native launch screen
│       ├── sounds.json                  # Ambient sound configuration and definitions
│       ├── alarm-sounds.json            # Alarm sound configuration and definitions
│       ├── Ambient.bundle/              # Ambient sound category
│       │   └── white-noise.mp3
│       ├── Nature.bundle/               # Nature sound category
│       │   └── heavy-rain-white-noise.mp3
│       ├── Mechanical.bundle/           # Mechanical sound category
│       │   └── fan-white-noise-heater.mp3
│       ├── AlarmSounds.bundle/          # Alarm sound category
│       │   ├── digital-alarm.caf
│       │   ├── classic-alarm.caf
│       │   ├── beep-alarm.caf
│       │   ├── siren-alarm.caf
│       │   └── buzzing-alarm.caf
│       └── Assets.xcassets/
│           └── [Asset catalogs]
└── TheNoiseClock.xcodeproj/             # Xcode project with AudioPlaybackKit dependency
    └── project.pbxproj                  # Project configuration with local package reference
```

### File Naming Conventions
- **Views**: Use descriptive names ending in `View` (e.g., `ClockView`, `AlarmRowView`)
- **ViewModels**: End with `ViewModel` (e.g., `ClockViewModel`, `AlarmViewModel`)
- **Services**: End with `Service` (e.g., `AlarmService`, `NotificationService`)
- **Models**: Use noun names (e.g., `Alarm`, `Sound`, `ClockStyle`)
- **Extensions**: Use `Type+Extensions` format (e.g., `Color+Extensions`)
- **Constants**: Use descriptive names ending in `Constants` (e.g., `AppConstants`)

### Code Organization Best Practices
- **Single Responsibility**: Each file should have one clear purpose
- **Dependency Injection**: Use protocols and dependency injection for testability
- **Protocol-Oriented Design**: Define protocols for services and data sources
- **Error Handling**: Centralized error types and handling patterns
- **Testing**: Separate test targets with comprehensive coverage

### Documentation Maintenance Requirements

**CRITICAL:** The PRD must be kept up-to-date with all code changes. The following procedures are mandatory:

#### Automatic PRD Updates
- **Every code change** that affects architecture, features, or file structure **MUST** include a corresponding PRD update
- **AI Assistant Responsibility**: When making code changes, the AI assistant must automatically:
  1. **Identify PRD sections** that need updating based on the changes made
  2. **Update relevant sections** without being asked
  3. **Add new features** to the appropriate feature sections
  4. **Update file structure** when new files or components are created
  5. **Document new requirements** or architectural decisions
  6. **Maintain consistency** between code and documentation

#### PRD Update Triggers
The following changes **automatically require** PRD updates:
- **New files or components** → Update file structure section
- **New features or functionality** → Update core features section
- **Architectural changes** → Update code organization principles
- **New services or models** → Update technical architecture
- **UI/UX changes** → Update user interaction sections
- **Configuration changes** → Update technical requirements
- **Bundle or resource changes** → Update resources section

#### Documentation Standards
- **Real-time updates**: PRD updates should happen in the same conversation as code changes
- **Comprehensive coverage**: All aspects of changes must be documented
- **Version consistency**: Code and documentation must always be in sync
- **No manual requests**: Users should not need to ask for PRD updates

## Key User Interactions

### Clock Tab
1. **View time**: Real-time clock display
2. **Access settings**: Tap gear icon in navigation bar
3. **Enter display mode**: Long-press anywhere on clock (0.6 seconds)
4. **Exit display mode**: Long-press again to return to normal mode

### Settings
1. **Time format**: Toggle 24-hour, seconds, AM/PM display
2. **Appearance**: Adjust colors, glow, size, opacity
3. **Display**: Control keep awake functionality for display mode
4. **Focus Modes**: Control how app behaves with Focus modes (Do Not Disturb)
5. **Overlays**: Control battery and date display
6. **Background**: Set background color and use presets

### Alarms Tab
1. **View alarms**: List of all created alarms with labels and repeat schedules
2. **Add alarm**: Tap + button to create new alarm with full editor
3. **Edit alarm**: Tap any alarm to open comprehensive editor
4. **Toggle alarm**: Use switch to enable/disable
5. **Delete alarm**: Swipe to delete or use delete button in editor
6. **Alarm editor features**:
   - Time picker with next trigger preview
   - Custom label editing
   - Repeat schedule selection
   - Sound picker with live preview
   - Volume and vibration controls
   - Snooze duration settings

### Noise Tab
1. **Sound Selection**: Browse sounds by category with system search in the navigation bar (iPhone and iPad)
2. **Sound Preview**: Long-press for 3-second preview
3. **Visual Feedback**: Grid layout with clear selection states
4. **Auto-stop**: Automatically stops current sound when selecting new one
5. **Play/Stop Controls**: Simple button with visual feedback
6. **Continuous playback**: Sounds loop until stopped
7. **Empty state guidance**: Prompt shown when no sound is selected
8. **Responsive layout**: Optimized for portrait and landscape orientations

## Technical Requirements

### iOS Compatibility
- **Minimum iOS version**: iOS 18.0+ (Latest SwiftUI features and performance optimizations)
- **Target devices**: iPhone and iPad with full adaptive layout support
- **Orientation support**: Portrait and landscape with dynamic type support
- **Accessibility**: Full VoiceOver and Dynamic Type support

### Modern iOS Technology Stack
- **SwiftUI**: Latest declarative UI framework with iOS 18+ and iOS 26 features
- **Observation Framework**: Modern @Observable pattern for state management
- **SwiftData**: Advanced data persistence with iOS 18+ SwiftData features
- **Async/Await**: Modern concurrency patterns throughout
- **Structured Concurrency**: Task groups and actors for complex operations
- **Swift 6**: Latest language features and safety improvements
- **iOS 26 Features**: Latest platform capabilities where available

### Dependencies
- **AudioPlaybackKit**: Local Swift package for reusable audio functionality
  - iOS 17.0+ and tvOS 17.0+ support
  - Generic sound management and configuration
  - Audio playback with background support
  - Wake lock management
  - Modern @Observable state management
- **Bedrock**: Local Swift package for design system and settings UI
  - App-wide theming with color providers
  - Branded launch experience and icon tooling
  - Reusable settings components (cards, toggles, sliders)
- **SwiftUI**: Native iOS UI framework with latest features
- **AVFoundation**: Audio playback with modern async patterns and background support
- **UserNotifications**: Alarm notifications with rich content support
- **Combine**: Timer publishers and reactive programming
- **Observation**: Modern state management with @Observable
- **Foundation**: Core system frameworks and utilities
- **UIKit**: UIFont integration for precise text measurement and font customization
- **UIApplication**: Screen wake lock management and idle timer control

### Build Configuration
- **xcconfig**: Centralized identifiers (bundle IDs, team ID, app groups)
- **Info.plist bridge**: App identifiers exposed via AppIdentifiers.swift

### Advanced Font and Typography Utilities
- **FontFamily enum**: Type-safe font family selection with allCases support
- **Font.Weight extension**: Enhanced weight enum with allCases and uiFontWeight properties
- **Font.Design extension**: Enhanced design enum with allCases and uiFontWidth properties
- **FontUtils.calculateOptimalFontSize()**: Binary search algorithm for precise font sizing
- **FontUtils.tightBoundingBox()**: Accurate text measurement with minimal padding
- **FontUtils.createUIFont()**: Creates UIFont instances with proper weight and design mapping
- **FontUtils.weightedFontName()**: Constructs proper font names for custom fonts
- **FontUtils.stringFromFontWeight()**: Converts Font.Weight enum to display strings
- **FontUtils.stringFromFontDesign()**: Converts Font.Design enum to display strings
- **Legacy compatibility methods**: Backward compatibility for existing code
  - FontUtils.optimalFontSize() and maximumStretchedFontSize()
  - FontUtils.customFont() and customUIFont()
  - FontUtils.dotSizeMultiplier() and timePickerFontSize()

### Performance Considerations
- **Smart timer management**: Conditional timers based on settings
- **Debounced persistence**: Batched UserDefaults writes
- **Memory management**: Proper cleanup of audio players
- **Battery optimization**: Efficient update mechanisms
- **Color caching**: Avoid repeated hex-to-Color conversions
- **Dictionary lookups**: O(1) alarm access instead of linear search
- **Smooth animations**: Hardware-accelerated transitions
- **Preloaded audio**: Instant sound playback
- **Binary search font sizing**: O(log n) font size calculation for optimal performance
- **Tight bounding box calculations**: Precise text measurement with minimal overhead
- **Dynamic font sizing**: Real-time font optimization based on container geometry
- **Component consolidation**: Reduced view hierarchy with unified ColonView
- **Type-safe enums**: Compile-time safety eliminates runtime string conversion overhead
- **Orientation-aware sizing**: Optimized font sizing algorithms for different orientations

## Recent Architectural Improvements

### Font System Refactoring (September 2025)
- **Type-Safe Font Architecture**: Migrated from string-based font selection to enum-based system
  - FontFamily enum with 10 font options (System, Helvetica, Arial, Times New Roman, Georgia, Verdana, Courier, Futura, Avenir, Roboto)
  - Font.Weight extension with allCases support and uiFontWeight mapping
  - Font.Design extension with allCases support and uiFontWidth mapping
- **Advanced Font Sizing**: Implemented binary search algorithm for optimal font sizing
  - calculateOptimalFontSize() with tight bounding box calculations
  - Real-time font size optimization based on container geometry
  - Precise text measurement with minimal padding and spacing
- **Component Consolidation**: Unified colon separator components
  - Replaced HorizontalColon and VerticalColon with single ColonView
  - Added isHorizontal boolean parameter for orientation control
  - Reduced code duplication by ~80 lines
- **Backward Compatibility**: Maintained compatibility with existing code
  - Legacy methods preserved for existing functionality
  - String-to-enum conversion in ClockStyle for UserDefaults persistence
  - Gradual migration path for all font-related components

### Code Quality Improvements
- **Enum-Based Architecture**: Eliminated string-based font selection errors
- **Type Safety**: Compile-time safety for font family, weight, and design selection
- **Performance Optimization**: O(log n) font sizing with binary search
- **Maintainability**: Single source of truth for font options with allCases
- **User Experience**: Real-time font preview with immediate visual feedback

## Future Enhancement Opportunities
- **Additional sound types**: More white noise variants
- **Sleep timer**: Auto-stop noise after specified time
- **Widget support**: Home screen clock widget
- **Apple Watch companion**: Watch app for quick time check
- **In-app purchases**: Premium sound packs
- **Custom sounds**: User-imported audio files
- **Multiple time zones**: World clock functionality
- **Alarm categories**: Group alarms by type (work, sleep, etc.)
- **Smart alarms**: Gradual volume increase
- **Weather integration**: Weather-based alarm sounds
- **Health integration**: Sleep tracking integration

## Build and Development

### Terminal Build Commands

The following terminal commands are used for building and testing the project. These commands have been tested and work reliably:

#### Basic Build Commands
```bash
# Navigate to project directory
cd /Users/mattbruce/Documents/Projects/TheNoiseClock

# Build for iOS Simulator (iPad mini)
xcodebuild -project TheNoiseClock.xcodeproj -scheme TheNoiseClock -destination 'platform=iOS Simulator,name=iPad mini (A17 Pro),OS=18.1' build

# Build for iOS Simulator (any device)
xcodebuild -project TheNoiseClock.xcodeproj -scheme TheNoiseClock -destination 'platform=iOS Simulator,name=Any iOS Simulator Device' build

# Build for physical device (requires provisioning profile)
xcodebuild -project TheNoiseClock.xcodeproj -scheme TheNoiseClock build
```

#### Error Checking Commands
```bash
# Check for build errors only (filtered output)
xcodebuild -project TheNoiseClock.xcodeproj -scheme TheNoiseClock -destination 'platform=iOS Simulator,name=iPad mini (A17 Pro),OS=18.1' build 2>&1 | grep -E "(error:|warning:|failed)" | head -10

# Quick syntax check for specific files
swift -frontend -parse TheNoiseClock/Views/Clock/Components/TimeDisplayView.swift
swift -frontend -parse TheNoiseClock/Views/Clock/Components/TimeSegment.swift
swift -frontend -parse TheNoiseClock/Views/Clock/Components/DigitView.swift
```

#### Available Simulators
The following simulators are available for testing:
- **iPad mini (A17 Pro)** - Primary testing device
- **iPad (10th generation)**
- **iPad Air 11-inch (M2)**
- **iPad Air 13-inch (M2)**
- **iPad Pro 11-inch (M4)**
- **iPad Pro 13-inch (M4)**
- **iPhone 16, 16 Plus, 16 Pro, 16 Pro Max**
- **iPhone SE (3rd generation)**

#### Build Troubleshooting
1. **Provisioning Profile Errors**: Use iOS Simulator builds instead of device builds
2. **Missing Files**: Ensure all new Swift files are added to the Xcode project target
3. **Preview Compilation Errors**: Break down complex expressions into computed properties
4. **Package Dependencies**: AudioPlaybackKit is included as local package dependency

#### Development Workflow
1. **Make code changes** in Xcode or via AI assistant
2. **Test build** using terminal commands above
3. **Fix any errors** identified in build output
4. **Test on simulator** using Xcode or terminal build
5. **Update PRD** if architectural changes are made

## Development Notes

### Project Information
- **Created**: September 7, 2025
- **Framework**: SwiftUI with iOS 18.0+ target (latest stable features)
- **Architecture**: Modern SwiftUI with @Observable pattern, MVVM, and Swift Package modularity
- **Package Architecture**: AudioPlaybackKit Swift package for reusable audio functionality
- **Testing**: Comprehensive unit and UI test targets with Swift Testing
- **Version control**: Git repository with feature branch workflow
- **Performance**: Optimized for battery life and smooth operation
- **Modern iOS**: Uses latest iOS 18+ and iOS 26 features with Swift 6 language improvements
- **Code Reusability**: Modular Swift package architecture enables code reuse across projects

### Modern iOS Development Practices
- **Swift 6**: Latest language features including strict concurrency checking
- **Async/Await**: Modern concurrency patterns throughout the codebase
- **Observation Framework**: @Observable for reactive state management
- **SwiftUI Navigation**: Latest NavigationStack and navigation APIs with iOS 18+ features
- **Accessibility**: Full VoiceOver and Dynamic Type support with iOS 26 enhancements
- **Adaptive Layout**: Support for all device sizes and orientations
- **Performance**: Optimized for 120Hz ProMotion displays and iOS 26 performance improvements
- **Memory Management**: ARC with proper weak references and cleanup
- **Error Handling**: Result types and proper error propagation
- **Testing**: Swift Testing framework for modern test writing
- **iOS 26 Integration**: Latest platform features and capabilities where applicable

### Code Quality Standards
- **SwiftLint**: Automated code style enforcement
- **Documentation**: Comprehensive inline documentation with DocC
- **Type Safety**: Leverage Swift's type system for compile-time safety
- **Protocol-Oriented**: Use protocols for abstraction and testability
- **Dependency Injection**: Constructor injection for better testability
- **SOLID Principles**: Single responsibility, open/closed, dependency inversion