TempoRep

A minimal, high-contrast tempo training timer for strength workouts, built with SwiftUI (iOS 17+).

In tempo training every rep follows a 4-part tempo like 4010, shown in the app as ↓4·0·↑1·0:

Position	Phase	Meaning
1st	Eccentric	lowering, in seconds
2nd	Pause	at the bottom
3rd	Concentric	lifting — 0 means explosive, timed as 1 s
4th	Pause	at the top

Each value goes in half-second steps (0–9), so ↓3·0·↑1.5·0 is valid too.

Features

• Tempo input as 4 digits with half-second precision (e.g. 1.5s), a toggle for which phase a rep starts with (eccentric or concentric), and a Reverse Direction option for exercises where the motion runs "the other way" visually (a lat pulldown's concentric phase pulls down) — swaps which arrow/voice-word marks which phase without changing what the digits mean or how long anything takes. The compact setup-screen steppers are for quick nudges; a "Custom Tempo" screen (via the ⓘ next to them) has one spacious row per phase with a description, plus Start-with and Reverse Direction in one place
• Reps per set, number of sets, rest between sets
• Huge phase name, readable from across the room — tinted violet during eccentric (lowering), blue during get-ready, and accent green during concentric (lifting) and everything else, with a brief colored flash at the top edge on every phase change (skipped under Reduce Motion)
• Live pacing track during a rep: a glowing dot rides a vertical line — descending through the eccentric, breathing at the stretched end, driving back up through the concentric — with the four tempo values beside it and the running one lit and enlarged. The dot's position is interpolated from the engine's wall-clock progress rather than a SwiftUI animation, so it can never disagree with the countdown or the spoken cue; an explosive (0/0.5) concentric gets a hard ease-out that visibly launches, while a 2s+ concentric stays linear because a controlled lift should look controlled. Honors Reverse Direction by mirroring the track. The countdown ring still appears during get-ready, rest and side-switch — the waiting phases
• Tempo shown as directional notation (↓4·0·↑1.5·0) everywhere it's displayed — arrows mark eccentric/concentric (reversed per-preset/session via Reverse Direction), dots separate the four digits — instead of a bare digit string
• Distinct sound + haptic cues for phase changes (single tap), rep completion (double tap), and set completion (triple ascending tap) — built with Core Haptics for genuinely different felt patterns, not just different impact intensities; falls back to plain UIImpactFeedbackGenerator/UINotificationFeedbackGenerator on hardware without a custom-haptics-capable Taptic Engine
• Haptic feedback throughout the UI too: steppers, toggles, pickers, presets, and the Start/Pause/Stop/Continue buttons (haptics only fire on a real device — the simulator can't drive the Taptic Engine at all)
• Localized in English, Dutch, French, and German — follows the iOS system language by default, with an override in Settings
• Optional voice countdown (toggle in Settings): spoken "Down / Hold / Up" per language, counted per second through multi-second phases (e.g. "Down, 2, 3, 4" for a 4s eccentric), "Rest", and a 3-2-1 lead-in before each set — uses a matching AVSpeechSynthesisVoice for the current language by default, or a specific installed voice picked in Settings (with an instant spoken preview, and each language remembering its own choice)
• Background audio mode: cues keep playing when the app is backgrounded or the screen is locked, and your music (Spotify etc.) keeps playing alongside
• Unilateral (single-side) mode: does all reps for one side, a switch pause, then all reps for the other side, within the same set — rest between sets only starts once both sides are done
• Bundled exercise database (873 exercises from the public-domain free-exercise-db, no network calls): searchable picker with a filter sheet (muscle/equipment), a favorites star per exercise, and a recents list; picking an exercise suggests unilateral mode, starting phase (deadlifts/pull-ups lead with the concentric phase), and a starting tempo for its primary muscle group (e.g. slower eccentric + explosive concentric for calves/arms) — always shown as an overridable suggestion, never applied silently once you've changed the digits yourself; or skip it and run a bare timer
• Presets (4 built-in — Squat, Push-Up, Single-Leg RDL, Deadlift — plus any you save) set exercise + tempo + reps + sets + rest + unilateral + direction settings all at once; long-press a saved one to delete it. Save a few tempos for the same exercise (e.g. one per training phase) and the presets row narrows to just that exercise's presets once it's selected. A preset whose tempo matches the selected exercise's own suggestion is badged "Recommended"
• Automatic rest countdown between sets
• Pause/resume and stop
• Settings (tempo, reps, sets, rest, voice) are remembered between launches
• Workout history: finished workouts are logged with exercise (if one was picked), tempo, sets × reps, and time under tension (shown as "15s" under a minute, "1:30" once it isn't, to avoid an ambiguous bare "0:15")
• Finish screen shows a checkmark animation, correctly-pluralized sets/reps ("1 rep", not "1 reps"), and time under tension for that workout
• Screen stays awake during a workout
• The workout screen supports landscape (phone propped on a shelf, in a stand, etc.) with an adapted side-by-side layout; every other screen stays portrait-only — see OrientationLock.swift
• Settings, History, and the exercise picker are plain native Form/List sheets (system materials, resizable via .presentationDetents) with the system's standard round close button, not a text "Done"; they follow the system light/dark appearance, while the workout screen and launch splash are deliberately always dark (see WorkoutView's doc comment)
• Every color, font, spacing, corner-radius, stroke width, letter-spacing, opacity, and animation value in the UI comes from one design-token file (DesignSystem.swift) — semantic tokens, a 4/8/12/16/24/32 spacing scale, and Dynamic Type text styles throughout (the oversized workout-display digits scale via @ScaledMetric instead, since they're bigger than any standard text style). Scripts/check-design-tokens.sh fails CI if any screen hardcodes one of those values instead, so this stays true for screens added later
• VoiceOver: tempo digit steppers and counters (reps/sets/rest/switch time) present as single adjustable elements with real labels, not unlabeled +/- buttons; the workout screen announces phase changes via UIAccessibility.post independent of the optional voice-cue feature; Reduce Motion replaces the finish-screen checkmark's pop-in with a plain crossfade
• Drift-free timing: state is derived from wall-clock elapsed time, not accumulated timer ticks
• Cues play even when the phone is on silent (.playback audio session category)
• No network access, no accounts, no tracking, no third-party SDKs — everything lives in local UserDefaults and the bundled exercise dataset (see PrivacyInfo.xcprivacy and PRIVACY_POLICY.md)

Requirements

• Xcode 16 or newer (the project uses the Xcode 16 project format)
• iOS 17+ deployment target

Running in the simulator

1. Open TempoRep.xcodeproj in Xcode
2. Select the TempoRep scheme and any iPhone simulator
3. Press ⌘R

Or from the command line:

xcodebuild build -project TempoRep.xcodeproj -scheme TempoRep \
  -destination 'platform=iOS Simulator,name=iPhone 16' CODE_SIGNING_ALLOWED=NO

Note: haptics don't fire in the simulator — run on a device to feel them. To run on a device, set your development team under Signing & Capabilities first.

Running the tests

Press ⌘U in Xcode, or from the command line:

xcodebuild test -project TempoRep.xcodeproj -scheme TempoRep \
  -destination 'platform=iOS Simulator,name=iPhone 16,OS=latest' CODE_SIGNING_ALLOWED=NO

TempoRepTests covers the timeline-building logic in WorkoutEngine.buildTimeline (bilateral/unilateral/switch-pause/zero-duration-phase-skipping/start-phase reordering), WorkoutConfig's Codable round-trip, the bundled exercise dataset, preset application, and localization catalog completeness across all 4 languages.

Project layout

TempoRep/
  TempoRepApp.swift              App entry point
  DesignSystem.swift          THE design token file — every color, spacing, radius, size, typography, tracking, opacity and motion value; nothing else may hardcode these
  Models/WorkoutModels.swift  Config, phases, timeline segments
  Models/Exercise.swift       Bundled exercise-database entry
  Models/WorkoutPreset.swift  Built-in and user-saved exercise+settings presets
  Engine/WorkoutEngine.swift  Elapsed-time-driven workout state machine
  Services/SoundPlayer.swift  Synthesized beep cues via AVFoundation
  Services/SpeechPlayer.swift  Voice cues via AVSpeechSynthesizer
  Services/VoicePreferenceStore.swift  Per-language chosen speech voice, persisted
  Services/HapticsPlayer.swift  UIKit feedback generators
  Services/HistoryStore.swift  Persisted log of completed workouts
  Services/LocalizationManager.swift  System-language / override language resolution
  Services/ExerciseDatabase.swift  Loads the bundled dataset, tracks recents
  Services/PresetStore.swift  Persisted log of user-saved presets
  Views/SplashView.swift      Brief launch screen with the wordmark
  Views/SetupView.swift       Tempo/reps/sets/rest/exercise configuration
  Views/CustomTempoView.swift  Spacious per-phase tempo editor, start-phase and reverse-direction options
  Views/WorkoutView.swift     In-workout display and controls, with a landscape layout
  Views/TempoPacingView.swift  Vertical pacing track + live tempo digits shown during a rep
  Services/OrientationLock.swift  Runtime portrait lock, released only while WorkoutView is on screen
  Views/HistoryView.swift     Workout history sheet
  Views/SettingsView.swift    Language override, voice countdown toggle, per-language speech voice picker
  Views/ExercisePickerView.swift  Searchable exercise picker
  Views/CloseButton.swift     Shared round "xmark.circle.fill" sheet-dismiss button
  Resources/exercises.json    Bundled exercise dataset (name/category/muscles/equipment, no images)
  Localizable.xcstrings       String catalog (en, nl, fr, de)
  PrivacyInfo.xcprivacy       Privacy manifest — no tracking, no collected data

TempoRepTests/
  WorkoutEngineTests.swift    Timeline-building logic (bilateral/unilateral/switch/reordering)
  WorkoutConfigTests.swift    Codable round-trip, computed properties
  WorkoutPresetTests.swift    Preset application and persistence shape
  ExerciseDatabaseTests.swift  Bundled dataset loads correctly, no duplicate IDs
  LocalizationCatalogTests.swift  Every checked key resolves in all 4 languages
  VoicePreferenceStoreTests.swift  Per-language voice override persistence and lookup

fastlane/metadata/           App Store listing text (name/subtitle/description/keywords) in en-US/nl-NL/fr-FR/de-DE
Scripts/check-design-tokens.sh  CI guard: fails if a screen hardcodes a design value instead of using a token
PRIVACY_POLICY.md            Ready-to-host privacy policy draft
APP_STORE_SUBMISSION.md      Checklist of what's done vs. what you still need to do before submitting
UI_MODERNIZATION.md          Design-system audit, native-iOS-26 pass, and the Live Activity proposal