FocusFlow Dev Log #1: Building the Timer Core

This week, I built the foundation of FocusFlow's Pomodoro timer using SwiftUI and Combine. Here's what I learned and what's next.

This Week's Progress

Built the foundation of FocusFlow's Pomodoro timer using SwiftUI and Combine. The core functionality is working, but there were some interesting challenges along the way.

Architecture Decisions

Timer State Management

@Published var timerState: TimerState = .idle
@Published var secondsRemaining: Int = 1500 // 25 minutes

Used Combine's Timer.publish for accurate countdown. Had to handle edge cases around:

• App backgrounding
• Timer precision on older devices
• State restoration after force quit

Background Audio

The trickiest part was keeping the timer running when the app is backgrounded. iOS has strict rules here. Solution:

• Background audio capability
• Silent audio track to keep app alive
• Local notifications for timer completion

UI Implementation

Clean, minimal design with:

• Large circular progress indicator
• Start/Pause/Reset controls
• Interval configuration (work/break durations)

SwiftUI's Canvas API made the circular timer beautiful and performant.

Metrics

• Lines of code: ~800
• Time spent: 12 hours
• Tests written: 15 unit tests
• Crashes: 0 (so far!)

Next Week

• Add ambient soundscapes (rain, cafe noise, forest)
• Implement audio mixing
• TestFlight beta to 10 users

Lessons Learned

1. Background execution is hard: iOS's strict background policies require creative solutions
2. Combine is powerful: Once you grok publishers, timer logic becomes elegant
3. Test early: Unit tests caught 3 timing bugs before they became issues

Stay tuned for next week's update on audio implementation!