fix(timer): restart completed timer from typed duration

[ryota-murakami]

Summary

• Restart completed timers from the selected typed duration instead of stale timeRemaining: 0
• Keep zero-duration starts inert
• Add an E2E regression for restarting after completion without pressing +/- stepper buttons

Root cause

After a timer completed, timeRemaining became 0 while initialTime still held the typed duration shown in the Minutes/Seconds inputs. start() used only timeRemaining, so Start briefly entered running state with a 0-second target and immediately completed again.

Tests

• pnpm lint
• pnpm typecheck
• pnpm exec playwright test e2e/timer-behavior.spec.ts -g "completed timer restarts" --project="Desktop Chrome"
• pnpm exec playwright test e2e/timer-behavior.spec.ts --project="Desktop Chrome"
• pnpm e2e:desktop
• pnpm build

Summary by CodeRabbit

• New Features

  • Timer now resumes from the last entered duration when started again, even after finishing, without needing to adjust controls.
  • Default timer length is standardized to five minutes.

• Bug Fixes

  • Improved timer countdown behavior so elapsed and remaining time stay accurate when starting, pausing, and completing.
  • Added coverage to verify completed timers can be restarted using the previously entered time.

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Project	Deployment	Actions	Updated (UTC)
coffee-timer	Ready	Preview, Comment	Jun 24, 2026 11:49am

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 5a9b4a6f-8acf-4b89-980e-5426fad40908

📥 Commits

Reviewing files that changed from the base of the PR and between fc0a870 and b4ea92a.

📒 Files selected for processing (3)

• e2e/timer-behavior.spec.ts
• lib/constants/time.ts
• lib/stores/timerStore.ts

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📝 Walkthrough

Walkthrough

Extracts MILLISECONDS_PER_SECOND and DEFAULT_TIMER_SECONDS constants into lib/constants/time.ts, replaces hardcoded literals throughout timerStore, adds a getStartDurationSeconds helper that resumes from the last typed duration on restart, and adds an e2e test verifying a completed timer restarts from the previously entered time.

Changes

Timer restart-from-typed-duration

Layer / File(s)	Summary
New constants and store initialization lib/constants/time.ts, lib/stores/timerStore.ts	Exports MILLISECONDS_PER_SECOND and DEFAULT_TIMER_SECONDS; updates the store's import group and replaces the hardcoded 300 initial values with DEFAULT_TIMER_SECONDS.
getStartDurationSeconds helper and reworked start() lib/stores/timerStore.ts	Adds getStartDurationSeconds(timeRemaining, initialTime) to pick the countdown length on restart, guards against <= 0 durations by zeroing state, and computes targetEndTime via MILLISECONDS_PER_SECOND.
MILLISECONDS_PER_SECOND in pause/tick/updateTimeRemaining + e2e test lib/stores/timerStore.ts, e2e/timer-behavior.spec.ts	Replaces inline 1000 literals with MILLISECONDS_PER_SECOND in all remaining ms-to-seconds conversions; adds a Playwright test that types 00:02, waits for completion, confirms inputs retain 00/02, and restarts to verify the timer counts from the typed duration.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 Tick tock, the bunny said,
The timer stopped, but don't feel dread!
Just press Start once more, hooray —
It hops from where you typed that day.
No stepper needed, constants shine,
Two seconds, then we're doing fine! 🕐

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: restarting a completed timer from the typed duration.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/fix-completed-timer-restart

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