fix(timeline): roll playhead seconds into the next minute

[soufian3hm]

Summary

formatPlayheadTime rounds the seconds component independently of the minutes/hours, so a time that rounds up to 60.0 does not carry into the next minute. During playback/scrubbing the editor's playhead clock then renders invalid labels.

Root cause

const s = ms / 1000;
const min = Math.floor(s / 60);
const sec = s % 60;          // e.g. 59.97
// sec.toFixed(1) -> "60.0", but `min` was already computed

(59.97).toFixed(1) becomes "60.0", which is appended to the already-computed minute.

Observed (before)

input (ms)	output	expected
59950	60.0s	1:00.0
59970	60.0s	1:00.0
119970	1:60.0	2:00.0

Fix

Round to the displayed precision (tenths of a second) first, then split into minutes/seconds so any carry rolls into the minute correctly. Existing outputs (1234 -> 1.2s, 61400 -> 1:01.4) are unchanged.

Tests

Added a regression test covering the rollover boundary. Full time.test.ts suite passes (7/7).

Risk

Minimal — pure display formatting, no behavioural change outside the rounding boundary; existing assertions preserved.

Summary by CodeRabbit

Release Notes

• Bug Fixes

  • Corrected video editor timeline playhead time formatting to properly round values near minute transitions, preventing display inconsistencies when time approaches 60 seconds.

• Tests

  • Added unit test to validate playhead time rounding behavior at minute boundaries.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: a69f1c28-d657-4fa9-a854-4aa2fe034b19

📥 Commits

Reviewing files that changed from the base of the PR and between 52dd842 and 4ac4b7d.

📒 Files selected for processing (2)

• src/components/video-editor/timeline/core/time.test.ts
• src/components/video-editor/timeline/core/time.ts

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📝 Walkthrough

Walkthrough

The PR fixes a rounding inconsistency in playhead time formatting. formatPlayheadTime now pre-rounds milliseconds to tenths of a second before computing minutes and seconds, ensuring that values near the 60-second threshold carry over into the next minute cleanly. A test validates this behavior.

Changes

Playhead Time Rounding

Layer / File(s)	Summary
Playhead time rounding and test src/components/video-editor/timeline/core/time.ts, src/components/video-editor/timeline/core/time.test.ts	formatPlayheadTime now rounds milliseconds to tenths of a second before deriving minutes and remaining seconds, preventing edge cases where values just under 60 seconds render with carry inconsistencies. A test case validates that near-60-second values (e.g., 59.950, 59.970 ms) round correctly into the next minute (1:00.0) format.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 A playhead near sixty did stumble and sway,
But rounding first fixes what formatting couldn't convey!
Now fifty-nine point-nine-seven rolls to one:zero,
No more six-zero nonsense—this fix is a hero! ✨

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The PR description covers the problem, root cause with code example, observed vs expected behavior, the fix approach, tests added, and risk assessment. However, it does not follow the repository's template structure with required sections like Type of Change checkbox, Related Issue(s), Screenshots/Video, and Testing Guide.	Restructure the description to match the template: add Type of Change (Bug Fix), Related Issue(s) section, optional Screenshots/Video sections, and a Testing Guide with step-by-step reproduction instructions.
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'fix(timeline): roll playhead seconds into the next minute' clearly summarizes the main fix: ensuring rounded seconds carry into the next minute.
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 unit tests (beta)

• Create PR with unit tests

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