Add video event model (toVideoEvents, assignEventLanes)

[horatiualmasan]

What has changed and why?

Adds a small, UI-agnostic utility layer for temporal video events, the foundation for the event bar on the video timeline. toVideoEvents maps classification annotations that carry a temporal span (e.g. ActivityNet-style imports) into sorted VideoEvents with label-derived colors; assignEventLanes greedily packs overlapping events into separate lanes so none hides another. Pure functions with no component dependencies, so they can be reused for any temporal-annotation source.

How has it been tested?

Unit tests in videoEvents.test.ts cover filtering, mapping, sorting, and lane assignment (including overlap cases).

Did you update CHANGELOG.md?

• Yes
• Not needed (internal change)

Summary by CodeRabbit

• New Features

  • Added support for converting classification annotations with time spans into sorted video timeline events.
  • Added automatic event lane assignment so overlapping events display on separate rows while reusing available lanes.
  • Added deterministic event colors and improved label contrast for timeline visualization.

• Tests

  • Added coverage for event conversion, sorting, filtering, overlap handling, and lane reuse.

[coderabbitai]

📝 Walkthrough

Walkthrough

Changes

Video event utilities

Layer / File(s)	Summary
Event transformation contract and implementation lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts, lightly_studio_view/src/lib/utils/videoEvents/videoEvents.test.ts, lightly_studio_view/src/lib/utils/index.ts	Defines video event types, converts eligible classification annotations with temporal spans into sorted events, derives colors, tests the transformation, and exports the utilities and types.
Lane allocation and validation lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts, lightly_studio_view/src/lib/utils/videoEvents/videoEvents.test.ts	Assigns overlapping events to separate lanes, reuses available lanes, reports the lane count, and tests allocation behavior.

Estimated code review effort: 2 (Simple) | ~15 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise and accurately summarizes the main change: adding the video event model utilities.
Description check	✅ Passed	The description matches the required template and includes change summary, testing details, and changelog status.
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.

✨ 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 horatiu-lig-9807-show-event-bars-on-the-timeline-3-events-model

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[horatiualmasan]

/review

[coderabbitai]

🧹 Nitpick comments (1)

lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts (1)

77-77: 📐 Maintainability & Code Quality | 🔵 Trivial | 💤 Low value

Consider using a secondary sort criterion for visual stability.

When multiple events start at the exact same time, sorting them secondarily by their end time (descending) guarantees that longer events are processed first. In the context of assignEventLanes, this places longer events on lower-indexed lanes, forming a clean visual "base" over which shorter, concurrent events stack neatly.

Consider updating the sort logic in both utility functions to maintain consistent event ordering:

• lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts#L77-L77: Update the sort inside assignEventLanes to (a, b) => a.startTimeS - b.startTimeS || b.endTimeS - a.endTimeS.
• lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts#L63-L63: Update the sort inside toVideoEvents identically so the default output is also thoroughly stable.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts` at line 77,
Update the event sorting in both toVideoEvents and assignEventLanes in
lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts:63-63 and
lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts:77-77 to sort by
startTimeS ascending, then endTimeS descending when start times match, ensuring
consistent stable ordering with longer concurrent events processed first.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts`:
- Line 77: Update the event sorting in both toVideoEvents and assignEventLanes
in lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts:63-63 and
lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts:77-77 to sort by
startTimeS ascending, then endTimeS descending when start times match, ensuring
consistent stable ordering with longer concurrent events processed first.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 9e9c2cf7-4cdc-479e-b22b-c3c9551bb5ed

📥 Commits

Reviewing files that changed from the base of the PR and between 2ffcae0 and 93bd70a.

📒 Files selected for processing (3)

• lightly_studio_view/src/lib/utils/index.ts
• lightly_studio_view/src/lib/utils/videoEvents/videoEvents.test.ts
• lightly_studio_view/src/lib/utils/videoEvents/videoEvents.ts