chore: simplify mouse UI drag orchestration

[hatayama]

Summary

• Complete the final R2-33 extraction so mouse UI simulation remains easier to review and maintain.
• Preserve all existing one-shot and incremental drag behavior while reducing the use case to a thin action dispatcher.

User Impact

• There is no intended user-visible behavior change.
• Drag target selection, response priority, animation timing, cancellation cleanup, and persistent drag state remain unchanged.

Changes

• Add a shared drag target resolver for path/raycast resolution and IDragHandler lookup.
• Reuse the resolver from one-shot drag and DragStart while preserving the observable failure order: start-target failure, drop-target failure, then no-handler fallback.
• Move DragStart, DragMove, DragEnd, and active-drag validation into MouseUiIncrementalDragExecutor.
• Keep MouseDragState ownership unchanged and pass the main-thread cleanup scheduler explicitly.
• Reduce SimulateMouseUiUseCase from 434 lines to 137 lines.

Verification

• Confirmed the resolver tests fail before implementation (0/3) and pass after implementation (3/3).
• Passed the focused EditMode suites (141/141).
• Passed the Simulate Mouse UI PlayMode suite before and after each extraction commit (32/32).
• Compiled the Unity package with 0 errors and 0 warnings.
• Compared the moved incremental drag block after normalizing static modifiers, scheduler arguments, and signatures; the only remaining difference was a trailing blank line.
• Verified both cleanup lambdas still call FinalizeDrag before MouseDragState.Clear with the same captures and timing.

Compatibility

• No IPC request or response shape changed, so the protocol version remains unchanged.
• R2-40 and R2-41 remain separate follow-up tasks.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR extracts drag target resolution into a new MouseUiDragTargetResolver, used by both MouseUiOneShotDragExecutor and a new MouseUiIncrementalDragExecutor, which now hosts the drag start/move/end lifecycle previously implemented inline in SimulateMouseUiUseCase. Tests cover the new resolver.

Changes

Drag target resolution and executor refactor

Layer / File(s)	Summary
MouseUiDragTargetResolver implementation and tests Packages/src/Editor/FirstPartyTools/SimulateMouseUi/MouseUiDragTargetResolver.cs, Assets/Tests/Editor/MouseUiDragTargetResolverTests.cs	New Resolve method computes starting raycast and drag target via bypass-path or UI raycast, resolving the nearest IDragHandler; tests cover handler-found, no-handler, and missing-path scenarios.
One-shot drag executor integration Packages/src/Editor/FirstPartyTools/SimulateMouseUi/MouseUiOneShotDragExecutor.cs	Replaces inline raycast/target-path resolution and IDragHandler lookup with a single call to MouseUiDragTargetResolver.Resolve, returning early on failure.
MouseUiIncrementalDragExecutor lifecycle Packages/src/Editor/FirstPartyTools/SimulateMouseUi/MouseUiIncrementalDragExecutor.cs	New static executor implements ExecuteDragStart/Move/End and ValidateDragStillActive, managing MouseDragState, overlay animation, interpolation, timeout handling, and cleanup.
SimulateMouseUiUseCase delegation Packages/src/Editor/FirstPartyTools/SimulateMouseUi/SimulateMouseUiUseCase.cs	Removes local drag implementations and UnityEditor import; ExecuteMouseAction now delegates drag cases to MouseUiIncrementalDragExecutor.

Estimated code review effort: 4 (Complex) | ~60 minutes

Sequence Diagram(s)

sequenceDiagram
  participant SimulateMouseUiUseCase
  participant MouseUiIncrementalDragExecutor
  participant MouseUiDragTargetResolver
  participant MouseDragState
  participant MouseUiOverlayState

  SimulateMouseUiUseCase->>MouseUiIncrementalDragExecutor: ExecuteDragStart()
  MouseUiIncrementalDragExecutor->>MouseUiDragTargetResolver: Resolve(bypass or raycast)
  MouseUiDragTargetResolver-->>MouseUiIncrementalDragExecutor: startRaycast, target, failure
  MouseUiIncrementalDragExecutor->>MouseDragState: set Target/PointerData
  MouseUiIncrementalDragExecutor->>MouseUiOverlayState: update start overlay

  SimulateMouseUiUseCase->>MouseUiIncrementalDragExecutor: ExecuteDragMove()
  MouseUiIncrementalDragExecutor->>MouseDragState: ValidateDragStillActive()
  MouseUiIncrementalDragExecutor->>MouseUiOverlayState: update move overlay

  SimulateMouseUiUseCase->>MouseUiIncrementalDragExecutor: ExecuteDragEnd()
  MouseUiIncrementalDragExecutor->>MouseDragState: FinalizeDrag / clear
  MouseUiIncrementalDragExecutor->>MouseUiOverlayState: dissipate overlay

Loading

Possibly related PRs

• hatayama/unity-cli-loop#996: Prior implementation of bypass-raycast/target-path drag resolution logic now centralized into MouseUiDragTargetResolver.
• hatayama/unity-cli-loop#1333: Overlaps with the same drag lifecycle area in SimulateMouseUiUseCase/drag executors regarding timeout-aware drag handling.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the refactor to mouse UI drag orchestration.
Description check	✅ Passed	The description is clearly aligned with the refactor and its stated no-behavior-change goal.
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 refactor/hatayama/extract-mouse-ui-incremental-drag

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[coderabbitai]

🧹 Nitpick comments (1)

Assets/Tests/Editor/MouseUiDragTargetResolverTests.cs (1)

38-117: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Consider adding a test for the non-bypass (raycast) resolution path.

All three tests use BypassRaycast = true, leaving the raycast branch (resolver lines 45-49) uncovered at the unit level. A test that sets up a Canvas with a raycast-target Graphic and calls Resolve with BypassRaycast = false would verify the UiRaycastHelper.RaycastUI → ExecuteEvents.GetEventHandler<IDragHandler> flow directly through the new resolver API.

🤖 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 `@Assets/Tests/Editor/MouseUiDragTargetResolverTests.cs` around lines 38 - 117,
Add a unit test that covers the non-bypass raycast path in
MouseUiDragTargetResolver.Resolve, since the current tests only exercise the
bypass flow via BypassRaycast = true. Create a Canvas with a raycast-target
Graphic, call Resolve with BypassRaycast = false, and assert the raycast result
and handler resolution from UiRaycastHelper.RaycastUI through
ExecuteEvents.GetEventHandler<IDragHandler>. Use
MouseUiDragTargetResolver.Resolve and the existing test helpers as the entry
points to keep the new test aligned with the current suite.

🤖 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 `@Assets/Tests/Editor/MouseUiDragTargetResolverTests.cs`:
- Around line 38-117: Add a unit test that covers the non-bypass raycast path in
MouseUiDragTargetResolver.Resolve, since the current tests only exercise the
bypass flow via BypassRaycast = true. Create a Canvas with a raycast-target
Graphic, call Resolve with BypassRaycast = false, and assert the raycast result
and handler resolution from UiRaycastHelper.RaycastUI through
ExecuteEvents.GetEventHandler<IDragHandler>. Use
MouseUiDragTargetResolver.Resolve and the existing test helpers as the entry
points to keep the new test aligned with the current suite.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 2f44ae6d-d0b3-45f9-ac8e-53e6122b5fdc

📥 Commits

Reviewing files that changed from the base of the PR and between 9da9360 and a9366ec.

⛔ Files ignored due to path filters (3)

• Assets/Tests/Editor/MouseUiDragTargetResolverTests.cs.meta is excluded by none and included by none
• Packages/src/Editor/FirstPartyTools/SimulateMouseUi/MouseUiDragTargetResolver.cs.meta is excluded by none and included by none
• Packages/src/Editor/FirstPartyTools/SimulateMouseUi/MouseUiIncrementalDragExecutor.cs.meta is excluded by none and included by none

📒 Files selected for processing (5)

• Assets/Tests/Editor/MouseUiDragTargetResolverTests.cs
• Packages/src/Editor/FirstPartyTools/SimulateMouseUi/MouseUiDragTargetResolver.cs
• Packages/src/Editor/FirstPartyTools/SimulateMouseUi/MouseUiIncrementalDragExecutor.cs
• Packages/src/Editor/FirstPartyTools/SimulateMouseUi/MouseUiOneShotDragExecutor.cs
• Packages/src/Editor/FirstPartyTools/SimulateMouseUi/SimulateMouseUiUseCase.cs

[cubic-dev-ai]

No issues found across 8 files

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