SportstimeAPI/.planning/phases/04-drag-interaction/04-01-SUMMARY.md

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phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	duration	completed
04-drag-interaction	01	ui	drag-drop uitableview haptics animations uikit	phase provides 03-visual-flattening ItineraryFlattener.flatten() for row-to-semantic translation	UITableViewDragDelegate/UITableViewDropDelegate implementation Lift animation with scale, shadow, and tilt Haptic feedback for grab and drop DragContext for tracking drag state	04-02	added patterns Modern drag delegates (UITableViewDragDelegate/UITableViewDropDelegate) for custom previews DragContext class for drag session state management Snapshot-based lift animation with CATransform3D	created modified SportsTime/Features/Trip/Views/ItineraryTableViewController.swift	Tasks 2-3 completed as part of Task 1 - delegate pattern required holistic implementation Lift animation parameters: 1.025x scale, 2-degree tilt, 0.25 shadow opacity Animation timing: 0.15s lift, 0.2s drop, spring damping 0.85/0.8 Separate haptic generators: light for grab, medium for drop	DragContext: Store drag state in session.localContext for access across delegate methods Snapshot-based animations: Create UIView snapshot for custom lift/drop effects Dual haptic generators: Prepare both at drag start for reduced latency	3min	2026-01-18

Phase 4 Plan 1: Modern Drag-Drop Delegates Summary

Modern UITableViewDragDelegate/UITableViewDropDelegate with iOS Reminders-style lift animation (1.025x scale, 2-degree tilt) and dual haptic feedback (light grab, medium drop)

Performance

• Duration: 3 min
• Started: 2026-01-18T22:41:34Z
• Completed: 2026-01-18T22:44:26Z
• Tasks: 3 (completed in single commit due to code interdependency)
• Files modified: 1

Accomplishments

• Migrated from legacy reordering to modern UITableViewDragDelegate/UITableViewDropDelegate
• Implemented custom lift animation with scale (1.025x), shadow, and 3D tilt (2 degrees)
• Added dual haptic feedback: light on grab, medium on successful drop
• Created DragContext class for managing drag session state across delegate methods
• Integrated existing constraint validation logic (computeValidDestinationRowsProposed, nearestValue)

Task Commits

All three tasks were completed in a single commit because the modern drag delegate pattern requires the lift animation and haptic feedback to be implemented together with the delegate methods:

1. Task 1: Migrate to Modern Drag-Drop Delegates - 749ca30 (feat)
2. Task 2: Implement Lift Animation - included in 749ca30 (code interdependency)
3. Task 3: Add Haptic Feedback - included in 749ca30 (code interdependency)

Plan metadata: (pending)

Files Created/Modified

• SportsTime/Features/Trip/Views/ItineraryTableViewController.swift - Added 364 lines:
  • DragContext class for drag state management
  • UITableViewDragDelegate extension (itemsForBeginning, dragPreviewParametersForRowAt, dragSessionWillBegin, dragSessionDidEnd)
  • UITableViewDropDelegate extension (performDropWith, dropSessionDidUpdate, dropSessionDidEnd)
  • Lift Animation Helpers extension (createLiftedSnapshot, animateLift, animateDrop)
  • New properties: lightHaptic, mediumHaptic, currentDragContext

Decisions Made

1. Unified implementation of Tasks 1-3 - The modern drag delegate pattern inherently requires lift animation and haptic feedback to be implemented as part of the delegate methods. Separating them into atomic commits would have required artificial refactoring steps that don't match how the code naturally fits together.

2. Animation parameters per CONTEXT.md:

   • Scale: 1.025 (middle of 1.02-1.03 range)
   • Tilt: 2 degrees around Y axis
   • Shadow: offset (0, 8), radius 16, opacity 0.25
   • Lift duration: 0.15s with spring damping 0.85
   • Drop duration: 0.2s with spring damping 0.8

3. Dual haptic generators - Created separate UIImpactFeedbackGenerator instances for light (grab) and medium (drop) to allow both to be prepared at drag start for reduced latency.

4. DragContext stored in session.localContext - Allows access to drag state across all delegate methods without relying on instance variables that could be stale.

Deviations from Plan

Implementation Structure

Tasks 2-3 completed as part of Task 1

• Issue: Plan assumed incremental implementation, but delegate pattern requires holistic approach
• Resolution: Implemented all three tasks together in single cohesive commit
• Impact: Same functionality delivered, single commit instead of three
• Verification: Build succeeded, all features present (lift animation, haptics, constraints)

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Total deviations: 1 (implementation structure) Impact on plan: No missing functionality. All DRAG-01, DRAG-06, DRAG-08 requirements implemented. Code is cleaner than artificial separation would have been.

Issues Encountered

None - implementation proceeded smoothly with existing constraint validation infrastructure.

User Setup Required

None - no external service configuration required.

Next Phase Readiness

Ready for Plan 04-02:

• Foundation for insertion line feedback established (UIDragPreviewParameters with rounded corners)
• Constraint validation integrated (validDestinationRowsProposed checked in dropSessionDidUpdate)
• Zone transition haptics preserved from existing code
• Remaining work: themed insertion line, invalid zone red tint, snap-back animation

Requirements status after this plan:

• DRAG-01: Lift animation on grab - IMPLEMENTED
• DRAG-06: Haptic feedback (light/medium) - IMPLEMENTED
• DRAG-08: Slight tilt during drag - IMPLEMENTED
• Foundation established for DRAG-02 through DRAG-05

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Phase: 04-drag-interaction Completed: 2026-01-18