# Project State: Itinerary Editor

## Project Reference

**Core Value:** Drag-and-drop that operates on semantic positions (day + sortOrder), not row indices - so user intent is preserved across data reloads.

**Current Focus:** Phase 2 Complete - Ready for Phase 3 (Visual Flattening)

## Current Position

**Phase:** 2 of 4 (Constraint Validation) - COMPLETE
**Plan:** 2 of 2 complete
**Status:** Phase complete
**Last activity:** 2026-01-18 - Completed 02-02-PLAN.md

```
Progress: [####------] 50%
Phase 1:  [##########] 100% (2/2 plans) COMPLETE
Phase 2:  [##########] 100% (2/2 plans) COMPLETE
Phase 3:  [----------] Not Started
Phase 4:  [----------] Not Started
```

## Performance Metrics

| Metric | Value |
|--------|-------|
| Total Requirements | 23 |
| Completed | 12 |
| Current Phase | 2 (complete) |
| Plans Executed | 4 |

## Accumulated Context

### Key Decisions

| Decision | Rationale | Phase |
|----------|-----------|-------|
| UITableView over SwiftUI List | SwiftUI drag-drop lacks insertion line precision | Pre-planning |
| (day, sortOrder) position model | Row indices break on reload; semantic position is stable | Pre-planning |
| Insertion lines (not zones) | User wants precise feedback on exact drop location | Pre-planning |
| Invalid drops rejected (snap back) | Cleaner than auto-clamping; user knows what happened | Pre-planning |
| Games get sortOrder from 100 + minutes since midnight | Range 100-1540 leaves room for negative sortOrder items | 01-01 |
| Normalization threshold at 1e-10 | Standard floating-point comparison for precision exhaustion | 01-01 |
| Day 1 = trip.startDate | 1-indexed, games belong to their start date | 01-01 |
| Swift Testing (@Test) over XCTest | Matches existing project test patterns | 01-02 |
| LocalItineraryItem conversion for testing | Avoids #Predicate macro issues with local captures | 01-02 |
| Edge case tests cover all boundaries | Day 0, beyond trip, exact sortOrder, negative/large values | 02-02 |
| Success criteria verification tests | Tests named 'success_*' directly verify ROADMAP criteria | 02-02 |

### Learned

- Previous attempts failed due to row-based thinking instead of semantic positioning
- Travel was incorrectly treated as structural ("travelBefore") instead of positional
- Hard-coded flatten order ignoring sortOrder caused reload issues
- SortOrderProvider provides static methods for all sortOrder calculations
- Trip extension provides instance methods for day number derivation
- 50 midpoint insertions maintain distinct sortOrder values before precision loss
- ItineraryConstraints provides isValidPosition(), validDayRange(), barrierGames() for drag validation
- Travel sortOrder constraints: must be AFTER (not equal to) departure game sortOrder

### TODOs

- [x] Create tests for semantic position persistence (Plan 01-02) - COMPLETE
- [x] Migrate constraint tests to Swift Testing (Plan 02-01) - COMPLETE
- [x] Add edge case tests and API documentation (Plan 02-02) - COMPLETE

### Blockers

None currently.

## Session Continuity

**Last Session:** 2026-01-18T21:13:45Z
**Stopped at:** Completed 02-02-PLAN.md (Phase 2 complete)
**Resume file:** .planning/phases/03-visual-flattening/03-01-PLAN.md

### Context for Next Session

Phase 2 complete with 22 constraint tests covering:
- CONS-01: Games cannot move (2 tests)
- CONS-02: Travel day range constraints (3 tests)
- CONS-03: Travel sortOrder constraints (5 tests)
- CONS-04: Custom item flexibility (2 tests)
- Edge cases: 8 tests
- Success criteria: 3 tests
- Barrier games: 1 test

API documentation ready for Phase 4 at CONSTRAINT-API.md.

Ready to start Phase 3: Visual Flattening (sortOrder-based flattening, deterministic ordering).

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*State initialized: 2026-01-18*
*Last updated: 2026-01-18*