# Checkout Flow Central Index

This document centralizes all documentation, findings, and tasks related to the checkout flow, including race conditions, seat holds, timeouts, and related bug fixes.

## Key Documentation

- [Race Condition Solution Summary](_CONTEXT/RACE-CONDITION-SOLUTION-COMPLETE.md)
- [Race Condition Test Findings](test-results/race-condition-test-findings.md)
- [E2E Testing Framework](_CONTEXT/E2E-TESTING-FRAMEWORK.md)
- [Operations Runbook](_CONTEXT/OPERATIONS-RUNBOOK.md)
- [Seating System Architecture](_CONTEXT/seating-system-architecture.md)
- [Final Security Checklist](_CONTEXT/FINAL-SECURITY-CHECKLIST.md)
- [Build Status Report](_CONTEXT/build-status-report.md)

## Task Tracker

### Completed Tasks

- Race condition eliminated with atomic seat operations ([RACE-CONDITION-SOLUTION-COMPLETE.md], [API/FIXLIST.md])
- Database-level hardening: unique constraints, hold expiry, idempotency ([E2E-IMPLEMENTATION-COMPLETE.md])
- E2E test suite implemented: happy paths, race conditions, data integrity ([E2E-IMPLEMENTATION-COMPLETE.md], [E2E-TESTING-FRAMEWORK.md])
- UI testability features: ARIA, countdown, visual states ([E2E-IMPLEMENTATION-COMPLETE.md])
- Smoke test complete, core API fix validated ([API/RUNLOG.md])
- Multi-seat selection reliability: 100% success ([API/FIXLIST.md])
- Payment failure handling, idempotent checkout ([E2E-TESTING-FRAMEWORK.md])
- Server-side instrumentation: structured logging, DB write path trace ([API/RUNLOG.md], [API/PHASE-1-COMPLETE.md])
- Data & identity integrity checks: seat identity normalization, DB constraints/indexes ([API/RUNLOG.md], [API/PHASE-1-COMPLETE.md])
- Anti-spam throttle precision bug resolved (`time()` → `microtime(true)`) ([API/PHASE-1-COMPLETE.md])
- API parallel holds working perfectly ([API/PHASE-1-COMPLETE.md])
- Regression test created for parallel holds ([API/PHASE-1-COMPLETE.md])
- Complete server-side observability added ([API/PHASE-1-COMPLETE.md])
- Documentation created for identity consistency and DB design ([API/PHASE-1-COMPLETE.md])

### Open Tasks

- Monitor key metrics post-deployment (seat selection success rate, booking errors, API response times, DB impact) ([DEPLOYMENT-CHECKLIST.md])
- Validate user experience (multi-seat selection, error handling, feedback) ([DEPLOYMENT-CHECKLIST.md])
- Remove old race-condition-prone code and archive outdated test files ([DEPLOYMENT-CHECKLIST.md])
- Implement webhook → seat confirmation integration and payment flow success tracking ([payment-test-execution-report.md])
- Add webhook processing metrics and operational alerting ([payment-test-execution-report.md])
- Document complete payment architecture and create troubleshooting runbooks ([payment-test-execution-report.md])
- Fix database cleanup/session isolation (blocking all other progress) ([E2E-TESTING-FIXES-SUMMARY.md])
- Verify multi-seat JavaScript fix and audit missing UI elements in test template ([E2E-TESTING-FIXES-SUMMARY.md])
- Schedule cleanup job for expired seat holds ([E2E-IMPLEMENTATION-COMPLETE.md])
- Add load testing for high concurrency and analytics integration ([E2E-IMPLEMENTATION-COMPLETE.md])
- Plan Vite migration for build modernization (optional) ([SECURITY-IMPLEMENTATION.md])
- GDPR/data export utilities, banner/content page setup, email deliverability, dry run, go-live ([status.md])
- Stock integrity fix: add row locks/atomic decrements in EventController.php ([status.md])
- Settlement system: build MBS settlement workflow ([status.md])
- Payment idempotency: prevent double-processing in StripeNotificationController.php ([status.md], recent GitHub issue)
- Cart expiry logic: session-based cart cleanup ([status.md])
- Admin order management: refund/resend functionality ([status.md])
- Door audit logging: enhance BoxOfficeController.php check-in logs ([status.md])
- DOM/state update determinism: verify class/data attributes per seat ([API/FIXLIST.md])
- Add distributed seat locking during cart-to-booking ([ticketing.md])
- Concurrency protection: row-level locks for seat allocation ([ticketing.md])
- Validate business rules at API level ([ticketing.md])
- Stock management: enforce category-wise ticket limits ([ticketing.md])
- Implement check-in state machine ([ticketing.md])
- Client-side flow analysis (FIXLIST item #7) ([API/PHASE-1-COMPLETE.md])
- Template/test alignment (FIXLIST item #13) ([API/PHASE-1-COMPLETE.md])
- Move to production SVG booking system ([API/PHASE-1-COMPLETE.md])
- Additional FIXLIST items as needed ([API/PHASE-1-COMPLETE.md])

### Unstarted Tasks

- Regularly review and update the central index and archive outdated documentation/test results
- Add acceptance criteria and rollback steps for all fixes
- Expand accessibility and notification coverage
- Expand system notification coverage (email templates)
- Add more accessibility tests (ARIA, keyboard nav)

## How to Use

- Update this index after every major fix, test, or finding.
- Link new documentation and test results here.
- Use the task tracker to monitor progress and assign responsibility.

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_Last updated: September 10, 2025_