---
phase: 01-purchase-data-layer
plan: 01
subsystem: payments
tags: [gtm, ga4, purchase, datalayer, tickets]
requires: []
provides:
  - Purchase event moved to post-payment confirmation view
  - Backend purchase payload builder for order and ticket lines
  - Safer JSON serialization for data layer payload
affects: [analytics, checkout, order-confirmation]
tech-stack:
  added: []
  patterns:
    - Build analytics payload in controller instead of in payment redirect view
key-files:
  created: []
  modified:
    - autoload/controls/class.Tickets.php
    - templates/tickets/order-confirm.php
    - templates/tickets/przelewy24.php
key-decisions:
  - "Emit purchase only on order confirmation after successful payment"
  - "Keep payload assembly in backend, render-only in view"
patterns-established:
  - "No purchase event on payment gateway redirect page"
duration: 6min
started: 2026-04-19T20:21:00+02:00
completed: 2026-04-19T20:27:00+02:00
---

# Phase 1 Plan 1: Purchase Data Layer Summary

Purchase tracking now triggers only after confirmed payment and sends an enriched ecommerce payload from backend data.

## Performance

| Metric | Value |
|--------|-------|
| Duration | 6 min |
| Started | 2026-04-19T20:21:00+02:00 |
| Completed | 2026-04-19T20:27:00+02:00 |
| Tasks | 3 completed |
| Files modified | 3 |

## Acceptance Criteria Results

| Criterion | Status | Notes |
|-----------|--------|-------|
| AC-1: Event tylko po potwierdzeniu platnosci | Pass | Event moved to `order-confirm.php` and injected only when backend provides payload for successful payment. |
| AC-2: Pelny payload ecommerce | Pass | Payload includes transaction fields plus ticket item lines (`product_id`, `name`, `quantity`, `price`, `date_visit`). |
| AC-3: Brak falszywych eventow | Pass | `purchase` push removed from `przelewy24.php` (pre-payment redirect page). |

## Accomplishments

- Added `buildPurchaseDataLayer()` in controller to centralize event payload mapping.
- Passed payload to confirmation view and emitted safe `dataLayer.push` with defensive `window.dataLayer` initialization.
- Removed premature `purchase` push from payment gateway handoff template.

## Task Commits

No git commits were created in APPLY (working tree changes only).

## Files Created/Modified

| File | Change | Purpose |
|------|--------|---------|
| `autoload/controls/class.Tickets.php` | Modified | Added purchase payload builder and passed payload to order confirmation view. |
| `templates/tickets/order-confirm.php` | Modified | Added safe and conditional purchase data layer push. |
| `templates/tickets/przelewy24.php` | Modified | Removed purchase event from pre-payment step. |

## Decisions Made

| Decision | Rationale | Impact |
|----------|-----------|--------|
| Emit `purchase` on `order_confirm` | This view reflects confirmed payment state rather than payment initiation. | Prevents false positive conversions in analytics. |
| Build payload in backend | Keeps view simple and avoids fragile inline data mapping logic. | Better maintainability and safer output handling. |

## Deviations from Plan

None. Plan executed as specified.

## Issues Encountered

| Issue | Resolution |
|-------|------------|
| None | - |

## Next Phase Readiness

**Ready:**
- Purchase event now has a stable post-payment trigger point.
- Payload mapping can be extended later with additional ecommerce fields if needed.

**Concerns:**
- Manual end-to-end checkout verification in browser/Tag Assistant still pending.

**Blockers:**
- None

---
*Phase: 01-purchase-data-layer, Plan: 01*
*Completed: 2026-04-19*