# Payment Integration Implementation Summary

## Overview
Complete payment integration for software upgrades using existing ecommerce infrastructure (transaction API, invoice API, PHPMailer, DomPDF).

## New Files to Create

### 1. `/webhook_mollie.php` (Root directory)
**Purpose**: Mollie webhook handler specifically for software upgrades
**Based on**: Existing webhook.php from commerce product
**Key features**:
- ✅ Uses `/v2/transactions/` API for status updates (consistent with commerce)
- ✅ Uses `/v2/invoice/` API for invoice generation
- ✅ Creates PDF invoice with DomPDF
- ✅ Sends email via PHPMailer
- ✅ Creates software license
- ✅ Multi-language support
- ✅ Sends to bookkeeping if configured

**Webhook URL**: `https://yourdomain.com/webhook_mollie.php`

### 2. `/api/v2/post/payment.php`
**Purpose**: Create Mollie payment for software upgrade
**Input**: serial_number, version_id, user_data
**Output**: {checkout_url, payment_id}
**Security**: Server-side price calculation

### 3. `/api/v2/get/payment.php`
**Purpose**: Retrieve payment status
**Input**: ?payment_id=xxx
**Output**: {payment_id, payment_status, serial_number, equipment_id, ...}

## Modified Files

### 1. `/assets/functions.php`
**Add new functions**:
- `generateUniqueLicenseKey()` - Generate unique license keys
- `generateSoftwareInvoice($invoice_data, $order_id, $language)` - Generate HTML invoice for software upgrades
  - Based on existing `generateInvoice()` function
  - Custom template for software licenses
  - Shows: Device serial number, software version, license key, expiry date
  - Returns: [$html_content, $customer_email, $order_id]

### 2. `/assets/softwaretool.js`
**Modify**:
- `processPayment()` - Call `/v2/post/payment` API
- `downloadAndInstallSoftware()` - Add serial number verification

### 3. `/softwaretool.php`
**Add**: Payment return detection (`?payment_id=xxx`)

## Database
**No changes needed** - Uses existing:
- `transactions` table (txn_id, payment_status, payment_amount, etc.)
- `transactions_items` table (item_id, item_options with JSON)

## Payment Status Codes (Matching Commerce System)
- `0` = Pending
- `1` = Paid
- `101` = Open/Pending (Mollie)
- `102` = Failed
- `103` = Expired
- `999` = Canceled

## Implementation Order

1. ✅ Add Mollie constants to config.php
2. Create helper functions in functions.php:
   - `generateUniqueLicenseKey()`
   - `generateSoftwareInvoice()`
3. Create `/api/v2/post/payment.php`
4. Create `/api/v2/get/payment.php`
5. Create `/webhook_mollie.php`
6. Modify frontend JavaScript
7. Modify softwaretool.php
8. Test in DEBUG mode
9. Test with Mollie sandbox
10. Deploy to production

## Key Benefits

1. **Consistent with ecommerce** - Uses same API structure
2. **Professional invoices** - PDF generation + email delivery
3. **Complete audit trail** - Transactions + invoices + licenses
4. **Multi-language** - Invoice language based on customer country
5. **Bookkeeping integration** - Auto-send to bookkeeping email
6. **Refund handling** - Webhook detects refunds (TODO: disable license)

## Invoice Email Template

The email will include:
- Subject: "Software Upgrade - Invoice: [ORDER_ID]"
- HTML body with invoice details
- PDF attachment (Invoice_[ORDER_ID].pdf)
- Sent to customer email + bookkeeping (if configured)

**Invoice contains:**
- Customer details (name, address, email)
- Order ID / Transaction ID
- Software upgrade details (version, device serial number)
- License key + expiry date (2099-12-31)
- Price breakdown
- Company information