MISSING APIs - TO BE IMPLEMENTED BY BACKEND
==============================================

Get User Balance
----------------
Get the current balance of the authenticated user.
Protocol: https
Root Path: api.Fastcheck.store
Type: GET
Path: /balance
HEADER: Authorization - {"sessionID": "1AF3781BF6B94604B771AEA1D44FA63A"} 
Request Parameters: 
{
}
Response (200-OK):
{
    "balance": 150000,
    "currency": "RUB"
}
Response (401-ERROR):
{
    "message": "not authorized"
}


Get Active FastChecks
---------------------
Get all active (unused) FastChecks created by the current user.
Protocol: https
Root Path: api.Fastcheck.store
Type: GET
Path: /fastcheck/active
HEADER: Authorization - {"sessionID": "1AF3781BF6B94604B771AEA1D44FA63A"} 
Request Parameters: 
{
}
Response (200-OK):
{
    "checks": [
        {
            "fastcheck": "1234-5678-0001",
            "amount": 15000,
            "currency": "RUB",
            "code": "5864",
            "createdAt": "2026-01-19T09:08:18Z",
            "expiration": "2026-01-26T09:08:18Z",
            "status": "active"
        },
        {
            "fastcheck": "1234-5678-0002",
            "amount": 25000,
            "currency": "RUB",
            "code": "1234",
            "createdAt": "2026-01-19T10:15:30Z",
            "expiration": "2026-01-26T10:15:30Z",
            "status": "active"
        }
    ]
}
Response (401-ERROR):
{
    "message": "not authorized"
}


Get FastCheck History
---------------------
Get all used/expired FastChecks (both created and accepted by user).
Protocol: https
Root Path: api.Fastcheck.store
Type: GET
Path: /fastcheck/history
HEADER: Authorization - {"sessionID": "1AF3781BF6B94604B771AEA1D44FA63A"} 
Request Parameters: 
{
}
Response (200-OK):
{
    "checks": [
        {
            "fastcheck": "1234-5678-0003",
            "amount": 5000,
            "currency": "RUB",
            "type": "created",
            "createdAt": "2026-01-15T09:08:18Z",
            "usedAt": "2026-01-15T10:20:00Z",
            "status": "used"
        },
        {
            "fastcheck": "9876-5432-0100",
            "amount": 10000,
            "currency": "RUB",
            "type": "accepted",
            "acceptedAt": "2026-01-14T14:30:00Z",
            "status": "used"
        }
    ]
}
Response (401-ERROR):
{
    "message": "not authorized"
}


Bank Top-Up Integration (To be provided by bank)
-------------------------------------------------
WHAT WE NEED FROM BANK:
1. Payment page URL or API endpoint to initialize payment
2. Required parameters:
   - Amount
   - Currency
   - Return URL (redirect after payment)
   - Callback URL (for payment confirmation webhook)
3. Payment confirmation webhook format
4. Transaction ID for tracking

EXPECTED FLOW:
1. User clicks "Top Up Balance"
2. Frontend redirects to bank payment page (or opens popup)
3. User completes card payment on bank side
4. Bank sends webhook to backend with payment confirmation
5. Backend updates user balance
6. Bank redirects user back to our app
7. Frontend refreshes balance