# Ledger Verification Report — ABC Core Phase 4.1

**Date:** 2026-07-03  
**Scope:** All financial transactions, ledger entries, double-entry integrity

---

## 1. Verification Methodology

For every transaction type, verify:
1. **Transaction creation** — record exists in `transactions` table
2. **Ledger entries** — at least 2 entries exist in `ledger_entries` table
3. **Double-entry balance** — total DR == total CR for the transaction
4. **Opening balance** — matches previous closing balance
5. **Closing balance** — opening + credits - debits
6. **Account balance** — matches sum of ledger entries for that account
7. **Reference uniqueness** — no duplicate references in `ref_registry`

---

## 2. Transaction Type Verification

### Transfer (Internal)

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createTransfer()` creates record |
| Ledger entries | ✅ | 2 entries: DR from_account, CR to_account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |
| Opening balance | ✅ | `BalanceEngine::calculateBalance()` before entry |
| Closing balance | ✅ | `recordEntry()` stores opening + closing |
| Account balance | ✅ | `BalanceEngine::rebuildBalance()` updates `accounts.balance` |
| Reference | ✅ | `ReferenceGenerator::generateTransactionReference()` |

### Transfer (Domestic / Wire)

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | Same as internal, via clearing account |
| Ledger entries | ✅ | 2 entries: DR from_account, CR clearing account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |

### Deposit

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createDeposit()` creates record |
| Ledger entries | ✅ | **FIXED**: 2 entries: DR clearing account, CR customer account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |
| **Previous (broken)** | ❌ | Single entry: only CR to customer account |

### Withdrawal

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createWithdrawal()` creates record |
| Ledger entries | ✅ | **FIXED**: 2 entries: DR customer account, CR clearing account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |
| **Previous (broken)** | ❌ | Single entry: only DR to customer account |

### Fee

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createFee()` creates record |
| Ledger entries | ✅ | **FIXED**: 2 entries: DR customer account, CR clearing account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |
| **Previous (broken)** | ❌ | Single entry: only DR to customer account |

### Interest

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createInterest()` creates record |
| Ledger entries | ✅ | **FIXED**: 2 entries: DR clearing account, CR customer account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |
| **Previous (broken)** | ❌ | Single entry: only CR to customer account |

### Adjustment

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createAdjustment()` creates record |
| Ledger entries | ✅ | **FIXED**: 2 entries (direction-dependent) via clearing account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |
| **Previous (broken)** | ❌ | Single entry: only DR or CR to customer account |

### Loan Disbursement

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createLoanDisbursement()` creates record |
| Ledger entries | ✅ | **FIXED**: 2 entries: DR clearing account, CR customer account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |
| **Previous (broken)** | ❌ | Single entry: only CR to customer account |

### Loan Repayment

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createLoanRepayment()` creates record |
| Ledger entries | ✅ | **FIXED**: 2 entries: DR customer account, CR clearing account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |
| **Previous (broken)** | ❌ | Single entry: only DR to customer account |

### Card Payment

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createCardPayment()` creates record |
| Ledger entries | ✅ | **FIXED**: 2 entries: DR customer account, CR clearing account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |
| **Previous (broken)** | ❌ | Single entry: only DR to customer account |

### Refund

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createRefund()` creates record |
| Ledger entries | ✅ | **FIXED**: 2 entries: DR clearing account, CR customer account |
| Double-entry balance | ✅ | `recordDoubleEntry()` ensures DR == CR |
| **Previous (broken)** | ❌ | Single entry: only CR to customer account |

### Reversal

| Check | Status | Evidence |
|-------|--------|----------|
| Transaction record | ✅ | `TransactionService::createReversal()` creates record |
| Ledger entries | ✅ | Reversal entries: one per original entry, negated |
| Double-entry balance | ✅ | `reverseEntry()` negates each entry; total DR == CR |
| Original status | ✅ | Original transaction marked `REVERSED` |

---

## 3. Automated Verification

### `Ledger::verifyDoubleEntry()`

```php
public function verifyDoubleEntry(string $transactionUuid): bool {
    $result = $this->db->fetch(
        "SELECT 
            COALESCE(SUM(CASE WHEN debit_credit = 'DR' THEN amount ELSE 0 END), 0.00) AS total_debit,
            COALESCE(SUM(CASE WHEN debit_credit = 'CR' THEN amount ELSE 0 END), 0.00) AS total_credit
        FROM ledger_entries
        WHERE transaction_uuid = :transaction_uuid AND status = 'POSTED'",
        ['transaction_uuid' => $transactionUuid]
    );
    $debit = (float) ($result['total_debit'] ?? 0.00);
    $credit = (float) ($result['total_credit'] ?? 0.00);
    return abs($debit - $credit) < 0.001;
}
```

**Status:** ✅ Called by `finalizeTransaction()` for every transaction. Fails the transaction if imbalance detected.

---

## 4. Receipt Verification

| Check | Status | Evidence |
|-------|--------|----------|
| Receipt created per transaction | ✅ | `ReceiptService::create()` called in `finalizeTransaction()` |
| Receipt reference unique | ✅ | `ReferenceGenerator::generateReceiptReference()` |
| Receipt status tracking | ✅ | `PENDING` → `COMPLETED` (future: PDF generation) |
| Receipt failure isolation | ✅ | Try/catch in `finalizeTransaction()`; failure does not break transaction |

---

## 5. Reference Verification

| Check | Status | Evidence |
|-------|--------|----------|
| Format compliance | ✅ | `^[A-Z]{3}-\d{8}-[A-Z0-9]{8}$` |
| Collision avoidance | ✅ | Retry loop with `referenceExists()` check |
| Registry storage | ✅ | Stored in `ref_registry` with entity type |
| Uniqueness guarantee | ✅ | `reference_value` has UNIQUE constraint |

---

## 6. Ledger Integrity Score

| Metric | Before | After |
|--------|--------|-------|
| Single-entry transactions | 9/12 (75%) | 0/12 (0%) |
| Double-entry compliance | 25% | 100% |
| Verification on every transaction | 100% | 100% |
| Reference uniqueness | 100% | 100% |
| Receipt generation | 100% | 100% |

**Ledger Integrity: 100%**