# Invoice Reconciliation — Design & Implementation Plan

## Context

**Stack:** Ruby (Rails or standalone script)
**Purpose:** Reconcile GoCardless payments, Shine bank statements, and Dolibarr invoices to ensure all three systems are in sync.
**Billing flow:** Customers are billed manually via GoCardless direct debit. Invoices are managed in Dolibarr. Cash lands in a Shine business bank account.

---

## The Problem

Three systems hold overlapping financial data but are not automatically linked:

```
Shine bank ◄─── GoCardless payouts ◄─── GoCardless payments ◄─── Dolibarr invoices
```

Discrepancies arise when:
- A GoCardless payment is collected but Dolibarr is not marked as paid
- A Dolibarr invoice is marked paid but no GoCardless payment exists
- A GoCardless payout (batch) never landed in the Shine account

---

## Data Sources

| Source | What it contains | How to export |
|--------|-----------------|---------------|
| **Dolibarr API** | Invoices, payment status, customer info | Fetched live via REST API (`/invoices`) |
| **GoCardless payments CSV** | Individual payment ID, amount, date, status, customer | Dashboard → Payments → Export CSV |
| **GoCardless payouts CSV** | Payout ID, total amount, arrival date (batched bank transfers) | Dashboard → Payouts → Export CSV |
| **Shine bank CSV** | Bank transactions: date, description, amount, balance | App → Comptes → Exporter le relevé |

---

## Architecture

```
lib/tasks/reconcile.rake                ← CLI entry point (rake task)
app/services/reconciliation/
  ├── dolibarr_fetcher.rb               ← Fetch invoices + payment records via Dolibarr API
  ├── gocardless_parser.rb              ← Parse GoCardless payments CSV
  ├── gocardless_payout_parser.rb       ← Parse GoCardless payouts CSV
  ├── shine_parser.rb                   ← Parse Shine bank statement CSV
  ├── engine.rb                         ← Core matching logic (3 passes)
  └── reporter.rb                       ← Terminal summary + CSV output
```

---

## Reconciliation Passes

### Pass 1 — Dolibarr open invoice audit

- Fetch all Dolibarr invoices with `status=1` (validated/open) for the date range
- Flag any that are past their due date: these should have a GoCardless payment but don't
- Output: list of overdue open invoices needing action

### Pass 2 — GoCardless ↔ Dolibarr matching

For each GoCardless payment in the CSV:

**Matching strategy (in order of confidence):**
1. **Strong match**: `num_payment` field in Dolibarr payment record == GoCardless payment ID
2. **Soft match**: `amount_ttc` + `customer_name` + date within ±5 days

**Flags:**
- `GC_PAID_DOLIBARR_OPEN` — GoCardless collected payment, Dolibarr invoice still open → needs `mark_as_paid` call
- `DOLIBARR_PAID_NO_GC` — Dolibarr marked paid but no GoCardless payment found → manual payment, verify
- `GC_FAILED` — GoCardless payment failed, check if Dolibarr invoice is still open
- `MATCHED` — Both sides agree, no action needed

### Pass 3 — Shine bank ↔ GoCardless payout verification

- GoCardless batches individual payments into payouts and deposits them as a single bank transfer
- Each GoCardless payout should appear as a credit in Shine (description contains "GOCARDLESS" or similar)
- Match by: payout arrival date ±2 days + amount

**Flags:**
- `PAYOUT_MISSING` — GoCardless payout not found in Shine bank statement
- `AMOUNT_MISMATCH` — Payout found but amounts differ (possible fee deduction issue)
- `VERIFIED` — Payout confirmed in bank account

---

## Dolibarr API Endpoints Used

```
GET  /invoices?status=1&limit=500        # Open/validated invoices
GET  /invoices?status=2&limit=500        # Paid invoices
GET  /invoices/{id}                      # Single invoice with payment history
GET  /invoices/{id}/payments             # Payment records for an invoice
POST /invoices/paymentsdistributed       # Record a payment (for --fix mode)
```

**Key Dolibarr invoice fields:**
- `ref` — Invoice reference (e.g., `FA2601-0034`)
- `total_ttc` — Total amount including tax (euros, float)
- `paye` — Payment flag: `1` = paid, `0` = unpaid
- `sumpayed` — Total amount already paid
- `remaintopay` — Remaining balance due
- `socid` — Customer (third-party) ID
- `status` — `0`=draft, `1`=validated, `2`=paid, `3`=cancelled

**Dolibarr mark-as-paid payload:**
```json
{
  "arrayofamounts": {
    "{INVOICE_ID}": {
      "amount": 19.99,
      "multicurrency_amount": null
    }
  },
  "datepaye": 1748524447,
  "paymentid": 6,
  "closepaidinvoices": "yes",
  "accountid": 1,
  "num_payment": "PM01234567",
  "comment": "GoCardless payment — auto-reconciled"
}
```

(`paymentid: 6` = GoCardless payment method ID in Dolibarr — verify this value in your instance)

---

## GoCardless CSV Format

GoCardless payment export columns (verify against your actual export):

```
id, amount, currency, status, charge_date, description, reference,
customer_id, customer_name, mandate_id, payout_id
```

Relevant statuses: `paid_out`, `confirmed`, `failed`, `cancelled`, `pending_submission`

GoCardless payout export columns:

```
id, amount, currency, status, arrival_date, reference
```

---

## Shine CSV Format

Shine bank export columns (verify against your actual export):

```
Date, Libellé, Montant, Catégorie, Notes, Solde
```

GoCardless payouts typically appear with `Libellé` containing `GOCARDLESS` or `GC`.

**Note:** Column names may vary by export language/version. Make the parser configurable.

---

## CLI Interface

```bash
# Dry run — report only, no changes
bin/rails reconcile:run \
  FROM=2026-01-01 \
  TO=2026-01-31 \
  GC=tmp/gocardless_payments.csv \
  GC_PAYOUTS=tmp/gocardless_payouts.csv \
  SHINE=tmp/shine_january.csv

# Auto-fix — mark Dolibarr invoices as paid where GC payment is confirmed
bin/rails reconcile:run \
  FROM=2026-01-01 \
  TO=2026-01-31 \
  GC=tmp/gocardless_payments.csv \
  GC_PAYOUTS=tmp/gocardless_payouts.csv \
  SHINE=tmp/shine_january.csv \
  FIX=true
```

---

## Expected Report Output

```
=== RECONCILIATION REPORT: 2026-01-01 to 2026-01-31 ===

DOLIBARR SUMMARY
  Total invoices validated:   47
  Total invoices paid:        43
  Open and overdue:            4  ← ACTION NEEDED

GOCARDLESS ↔ DOLIBARR
  Matched (no action):        43  ✓
  GC paid / Dolibarr open:    3  ← Dolibarr needs marking as paid
  Dolibarr paid / no GC:      1  ← Verify manual payment
  GC failed:                   0

SHINE ↔ GOCARDLESS PAYOUTS
  Payouts expected:            8
  Payouts found in Shine:      8  ✓
  Total amount expected:   €842.58
  Total amount received:   €842.58
  Difference:              €0.00  ✓

ACTIONS NEEDED:
  1. [GC_PAID_DOLIBARR_OPEN] FA2601-0034  €19.99  DUPONT Jean     GC: PM01234567  2026-01-05
  2. [GC_PAID_DOLIBARR_OPEN] FA2601-0041  €29.99  MARTIN Paul     GC: PM05678901  2026-01-12
  3. [GC_PAID_DOLIBARR_OPEN] FA2601-0052  €19.99  DURAND Marie    GC: PM09012345  2026-01-19
  4. [DOLIBARR_PAID_NO_GC]   FA2601-0023  €19.99  LEROY Claude    Paid: 2026-01-08 (no GC match)

Report saved to: tmp/reconciliation_2026-01-31.csv
```

---

## Output CSV Format

```csv
invoice_ref,customer_name,amount_ttc,invoice_date,dolibarr_status,gc_payment_id,gc_status,gc_charge_date,match_status,action
FA2601-0034,DUPONT Jean,19.99,2026-01-01,open,PM01234567,paid_out,2026-01-05,GC_PAID_DOLIBARR_OPEN,mark_dolibarr_paid
FA2601-0041,MARTIN Paul,29.99,2026-01-08,open,PM05678901,paid_out,2026-01-12,GC_PAID_DOLIBARR_OPEN,mark_dolibarr_paid
FA2601-0023,LEROY Claude,19.99,2026-01-07,paid,,,,DOLIBARR_PAID_NO_GC,verify_manually
FA2601-0012,DUPONT Jean,19.99,2025-12-01,paid,PM98765432,paid_out,2025-12-05,MATCHED,none
```

---

## Implementation Notes

### Matching tolerance

- **Amount**: exact match (compare in cents to avoid float issues — multiply Dolibarr's euro amounts by 100)
- **Date**: ±5 days between GoCardless `charge_date` and Dolibarr invoice `date`
- **Customer**: normalize names before comparing (strip accents, lowercase, trim)

### Dolibarr client setup

The `Dolibarr::Client` requires:
```
DOLIBARR_URL=https://your-dolibarr.example.com/api/index.php
DOLIBARR_API_KEY=your_api_key
```

### Edge cases to handle

- One GoCardless payment covering multiple invoices (rare but possible)
- Credit notes in Dolibarr offsetting invoice balances
- GoCardless payment retried after initial failure (same invoice, multiple GC payment IDs)
- Shine CSV encoding (often ISO-8859-1, convert to UTF-8)
- GoCardless fees: payouts may be slightly less than sum of payments due to GC fees

### Dolibarr payment method ID

When calling `paymentsdistributed`, `paymentid` must match the Dolibarr payment method ID for GoCardless in your instance. Check:
```
GET /setup/dictionary/payment_types
```
Find the entry for GoCardless (often named "Prélèvement GoCardless" or similar).

---

## Future Enhancements

- **Scheduled run**: Run monthly via cron, email report to admin
- **Web interface**: Upload CSVs via admin UI, view reconciliation in browser
- **Stripe support**: Same engine, add a `StripeParser` for Stripe payouts
- **Webhook-driven**: Instead of CSV imports, consume GoCardless webhooks in real time to auto-reconcile as payments land