Add API Reference

API-Reference.md

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+# API Reference
+ 
+Base URL: `http://localhost:8080/api/v1`
+ 
+All request and response bodies are JSON. All endpoints return `Content-Type: application/json`.
+ 
+---
+ 
+## Health
+ 
+### `GET /health`
+ 
+Returns 200 if the database is reachable.
+ 
+**Response:**
+```json
+{"status": "ok"}
+```
+ 
+Returns 503 if the database ping fails.
+ 
+---
+ 
+## Reference Data
+ 
+Reference data (departments and GL accounts) must be created before budget lines or actuals, as they are foreign-key parents.
+ 
+---
+ 
+### Departments
+ 
+#### `POST /departments`
+ 
+Create a department.
+ 
+**Request body:**
+```json
+{
+  "code": "ENG",
+  "name": "Engineering"
+}
+```
+ 
+#### `GET /departments`
+ 
+List all departments.
+ 
+**Response:**
+```json
+[
+  {"id": 1, "code": "ENG", "name": "Engineering"},
+  {"id": 2, "code": "MKT", "name": "Marketing"}
+]
+```
+ 
+#### `DELETE /departments/{id}`
+ 
+Delete a department by ID.
+ 
+---
+ 
+### GL Accounts
+ 
+#### `POST /gl-accounts`
+ 
+Create a GL account.
+ 
+**Request body:**
+```json
+{
+  "code": "6100",
+  "description": "Salaries & Wages",
+  "type": "headcount",
+  "favour_high": false
+}
+```
+ 
+`favour_high` drives the favourability logic. Set to `true` for revenue accounts (higher actual = good), `false` for cost accounts (lower actual = good).
+ 
+**Account types:** `revenue`, `cogs`, `opex`, `capex`, `headcount`
+ 
+#### `GET /gl-accounts`
+ 
+List all GL accounts.
+ 
+#### `DELETE /gl-accounts/{id}`
+ 
+Delete a GL account by ID.
+ 
+---
+ 
+## Budgets
+ 
+#### `POST /budgets`
+ 
+Create a budget line.
+ 
+**Request body:**
+```json
+{
+  "department_id": 1,
+  "gl_account_id": 3,
+  "fiscal_year": 2024,
+  "fiscal_period": 9,
+  "version": "original",
+  "amount": 4200000,
+  "currency": "DKK",
+  "notes": "Headcount plan P09"
+}
+```
+ 
+**Budget versions:** `original`, `forecast1`, `forecast2`, `forecast3`
+ 
+#### `PUT /budgets/{id}`
+ 
+Update a budget line's amount or notes.
+ 
+**Request body:**
+```json
+{
+  "amount": 4350000,
+  "notes": "Revised after headcount change"
+}
+```
+ 
+#### `DELETE /budgets/{id}`
+ 
+Delete a budget line by ID.
+ 
+---
+ 
+## Actuals
+ 
+#### `POST /actuals/ingest`
+ 
+Upsert an actual. Idempotent by `(fiscal_year, fiscal_period, department_id, gl_account_id)` — posting the same period twice updates the amount rather than creating a duplicate.
+ 
+**Request body:**
+```json
+{
+  "department_id": 1,
+  "gl_account_id": 3,
+  "fiscal_year": 2024,
+  "fiscal_period": 9,
+  "amount": 4380000,
+  "currency": "DKK",
+  "source": "SAP_EXPORT"
+}
+```
+ 
+Designed to accept bulk ERP export feeds. POST each line individually or build a batch wrapper around the endpoint.
+ 
+---
+ 
+## Variance
+ 
+### Query Parameters (both variance endpoints)
+ 
+| Parameter | Example | Description |
+|---|---|---|
+| `year` | `2024` | Fiscal year (required) |
+| `period` | `9` | Fiscal period 1–12 (required) |
+| `dept` | `ENG` | Department code — omit to return all departments |
+| `version` | `original` | Budget version (defaults to `original`) |
+ 
+---
+ 
+#### `GET /variance`
+ 
+Full variance report for the given filters.
+ 
+**Example:**
+```
+GET /api/v1/variance?year=2024&period=9&dept=ENG
+```
+ 
+**Response:**
+```json
+{
+  "department": "ENG",
+  "fiscal_year": 2024,
+  "fiscal_period": 9,
+  "version": "original",
+  "currency": "DKK",
+  "total_budget": 6740000,
+  "total_actual": 7074600,
+  "total_variance": -334600,
+  "total_variance_pct": -4.97,
+  "lines": [
+    {
+      "gl_code": "6100",
+      "gl_description": "Salaries & Wages",
+      "gl_type": "headcount",
+      "budget": 4200000,
+      "actual": 4380000,
+      "variance_abs": -180000,
+      "variance_pct": -4.29,
+      "status": "unfavourable",
+      "currency": "DKK"
+    },
+    {
+      "gl_code": "5000",
+      "gl_description": "Cloud Infrastructure",
+      "gl_type": "cogs",
+      "budget": 850000,
+      "actual": 791000,
+      "variance_abs": 59000,
+      "variance_pct": 6.94,
+      "status": "favourable",
+      "currency": "DKK"
+    }
+  ]
+}
+```
+ 
+`variance_abs` = actual − budget. Positive means over-budget for costs, under-budget for revenue.
+ 
+`status` is `"favourable"` or `"unfavourable"` based on the account's `favour_high` flag — see [Finance Concepts](Finance-Concepts).
+ 
+---
+ 
+#### `GET /variance/alerts`
+ 
+Returns only the GL lines where absolute variance percentage exceeds the threshold.
+ 
+**Additional query parameter:**
+ 
+| Parameter | Example | Description |
+|---|---|---|
+| `threshold` | `15` | Alert threshold as a percentage (default: `10`) |
+ 
+**Example:**
+```
+GET /api/v1/variance/alerts?year=2024&period=9&threshold=15
+```
+ 
+Returns the same line-level structure as the full variance report, filtered to lines where `abs(variance_pct) > threshold`.