feat: add api documentation

docs/api.md

@@ -1 +1,106 @@
 # API Documentation
+
+## Overview
+
+This documentation describes the available API endpoints in the different DataAggregator services.
+
+## Services
+
+### 1. DataAggregator.Collector
+
+Service responsible for collecting data from various sources.
+
+#### Endpoints
+
+##### Health Check
+
+**GET** `/api/HealthCheck`
+
+Retrieves the health status of the collector.
+
+**Responses:**
+- **200 OK** : Returns a `HealthStatus` object
+- **500 Internal Server Error** : Error while retrieving status
+
+**Response Model:**
+```json
+{
+  "status": "Healthy|Degraded|Unhealthy",
+  "message": "Description of current status",
+  "lastDataSent": "2024-01-01T00:00:00Z",
+  "bufferSize": 0,
+  "databaseConnected": true,
+  "timestamp": "2024-01-01T00:00:00Z"
+}
+```
+
+**Status Codes:**
+- `Healthy` : Collector is running normally
+- `Degraded` : Minor issues (full buffer, no recent data)
+- `Unhealthy` : Critical issues (no database connection)
+
+---
+
+### 2. DataAggregator.Registration
+
+Service responsible for registering and managing collector devices.
+
+#### Base URL
+```
+http://localhost:5001/api
+```
+
+#### Endpoints
+
+##### Device Registration
+
+**POST** `/api/DeviceRegistration/register`
+
+Registers a new collector device.
+
+**Request Body:**
+```json
+{
+  "deviceName": "Device name",
+  "healthCheckEndpoint": "http://endpoint:port/api/HealthCheck",
+  "additionalConfiguration": {}
+}
+```
+
+**Responses:**
+- **200 OK** : Returns a `DeviceRegistrationResponse` object
+- **400 Bad Request** : Invalid request data
+- **500 Internal Server Error** : Server error
+
+##### Get Device Information
+
+**GET** `/api/DeviceRegistration/{deviceName}`
+
+Retrieves information about a specific device by its name.
+
+**Parameters:**
+- `deviceName` (string) : Device name
+
+**Responses:**
+- **200 OK** : Returns a `CollectorInfoDto` object
+- **400 Bad Request** : Missing device name
+- **404 Not Found** : Device not found
+- **500 Internal Server Error** : Server error
+
+##### List All Devices
+
+**GET** `/api/DeviceRegistration`
+
+Retrieves the list of all registered devices.
+
+**Responses:**
+- **200 OK** : Returns a list of `CollectorInfoDto` objects
+- **500 Internal Server Error** : Server error
+
+---
+
+### 3. DataAggregator.Processor
+
+Service responsible for processing and analyzing collected data.
+
+**Note:** This service currently does not have public API endpoints. It operates as a background processing service.