# Module: Azaion.Common.Entities.DetectionClass

## Purpose
Domain entity for a single detection class shown to operators in the Detection Classes admin table. Persisted to the `detection_classes` table; managed via the `/classes` admin endpoints introduced by AZ-513.

> **Cycle 1 (2026-05-13) origin** — added by AZ-513 to back the new admin `/classes` CRUD endpoints; previously the read path was served by another service (likely `annotations/`) and admin/ had no own model for it.

## Public Interface

| Property | Type | Description |
|----------|------|-------------|
| `Id` | `int` | Auto-assigned identity (DB-generated via `InsertWithInt32IdentityAsync`) |
| `Name` | `string` | Full display name (max 120 chars per validator) |
| `ShortName` | `string` | Short label used in tight UI (max 20 chars) |
| `Color` | `string` | UI color (e.g. `"#FF0000"`, max 20 chars — accepts hex strings or named-color tokens) |
| `MaxSizeM` | `double` | Maximum real-world object size in meters (must be > 0) |
| `PhotoMode` | `string?` | Optional capture-mode hint (max 20 chars when present) |
| `CreatedAt` | `DateTime` | UTC creation timestamp set by the service on insert |

## Internal Logic
Plain POCO; no behaviour. Identity is assigned by the database on insert (`InsertWithInt32IdentityAsync`).

## Dependencies
None (no `using` directives on `Azaion.Services` / external libs).

## Consumers
- `Azaion.Services.DetectionClassService` — CRUD operations
- `AzaionDb.DetectionClasses` — linq2db table mapping (see `common_database_azaion_db.md`)
- `Azaion.AdminApi.Program` — `POST/PATCH/DELETE /classes` endpoints

## Data Models
Maps 1:1 to the `detection_classes` PostgreSQL table.

## Configuration
None.

## External Integrations
None directly; persisted via `IDbFactory` → PostgreSQL.

## Security
Data is operator-controlled metadata; no PII or secrets.

## Tests
- `e2e/Azaion.E2E/Tests/DetectionClassesTests.cs` — covers AZ-513 ACs 1–9