# API Reference

This document provides a comprehensive reference for all API endpoints in the STUPA PDF API system.

## Base URL

- **Development**: `http://localhost:8000`
- **Production**: `https://your-domain.com/api`

## Authentication

The API uses two types of authentication:

### Application Key Authentication
- **Header**: `X-PA-KEY`
- **Purpose**: Access specific application data
- **Scope**: Read/write access to single application

### Master Key Authentication
- **Header**: `X-MASTER-KEY`
- **Purpose**: Administrative access
- **Scope**: Full access to all resources

### Query Parameter Authentication
For endpoints that need to work with direct browser access (like PDF downloads), you can use:
- **Parameter**: `key`
- **Example**: `/applications/25-0001?format=pdf&key=your-app-key`

## Response Format

All API responses follow this general structure:

```json
{
  "data": { ... },      // For successful responses
  "detail": "...",      // For error messages
  "status": "success"   // Optional status indicator
}
```

## Error Responses

```json
{
  "detail": "Error message here"
}
```

Common HTTP status codes:
- `200 OK` - Success
- `201 Created` - Resource created
- `400 Bad Request` - Invalid request data
- `401 Unauthorized` - Missing or invalid authentication
- `403 Forbidden` - Insufficient permissions
- `404 Not Found` - Resource not found
- `429 Too Many Requests` - Rate limit exceeded
- `500 Internal Server Error` - Server error

## Endpoints

### Health Check

#### GET /
Check if the API is running.

**Response:**
```json
{
  "message": "STUPA PDF API"
}
```

---

### PDF Upload and Processing

#### POST /upload
Upload a PDF form and create a new application.

**Request:**
- **Content-Type**: `multipart/form-data`
- **Body**:
  - `file` (required): PDF file to upload
  - `form_type` (required): Type of form (`"pa_form"` or `"vsm_form"`)

**Response:**
```json
{
  "pa_id": "25-0001",
  "pa_key": "generated-secure-key",
  "data": {
    "projectBeginn": "2025-01-01",
    "name": "Student Project",
    // ... other parsed data
  }
}
```

**Example:**
```bash
curl -X POST "http://localhost:8000/upload" \
  -F "file=@application.pdf" \
  -F "form_type=pa_form"
```

---

### Application Management

#### GET /applications/{pa_id}
Retrieve application data.

**Parameters:**
- `pa_id` (path): Application ID (e.g., "25-0001")
- `format` (query): Response format (`"json"` or `"pdf"`)
- `key` (query): Application key (alternative to header)

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Response (JSON):**
```json
{
  "pa_id": "25-0001",
  "created_at": "2024-01-01T00:00:00",
  "updated_at": "2024-01-01T00:00:00",
  "data": {
    "projectBeginn": "2025-01-01",
    "name": "Student Project",
    // ... full application data
  }
}
```

**Response (PDF):**
Binary PDF file with filled form.

---

#### PUT /applications/{pa_id}
Update application data.

**Parameters:**
- `pa_id` (path): Application ID

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Request Body:**
```json
{
  "projectBeginn": "2025-01-01",
  "name": "Updated Project Name",
  // ... fields to update
}
```

**Response:**
```json
{
  "pa_id": "25-0001",
  "data": {
    // ... updated application data
  }
}
```

---

#### DELETE /applications/{pa_id}
Delete an application (admin only).

**Parameters:**
- `pa_id` (path): Application ID

**Headers:**
- `X-MASTER-KEY` (required)

**Response:**
```json
{
  "detail": "Application deleted successfully"
}
```

---

### Attachment Management

#### GET /applications/{pa_id}/attachments
List all attachments for an application.

**Parameters:**
- `pa_id` (path): Application ID

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Response:**
```json
{
  "attachments": [
    {
      "id": 1,
      "filename": "receipt.pdf",
      "content_type": "application/pdf",
      "size": 102400,
      "created_at": "2024-01-01T00:00:00"
    }
  ],
  "total_count": 1,
  "total_size": 102400
}
```

---

#### POST /applications/{pa_id}/attachments
Upload a new attachment.

**Parameters:**
- `pa_id` (path): Application ID

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Request:**
- **Content-Type**: `multipart/form-data`
- **Body**:
  - `file` (required): File to upload

**Response:**
```json
{
  "id": 1,
  "filename": "receipt.pdf",
  "content_type": "application/pdf",
  "size": 102400,
  "created_at": "2024-01-01T00:00:00"
}
```

**Limits:**
- Maximum 30 attachments per application
- Maximum 100MB total size per application
- Maximum 50MB per file

---

#### GET /applications/{pa_id}/attachments/{attachment_id}
Download a specific attachment.

**Parameters:**
- `pa_id` (path): Application ID
- `attachment_id` (path): Attachment ID

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Response:**
Binary file data

---

#### DELETE /applications/{pa_id}/attachments/{attachment_id}
Delete an attachment.

**Parameters:**
- `pa_id` (path): Application ID
- `attachment_id` (path): Attachment ID

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Response:**
```json
{
  "detail": "Attachment deleted successfully"
}
```

---

### Comparison Offers

#### GET /applications/{pa_id}/costs/{cost_position_index}/offers
Get comparison offers for a cost position.

**Parameters:**
- `pa_id` (path): Application ID
- `cost_position_index` (path): Cost position index (0-based)

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Response:**
```json
{
  "cost_position_index": 0,
  "offers": [
    {
      "id": 1,
      "supplier_name": "Supplier A",
      "amount": 1000.00,
      "description": "Standard package",
      "url": "https://supplier-a.com/quote",
      "attachment_id": null,
      "is_preferred": false,
      "created_at": "2024-01-01T00:00:00"
    }
  ],
  "no_offers_required": false,
  "justification": null
}
```

---

#### POST /applications/{pa_id}/costs/{cost_position_index}/offers
Create a new comparison offer.

**Parameters:**
- `pa_id` (path): Application ID
- `cost_position_index` (path): Cost position index

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Request Body:**
```json
{
  "supplier_name": "Supplier A",
  "amount": 1000.00,
  "description": "Standard package",
  "url": "https://supplier-a.com/quote",
  "attachment_id": null,
  "is_preferred": false
}
```

**Response:**
```json
{
  "id": 1,
  "supplier_name": "Supplier A",
  "amount": 1000.00,
  "description": "Standard package",
  "url": "https://supplier-a.com/quote",
  "attachment_id": null,
  "is_preferred": false,
  "created_at": "2024-01-01T00:00:00"
}
```

---

#### PUT /applications/{pa_id}/costs/{cost_position_index}/offers/{offer_id}/preferred
Set an offer as preferred.

**Parameters:**
- `pa_id` (path): Application ID
- `cost_position_index` (path): Cost position index
- `offer_id` (path): Offer ID

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Response:**
```json
{
  "detail": "Preferred offer updated successfully"
}
```

---

#### DELETE /applications/{pa_id}/costs/{cost_position_index}/offers/{offer_id}
Delete a comparison offer.

**Parameters:**
- `pa_id` (path): Application ID
- `cost_position_index` (path): Cost position index
- `offer_id` (path): Offer ID

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Response:**
```json
{
  "detail": "Offer deleted successfully"
}
```

---

#### PUT /applications/{pa_id}/costs/{cost_position_index}/justification
Update justification for not requiring comparison offers.

**Parameters:**
- `pa_id` (path): Application ID
- `cost_position_index` (path): Cost position index

**Headers:**
- `X-PA-KEY` or `X-MASTER-KEY`

**Request Body:**
```json
{
  "no_offers_required": true,
  "justification": "This is a unique service provider with no alternatives..."
}
```

**Response:**
```json
{
  "detail": "Justification updated successfully"
}
```

---

## Rate Limiting

The API implements rate limiting to prevent abuse:

- **Per IP**: 60 requests per minute (configurable)
- **Per Key**: 30 requests per minute (configurable)
- **Excluded**: localhost and Docker internal IPs

Rate limit headers in responses:
- `X-RateLimit-Limit`: Maximum requests allowed
- `X-RateLimit-Remaining`: Requests remaining
- `X-RateLimit-Reset`: Unix timestamp when limit resets

---

## WebSocket Endpoints

Currently, the API does not provide WebSocket endpoints. All communication is via REST HTTP.

---

## Pagination

For endpoints that return lists, pagination may be implemented in future versions using:
- `limit`: Number of items per page
- `offset`: Starting position
- `page`: Page number (alternative to offset)

---

## Versioning

The API currently does not use versioning. Future versions may implement versioning via:
- URL path: `/v1/applications`
- Header: `Accept: application/vnd.stupa.v1+json`

---

## OpenAPI Documentation

Complete OpenAPI 3.0 documentation is available at:
- **Swagger UI**: `/docs`
- **ReDoc**: `/redoc`
- **OpenAPI JSON**: `/openapi.json`

These provide interactive documentation with the ability to test endpoints directly.