## ADDED Requirements

### Requirement: Upload endpoint
The system SHALL provide a `POST /api/upload` endpoint that accepts a CSV file via multipart form data. The endpoint SHALL parse the CSV using papaparse, validate the format, and insert all candle records into the `candles` table within a single database transaction. On success, the endpoint SHALL return a JSON response with the count of inserted records. On failure, it SHALL return an appropriate error status and message.

#### Scenario: Successful upload
- **WHEN** a valid CSV file is sent to POST /api/upload
- **THEN** endpoint returns `{ "success": true, "count": <number> }` with HTTP 200

#### Scenario: Invalid CSV upload
- **WHEN** a CSV with missing or invalid headers is sent to POST /api/upload
- **THEN** endpoint returns `{ "error": "<description>" }` with HTTP 400

#### Scenario: No file provided
- **WHEN** POST /api/upload is called without a file
- **THEN** endpoint returns `{ "error": "No file provided" }` with HTTP 400

### Requirement: Get annotations endpoint
The system SHALL provide a `GET /api/annotations` endpoint that returns all annotations from the database as a JSON array. Each annotation object SHALL include: `id`, `timestamp`, `label_type`, `geometry` (parsed from JSON string or null), and `created_at`.

#### Scenario: Fetch all annotations
- **WHEN** GET /api/annotations is called
- **THEN** endpoint returns a JSON array of all annotation objects with HTTP 200

#### Scenario: No annotations exist
- **WHEN** GET /api/annotations is called and no annotations are in the database
- **THEN** endpoint returns an empty JSON array `[]` with HTTP 200

### Requirement: Create annotation endpoint
The system SHALL provide a `POST /api/annotations` endpoint that accepts a JSON body with fields: `timestamp` (required, integer), `label_type` (required, string), and `geometry` (optional, object). The endpoint SHALL validate the input, serialize geometry to JSON string if present, and insert the record into the `annotations` table. On success, it SHALL return the created annotation object with its assigned `id`.

#### Scenario: Create a marker annotation
- **WHEN** POST /api/annotations is called with `{ "timestamp": 1700000000, "label_type": "break_up" }`
- **THEN** endpoint saves the annotation and returns the created object with `id` and HTTP 201

#### Scenario: Create a line annotation
- **WHEN** POST /api/annotations is called with `{ "timestamp": 1700000000, "label_type": "line", "geometry": { "startTime": 1700000000, "startPrice": 1.05, "endTime": 1700100000, "endPrice": 1.06 } }`
- **THEN** endpoint saves the annotation with serialized geometry JSON and returns the created object with HTTP 201

#### Scenario: Invalid annotation data
- **WHEN** POST /api/annotations is called with missing required fields
- **THEN** endpoint returns `{ "error": "<description>" }` with HTTP 400

### Requirement: Delete annotation endpoint
The system SHALL provide a `DELETE /api/annotations/[id]` endpoint that removes an annotation by its ID. On success, it SHALL return HTTP 200. If the annotation does not exist, it SHALL return HTTP 404.

#### Scenario: Delete existing annotation
- **WHEN** DELETE /api/annotations/5 is called and annotation with id 5 exists
- **THEN** endpoint removes the annotation and returns HTTP 200

#### Scenario: Delete non-existent annotation
- **WHEN** DELETE /api/annotations/999 is called and no annotation with that id exists
- **THEN** endpoint returns HTTP 404

### Requirement: Export annotations endpoint
The system SHALL provide a `GET /api/export` endpoint that returns all annotations as a downloadable CSV file. The CSV SHALL have columns: `timestamp`, `label_type`, `price` (extracted from geometry for lines, or the candle's close price for markers). The response SHALL set `Content-Type: text/csv` and `Content-Disposition: attachment; filename="annotations.csv"` headers.

#### Scenario: Export as CSV
- **WHEN** GET /api/export is called and annotations exist
- **THEN** endpoint returns a CSV file download with all annotations

#### Scenario: Export with no data
- **WHEN** GET /api/export is called and no annotations exist
- **THEN** endpoint returns a CSV file with only the header row

### Requirement: Get candles endpoint
The system SHALL provide a `GET /api/candles` endpoint that returns all candle records from the database as a JSON array, ordered by time ascending. Each object SHALL include: `time`, `open`, `high`, `low`, `close`.

#### Scenario: Fetch all candles
- **WHEN** GET /api/candles is called
- **THEN** endpoint returns a JSON array of candle objects ordered by time ascending with HTTP 200

#### Scenario: No candles exist
- **WHEN** GET /api/candles is called and no candle data is in the database
- **THEN** endpoint returns an empty JSON array `[]` with HTTP 200
