# Invoice Generator

A powerful and flexible command-line tool for generating PDF invoices from simple JSON data files. It features an interactive mode for ease of use and a robust, non-interactive mode for scripting and automation.

## Features

- **Interactive & Non-Interactive Modes**: Use the simple interactive wizard (`npm start`) or pass arguments directly for scripted use.
- **Safe Preview-First Workflow**: Always generates a development preview first. You must confirm before the official invoice is created and recorded, preventing accidental invoice generation.
- **Data-Driven**: Senders, clients, and products are managed in simple `.json` files, making them easy to update without changing code.
- **Automatic Invoice Numbering**: Invoice numbers are automatically incremented based on the year and existing records. The sequence resets annually.
- **Organized Output**: Generated PDFs are neatly stored in folders organized by sender (`invoice/<sender_name>/`).
- **Unit Tested**: Core logic is verified with unit tests using Jest.

## Prerequisites

- [Node.js](https://nodejs.org/) (v16 or higher recommended)
- [npm](https://www.npmjs.com/) (comes with Node.js)

## Setup

1.  Clone the repository or download the source code.
2.  Open your terminal in the project directory.
3.  Install the dependencies:
    ```bash
    npm install
    ```

## Usage

There are two primary ways to generate an invoice:

### 1. Interactive Mode (Recommended for most users)

Run the interactive wizard. The tool will guide you through selecting a sender, client, and one or more products.

```bash
npm start
```

The script will first generate a **development preview** PDF. After you review it, you will be prompted to confirm whether you want to create the final **production** invoice.

### 2. Non-Interactive / Scripted Mode

You can also generate an invoice by passing command-line arguments. This is useful for automation and scripting.

The basic command is:
`npm run generate -- --sender <sender_key> --client <client_key> --products <product_key_1> <product_key_2>`

**Example:**

```bash
npm run generate -- --sender company1 --client company4 --products linkedin_scraper web_design
```

Like the interactive mode, this will also generate a preview and prompt for confirmation before creating the production invoice.

### Running Tests

To run the automated tests for the project:

```bash
npm test
```

## How the Data Files Work

All data is managed in the `data/` directory.

### `sender.json`

Stores your company or sender profiles. Each key represents a unique sender.

```json
{
  "company1": { "company": "Your Company", "address": ... },
  "company2": { "company": "Another Profile", "address": ... }
}
```

### `client.json`

Stores your client profiles. The `invoiceFileName` key is optional; if provided, it will be used for the generated PDF's filename.

```json
{
  "company3": { "company": "First Client", "address": ... },
  "company4": { "company": "Second Client", "invoiceFileName": "second_client_invoices", "address": ... }
}
```

### `products.json`

A catalog of the services or products you offer.

```json
{
  "linkedin_scraper": {
    "description": "LinkedIn Scraper Bot",
    "price": 250,
    "taxRate": 0
  },
  "web_design": { "description": "Website Design", "price": 1200, "taxRate": 0 }
}
```

### `invoices.json`

This file is your ledger. It's **automatically updated** when you create a production invoice. It tracks all generated invoices to determine the next sequential number. You should not need to edit this file manually.

```json
{
  "invoices": [
    {
      "number": "2024-0001",
      "date": "2024-07-31",
      ...
    }
  ]
}
```