# Graph with Reflection and Rewriting Nodes

This project demonstrates a simple data processing graph in **Python** that uses **LangChain** with **OpenAI** or **Ollama** to perform reflection and rewriting of text.  
The graph is built from reusable node classes and can be extended with additional nodes as needed.

## Features

- **ReflectionNode** – Generates reflective insights from input text using an LLM.
- **RewritingNode** – Rewrites the reflection in a specified style (e.g., formal, concise).
- **Graph** – Connects nodes and executes them in sequence.
- **Configurable LLM provider** – Switch between OpenAI and Ollama via the `LLM_PROVIDER` environment variable.
- **Unit tests** – Verify node behavior with mocked LLM responses.

## Requirements

- Python 3.10+
- `langchain`
- `openai` (for OpenAI provider)
- `python-dotenv` (optional, for loading environment variables)

Install dependencies:

```bash
pip install -r requirements.txt
```

## Configuration

Set the LLM provider by defining the `LLM_PROVIDER` environment variable:

```bash
export LLM_PROVIDER=openai   # or ollama
```

If using OpenAI, ensure that the `OPENAI_API_KEY` environment variable is set.  
If using Ollama, ensure that the Ollama server is running locally and the model name matches the one configured in `src/llm_integration.py`.

## Usage

Run the graph with a text input:

```bash
python -m src.main "Your input text goes here."
```

Or pipe text via stdin:

```bash
echo "Some text" | python -m src.main
```

The output will be the rewritten text produced by the `RewritingNode`.

## Running Tests

Execute the test suite with:

```bash
python -m unittest discover tests
```

## Project Structure

```
src/
├── llm_integration.py   # LLM client factory
├── nodes.py             # Node definitions
├── graph.py            # Graph construction and execution
└── main.py              # CLI entry point
tests/
└── test_nodes.py        # Unit tests for nodes
requirements.txt
README.md
```

## Extending the Graph

To add new nodes:

1. Create a new class inheriting from `BaseNode` in `src/nodes.py`.
2. Implement the `process` method.
3. Add the node to the graph in `src/graph.py` and connect it with `add_edge`.

## License

MIT License