{
  description = "A simple flake";

  inputs.nixpkgs.url = "nixpkgs/nixos-unstable";

  outputs = { self, nixpkgs }: {

    defaultPackage.x86_64-linux = let
      pkgs = nixpkgs.legacyPackages.x86_64-linux;
      python = pkgs.python311;
      pythonPackages = python.pkgs;

      piper_model_url = "https://huggingface.co/rhasspy/piper-voices/resolve/v1.0.0/en/en_US/hfc_female/medium/en_US-hfc_female-medium.onnx?download=true";
      piper_model_json_url = "https://huggingface.co/rhasspy/piper-voices/resolve/v1.0.0/en/en_US/hfc_female/medium/en_US-hfc_female-medium.onnx.json?download=true.json";
      whisper_model_tiny_url = "https://huggingface.co/ggerganov/whisper.cpp/resolve/main/ggml-tiny.bin?download=true";
      whisper_model_base_url = "https://huggingface.co/ggerganov/whisper.cpp/resolve/main/ggml-base.bin?download=true";
      whisper_model_small_url = "https://huggingface.co/ggerganov/whisper.cpp/resolve/main/ggml-small.bin?download=true";
      whisper_model_small_tdrz_url = "https://huggingface.co/akashmjn/tinydiarize-whisper.cpp/resolve/main/ggml-small.en-tdrz.bin?download=true";
      haracascade_face_url = "https://raw.githubusercontent.com/opencv/opencv/master/data/haarcascades/haarcascade_frontalface_default.xml";

      piper_model = pkgs.fetchurl {
        name = "hfc_female/medium/en_US-hfc_female-medium.onnx";
        url = piper_model_url;
        sha256 = "sha256-kUxHN4j8H6i2Os4c3NtEWI9K5SPTqzffFTZhaDWhQLc="; # replace with the correct sha256
      };

      piper_model_json = pkgs.fetchurl {
        name = "hfc_female/medium/en_US-hfc_female-medium.onnx.json";
        url = piper_model_json_url;
        sha256 = "sha256-A/H6BiK4BGMoNZLZesqfbomuw0WlxWtyV3I+AJPFi2w="; # replace with the correct sha256
      };

      whisper_model_tiny = pkgs.fetchurl {
        name = "ggml-tiny.bin";
        url = whisper_model_tiny_url;
        sha256 = "sha256-vgfgSOHlma1GNByNKhNWRQl6U4IhZ4t6zdGxkZxuGyE=";
      };

      whisper_model_base = pkgs.fetchurl {
        name = "ggml-base.bin";
        url = whisper_model_base_url;
        sha256 = "sha256-YO1bw90U7qhWST0zQ0m0BXgt3K8AKNS130CINF+6Lv4=";
      };
      whisper_model_small = pkgs.fetchurl {
        name = "ggml-small.bin";
        url = whisper_model_small_url;
        sha256 = "sha256-G+OpsgY4Z7k35k4ux0gzZKeZF+FX+pjF2UtcH//qmHs=";
      };

      whisper_model_small_tdrz = pkgs.fetchurl {
        name = "ggml-small.en-tdrz.bin";
        url = whisper_model_small_url;
        sha256 = "sha256-G+OpsgY4Z7k35k4ux0gzZKeZF+FX+pjF2UtcH//qmHs=";
      };

      haracascade_face = pkgs.fetchurl {
        name = "haarcascade_frontalface_default.xml";
        url = haracascade_face_url;
        sha256 = "sha256-D31FJ4ROtRTUpJSOgi2pD7sWo0oLu7xq3GSYdHpar7A=";
      };




    in pkgs.mkShell {
      nativeBuildInputs = with pkgs; [
        python
        piper-tts
        alsa-utils # for aplay for piper-tts to stream to
        openai-whisper-cpp # for stt
        opencv
        
        (pythonPackages.numpy)
        (pythonPackages.pytorch)

        (pythonPackages.langchain)
        (pythonPackages.mwxml)
        (pythonPackages.mwparserfromhell) #dependency langchain document fetcher
        (pythonPackages.sentence-transformers) #dependency for langchain embedding
        (pythonPackages.chromadb) #vector search
        (pythonPackages.opencv4)
        (pythonPackages.pillow)

      ];
      
      WHISPER_AUDIO_DEVICE = "1";
      WHISPER_MODEL_PATH = whisper_model_tiny;
      PIPER_MODEL_PATH = piper_model;
      PIPER_MODEL_JSON_PATH =piper_model_json;
      HARA_CASCADE_FACE_PATH = haracascade_face;
      OLLAMA_HOST = "http://localhost:11434";
      IMAGE_DESCRIPTION_CAMERA = "0";
      IMAGE_DESCRIPTION_MODEL = "llava";


      shellHook = ''
        #need to set ollama url first, before pulling models needed for the project
        ollama pull llava
        ollama pull llama3
      '';

    };
  };
}