from typing import Union, List
from langchain.embeddings import HuggingFaceEmbeddings

class EmbeddingModel:
    """
    A flexible embedding model wrapper supporting multiple backend models.
    """

    def __init__(self, model_type: str = "huggingface", model_name: str = "all-MiniLM-L6-v2"):
        self.model_type = model_type
        self.model_name = model_name
        self.model = self._load_model()

    def _load_model(self):
        if self.model_type == "huggingface":
            return HuggingFaceEmbeddings(model_name=self.model_name)

        # Implementation for other model types can be added here

        else:
            raise ValueError(f"Unsupported model type: {self.model_type}")

    def embed(self, text: Union[str, List[str]]):
        """
        Generate embeddings for the given text.

        :param text: A string or list of strings.
        :return: A list of embeddings.
        """
        if self.model_type == "huggingface":

            if isinstance(text, list):
                return [self.model.embed_query(t) for t in text]
            return self.model.embed_query(text)

        elif self.model_type == "sentence_transformers":
            return self.model.encode(text, convert_to_tensor=True).tolist()

        else:
            raise NotImplementedError(f"Embedding for {self.model_type} is not implemented.")