import os
from sentence_transformers import SentenceTransformer

class ModelManager:
    def __init__(self, default_model="all-MiniLM-L6-v2"):
        self.current_model_name = default_model
        self.model = SentenceTransformer(default_model)
        self.available_models = [
            "all-MiniLM-L6-v2",
            "paraphrase-MiniLM-L3-v2",
            "multi-qa-MiniLM-L6-cos-v1"
        ]

    def switch_model(self, model_name):
        if model_name not in self.available_models:
            raise ValueError(f"Model '{model_name}' is not in the list of available models.")
        self.current_model_name = model_name
        self.model = SentenceTransformer(model_name)
        return f"Switched to model: {model_name}"

    def get_current_model(self):
        return self.current_model_name

    def list_models(self):
        return self.available_models