import torch
import sentencepiece
from transformers import AutoModelForCausalLM, AutoTokenizer, pipeline
from langchain import PromptTemplate,  LLMChain, HuggingFacePipeline
import ast
class Models():
    def __init__(self) -> None:
        self.template = """
              A virtual assistant answers questions from a user based on the provided text.
              USER: Text: {input_text}
              ASSISTANT: I’ve read this text.
              USER: What describes {entity_type} in the text?
              ASSISTANT:
            """
        self.load_trained_models()
        
    def load_trained_models(self):
        #is it best to keep in memory why not pickle?
        checkpoint = "Universal-NER/UniNER-7B-all"
        
        ner_model = AutoModelForCausalLM.from_pretrained(checkpoint, device_map="auto", torch_dtype=torch.float16, offload_folder="offload", offload_state_dict = True)
        tokenizer = AutoTokenizer.from_pretrained("Universal-NER/UniNER-7B-all", use_fast=False, padding="max_length")
        hf_pipeline = pipeline(
            "text-generation", #task
            model=ner_model,
            max_length=1000,
            tokenizer=tokenizer,
            trust_remote_code=True,
            do_sample=True,
            top_k=10,
            num_return_sequences=1
        )
    
        self.llm = HuggingFacePipeline(pipeline = hf_pipeline, model_kwargs = {'temperature':0})
        self.prompt = PromptTemplate(template=self.template, input_variables=["input_text","entity_type"])
        self.llm_chain = LLMChain(prompt=self.prompt, llm=self.llm)
        
    def extract_ner(self, context, entity_type):
        return ast.literal_eval(self.llm_chain.run({"input_text":context,"entity_type":entity_type}))
    
    def get_ner(self, clean_lines, entity):
        tokens = []
        try_num = 0
        while try_num < 5 and tokens == []:
            tokens = self.extract_ner(' '.join(clean_lines), entity)
        if len(tokens) == 0:
            raise ValueError("Couldnt extract {entity}")
        return tokens