from typing import List, Tuple, Dict, Optional


class QAPrompt:
    def __init__(self):
        super().__init__()
        self._template = """
'Use the following pieces of context to answer the question at the end.
If you don''t know the answer, just say that you don''t know, don''t try to make
up an answer.

{context}

Question: {question}

Helpful Answer:'
"""

    def __call__(self, question: str, docs: List[str], history=Optional[List[Tuple]]) -> List[Dict[str, str]]:
        """
        history:
            List[Tuple]: [(question1, answer1), (question2, answer2)]
        """
        context = '\n'.join(docs)
        prompt_str = self._template.format(context=context, question=question)
        ret = [{'question': prompt_str}]
        if not isinstance(history, list):
            return ret
        else:
            history_data = []
            for item in history:
                history_data.append({'question': item[0], 'answer': item[1]})
            return history + ret