utils.py

from typing import List


def format_as_chat(message: str, history: List[List[str]]) -> str:
    """
    Given a message and a history of previous messages, returns a string that formats the conversation as a chat.
    Uses the format expected by Meta Llama 3 Instruct.

    :param message: A string containing the user's most recent message
    :param history: A list of lists of previous messages, where each sublist is a conversation turn:
        [[user_message1, assistant_reply1], [user_message2, assistant_reply2], ...]
    """
    formatted_prompt = "<|begin_of_text|>"

    if len(history) == 0:
        return formatted_prompt + f"<|start_header_id|>user<|end_header_id|>\n\n{message}<|eot_id|>"

    for conv_turn in history:
        prompt = f"<|start_header_id|>user<|end_header_id|>\n\n{
            conv_turn[0]}<|eot_id|>"
        reply = f"<|start_header_id|>assistant<|end_header_id|>\n\n{
            conv_turn[1]}<|eot_id|>"
        # Add conversation turn to full prompt
        formatted_prompt += prompt + reply

    # Add last message
    formatted_prompt += \
        f"<|start_header_id|>user<|end_header_id|>\n\n{message}<|eot_id|>"

    return formatted_prompt