# What is this?
## Helper utilities for cost_per_token()

import traceback
from typing import List, Literal, Optional, Tuple

import litellm
from litellm import verbose_logger


def _generic_cost_per_character(
    model: str,
    custom_llm_provider: str,
    prompt_characters: float,
    completion_characters: float,
    custom_prompt_cost: Optional[float],
    custom_completion_cost: Optional[float],
) -> Tuple[Optional[float], Optional[float]]:
    """
    Generic function to help calculate cost per character.
    """
    """
    Calculates the cost per character for a given model, input messages, and response object.

    Input:
        - model: str, the model name without provider prefix
        - custom_llm_provider: str, "vertex_ai-*"
        - prompt_characters: float, the number of input characters
        - completion_characters: float, the number of output characters

    Returns:
        Tuple[Optional[float], Optional[float]] - prompt_cost_in_usd, completion_cost_in_usd. 
        - returns None if not able to calculate cost.

    Raises:
        Exception if 'input_cost_per_character' or 'output_cost_per_character' is missing from model_info
    """
    args = locals()
    ## GET MODEL INFO
    model_info = litellm.get_model_info(
        model=model, custom_llm_provider=custom_llm_provider
    )

    ## CALCULATE INPUT COST
    try:
        if custom_prompt_cost is None:
            assert (
                "input_cost_per_character" in model_info
                and model_info["input_cost_per_character"] is not None
            ), "model info for model={} does not have 'input_cost_per_character'-pricing\nmodel_info={}".format(
                model, model_info
            )
            custom_prompt_cost = model_info["input_cost_per_character"]

        prompt_cost = prompt_characters * custom_prompt_cost
    except Exception as e:
        verbose_logger.error(
            "litellm.litellm_core_utils.llm_cost_calc.utils.py::cost_per_character(): Exception occured - {}\n{}\nDefaulting to None".format(
                str(e), traceback.format_exc()
            )
        )

        prompt_cost = None

    ## CALCULATE OUTPUT COST
    try:
        if custom_completion_cost is None:
            assert (
                "output_cost_per_character" in model_info
                and model_info["output_cost_per_character"] is not None
            ), "model info for model={} does not have 'output_cost_per_character'-pricing\nmodel_info={}".format(
                model, model_info
            )
            custom_completion_cost = model_info["output_cost_per_character"]
        completion_cost = completion_characters * custom_completion_cost
    except Exception as e:
        verbose_logger.error(
            "litellm.litellm_core_utils.llm_cost_calc.utils.py::cost_per_character(): Exception occured - {}\n{}\nDefaulting to None".format(
                str(e), traceback.format_exc()
            )
        )

        completion_cost = None

    return prompt_cost, completion_cost
