import copy
import warnings
from dataclasses import dataclass
from typing import Callable, List, Optional

import torch
from torch import nn
from transformers.generation.utils import LogitsProcessorList, StoppingCriteriaList
from transformers.utils import logging

logger = logging.get_logger(__name__)


@dataclass
class GenerationConfig:
    max_length: int = 64
    top_p: float = 0.8
    temperature: float = 0.8
    do_sample: bool = True
    repetition_penalty: float = 1.0


@torch.inference_mode()
def generate_interactive(
    model,
    tokenizer,
    prompt,
    generation_config: Optional[GenerationConfig] = None,
    logits_processor: Optional[LogitsProcessorList] = None,
    stopping_criteria: Optional[StoppingCriteriaList] = None,
    prefix_allowed_tokens_fn: Optional[Callable[[int, torch.Tensor], List[int]]] = None,
    additional_eos_token_id: Optional[int] = None,
    **kwargs,
):
    inputs = tokenizer([prompt], padding=True, return_tensors="pt")
    input_length = len(inputs["input_ids"][0])
    for k, v in inputs.items():
        inputs[k] = v.cuda()
    input_ids = inputs["input_ids"]
    batch_size, input_ids_seq_length = input_ids.shape[0], input_ids.shape[-1]  # noqa: F841  # pylint: disable=W0612
    if generation_config is None:
        generation_config = model.generation_config
    generation_config = copy.deepcopy(generation_config)
    model_kwargs = generation_config.update(**kwargs)
    bos_token_id, eos_token_id = (  # noqa: F841  # pylint: disable=W0612
        generation_config.bos_token_id,
        generation_config.eos_token_id,
    )
    if isinstance(eos_token_id, int):
        eos_token_id = [eos_token_id]
    if additional_eos_token_id is not None:
        eos_token_id.append(additional_eos_token_id)
    has_default_max_length = kwargs.get("max_length") is None and generation_config.max_length is not None
    if has_default_max_length and generation_config.max_new_tokens is None:
        warnings.warn(
            f"Using `max_length`'s default ({generation_config.max_length}) to control the generation length. "
            "This behaviour is deprecated and will be removed from the config in v5 of Transformers -- we"
            " recommend using `max_new_tokens` to control the maximum length of the generation.",
            UserWarning,
        )
    elif generation_config.max_new_tokens is not None:
        generation_config.max_length = generation_config.max_new_tokens + input_ids_seq_length
        if not has_default_max_length:
            logger.warn(  # pylint: disable=W4902
                f"Both `max_new_tokens` (={generation_config.max_new_tokens}) and `max_length`(="
                f"{generation_config.max_length}) seem to have been set. `max_new_tokens` will take precedence. "
                "Please refer to the documentation for more information. "
                "(https://huggingface.co/docs/transformers/main/en/main_classes/text_generation)",
                UserWarning,
            )

    if input_ids_seq_length >= generation_config.max_length:
        input_ids_string = "input_ids"
        logger.warning(
            f"Input length of {input_ids_string} is {input_ids_seq_length}, but `max_length` is set to"
            f" {generation_config.max_length}. This can lead to unexpected behavior. You should consider"
            " increasing `max_new_tokens`."
        )

    # 2. Set generation parameters if not already defined
    logits_processor = logits_processor if logits_processor is not None else LogitsProcessorList()
    stopping_criteria = stopping_criteria if stopping_criteria is not None else StoppingCriteriaList()

    logits_processor = model._get_logits_processor(
        generation_config=generation_config,
        input_ids_seq_length=input_ids_seq_length,
        encoder_input_ids=input_ids,
        prefix_allowed_tokens_fn=prefix_allowed_tokens_fn,
        logits_processor=logits_processor,
    )

    stopping_criteria = model._get_stopping_criteria(
        generation_config=generation_config, stopping_criteria=stopping_criteria
    )
    logits_warper = model._get_logits_warper(generation_config)

    unfinished_sequences = input_ids.new(input_ids.shape[0]).fill_(1)
    scores = None
    while True:
        model_inputs = model.prepare_inputs_for_generation(input_ids, **model_kwargs)
        # forward pass to get next token
        outputs = model(
            **model_inputs,
            return_dict=True,
            output_attentions=False,
            output_hidden_states=False,
        )

        next_token_logits = outputs.logits[:, -1, :]

        # pre-process distribution
        next_token_scores = logits_processor(input_ids, next_token_logits)
        next_token_scores = logits_warper(input_ids, next_token_scores)

        # sample
        probs = nn.functional.softmax(next_token_scores, dim=-1)
        if generation_config.do_sample:
            next_tokens = torch.multinomial(probs, num_samples=1).squeeze(1)
        else:
            next_tokens = torch.argmax(probs, dim=-1)

        # update generated ids, model inputs, and length for next step
        input_ids = torch.cat([input_ids, next_tokens[:, None]], dim=-1)
        model_kwargs = model._update_model_kwargs_for_generation(outputs, model_kwargs, is_encoder_decoder=False)
        unfinished_sequences = unfinished_sequences.mul((min(next_tokens != i for i in eos_token_id)).long())

        output_token_ids = input_ids[0].cpu().tolist()
        output_token_ids = output_token_ids[input_length:]
        for each_eos_token_id in eos_token_id:
            if output_token_ids[-1] == each_eos_token_id:
                output_token_ids = output_token_ids[:-1]
        response = tokenizer.decode(output_token_ids)

        yield response
        # stop when each sentence is finished, or if we exceed the maximum length
        if unfinished_sequences.max() == 0 or stopping_criteria(input_ids, scores):
            break