import warnings
from typing import List, Optional, Tuple, Union

import numpy as np
import PIL
import torch
from accelerate import Accelerator, DistributedType
from accelerate.state import AcceleratorState
from decord import VideoReader, cpu
from torchvision.transforms.functional import to_pil_image
from tqdm import tqdm
from transformers import AutoConfig, AutoProcessor, MllamaForConditionalGeneration

from lmms_eval import utils
from lmms_eval.api.instance import Instance
from lmms_eval.api.model import lmms
from lmms_eval.api.registry import register_model

warnings.filterwarnings("ignore")

from loguru import logger as eval_logger

DEFAULT_IMAGE_TOKEN = "<|image|>"


@register_model("llama_vision")
class LlamaVision(lmms):
    def __init__(
        self,
        pretrained: str = "meta-llama/Llama-3.2-11B-Vision",
        revision: str = "main",
        device: str = "cuda",
        dtype: Optional[Union[str, torch.dtype]] = "auto",
        batch_size: int = 1,
        trust_remote_code: Optional[bool] = False,
        attn_implementation: Optional[str] = None,
        device_map: str = "",
        max_frames_num: Optional[int] = 32,
        **kwargs,
    ) -> None:
        super().__init__()
        # Do not use kwargs for now
        assert kwargs == {}, f"Unexpected kwargs: {kwargs}"

        accelerator = Accelerator()
        if accelerator.num_processes > 1 and device_map == "":
            self._device = torch.device(f"cuda:{accelerator.local_process_index}")
            self.device_map = f"cuda:{accelerator.local_process_index}"
        else:
            self._device = torch.device(device)
            self.device_map = device_map
        if isinstance(dtype, str) and dtype != "auto":
            dtype = getattr(torch, dtype)

        self.max_frames_num = max_frames_num
        self._model = MllamaForConditionalGeneration.from_pretrained(pretrained, revision=revision, torch_dtype=dtype, device_map=self.device_map, trust_remote_code=trust_remote_code, attn_implementation=attn_implementation)
        self.model.eval()
        self.processor = AutoProcessor.from_pretrained(pretrained)
        if accelerator.num_processes > 1 and device_map == "":
            assert accelerator.distributed_type in [DistributedType.FSDP, DistributedType.MULTI_GPU, DistributedType.DEEPSPEED], "Unsupported distributed type provided. Only DDP and FSDP are supported."
            # If you want to use DistributedType.DEEPSPEED, you have to run accelerate config before using the model
            # Also, you have to select zero stage 0 (equivalent to DDP) in order to make the prepare model works
            # I tried to set different parameters in the kwargs to let default zero 2 stage works, but it didn't work.
            if accelerator.distributed_type == DistributedType.DEEPSPEED:
                kwargs = {
                    "train_micro_batch_size_per_gpu": self.batch_size_per_gpu,
                    "train_batch_size": self.batch_size_per_gpu * accelerator.num_processes,
                }
                AcceleratorState().deepspeed_plugin.deepspeed_config_process(must_match=True, **kwargs)
                eval_logger.info("Detected that you are using DistributedType.DEEPSPEED. Make sure you run `accelerate config` and set zero stage to 0")
            if accelerator.distributed_type == DistributedType.FSDP or accelerator.distributed_type == DistributedType.DEEPSPEED:
                self._model = accelerator.prepare(self.model)
            else:
                self._model = accelerator.prepare_model(self.model, evaluation_mode=True)
            self.accelerator = accelerator
            if self.accelerator.is_local_main_process:
                eval_logger.info(f"Using {accelerator.num_processes} devices with data parallelism")
            self._rank = self.accelerator.local_process_index
            self._world_size = self.accelerator.num_processes
        elif accelerator.num_processes == 1 and device_map == "auto":
            eval_logger.info(f"Using {accelerator.num_processes} devices with pipeline parallelism")
            self._rank = 0
            self._world_size = 1
        else:
            eval_logger.info(f"Using single device: {self._device}")
            self.model.to(self._device)
            self._rank = 0
            self._world_size = 1
        self.accelerator = accelerator

    @property
    def config(self):
        # return the associated transformers.AutoConfig for the given pretrained model.
        return self._config

    @property
    def tokenizer(self):
        return self._tokenizer

    @property
    def model(self):
        # returns the model, unwrapping it if using Accelerate
        if hasattr(self, "accelerator"):
            return self.accelerator.unwrap_model(self._model)
        else:
            return self._model

    @property
    def eot_token_id(self):
        # we use EOT because end of *text* is more accurate for what we're doing than end of *sentence*
        return self.tokenizer.eos_token_id

    @property
    def max_length(self):
        return self._max_length

    @property
    def batch_size(self):
        return self.batch_size_per_gpu

    @property
    def device(self):
        return self._device

    @property
    def rank(self):
        return self._rank

    @property
    def world_size(self):
        return self._world_size

    def tok_encode(self, string: str, left_truncate_len=None, add_special_tokens=None) -> List[int]:
        """ """
        add_special_tokens = False if add_special_tokens is None else add_special_tokens
        encoding = self.tokenizer.encode(string, add_special_tokens=add_special_tokens)
        # left-truncate the encoded context to be at most `left_truncate_len` tokens long
        if left_truncate_len:
            encoding = encoding[-left_truncate_len:]
        return encoding

    def tok_decode(self, tokens):
        return self.tokenizer.decode(tokens)

    def loglikelihood(self, requests: List[Instance]) -> List[Tuple[float, bool]]:
        assert False, "Not implemented"

    def flatten(self, input):
        new_list = []
        for i in input:
            for j in i:
                new_list.append(j)
        return new_list

    def load_video(self, video_path, max_frames_num):
        if type(video_path) == str:
            vr = VideoReader(video_path, ctx=cpu(0))
        else:
            vr = VideoReader(video_path[0], ctx=cpu(0))
        total_frame_num = len(vr)
        uniform_sampled_frames = np.linspace(0, total_frame_num - 1, max_frames_num, dtype=int)
        frame_idx = uniform_sampled_frames.tolist()
        spare_frames = vr.get_batch(frame_idx).asnumpy()
        return spare_frames  # (frames, height, width, channels)

    def generate_until(self, requests: List[Instance]) -> List[str]:
        res = []

        pbar = tqdm(total=len(requests), disable=(self.rank != 0), desc="Model Responding")

        for contexts, gen_kwargs, doc_to_visual, doc_id, task, split in [reg.args for reg in requests]:
            visuals = [doc_to_visual(self.task_dict[task][split][doc_id])]
            visuals = self.flatten(visuals)

            messages = [{"role": "user", "content": []}]
            images = []

            for visual in visuals:
                if isinstance(visual, str):
                    frames = self.load_video(visual, self.max_frames_num)
                    frames = torch.from_numpy(frames).permute(0, 3, 1, 2)
                    images.extend([to_pil_image(frame) for frame in frames])
                elif isinstance(visual, PIL.Image.Image):
                    images.append(visual)

            for _ in range(len(images)):
                messages[-1]["content"].append({"type": "image"})
            messages[-1]["content"].append({"type": "text", "text": contexts})
            prompt = self.processor.apply_chat_template(messages, add_generation_prompt=True)
            inputs = self.processor(images, prompt, add_special_tokens=False, return_tensors="pt").to(self.model.device)

            if "max_new_tokens" not in gen_kwargs:
                gen_kwargs["max_new_tokens"] = 1024
            if "temperature" not in gen_kwargs:
                gen_kwargs["temperature"] = 0
            if "top_p" not in gen_kwargs:
                gen_kwargs["top_p"] = None
            if "num_beams" not in gen_kwargs:
                gen_kwargs["num_beams"] = 1
            if "do_sample" not in gen_kwargs:
                gen_kwargs["do_sample"] = False

            with torch.no_grad():
                output = self.model.generate(
                    **inputs,
                    max_new_tokens=gen_kwargs["max_new_tokens"],
                    temperature=gen_kwargs["temperature"],
                    do_sample=gen_kwargs["do_sample"],
                )
                output = output[:, inputs["input_ids"].shape[-1] :]
                res.append(self.processor.decode(output[0], skip_special_tokens=True))

            pbar.update(1)
        pbar.close()
        return res

    def generate_until_multi_round(self, requests) -> List[str]:
        raise NotImplementedError("TODO: Implement multi-round generation for LLaVAHF")
