import logging
import os
import json
from pathlib import Path
from typing import List

import torch
import numpy

from towhee import register
from towhee.operator.base import NNOperator
from towhee.types.video_frame import VideoFrame
from towhee.models.utils.video_transforms import transform_video
from towhee.models import timesformer

log = logging.getLogger()


@register(output_schema=['labels', 'scores', 'features'])
class Timesformer(NNOperator):
    """
    Generate a list of class labels given a video input data.
    Default labels are from [Kinetics400 Dataset](https://deepmind.com/research/open-source/kinetics).

    Args:
        model_name (`str`):
            Supported model names:
            - timesformer_k400_8x224
        skip_preprocess (`str`):
            Flag to skip video transforms.
        classmap (`dict=None`):
            The dictionary maps classes to integers.
        topk (`int=5`):
            The number of classification labels to be returned (ordered by possibility from high to low).
    """
    def __init__(self,
                 model_name: str = 'timesformer_k400_8x224',
                 framework: str = 'pytorch',
                 skip_preprocess: bool = False,
                 classmap: dict = None,
                 topk: int = 5,
                 ):
        super().__init__(framework=framework)
        self.model_name = model_name
        self.skip_preprocess = skip_preprocess
        self.topk = topk
        if classmap is None:
            class_file = os.path.join(str(Path(__file__).parent), 'kinetics_400.json')
            with open(class_file, 'r') as f:
                kinetics_classes = json.load(f)
            self.classmap = {}
            for k, v in kinetics_classes.items():
                self.classmap[v] = str(k).replace('"', '')
        else:
            self.classmap = classmap
        self.device = 'cuda' if torch.cuda.is_available() else 'cpu'

        self.model = timesformer.create_model(model_name=model_name, pretrained=True, device=self.device)
        self.cfg = timesformer.get_configs(model_name=model_name)
        self.cfg.update(side_size=self.cfg['img_size'], crop_size=self.cfg['img_size'])

    def __call__(self, video: List[VideoFrame]):
        """
        Args:
            video (`List[VideoFrame]`):
                Video path in string.

        Returns:
            (labels, scores)
                A tuple of lists (labels, scores).
            OR emb
                Video embedding.
        """
        # Convert list of towhee.types.Image to numpy.ndarray in float32
        video = numpy.stack([img.astype(numpy.float32)/255. for img in video], axis=0)
        assert len(video.shape) == 4
        video = video.transpose(3, 0, 1, 2)  # twhc -> ctwh

        # Transform video data given configs
        if self.skip_preprocess:
            self.cfg.update(num_frames=None)

        data = transform_video(
            video=video,
            **self.cfg
        )
        inputs = data.to(self.device)[None, ...]

        feats = self.model.forward_features(inputs)
        features = feats.to('cpu').squeeze(0).detach().numpy()

        outs = self.model.head(feats)
        post_act = torch.nn.Softmax(dim=1)
        preds = post_act(outs)
        pred_scores, pred_classes = preds.topk(k=self.topk)
        labels = [self.classmap[int(i)] for i in pred_classes[0]]
        scores = [round(float(x), 5) for x in pred_scores[0]]

        return labels, scores, features