"""API factory."""

import functools
import os.path as osp

import albumentations as alb
import torch
from xirl import models
from xirl import transforms

TRANSFORMS = {
    "random_resized_crop":
        functools.partial(
            alb.RandomResizedCrop, scale=(0.8, 1.0), ratio=(0.75, 1.333),
            p=1.0),
    "center_crop":
        functools.partial(alb.CenterCrop, p=1.0),
    "global_resize":
        functools.partial(alb.Resize, p=1.0),
    "grayscale":
        functools.partial(alb.ToGray, p=0.2),
    "vertical_flip":
        functools.partial(alb.VerticalFlip, p=0.5),
    "horizontal_flip":
        functools.partial(alb.HorizontalFlip, p=0.5),
    "gaussian_blur":
        functools.partial(
            alb.GaussianBlur,
            blur_limit=(13, 13),
            sigma_limit=(1.0, 2.0),
            p=0.2,
        ),
    "color_jitter":
        functools.partial(
            alb.ColorJitter,
            brightness=0.4,
            contrast=0.4,
            hue=0.1,
            saturation=0.1,
            p=0.8,
        ),
    "rotate":
        functools.partial(alb.Rotate, limit=(-5, 5), border_mode=0, p=0.5),
    "normalize":
        functools.partial(
            alb.Normalize,
            mean=transforms.PretrainedMeans.IMAGENET,
            std=transforms.PretrainedStds.IMAGENET,
            p=1.0,
        ),
}

MODELS = {
    "resnet18_linear": models.Resnet18LinearEncoderNet,
    "resnet18_clip_linear": models.Resnet18LinearEncoderAndTextEncoderNet,
    "resnet18_classifier": models.GoalClassifier,
    "resnet18_features": models.Resnet18RawImageNetFeaturesNet,
    "resnet18_linear_ae": models.Resnet18LinearEncoderAutoEncoderNet,
}

def model_from_config(config):
    """Create a model from a config."""
    kwargs = {
        "num_ctx_frames": config.frame_sampler.num_context_frames,
        "normalize_embeddings": config.model.normalize_embeddings,
        "learnable_temp": config.model.learnable_temp,
    }
    if config.model.model_type == "resnet18_linear":
        kwargs["embedding_size"] = config.model.embedding_size
    elif config.model.model_type == "resnet18_clip_linear":
        kwargs["embedding_size"] = config.model.embedding_size
    elif config.model.model_type == "resnet18_linear_ae":
        kwargs["embedding_size"] = config.model.embedding_size
    return MODELS[config.model.model_type](**kwargs)

def create_transform(name, *args, **kwargs):
    """Create an image augmentation from its name and args."""
    # pylint: disable=invalid-name
    if "::" in name:
        # e.g., `rotate::{'limit': (-45, 45)}`
        name, __kwargs = name.split("::")
        _kwargs = eval(__kwargs)  # pylint: disable=eval-used
    else:
        _kwargs = {}
    _kwargs.update(kwargs)
    return TRANSFORMS[name](*args, **_kwargs)

def dataset_from_config(config, downstream, split, debug):
    """Create a video dataset from a config."""
    dataset_path = osp.join(config.data.root, split)

    image_size = config.data_augmentation.image_size
    if isinstance(image_size, int):
        image_size = (image_size, image_size)
    image_size = tuple(image_size)

    # Note(kevin): We used to disable data augmentation on all downstream
    # dataloaders. I've decided to keep them for train downstream loaders.
    if debug:
        # The minimum data augmentation we want to keep is resizing when
        # debugging.
        aug_names = ["global_resize"]
    else:
        if split == "train":
            aug_names = config.data_augmentation.train_transforms
        else:
            aug_names = config.data_augmentation.eval_transforms

    # Create a list of data augmentation callables.
    aug_funcs = []
    for name in aug_names:
        if "resize" in name or "crop" in name:
            aug_funcs.append(create_transform(name, *image_size))
        else:
            aug_funcs.append(create_transform(name))

    augmentor = transforms.VideoAugmentor({SequenceType.FRAMES: aug_funcs})

    # Restrict action classes if they have been provided. Else, load all
    # from the data directory.
    c_action_class = (
        config.data.downstream_action_class
        if downstream else config.data.pretrain_action_class
    )
    if c_action_class:
        action_classes = c_action_class
    else:
        action_classes = get_subdirs(
            dataset_path,
            basename=True,
            nonempty=True,
            sort_lexicographical=True,
        )

    # We need to separate out the dataclasses for each action class when
    # creating downstream datasets.
    if downstream:
        dataset = {}
        for action_class in action_classes:
            frame_sampler = frame_sampler_from_config(config, downstream=True)
            single_class_dataset = VideoDataset(
                dataset_path,
                frame_sampler,
                seed=config.seed,
                augmentor=augmentor,
                max_vids_per_class=config.data.max_vids_per_class,
            )
            single_class_dataset.restrict_subdirs(action_class)
            dataset[action_class] = single_class_dataset
    else:
        frame_sampler = frame_sampler_from_config(config, downstream=False)
        dataset = VideoDataset(
            dataset_path,
            frame_sampler,
            seed=config.seed,
            augmentor=augmentor,
            max_vids_per_class=config.data.max_vids_per_class,
        )
        dataset.restrict_subdirs(action_classes)

    return dataset