import os
import pickle

from dassl.data.datasets import DATASET_REGISTRY, Datum, DatasetBase
from dassl.utils import mkdir_if_missing

from .oxford_pets import OxfordPets
from .dtd import DescribableTextures as DTD


@DATASET_REGISTRY.register()
class Food101(DatasetBase):

    dataset_dir = "food-101"

    def __init__(self, cfg):
        root = os.path.abspath(os.path.expanduser(cfg.DATASET.ROOT))
        self.dataset_dir = os.path.join(root, self.dataset_dir)
        self.image_dir = os.path.join(self.dataset_dir, "images")
        self.split_path = os.path.join(self.dataset_dir, "split_zhou_Food101.json")
        self.split_fewshot_dir = os.path.join(self.dataset_dir, "split_fewshot")
        mkdir_if_missing(self.split_fewshot_dir)

        if os.path.exists(self.split_path):
            train, val, test = OxfordPets.read_split(self.split_path, self.image_dir)
        else:
            train, val, test = DTD.read_and_split_data(self.image_dir)
            OxfordPets.save_split(train, val, test, self.split_path, self.image_dir)

        ### given/query/db
        from .eurosat import split_test_into_given_query_db
        test_given, test_query, test_db = split_test_into_given_query_db(test)

        num_shots = cfg.DATASET.NUM_SHOTS
        if num_shots >= 1:
            seed = cfg.SEED
            preprocessed = os.path.join(self.split_fewshot_dir, f"shot_{num_shots}-seed_{seed}.pkl")
            
            if os.path.exists(preprocessed):
                print(f"Loading preprocessed few-shot data from {preprocessed}")
                with open(preprocessed, "rb") as file:
                    data = pickle.load(file)
                    train, val = data["train"], data["val"]
            else:
                train = self.generate_fewshot_dataset(train, num_shots=num_shots)
                val = self.generate_fewshot_dataset(val, num_shots=min(num_shots, 4))
                data = {"train": train, "val": val}
                print(f"Saving preprocessed few-shot data to {preprocessed}")
                with open(preprocessed, "wb") as file:
                    pickle.dump(data, file, protocol=pickle.HIGHEST_PROTOCOL)

        subsample = cfg.DATASET.SUBSAMPLE_CLASSES

        train, val, test, test_given, test_query, test_db = OxfordPets.subsample_classes(train, val, test, test_given,
                                                                                         test_query, test_db,
                                                                                         subsample=subsample)
        super().__init__(train_x=train, val=val, test=test, test_given=test_given, test_query=test_query,
                         test_db=test_db)
