import numpy as np
from sklearn.preprocessing import (
    MinMaxScaler,
    StandardScaler,
    RobustScaler,
    PowerTransformer
)


def process_data(data, dense_col=None, normalizer="min_max",
                 transformer=("log", "sqrt", "square")):

    if not dense_col:
        print("nothing to preprocessing...")
        return data

    if not isinstance(dense_col, list):
        raise ValueError("dense_col must be a list...")

    if normalizer.lower() == "min_max":
        scaler = MinMaxScaler()
    elif normalizer.lower() == "standard":
        scaler = StandardScaler()
    elif normalizer.lower() == "robust":
        scaler = RobustScaler()
    elif normalizer.lower() == "power":
        scaler = PowerTransformer()
    else:
        raise ValueError("unknown normalize type...")

    dense_col_transformed = dense_col.copy()
    if isinstance(data, (list, tuple)):
        for i, d in enumerate(data):
            if i == 0:  # assume train_data is the first one
                d[dense_col] = scaler.fit_transform(
                    d[dense_col]).astype(np.float32)
            else:
                d[dense_col] = scaler.transform(
                    d[dense_col]).astype(np.float32)

            for col in dense_col:
                if d[col].min() < 0.0:
                    print("can't transform negative values...")
                    continue
                if transformer is not None:
                    if "log" in transformer:
                        name = col + "_log"
                        d[name] = np.log1p(d[col])
                        if i == 0:
                            dense_col_transformed.append(name)
                    if "sqrt" in transformer:
                        name = col + "_sqrt"
                        d[name] = np.sqrt(d[col])
                        if i == 0:
                            dense_col_transformed.append(name)
                    if "square" in transformer:
                        name = col + "_square"
                        d[name] = np.square(d[col])
                        if i == 0:
                            dense_col_transformed.append(name)

    else:
        data[dense_col] = scaler.fit_transform(data[dense_col])
        for col in dense_col:
            if data[col].min() < 0.0:
                print("can't transform negative values...")
                continue
            if transformer is not None:
                if "log" in transformer:
                    name = col + "_log"
                    data[name] = np.log1p(data[col])
                    dense_col_transformed.append(name)
                if "sqrt" in transformer:
                    name = col + "_sqrt"
                    data[name] = np.sqrt(data[col])
                    dense_col_transformed.append(name)
                if "square" in transformer:
                    name = col + "_square"
                    data[name] = np.square(data[col])
                    dense_col_transformed.append(name)

    return data, dense_col_transformed


def split_multi_value(data, multi_value_col, sep, max_len=None,
                      pad_val="missing", user_col=None, item_col=None):
    if max_len is not None:
        assert (
                isinstance(max_len, (list, tuple))
                and len(max_len) == len(multi_value_col)
        ), "max_len must be list and have same length as multi_value_col"

    if not isinstance(pad_val, (list, tuple)):
        pad_val = [pad_val] * len(multi_value_col)
    assert len(multi_value_col) == len(pad_val), (
        "length of multi_sparse_col and pad_val doesn't match")

    user_sparse_col, item_sparse_col, multi_sparse_col = [], [], []
    for j, col in enumerate(multi_value_col):
        sparse_col = []
        data[col] = (
            data[col]
            .str.strip(sep + " ")
            .str.replace("\s+", "", regex=True)
            .str.lower()
        )
        data.loc[data[col] == "", col] = pad_val
        split_col = data[col].str.split(sep)
        col_len = (
            int(split_col.str.len().max())
            if max_len is None
            else max_len[j]
        )
        for i in range(col_len):
            new_col_name = col + f"_{i+1}"
            sparse_col.append(new_col_name)
            data[new_col_name] = split_col.str.get(i)
            data[new_col_name].fillna(pad_val[j], inplace=True)

        multi_sparse_col.append(sparse_col)
        if user_col is not None and col in user_col:
            user_sparse_col.extend(sparse_col)
        elif item_col is not None and col in item_col:
            item_sparse_col.extend(sparse_col)

    data.fillna(pad_val[0], inplace=True)
    data.drop(multi_value_col, axis=1, inplace=True)
    return multi_sparse_col, user_sparse_col, item_sparse_col
