import math
import os
from functools import reduce
from typing import Optional

import pandas as pd


class Data:
    def __init__(self, base_path):
        self.base_path = base_path
        self.df: Optional[pd.DataFrame] = None
        self.current_file_name = ''

    def read_folder(self):
        l = [file for file in os.listdir(f'{self.base_path}') if file.endswith('.tsv')]
        return sorted(l, reverse=True)

    def read_data(self, file_name):
        if file_name is None:
            return None
        self.current_file_name = file_name
        self.df = pd.read_csv(f'{self.base_path}/{file_name}', index_col=0, sep='\t')

    def read_data_old(self, path):
        if path is None:
            return None
        files_names = [file for file in os.listdir(f'{self.base_path}/{path}') if file.endswith('.tsv')]
        frames = [pd.read_csv(f'{self.base_path}/{path}/{f}', index_col=0, sep='\t') for f in files_names]
        if frames is None or len(frames) == 0:
            return None
        elif len(frames) == 1:
            self.df = frames[0]
        else:
            self.df = reduce(
                lambda left, right: left.merge(right, left_index=True, right_index=True,
                                               sort=True,
                                               how='outer'), frames[1:], frames[0])

    def get_columns(self):
        if self.df is None:
            return []
        else:
            return list(self.df.columns)