import os

from entities.items.food import Food
from entities.elf import Elf


class CalorieList:
    """
    Day 1 - Calorie List

    The Elves take turns writing down the number of Calories contained by the various meals, snacks, rations, etc. that they've brought with them, one item per line.
    Each Elf separates their own inventory from the previous Elf's inventory (if any) by a blank line.
    """

    def __init__(self, path: str):
        if not os.path.isfile(path):
            raise FileNotFoundError(f"File was not found or isn't a file: {path}")

        self.file_path = path

    def parse_file(self):
        """
        read the file and parse its contents
        :return:
        """
        elf_invs = []
        with open(self.file_path, "r") as file:
            curr_elf_inventory = []
            for line in file:
                line = line.replace("\n", "")
                if line.isnumeric():
                    curr_elf_inventory.append(int(line))
                elif len(line) == 0:  # line is empty, next inventory
                    elf_invs.append(curr_elf_inventory)
                    curr_elf_inventory = list()
                else:
                    raise ValueError(f"Unexpected line encountered in calorie list file: {line}")
        elf_invs.append(curr_elf_inventory)

        elves = []
        for inv in elf_invs:
            elf = Elf()
            for calories in inv:
                elf.add_to_inventory(Food(calories))
            elves.append(elf)

        return elves