import json
import os
from dotenv import load_dotenv
from nonce_finder import NonceFinder


class Block:
    def __init__(
            self,
            name,
            amount,
            to_whom_name,
            nonce=0,
            prev_hash='00000000000000000000000000000000'
    ):
        self.name = name
        self.amount = amount
        self.to_whom_name = to_whom_name
        self.nonce = nonce
        self.prev_hash = prev_hash
        self.standard_path = 'blockchain_blocks/'
        dotenv_path = os.path.join(os.path.dirname(__file__), '.env')
        if os.path.exists(dotenv_path):
            load_dotenv(dotenv_path)
        self.key = os.environ.get('KEY')

    def get_last_block(self):
        """ Получение номера последнего блока """
        try:
            files = [int(f.split('.')[0])
                     for f in os.listdir(self.standard_path) if f.endswith('.txt')]
            return max(files, default=0)
        except ValueError:
            return 0

    def data_creator(self):
        """ Создание данных блока """
        return [
            {'nonce': self.nonce},
            {'from': self.name, 'amount': self.amount, 'to_whom': self.to_whom_name},
            {'preview_hash': self.prev_hash}
        ]

    def get_last_block_hash(self, filename):
        """ Получение хэша последнего блока """
        with open(
                os.path.join(self.standard_path, str(int(filename) - 1) + '.txt'),
                'r'
        ) as file:
            return json.load(file)[1]

    def block_creator(self):
        """ Создание нового блока """
        last_file = self.get_last_block()
        filename = str(last_file + 1)
        data = self.data_creator()
        if last_file != 0:
            data[2]['preview_hash'] = self.get_last_block_hash(filename)
        block_hash = NonceFinder(data, 4, self.key).create_pow()[1]
        result_dump_data = [data, block_hash]
        with open(os.path.join(self.standard_path, filename + '.txt'), 'w') as file:
            json.dump(result_dump_data, file, indent=4, ensure_ascii=False)
        if last_file == 0:
            print('[+] Создан первый блок')
        else:
            print(f'[+] Блок {filename} создан')

    def blockchain_checker(self):
        """ Проверка целостности блокчейна """
        files = sorted([f for f in os.listdir(self.standard_path) if f.endswith('.txt')],
                       key=lambda x: int(x.split('.')[0]))
        for file in files[1:]:
            with open(os.path.join(self.standard_path, file), 'r') as current_file:
                current_block = json.load(current_file)
                prev_hash = current_block[0][2]['preview_hash']
            prev_file = str(int(file.split('.')[0]) - 1) + ".txt"
            with open(os.path.join(self.standard_path, prev_file), 'r') as _file:
                prev_block_data = json.load(_file)[0]
            real_prev_block_hash = NonceFinder(
                prev_block_data,
                4,
                self.key
            ).create_pow()[1]
            if prev_hash == real_prev_block_hash:
                print(f'[+] Блок {prev_file} верен')
            else:
                print(f'[-] В блоке {prev_file} допущена ошибка!')
        if len(files) <= 1:
            print('[+] Для начала проверки цепочки блоков, создайте больше блоков!')