python

    
import json
import os
import re

from typing import List, Dict

DECKS_FOLDER = 'Preconstructed Decks'

def load_decks(file_path: str) -> List[Dict]:
    with open(file_path, 'r') as f:
        return json.load(f)

def format_deck_name(name: str) -> str:
    name = name.lower().replace(' ', '_').replace('-', '_')
    return re.sub(r'[^a-z0-9_]', '', name)

def get_deck_info(deck: Dict) -> Dict:
    return {
        'name': format_deck_name(deck['name']),
        'type': deck['type'],
        'set_code': deck['set_code'].upper(),
        'set_name': deck['set_name'],
        'release_date': deck['release_date'],
        'deck_folder': DECKS_FOLDER,
        'cards': deck['cards'],
        'sideboard': deck['sideboard']
    }

def build_deck_text(deck_info: Dict) -> str:
    lines = [
        f'// {deck_info["name"]}',
        f'// Set: {deck_info["set_name"]} ({deck_info["set_code"]})',
        f'// Release Date: {deck_info["release_date"]}',
        '',
    ]

    for card in deck_info['cards']:
        lines.append(f'{card["count"]} [{card["set_code"]}:{card["number"]}] {card["name"]}')

    lines.append('')
    lines.append('SB:')

    for card in deck_info['sideboard']:
        lines.append(f'{card["count"]} [{card["set_code"]}:{card["number"]}] {card["name"]}')

    return '\n'.join(lines)

def build_deck_path(deck_info: Dict) -> str:
    return os.path.join(deck_info['deck_folder'],
                        deck_info['type'],
                        deck_info['set_code'])

def write_deck_file(deck_info: Dict, deck_text: str) -> None:
    deck_path = build_deck_path(deck_info)
    os.makedirs(deck_path, exist_ok=True)

    filename = f"{deck_info['name']}.dck"
    file_path = os.path.join(deck_path, filename)

    with open(file_path, 'w') as f:
        f.write(deck_text)

def migrate_decks(input_file: str, error_file: str) -> None:
    decks = load_decks(input_file)

    error_decks: List[Dict] = []
    for deck in decks:
        try:
            deck_info = get_deck_info(deck)
            deck_text = build_deck_text(deck_info)
            write_deck_file(deck_info, deck_text)
        except KeyError:
            error_decks.append(deck)

    if error_decks:
        with open(error_file, 'w') as f:
            json.dump(error_decks, f)

if __name__ == '__main__':
    migrate_decks('decks_v2.json', 'error_decks.json')