"""Синтетические заказы, не реальные продажи. Детерминированно по seed."""
import argparse
import csv
from datetime import date, timedelta
from pathlib import Path
import random

FIELDS = ('order_id', 'line_id', 'order_date', 'category', 'quantity', 'unit_price')


def generate(output, seed=42):
    rng = random.Random(seed)
    rows = []
    categories = ('Книги', 'Электроника', 'Дом')
    formats = ('%Y-%m-%d', '%d.%m.%Y', '%Y/%m/%d')
    for day in range(30):
        if day == 12:  # intentionally absent calendar day
            continue
        for index in range(10):
            price = rng.randint(10000, 150000)
            quantity = rng.randint(1, 4)
            if day == 22:  # analytical signal deliberately planted, not bad source data
                quantity *= 20
            rows.append([f'SYN-{day:02d}-{index:02d}', '1',
                         (date(2026, 1, 1) + timedelta(days=day)).strftime(formats[index % 3]),
                         '  ' + categories[index % 3] + '  ', str(quantity),
                         f'{price // 100}.{price % 100:02d}'])
    rows.append(rows[0].copy())
    conflict = rows[1].copy()
    conflict[4] = '99'
    rows.append(conflict)
    defects = [('category', ''), ('quantity', ''), ('order_date', '02/03/2026'),
               ('order_date', '2026-02-30'), ('quantity', '0'), ('quantity', '-2'),
               ('unit_price', '0'), ('unit_price', '12.345'), ('unit_price', 'NaN')]
    for index, (field, value) in enumerate(defects):
        row = rows[2].copy()
        row[0] = f'SYN-DEFECT-{index}'
        row[FIELDS.index(field)] = value
        rows.append(row)
    output = Path(output)
    output.parent.mkdir(parents=True, exist_ok=True)
    with output.open('w', encoding='utf-8', newline='') as stream:
        writer = csv.writer(stream)
        writer.writerow(FIELDS)
        writer.writerows(rows)
    return len(rows)


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--output', type=Path, required=True)
    parser.add_argument('--seed', type=int, default=42)
    args = parser.parse_args()
    print(f'Synthetic CSV: {generate(args.output, args.seed)} rows, seed={args.seed}')