from dataclasses import dataclass
import datetime
import re
from dataclass_defs import ProcessedRow, SheetsRow

INTERVAL_ABBREVS = {
    "pv": datetime.timedelta(days=1),
    "vk": datetime.timedelta(days=7),
    "kk": datetime.timedelta(days=30),
    "v": datetime.timedelta(days=365),
}


def _calculate_interval(interval_str: str):
    match = re.search(r"(\d+)(\w+)", interval_str)
    number = int(match[1])
    abbrev = match[2]

    try:
        interval = INTERVAL_ABBREVS[abbrev]
    except KeyError:
        raise Exception(f'"{interval_str}" is an invalid interval string!')

    total_interval = datetime.timedelta(seconds=interval.total_seconds() * number)
    return total_interval


def _timestamp_to_date(timestamp: str) -> datetime.datetime:
    return datetime.datetime.strptime(timestamp, "%Y-%m-%d")


def _date_to_timestamp(date: datetime.datetime) -> str:
    return datetime.datetime.strftime(date, "%Y-%m-%d")


def _process_row(row: SheetsRow):
    interval = _calculate_interval(row.interval)

    if row.last_done is not None:
        last_done_date = _timestamp_to_date(row.last_done)
        next_date = last_done_date + interval
        next_date_str = _date_to_timestamp(next_date)
    else:
        last_done_date = datetime.datetime.now()
        next_date = datetime.datetime.now()
        next_date_str = _date_to_timestamp(next_date)

    return ProcessedRow(
        name=row.name,
        next_datestamp=next_date_str,
        next_date=next_date,
        last_datestamp=row.last_done,
        last_date=last_done_date,
        interval=row.interval,
    )


def process_rows(rows: list[SheetsRow]) -> list[ProcessedRow]:
    return [_process_row(row) for row in rows]


def _is_this_week(processed_row: ProcessedRow):
    next_date = processed_row.next_date
    today = datetime.datetime.now()
    current_week_start = today - datetime.timedelta(days=today.weekday())
    current_week_end = current_week_start + datetime.timedelta(days=7)
    return next_date > current_week_start and next_date < current_week_end


def filter_only_this_week(rows: list[ProcessedRow]) -> list[ProcessedRow]:
    return [row for row in rows if _is_this_week(row)]