from datetime import date, timedelta

import ciso8601

from .base import FormatColumn

epoch_start = date(1970, 1, 1)
epoch_end = date(2149, 6, 6)

epoch_start_date32 = date(1900, 1, 1)
epoch_end_date32 = date(2299, 12, 31)


class LazyLUT(dict):
    def __init__(self, *args, _factory, **kwargs):
        super().__init__(*args, **kwargs)
        self._default_factory = _factory

    def __missing__(self, key):
        return self.setdefault(key, self._default_factory(key))


lazy_date_lut = LazyLUT(_factory=lambda x: epoch_start + timedelta(x))
lazy_date_lut_reverse = LazyLUT(_factory=lambda x: (x - epoch_start).days)


class DateColumn(FormatColumn):
    ch_type = "Date"
    py_types = (date,)
    format = "H"

    min_value = epoch_start
    max_value = epoch_end

    date_lut = lazy_date_lut
    date_lut_reverse = lazy_date_lut_reverse

    def before_write_items(self, items, nulls_map=None):
        null_value = self.null_value

        date_lut_reverse = self.date_lut_reverse
        min_value = self.min_value
        max_value = self.max_value

        for i, item in enumerate(items):
            if nulls_map and nulls_map[i]:
                items[i] = null_value
                continue
            if isinstance(item, str):
                item = ciso8601.parse_datetime(item).date()
            if item is not date:
                item = date(item.year, item.month, item.day)
            if min_value <= item <= max_value:
                items[i] = date_lut_reverse[item]
            else:
                items[i] = 0

    def after_read_items(self, items, nulls_map=None):
        date_lut = self.date_lut

        if nulls_map is None:
            return tuple(date_lut[item] for item in items)
        else:
            return tuple(
                (None if is_null else date_lut[items[i]]) for i, is_null in enumerate(nulls_map)
            )


class Date32Column(DateColumn):
    ch_type = "Date32"
    format = "i"

    min_value = epoch_start_date32
    max_value = epoch_end_date32

    date_lut = lazy_date_lut
    date_lut_reverse = lazy_date_lut_reverse