"""Define `asccol` data specifications."""

import math

import asccol


def simple_time(s):
    """Convert an HHMM string to an (H, M) tuple."""
    hhmm = int(s)
    return divmod(hhmm, 100)


def filtered_int(s):
    """Like int, but ignore the special value 999."""
    val = int(s)
    return val if val != 999 else math.nan


def filtered_float(s):
    """Like float, but ignore the special values 444.0, 99.9, etc."""
    val = float(s)
    return val if val not in (444.0, 99.9, 999.9, 9999.9) else math.nan


ONE_HOUR = asccol.DataSpec(
    leading=2,  # 2 lines to delete
    cols=(
        ('year', int, 4),  # name, type (converter function), width
        ('jdate', int, 4),
        ('month', int, 3),
        ('day', int, 3),
        ('time', simple_time, 5),
        ('temp', filtered_float, 7),
        ('pressure', filtered_float, 7),
        ('wind_speed', filtered_float, 7),
        ('wind_dir', filtered_float, 7),
        ('rel_hum', filtered_float, 7),
        ('delta_t', filtered_float, 7),
    ),
)