import re
import enum
import datetime

RE_PHENOM = re.compile(r'''
    ^/ (?P<typeof>[OTEX])
    \. (?P<actions>[A-Z]{3})
    \. (?P<wfo>[A-Z]{4})
    \. (?P<phenom>[A-Z]{2})
    \. (?P<sig>[A-Z])
    \. (?P<etn>\d{4})
    \. (?P<time_start>\d{6}T\d{4}Z)
    - (?P<time_end>\d{6}T\d{4}Z)
    /$
''', re.X)

RE_HYDRO = re.compile(r'''
    ^/ (?P<severity>[0N1])
    \. (?P<cause>[A-Z]{2})
    \. (?P<time_start>\d{6}T\d{4}Z)
    - (?P<time_end>\d{6}T\d{4}Z)
    \. (?P<record>[A-Z]{2})
    /$
''', re.X)

def parse_timestamp(text: str):
    return datetime.datetime.strptime(
        text, '%y%m%dT%H%M%SZ'
    ).astimezone(datetime.UTC)

class VTECEventType(enum.StrEnum):
    OPERATIONAL       = 'O'
    TEST              = 'T'
    EXPERIMENTAL      = 'E'
    EXPERIMENTAL_VTEC = 'X'

class VTECEvent():
    typeof:          str
    actions:         str
    wfo:             str
    phenom:          str
    sig:             str
    etn:             int
    timestamp_start: datetime.datetime
    timestamp_end:   datetime.datetime

    @staticmethod
    def parse(text: str) -> __class__:
        match = RE_PHENOM.match(text)

        if match is None:
            return

        event = VTECEvent()
        event.typeof  = match['typeof']
        event.actions = match['actions']
        event.wfo     = match['wfo']
        event.phenom  = match['phenom']
        event.sig     = match['sig']
        event.etn     = int(match['etn'])

        event.timestamp_start = parse_timestamp(match['time_start'])
        event.timestamp_end   = parse_timestamp(match['time_end'])

        return event

class VTECHydroEvent():
    __slots__ = (
        'severity', 'cause', 'record',
        'timestamp_start', 'timestamp_end'
    )

    severity:        str
    cause:           str
    record:          str
    timestamp_start: datetime.datetime
    timestamp_end:   datetime.datetime

    @staticmethod
    def parse(text: str) -> __class__:
        match = RE_HYDRO.match(text)

        if match is None:
            return

        event = VTECHydroEvent()
        event.severity = match['severity']
        event.cause    = match['cause']

        event.timestamp_start = parse_timestamp(match['time_start'])
        event.timestamp_end   = parse_timestamp(match['time_end'])

        return event