import re
from aprslib.exceptions import ParseError

__all__ = [
    '_parse_weather',
    '_parse_weather_data',
    ]

def _parse_weather(body):
    match = re.match("^(\d{8})c[\. \d]{3}s[\. \d]{3}g[\. \d]{3}t[\. \d]{3}", body)
    if not match:
        raise ParseError("invalid positionless weather report format")

    comment, weather = _parse_weather_data(body[8:])

    parsed = {
        'format': 'wx',
        'wx_raw_timestamp': match.group(1),
        'comment': comment.strip(' '),
        'weather': weather,
        }

    return ('', parsed)


def _parse_weather_data(body):
    wind_multiplier = 0.44704
    rain_multiplier = 0.254

    key_map = {
        'g': 'wind_gust',
        'c': 'wind_direction',
        't': 'temperature',
        'S': 'wind_speed',
        'r': 'rain_1h',
        'p': 'rain_24h',
        'P': 'rain_since_midnight',
        'h': 'humidity',
        'b': 'pressure',
        'l': 'luminosity',
        'L': 'luminosity',
        's': 'snow',
        '#': 'rain_raw',
    }
    val_map = {
        'g': lambda x: int(x) * wind_multiplier,
        'c': lambda x: int(x),
        'S': lambda x: int(x) * wind_multiplier,
        't': lambda x: (float(x) - 32) / 1.8,
        'r': lambda x: int(x) * rain_multiplier,
        'p': lambda x: int(x) * rain_multiplier,
        'P': lambda x: int(x) * rain_multiplier,
        'h': lambda x: int(x),
        'b': lambda x: float(x) / 10,
        'l': lambda x: int(x) + 1000,
        'L': lambda x: int(x),
        's': lambda x: float(x) * 25.4,
        '#': lambda x: int(x),
    }

    parsed = {}

    # parse weather data
    body = re.sub(r"^([0-9]{3})/([0-9]{3})", "c\\1s\\2", body)
    body = body.replace('s', 'S', 1)

    data = re.findall(r"([cSgtrpPlLs#]\d{3}|t-\d{2}|h\d{2}|b\d{5}|s\.\d{2}|s\d\.\d)", body)
    data = map(lambda x: (key_map[x[0]] , val_map[x[0]](x[1:])), data)

    parsed.update(dict(data))

    # strip weather data
    body = re.sub(r"([cSgtrpPlLs#][0-9\-\. ]{3}|h[0-9\. ]{2}|b[0-9\. ]{5})", '', body)

    return (body, parsed)