import csv
import re
import shapely

from nexrad.db    import DatabaseTable
from nexrad.coord import COORD_SYSTEM

"""
Implements a parser and wrapper class for the WSR-88D radar list
available at the following location (accessed 10 Feb 2025):

    https://apollo.nvu.vsc.edu/classes/remote/lecture_notes/radar/88d/88D_locations.html

The input TSV file is created by copying and pasting the tabular data
from a web browser into a text file.
"""

RE_PARSE = re.compile(r'^\s*(\d+)([NS]*)\s+/\s+(\d+)([EW]*)\s*$')

def parse_int(text: str):
    size = len(text)

    degree = int(text[0:size-4])
    minute = int(text[size-4:size-2])
    second = int(text[size-2:])

    return degree + (minute  / 60) + (second / 3600)

def parse(text: str):
    match = RE_PARSE.match(text)

    if match is None:
        raise Exception("Invalid coordinates '%s'" % text)

    sign_lon =  1 if match[4] == 'E' else -1
    sign_lat = -1 if match[2] == 'S' else  1

    lon = parse_int(match[3])
    lat = parse_int(match[1])

    return shapely.Point(sign_lon * lon, sign_lat * lat)

RADAR_RANGE = 230000

class Radar(DatabaseTable):
    __slots__ = (
        'call', 'wban', 'name', 'coord', 'site_elevation', 'tower_height',
    )

    __table__ = 'nexrad_radar'
    __key__   = 'call'

    __columns__ = (
        'call', 'wban', 'name', 'coord', 'site_elevation', 'tower_height'
    )

    __columns_read__ = {
        'coord': 'ST_AsText(coord) as coord'
    }

    __values_read__ = {
        'coord': shapely.from_wkt
    }

    __columns_write__ = {
        'coord': 'MakePoint(:coord_lon, :coord_lat, {crs})'.format(crs=COORD_SYSTEM)
    }

    __values_write__ = {
        'coord': lambda v: {'coord_lon': v.x, 'coord_lat': v.y}
    }

    call:           str
    wban:           int
    name:           str
    coord:          shapely.Point
    site_elevation: float
    tower_height:   float

    @staticmethod
    def from_tsv_row(row: list):
        radar = Radar()
        radar.call           = row[1]
        radar.wban           = int(row[0]) if row[0] != 'PENDING' else None
        radar.name           = row[2]
        radar.coord          = parse(row[3])
        radar.site_elevation = 0.3048 * float(row[4])
        radar.tower_height   = float(row[5])

        return radar

    @staticmethod
    def each_from_tsv(file: str):
        with open(file) as fh:
            reader = csv.reader(fh, delimiter='\t')

            for row in reader:
                for i in range(0, len(row)):
                    row[i] = row[i].rstrip()

                yield Radar.from_tsv_row(row)