import math
import os
import requests

def deg2num(lat_deg, lon_deg, zoom):
    lat_rad = math.radians(lat_deg)
    n = 2.0 ** zoom
    xtile = int((lon_deg + 180.0) / 360.0 * n)
    ytile = int((1.0 - math.log(math.tan(lat_rad) + (1 / math.cos(lat_rad))) / math.pi) / 2.0 * n)
    return (xtile, ytile)


COMBO_MAP_MAX_BOUNDS = {
    "corner1": {"lat": 45.9134, "lng": 4.6733},
    "corner2": {"lat": 45.5583, "lng": 5.1574}
}

for zoom in range(3, 20):
    xtile1, ytile1 = deg2num(COMBO_MAP_MAX_BOUNDS['corner1']['lat'],
                             COMBO_MAP_MAX_BOUNDS['corner1']['lng'],
                             zoom)
    xtile2, ytile2 = deg2num(COMBO_MAP_MAX_BOUNDS['corner2']['lat'],
                             COMBO_MAP_MAX_BOUNDS['corner2']['lng'],
                             zoom)
    for xtile in range(xtile1, xtile2+1):
        for ytile in range(ytile1, ytile2+1):
            path = '%s/%s/%s.png' % (zoom, xtile, ytile)
            if os.path.exists(path):
                continue
            url = 'https://tiles.entrouvert.org/hdm/%s/%s/%s.png' % (zoom, xtile, ytile)
            print url
            if not os.path.exists(os.path.dirname(path)):
                os.makedirs(os.path.dirname(path))
            r = requests.get(url)
            if r.status_code != 200:
                continue
            with open(path, 'w') as fd:
                fd.write(r.content)