import urllib.request
import zipfile
import os
import sys

SRTM_DIR = '/home/slin/enduro-trails/data/srtm'
BASE_URL = 'https://srtm.kurviger.de/SRTM3/Eurasia'

tiles = []
for lat in [54, 55, 56]:
    for lon in range(41, 47):
        tiles.append(f'N{lat}E{lon:03d}')

os.chdir(SRTM_DIR)
count = 0

for tile in tiles:
    hgt = f'{tile}.hgt'
    if os.path.exists(hgt):
        print(f'  EXISTS: {hgt}')
        continue
    
    url = f'{BASE_URL}/{tile}.hgt.zip'
    tmp = f'/tmp/{tile}.hgt.zip'
    
    try:
        print(f'  Downloading {tile}...', end=' ', flush=True)
        urllib.request.urlretrieve(url, tmp)
        
        if os.path.getsize(tmp) > 0:
            with zipfile.ZipFile(tmp, 'r') as z:
                z.extractall('.')
            os.remove(tmp)
            size = os.path.getsize(hgt) if os.path.exists(hgt) else 0
            print(f'OK ({size // 1024}KB)')
            count += 1
        else:
            print('EMPTY')
            os.remove(tmp)
    except Exception as e:
        print(f'FAIL: {e}')
        if os.path.exists(tmp):
            os.remove(tmp)

print(f'\nDownloaded: {count} new files')
print(f'Total HGT: {len([f for f in os.listdir(".") if f.endswith(".hgt")])}')