#!/usr/bin/env python

from __future__ import print_function
import os
import shutil
import subprocess
import sys
import tarfile

try:
    from urllib.request import urlopen
except ImportError:
    from urllib2 import urlopen

baseUrl = 'http://www.nndc.bnl.gov/endf/b7.1/aceFiles/'
files = ['ENDF-B-VII.1-neutron-293.6K.tar.gz',
         'ENDF-B-VII.1-neutron-300K.tar.gz',
         'ENDF-B-VII.1-neutron-900K.tar.gz',
         'ENDF-B-VII.1-neutron-1500K.tar.gz',
         'ENDF-B-VII.1-tsl.tar.gz']
block_size = 16384

# ==============================================================================
# DOWNLOAD FILES FROM NNDC SITE

filesComplete = []
for f in files:
    # Establish connection to URL
    url = baseUrl + f
    req = urlopen(url)

    # Get file size from header
    file_size = int(req.info().getheaders('Content-Length')[0])
    downloaded = 0

    # Check if file already downloaded
    if os.path.exists(f):
        if os.path.getsize(f) == file_size:
            print('Skipping ' + f)
            filesComplete.append(f)
            continue
        else:
            if sys.version_info[0] < 3:
                overwrite = raw_input('Overwrite {0}? ([y]/n) '.format(f))
            else:
                overwrite = input('Overwrite {0}? ([y]/n) '.format(f))
            if overwrite.lower().startswith('n'):
                continue

    # Copy file to disk
    print('Downloading {0}... '.format(f), end='')
    with open(f, 'wb') as fh:
        while True:
            chunk = req.read(block_size)
            if not chunk: break
            fh.write(chunk)
            downloaded += len(chunk)
            status = '{0:10}  [{1:3.2f}%]'.format(downloaded, downloaded * 100. / file_size)
            print(status + chr(8)*len(status), end='')
        print('')
        filesComplete.append(f)

# ==============================================================================
# EXTRACT FILES FROM TGZ

for f in files:
    if not f in filesComplete:
        continue

    # Extract files
    suffix = f[f.rindex('-') + 1:].rstrip('.tar.gz')
    with tarfile.open(f, 'r') as tgz:
        print('Extracting {0}...'.format(f))
        tgz.extractall(path='nndc/' + suffix)

# ==============================================================================
# COPY CROSS_SECTIONS.XML

print('Copying cross_sections_nndc.xml...')
shutil.copyfile('cross_sections_nndc.xml', 'nndc/cross_sections.xml')

# ==============================================================================
# PROMPT USER TO DELETE .TAR.GZ FILES

# Ask user to delete
if sys.version_info[0] < 3:
    response = raw_input('Delete *.tar.gz files? ([y]/n) ')
else:
    response = input('Delete *.tar.gz files? ([y]/n) ')

# Delete files if requested
if not response or response.lower().startswith('y'):
    for f in files:
        if os.path.exists(f):
            print('Removing {0}...'.format(f))
            os.remove(f)