#!/usr/bin/env python2

import subprocess
import time
import tempfile
import urllib
import json
import sys
import os
import os.path as path
import shutil

# Used later when choosing between a dpkg or rpm based distro.

def pkg_format():
    with open(os.devnull, 'w') as FNULL:
        try:
            subprocess.call(['apt-get', '--help'], stdout=FNULL, stderr=FNULL)
            return 'apt'
        except:
            pass

        try:
            subprocess.call(['yum', '--help'], stdout=FNULL, stderr=FNULL)
            return 'yum'
        except:
            pass

        return ''

print 'Determining download link...'
download_manager = urllib.urlopen('https://s3.amazonaws.com/info-mongodb-com/com-download-center/compass.json')
jsn = json.loads(download_manager.read())
download_manager.close()

platform = sys.platform

# Sometimes sys.platform gives us 'linux2' and we only want 'linux'
if platform.startswith('linux'):
    platform = 'linux'

if platform == 'linux' and os.getuid() != 0:
    print 'You must run this script as root.'
    sys.exit(1)

ver = filter(lambda x: 'Stable' in x['version'], jsn['versions'])[0]
links = filter(lambda x: x['os'] == platform, ver['platform'])

if len(links) == 0:
    print 'Platform %s not supported.' % sys.platform
    sys.exit(1)

if platform == 'linux':
    if pkg_format() == 'apt':
        links = filter(lambda x: 'Ubuntu' in x['name'], links)
    elif pkg_format() == 'yum':
        links = filter(lambda x: 'RedHat' in x['name'], links)
    else:
        print 'Unsupported Linux Distribution.'
        sys.exit(1)

dl = links[0]['download_link']


def dl_progress(count, block_size, total_size):
    global start_time
    if count == 0:
        start_time = time.time()
        return
    duration = time.time() - start_time
    progress_size = int(count * block_size)
    speed = int(progress_size / (1024 * duration))
    percent = int(count * block_size * 100 / total_size)
    sys.stdout.write("\rDownloading Compass... %d%%" % percent)
    sys.stdout.flush()


fn, headers = urllib.urlretrieve(dl, reporthook=dl_progress)
# Download progress doesn't end with a newline so add it here.
print ''


if platform == 'darwin':
    tmp = tempfile.mkdtemp()
    subprocess.check_call(['hdiutil', 'attach', '-mountpoint', tmp, fn])
    try:
        apps = [f for f in os.listdir(tmp) if f.endswith('.app')]
        for a in apps:
            if path.isdir('/Applications/' + f):
                print 'Old version found removing...'
                shutil.rmtree('/Applications/' + f)
            print 'Copying %s to /Applications' % f
            shutil.copytree(path.join(tmp, f), '/Applications/' + f)
    # We don't really care about what errors come up here. Just log the failure
    # and use the finally to make sure we always unmount the dmg.
    except Exception as e:
        print e
    finally:
        subprocess.check_call(['hdiutil', 'detach', tmp])
elif platform == 'linux':
    if pkg_format() == 'yum':
        install = ['yum', 'install', '--assumeyes', fn]
    elif pkg_format() == 'apt':
        install = ['apt-get', 'install', '--yes', fn]
    else:
        print 'No available installation methods.'
        sys.exit(1)

    subprocess.call(install)
else:
    print 'Unrecognized platform %s' % sys.platform
    sys.exit(1)