import os
import subprocess

from xml.dom import minidom

scripts_dir = os.path.dirname(__file__)
base_dir = os.path.dirname(scripts_dir)

def get_distribution():
    if 'SJH_DISTRIBUTION' in os.environ:
        return os.environ['SJH_DISTRIBUTION'].split('-')

    # Fedora
    if os.path.exists('/etc/fedora-release'):
        name = 'fedora'

        f = open('/etc/fedora-release')
        full_name = f.read()
        f.close()

        if 'Rawhide' in full_name:
            version = 'rawhide'
        else:
            version = full_name.split(' ')[2]

        return name, version

    # Debian and Ubuntu
    try:
        out, err = subprocess.Popen(['lsb_release', '-is'],
                                    stdout=subprocess.PIPE).communicate()
        name = out.strip().lower()

        out, err = subprocess.Popen(['lsb_release', '-rs'],
                                    stdout=subprocess.PIPE).communicate()
        version = out.strip()

        if name == 'debian' and version == 'testing':
            version = 'unstable'

        return name, version
    except OSError:
        pass

    return None, None

def check_package(package):
    name, version = get_distribution()
    if name in ['fedora', 'mandrivalinux']:
        ret = subprocess.call(['rpm', '--quiet', '-q', package])
        return ret == 0
    elif name in ['ubuntu', 'debian']:
        cmd = ["dpkg-query", "-f='${status}'", "-W", package]
        out, err = subprocess.Popen(cmd, stdout=subprocess.PIPE).communicate()
        return out.find('install ok installed') != -1

    return None

def parse_dependencies():
    name, version = get_distribution()
    if name is None or version is None:
        return None

    filename = os.path.join(base_dir, 'config', 'sysdeps',
                            '%s-%s.xml' % (name, version))

    if not os.path.exists(filename):
        return None

    return minidom.parse(filename)

def get_packages():
    document = parse_dependencies()
    if document is None:
        return []

    packages = []
    root = document.childNodes[0]

    for node in root.childNodes:
        if node.nodeType == node.ELEMENT_NODE:
            if node.nodeName == 'package':
                name = node.getAttribute('name')
                if node.hasAttribute('source'):
                    source = node.getAttribute('source')
                else:
                    source = None

                packages.append((name, source))

    return packages