#
# misc.py - misc functions for the Ubuntu Developer Tools scripts.
#
# Copyright (C) 2008,      Jonathan Davies <jpds@ubuntu.com>,
#               2008-2009, Siegfried-Angel Gevatter Pujals <rainct@ubuntu.com>,
#               2010,      Stefano Rivera <stefanor@ubuntu.com>
#
# ##################################################################
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 3
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# See file /usr/share/common-licenses/GPL for more details.
#
# ##################################################################

# Modules.
import os
import os.path
from subprocess import Popen, PIPE

from ubuntutools.lp.udtexceptions import PocketDoesNotExistError

_system_distribution = None
def system_distribution():
    """ system_distro() -> string

    Detect the system's distribution and return it as a string. If the
    name of the distribution can't be determined, print an error message
    and return None.
    """
    global _system_distribution
    if _system_distribution is None:
        try:
            if os.path.isfile('/usr/bin/dpkg-vendor'):
                process = Popen(('dpkg-vendor', '--query', 'vendor'),
                                stdout=PIPE)
            else:
                process = Popen(('lsb_release', '-cs'), stdout=PIPE)
            output = process.communicate()[0]
        except OSError:
            print ('Error: Could not determine what distribution you are '
                   'running.')
            return None
        if process.returncode != 0:
            print 'Error determininng system distribution'
            return None
        _system_distribution = output.strip()
    return _system_distribution

def host_architecture():
    """ host_architecture -> string

    Detect the host's architecture and return it as a string. If the
    architecture can't be determined, print an error message and return None.
    """

    arch = Popen(['dpkg', '--print-architecture'], stdout=PIPE, \
                 stderr=PIPE).communicate()[0].split()

    if not arch or 'not found' in arch[0]:
        print 'Error: Not running on a Debian based system; could not ' \
            'detect its architecture.'
        return None

    return arch[0]

def readlist(filename, uniq=True):
    """ readlist(filename, uniq) -> list

    Read a list of words from the indicated file. If 'uniq' is True, filter
    out duplicated words.
    """

    if not os.path.isfile(filename):
        print 'File "%s" does not exist.' % filename
        return False

    content = open(filename).read().replace('\n', ' ').replace(',', ' ')

    if not content.strip():
        print 'File "%s" is empty.' % filename
        return False

    items = [item for item in content.split() if item]

    if uniq:
        items = list(set(items))

    return items

def split_release_pocket(release):
    '''Splits the release and pocket name.

    If the argument doesn't contain a pocket name then the 'Release' pocket
    is assumed.

    Returns the release and pocket name.
    '''
    pocket = 'Release'

    if release is None:
        raise ValueError('No release name specified')

    if '-' in release:
        (release, pocket) = release.split('-')
        pocket = pocket.capitalize()

        if pocket not in ('Release', 'Security', 'Updates', 'Proposed',
                'Backports'):
            raise PocketDoesNotExistError("Pocket '%s' does not exist." % \
                                          pocket)

    return (release, pocket)

def dsc_name(package, version):
    "Return the source package dsc filename for the given package"
    if ':' in version:
        version = version.split(':', 1)[1]
    return '%s_%s.dsc' % (package, version)

def dsc_url(mirror, component, package, version):
    "Build a source package URL"
    group = package[:4] if package.startswith('lib') else package[0]
    filename = dsc_name(package, version)
    return os.path.join(mirror, 'pool', component, group, package, filename)