# -*- coding: utf-8 -*-
'''
Installation of Cygwin packages.

A state module to manage cygwin packages. Packages can be installed
or removed.

.. code-block:: yaml

    dos2unix:
      cyg.installed
'''
from __future__ import absolute_import
import logging

LOG = logging.getLogger(__name__)


def __virtual__():
    '''
    Only load if cyg module is available in __salt__.
    '''
    return 'cyg.list' in __salt__


def installed(name,
              cyg_arch='x86_64',
              mirrors=None):
    '''
    Make sure that a package is installed.

    name
        The name of the package to install

    cyg_arch : x86_64
        The cygwin architecture to install the package into.
        Current options are x86 and x86_64

    mirrors : None
        List of mirrors to check.
        None will use a default mirror (kernel.org)

    CLI Example:

    .. code-block:: yaml

        rsync:
          cyg.installed:
            - mirrors:
              - http://mirror/without/public/key: ""
              - http://mirror/with/public/key: http://url/of/public/key
    '''
    ret = {'name': name, 'result': None, 'comment': '', 'changes': {}}

    if cyg_arch not in ['x86', 'x86_64']:
        ret['result'] = False
        ret['comment'] = 'The \'cyg_arch\' argument must\
 be one of \'x86\' or \'x86_64\''
        return ret

    LOG.debug('Installed State: Initial Mirror list: {0}'.format(mirrors))

    if not __salt__['cyg.check_valid_package'](name,
                                               cyg_arch=cyg_arch,
                                               mirrors=mirrors):
        ret['result'] = False
        ret['comment'] = 'Invalid package name.'
        return ret

    pkgs = __salt__['cyg.list'](name, cyg_arch)
    if name in pkgs:
        ret['result'] = True
        ret['comment'] = 'Package is already installed.'
        return ret

    if __opts__['test']:
        ret['comment'] = 'The package {0} would\
 have been installed'.format(name)
        return ret

    if __salt__['cyg.install'](name,
                               cyg_arch=cyg_arch,
                               mirrors=mirrors):
        ret['result'] = True
        ret['changes'][name] = 'Installed'
        ret['comment'] = 'Package was successfully installed'
    else:
        ret['result'] = False
        ret['comment'] = 'Could not install package.'

    return ret


def removed(name, cyg_arch='x86_64', mirrors=None):
    '''
    Make sure that a package is not installed.

    name
        The name of the package to uninstall

    cyg_arch : x86_64
        The cygwin architecture to remove the package from.
        Current options are x86 and x86_64

    mirrors : None
        List of mirrors to check.
        None will use a default mirror (kernel.org)

    CLI Example:

    .. code-block:: yaml

        rsync:
          cyg.removed:
            - mirrors:
              - http://mirror/without/public/key: ""
              - http://mirror/with/public/key: http://url/of/public/key
    '''
    ret = {'name': name, 'result': None, 'comment': '', 'changes': {}}

    if cyg_arch not in ['x86', 'x86_64']:
        ret['result'] = False
        ret['comment'] = 'The \'cyg_arch\' argument must\
 be one of \'x86\' or \'x86_64\''
        return ret

    if not __salt__['cyg.check_valid_package'](name,
                                               cyg_arch=cyg_arch,
                                               mirrors=mirrors):
        ret['result'] = False
        ret['comment'] = 'Invalid package name.'
        return ret

    if name not in __salt__['cyg.list'](name, cyg_arch):
        ret['result'] = True
        ret['comment'] = 'Package is not installed.'
        return ret

    if __opts__['test']:
        ret['comment'] = 'The package {0} would have been removed'.format(name)
        return ret
    if __salt__['cyg.uninstall'](name, cyg_arch):
        ret['result'] = True
        ret['changes'][name] = 'Removed'
        ret['comment'] = 'Package was successfully removed.'
    else:
        ret['result'] = False
        ret['comment'] = 'Could not remove package.'
    return ret


def updated(name=None, cyg_arch='x86_64', mirrors=None):
    '''
    Make sure all packages are up to date.

    name : None
        No affect, salt fails poorly without the arg available

    cyg_arch : x86_64
        The cygwin architecture to update.
        Current options are x86 and x86_64

    mirrors : None
        List of mirrors to check.
        None will use a default mirror (kernel.org)

    CLI Example:

    .. code-block:: yaml

        rsync:
          cyg.updated:
            - mirrors:
              - http://mirror/without/public/key: ""
              - http://mirror/with/public/key: http://url/of/public/key
    '''
    ret = {'name': 'cyg.updated', 'result': None, 'comment': '', 'changes': {}}

    if cyg_arch not in ['x86', 'x86_64']:
        ret['result'] = False
        ret['comment'] = 'The \'cyg_arch\' argument must\
 be one of \'x86\' or \'x86_64\''
        return ret

    if __opts__['test']:
        ret['comment'] = 'All packages would have been updated'
        return ret

    if not mirrors:
        LOG.warn('No mirror given, using the default.')

    before = __salt__['cyg.list'](cyg_arch=cyg_arch)
    if __salt__['cyg.update'](cyg_arch, mirrors=mirrors):
        after = __salt__['cyg.list'](cyg_arch=cyg_arch)
        differ = DictDiffer(after, before)
        ret['result'] = True
        if differ.same():
            ret['comment'] = 'Nothing to update.'
        else:
            ret['changes']['added'] = list(differ.added())
            ret['changes']['removed'] = list(differ.removed())
            ret['changes']['changed'] = list(differ.changed())
            ret['comment'] = 'All packages successfully updated.'
    else:
        ret['result'] = False
        ret['comment'] = 'Could not update packages.'
    return ret


# https://github.com/hughdbrown/dictdiffer
# DictDiffer is licensed as MIT code
# A dictionary difference calculator
# Originally posted as:
# http://stackoverflow.com/a/1165552


class DictDiffer(object):
    '''
    Calculate the difference between two dictionaries.

    (1) items added
    (2) items removed
    (3) keys same in both but changed values
    (4) keys same in both and unchanged values
    '''
    def __init__(self, current_dict, past_dict):
        '''
        Iitialize the differ.
        '''
        self.current_dict, self.past_dict = current_dict, past_dict
        self.current_keys, self.past_keys = [
            set(d.keys()) for d in (current_dict, past_dict)
        ]
        self.intersect = self.current_keys.intersection(self.past_keys)

    def same(self):
        '''
        True if the two dicts are the same.
        '''
        return self.current_dict == self.past_dict

    def added(self):
        '''
        Return a set of additions to past_dict.
        '''
        return self.current_keys - self.intersect

    def removed(self):
        '''
        Return a set of things removed from past_dict.
        '''
        return self.past_keys - self.intersect

    def changed(self):
        '''
        Return a set of the keys with changed values.
        '''
        return set(o for o in self.intersect
                   if self.past_dict[o] != self.current_dict[o])

    def unchanged(self):
        '''
        Return a set of the keys with unchanged values.
        '''
        return set(o for o in self.intersect
                   if self.past_dict[o] == self.current_dict[o])
