#!/usr/bin/env python
""" Helper script for the Packages plugin, used if yum library support
is enabled.  The yum libs have horrific memory leaks, so apparently
the right way to get around that in long-running processes it to have
a short-lived helper.  No, seriously -- check out the yum-updatesd
code.  It's pure madness. """

import os
import sys
import yum
import logging
import Bcfg2.Logger
from optparse import OptionParser
try:
    import json
except ImportError:
    import simplejson as json


def pkg_to_tuple(package):
    """ json doesn't distinguish between tuples and lists, but yum
    does, so we convert a package in list format to one in tuple
    format """
    if isinstance(package, list):
        return tuple(package)
    else:
        return package


def pkgtup_to_string(package):
    """ given a package tuple, return a human-readable string
    describing the package """
    if package[3] in ['auto', 'any']:
        return package[0]

    rv = [package[0], "-"]
    if package[2]:
        rv.extend([package[2], ':'])
    rv.extend([package[3], '-', package[4]])
    if package[1]:
        rv.extend(['.', package[1]])
    return ''.join(str(e) for e in rv)


class DepSolver(object):
    """ Yum dependency solver """

    def __init__(self, cfgfile, verbose=1):
        self.cfgfile = cfgfile
        self.yumbase = yum.YumBase()
        # pylint: disable=E1121,W0212
        try:
            self.yumbase.preconf.debuglevel = verbose
            self.yumbase.preconf.fn = cfgfile
            self.yumbase._getConfig()
        except AttributeError:
            self.yumbase._getConfig(cfgfile, debuglevel=verbose)
        # pylint: enable=E1121,W0212
        self.logger = logging.getLogger(self.__class__.__name__)
        self._groups = None

    def get_groups(self):
        """ getter for the groups property """
        if self._groups is not None:
            return self._groups
        else:
            return ["noarch"]

    def set_groups(self, groups):
        """ setter for the groups property """
        self._groups = set(groups).union(["noarch"])

    groups = property(get_groups, set_groups)

    def get_package_object(self, pkgtup, silent=False):
        """ given a package tuple, get a yum package object """
        try:
            matches = yum.packageSack.packagesNewestByName(
                self.yumbase.pkgSack.searchPkgTuple(pkgtup))
        except yum.Errors.PackageSackError:
            if not silent:
                self.logger.warning("Package '%s' not found" %
                                    self.get_package_name(pkgtup))
            matches = []
        except yum.Errors.RepoError:
            err = sys.exc_info()[1]
            self.logger.error("Temporary failure loading metadata for %s: %s" %
                              (self.get_package_name(pkgtup), err))
            matches = []

        pkgs = self._filter_arch(matches)
        if pkgs:
            return pkgs[0]
        else:
            return None

    def get_group(self, group, ptype="default"):
        """ Resolve a package group name into a list of packages """
        if group.startswith("@"):
            group = group[1:]

        try:
            if self.yumbase.comps.has_group(group):
                group = self.yumbase.comps.return_group(group)
            else:
                self.logger.error("%s is not a valid group" % group)
                return []
        except yum.Errors.GroupsError:
            err = sys.exc_info()[1]
            self.logger.warning(err)
            return []

        if ptype == "default":
            return [p
                    for p, d in list(group.default_packages.items())
                    if d]
        elif ptype == "mandatory":
            return [p
                    for p, m in list(group.mandatory_packages.items())
                    if m]
        elif ptype == "optional" or ptype == "all":
            return group.packages
        else:
            self.logger.warning("Unknown group package type '%s'" % ptype)
            return []

    def _filter_arch(self, packages):
        """ filter packages in the given list that do not have an
        architecture in the list of groups for this client """
        matching = []
        for pkg in packages:
            if pkg.arch in self.groups:
                matching.append(pkg)
            else:
                self.logger.debug("%s has non-matching architecture (%s)" %
                                  (pkg, pkg.arch))
        if matching:
            return matching
        else:
            # no packages match architecture; we'll assume that the
            # user knows what s/he is doing and this is a multiarch
            # box.
            return packages

    def get_package_name(self, package):
        """ get the name of a package or virtual package from the
        internal representation used by this Collection class """
        if isinstance(package, tuple):
            if len(package) == 3:
                return yum.misc.prco_tuple_to_string(package)
            else:
                return pkgtup_to_string(package)
        else:
            return str(package)

    def complete(self, packagelist):
        """ resolve dependencies and generate a complete package list
        from the given list of initial packages """
        packages = set()
        unknown = set()
        for pkg in packagelist:
            if isinstance(pkg, tuple):
                pkgtup = pkg
            else:
                pkgtup = (pkg, None, None, None, None)
            pkgobj = self.get_package_object(pkgtup)
            if not pkgobj:
                self.logger.debug("Unknown package %s" %
                                  self.get_package_name(pkg))
                unknown.add(pkg)
            else:
                if self.yumbase.tsInfo.exists(pkgtup=pkgobj.pkgtup):
                    self.logger.debug("%s added to transaction multiple times"
                                      % pkgobj)
                else:
                    self.logger.debug("Adding %s to transaction" % pkgobj)
                    self.yumbase.tsInfo.addInstall(pkgobj)
        self.yumbase.resolveDeps()

        for txmbr in self.yumbase.tsInfo:
            packages.add(txmbr.pkgtup)
        return list(packages), list(unknown)

    def clean_cache(self):
        """ clean the yum cache """
        for mdtype in ["Headers", "Packages", "Sqlite", "Metadata",
                       "ExpireCache"]:
            # for reasons that are entirely obvious, all of the yum
            # API clean* methods return a tuple of 0 (zero, always
            # zero) and a list containing a single message about how
            # many files were deleted.  so useful.  thanks, yum.
            msg = getattr(self.yumbase, "clean%s" % mdtype)()[1][0]
            if not msg.startswith("0 "):
                self.logger.info(msg)


def main():
    parser = OptionParser()
    parser.add_option("-c", "--config", help="Config file")
    parser.add_option("-v", "--verbose", help="Verbosity level",
                      action="count")
    (options, args) = parser.parse_args()

    if options.verbose:
        level = logging.DEBUG
        clevel = logging.DEBUG
    else:
        level = logging.WARNING
        clevel = logging.INFO
    Bcfg2.Logger.setup_logging('bcfg2-yum-helper', to_syslog=True,
                               to_console=clevel, level=level)
    logger = logging.getLogger('bcfg2-yum-helper')

    try:
        cmd = args[0]
    except IndexError:
        logger.error("No command given")
        return 1

    if not os.path.exists(options.config):
        logger.error("Config file %s not found" % options.config)
        return 1

    # pylint: disable=W0702
    rv = 0
    depsolver = DepSolver(options.config, options.verbose)
    if cmd == "clean":
        try:
            depsolver.clean_cache()
            print(json.dumps(True))
        except:
            logger.error("Unexpected error cleaning cache: %s" %
                         sys.exc_info()[1], exc_info=1)
            print(json.dumps(False))
            rv = 2
    elif cmd == "complete":
        try:
            data = json.loads(sys.stdin.read())
        except:
            logger.error("Unexpected error decoding JSON input: %s" %
                         sys.exc_info()[1])
            rv = 2
        try:
            depsolver.groups = data['groups']
            (packages, unknown) = depsolver.complete(
                [pkg_to_tuple(p) for p in data['packages']])
            print(json.dumps(dict(packages=list(packages),
                                  unknown=list(unknown))))
        except:
            logger.error("Unexpected error completing package set: %s" %
                         sys.exc_info()[1], exc_info=1)
            print(json.dumps(dict(packages=[], unknown=data['packages'])))
            rv = 2
    elif cmd == "get_groups":
        try:
            data = json.loads(sys.stdin.read())
            rv = dict()
            for gdata in data:
                if "type" in gdata:
                    packages = depsolver.get_group(gdata['group'],
                                                   ptype=gdata['type'])
                else:
                    packages = depsolver.get_group(gdata['group'])
                rv[gdata['group']] = list(packages)
            print(json.dumps(rv))
        except:
            logger.error("Unexpected error getting groups: %s" %
                         sys.exc_info()[1], exc_info=1)
            print(json.dumps(dict()))
            rv = 2
    else:
        logger.error("Unknown command %s" % cmd)
        print(json.dumps(None))
        rv = 2
    return rv

if __name__ == '__main__':
    sys.exit(main())
