'''This module implements a package management scheme for all images'''
__revision__ = '$Revision$'

from copy import deepcopy
from re import compile as regcompile
from syslog import syslog, LOG_ERR

from Bcfg2.Server.Plugin import Plugin, PluginInitError, PluginExecutionError, DirectoryBacked, XMLFileBacked

class PackageEntry(XMLFileBacked):
    '''PackageEntry is a set of packages and locations for a single image'''
    __identifier__ = 'image'
    splitters = {'rpm':regcompile('^(?P<name>[\w\+\d\.]+(-[\w\+\d\.]+)*)-' + \
                                  '(?P<version>[\w\d\.]+-([\w\d\.]+))\.(?P<arch>\w+)\.rpm$'),
                 'encap':regcompile('^(?P<name>\w+)-(?P<version>[\w\d\.-]+).encap.*$')}

    def __init__(self, filename):
        XMLFileBacked.__init__(self, filename)
        self.packages = {}
        
    def Index(self):
        '''Build internal data structures'''
        XMLFileBacked.Index(self)
        self.packages = {}
        for location in self.entries:
            for pkg in location.getchildren():
                if location.attrib.has_key('type'):
                    pkg.set('type', location.get('type'))
                if pkg.attrib.has_key("simplefile"):
                    self.packages[pkg.get('name')] = {}
                    for key in pkg.attrib:
                        self.packages[pkg.get('name')][key] = pkg.attrib[key]
                    # most attribs will be set from pkg
                    self.packages[pkg.get('name')]['url'] = "%s/%s" % (location.get('uri'), pkg.get('simplefile'))
                elif pkg.attrib.has_key("file"):
                    if self.splitters.has_key(pkg.get('type')):
                        mdata = self.splitters[pkg.get('type')].match(pkg.get('file'))
                        if not mdata:
                            syslog(LOG_ERR, "Failed to match pkg %s" % pkg.get('file'))
                            continue
                        pkgname = mdata.group('name')
                        self.packages[pkgname] = mdata.groupdict()
                        self.packages[pkgname]['url'] = location.get('uri') + '/' + pkg.get('file')
                        self.packages[pkgname]['type'] = pkg.get('type')
                    else:
                        derived = [(ptype, self.splitters[ptype].match(pkg.get('file')).groupdict())
                                    for ptype in self.splitters if self.splitters[ptype].match(pkg.get('file'))]
                        if not derived:
                            syslog("Failed to match pkg %s" % pkg.get('file'))
                        else:
                            (ptype, mdata) = derived[0]
                            pkgname = mdata['name']
                            self.packages[pkgname] = mdata
                            self.packages[pkgname]['url'] = location.get('uri') + '/' + pkg.get('file')
                            self.packages[pkgname]['type'] = ptype
                else:
                    self.packages[pkg.get('name')] = pkg.attrib

class PackageDir(DirectoryBacked):
    '''A directory of package files'''
    __child__ = PackageEntry

class Pkgmgr(Plugin):
    '''This is a generator that handles package assignments'''
    __name__ = 'Pkgmgr'
    __version__ = '$Id$'
    __author__ = 'bcfg-dev@mcs.anl.gov'

    def __init__(self, core, datastore):
        Plugin.__init__(self, core, datastore)
        try:
            self.pkgdir = PackageDir(self.data, self.core.fam)
        except OSError:
            self.LogError("Pkgmgr: Failed to load package indices")
            raise PluginInitError

    def FindHandler(self, entry):
        '''Non static mechanism of determining entry provisioning'''
        if entry.tag != 'Package':
            raise PluginExecutionError, (entry.tag, entry.get('name'))
        return self.LocatePackage

    def LocatePackage(self, entry, metadata):
        '''Locates a package entry for particular metadata'''
        pkgname = entry.get('name')
        if self.pkgdir.entries.has_key("%s.xml" % metadata.hostname):
            pkglist = self.pkgdir["%s.xml" % metadata.hostname]
            if pkglist.packages.has_key(pkgname):
                pkginfo = pkglist.packages[pkgname]
                [entry.attrib.__setitem__(field, pkginfo[field]) for field in pkginfo]
                return
        elif not self.pkgdir.entries.has_key("%s.xml" % metadata.image):
            self.LogError("Pkgmgr: no package index for image %s" % metadata.image)
            raise PluginExecutionError, ("Image", metadata.image)
        pkglist = self.pkgdir["%s.xml" % (metadata.image)]
        if pkglist.packages.has_key(pkgname):
            pkginfo = pkglist.packages[pkgname]
            [entry.attrib.__setitem__(x, pkginfo[x]) for x in pkginfo]
        else:
            raise PluginExecutionError, ("Package", pkgname)