'''This module implements a config file repository'''
__revision__ = '$Revision$'

from os import stat
from re import compile as regcompile
from stat import S_ISDIR, ST_MODE
from syslog import syslog, LOG_INFO, LOG_ERR

from Bcfg2.Server.Plugin import Plugin, PluginExecutionError, FileBacked

import binascii
import exceptions

specific = regcompile('(.*/)(?P<filename>[\S\-.]+)\.((H_(?P<hostname>\S+))|' +
                      '(G(?P<prio>\d+)_(?P<group>\S+)))$')

class SpecificityError(Exception):
    '''Thrown in case of filename parse failure'''
    pass

class FileEntry(FileBacked):
    '''The File Entry class pertains to the config files contained in a particular directory.
    This includes :info, all base files and deltas'''

    def __init__(self, myid, name):
        FileBacked.__init__(self, name)
        self.name = name
        self.identity = myid
        self.all = False
        self.hostname = False
        self.group = False
        self.op = False
        self.prio = False
        if name.split('.')[-1] in ['cat', 'diff']:
            self.op = name.split('.')[-1]
            name = name[:-(len(self.op) + 1)]
        if self.name.split('/')[-1] == myid.split('/')[-1]:
            self.all = True
        else:
            data = specific.match(name)
            if not data:
                syslog(LOG_ERR, "Cfg: Failed to match %s" % name)
                raise SpecificityError
            if data.group('hostname') != None:
                self.hostname = data.group('hostname')
            else:
                self.group = data.group('group')
                self.prio = int(data.group('prio'))

    def __cmp__(self, other):
        data = [[getattr(self, field) for field in ['all', 'group', 'hostname']],
                [getattr(other, field) for field in ['all', 'group', 'hostname']]]
        for index in range(3):
            if data[0][index] and not data[1][index]:
                return -1
            elif data[1][index] and not data[0][index]:
                return 1
            elif data[0][index] and data[1][index]:
                if hasattr(self, 'prio')  and hasattr(other, 'prio'):
                    return self.prio - other.prio
                else:
                    return 0
            else:
                pass
        syslog(LOG_ERR, "Cfg: Critical: Ran off of the end of the world sorting %s" % (self.name))

    def applies(self, metadata):
        '''Predicate if fragment matches client metadata'''
        if self.all or (self.hostname == metadata.hostname) or \
           (self.group in metadata.groups):
            return True
        else:
            return False

class ConfigFileEntry(object):
    '''ConfigFileEntry is a repository entry for a single file, containing
    all data for all clients.'''
    info = regcompile('^owner:(\s)*(?P<owner>\w+)|group:(\s)*(?P<group>\w+)|' +
                      'perms:(\s)*(?P<perms>\w+)|encoding:(\s)*(?P<encoding>\w+)|' +
                      '(?P<paranoid>paranoid(\s)*)$')
    
    def __init__(self, path, repopath):
        object.__init__(self)
        self.path = path
        self.repopath = repopath
        self.fragments = []
        self.metadata = {'encoding': 'ascii', 'owner':'root', 'group':'root', 'perms':'0644'}
        self.paranoid = False

    def read_info(self):
        '''read in :info metadata'''
        filename = "%s/:info" % self.repopath
        for line in open(filename).readlines():
            match = self.info.match(line)
            if not match:
                continue
            else:
                mgd = match.groupdict()
                if mgd['owner']:
                    self.metadata['owner'] = mgd['owner']
                elif mgd['group']:
                    self.metadata['group'] = mgd['group']
                elif mgd['encoding']:
                    self.metadata['encoding'] = mgd['encoding']
                elif mgd['perms']:
                    self.metadata['perms'] = mgd['perms']
                    if len(self.metadata['perms']) == 3:
                        self.metadata['perms'] = "0%s" % (self.metadata['perms'])
                elif mgd['paranoid']:
                    self.paranoid = True

    def AddEntry(self, name):
        '''add new file additions for a single cf file'''
        if name[-5:] == ':info':
            return self.read_info()

        try:
            self.fragments.append(FileEntry(self.path, name))
            self.fragments.sort()
        except SpecificityError:
            return

    def HandleEvent(self, event):
        '''Handle FAM updates'''
        action = event.code2str()
        if event.filename == ':info':
            if action in ['changed', 'exists', 'created']:
                return self.read_info()
        if event.filename != self.path.split('/')[-1]:
            if not specific.match('/' + event.filename):
                syslog(LOG_INFO, 'Cfg: Suppressing event for bogus file %s' % event.filename)
                return

        entries = [entry for entry in self.fragments if
                   entry.name.split('/')[-1] == event.filename]

        if len(entries) == 0:
            syslog(LOG_ERR, "Cfg: Failed to match entry for spec %s" % (event.filename))
        elif len(entries) > 1:
            syslog(LOG_ERR, "Cfg: Matched multiple entries for spec %s" % (event.filename))
            
        if action == 'deleted':
            syslog(LOG_INFO, "Cfg: Removing entry %s" % event.filename)
            for entry in entries:
                syslog(LOG_INFO, "Cfg: Removing entry %s" % (entry.name))
                self.fragments.remove(entry)
                self.fragments.sort()
            syslog(LOG_INFO, "Cfg: Entry deletion completed")
        elif action in ['changed', 'exists', 'created']:
            [entry.HandleEvent(event) for entry in entries]
        else:
            syslog(LOG_ERR, "Cfg: Unhandled Action %s for file %s" % (action, event.filename))

    def GetConfigFile(self, entry, metadata):
        '''Fetch config file from repository'''
        name = entry.attrib['name']
        filedata = ""
        # first find basefile
        try:
            basefile = [bfile for bfile in self.fragments if bfile.applies(metadata) and not bfile.op][-1]
        except IndexError:
            syslog(LOG_ERR, "Cfg: Failed to locate basefile for %s" % name)
            raise PluginExecutionError, ('basefile', name)
        filedata += basefile.data

        for delta in [delta for delta in self.fragments if delta.applies(metadata) and delta.op]:
            # find applicable deltas
            lines = filedata.split('\n')
            if not lines[-1]:
                lines = lines[:-1]
            dlines = [dline for dline in delta.data.split('\n') if dline]
            for line in dlines:
                if line[0] == '-':
                    if line[1:] in lines:
                        lines.remove(line[1:])
                else:
                    lines.append(line[1:])
            filedata = "\n".join(lines) + "\n"
            
        [entry.attrib.__setitem__(key, value) for (key, value) in self.metadata.iteritems()]
        if self.paranoid:
            entry.attrib['paranoid'] = 'true'
        if entry.attrib['encoding'] == 'base64':
            entry.text = binascii.b2a_base64(filedata)
        else:
            try:
                entry.text = filedata
            except exceptions.AttributeError:
                syslog(LOG_ERR, "Failed to marshall file %s. Mark it as base64" % (entry.get('name')))

class Cfg(Plugin):
    '''This generator in the configuration file repository for bcfg2'''
    __name__ = 'Cfg'
    __version__ = '$Id$'
    __author__ = 'bcfg-dev@mcs.anl.gov'
    tempfile = regcompile("^.*~$|^.*\.swp")

    def __init__(self, core, datastore):
        Plugin.__init__(self, core, datastore)
        self.entries = {}
        self.Entries = {'ConfigFile':{}}
        self.famID = {}
        self.directories = []
        self.AddDirectoryMonitor(self.data)
        # eventually flush fam events here so that all entries built here
        # ready to go

    def AddDirectoryMonitor(self, name):
        '''Add new directory to FAM structures'''
        if name not in self.directories:
            try:
                stat(name)
            except OSError:
                self.LogError("Failed to open directory %s" % (name))
                return
            reqid = self.core.fam.AddMonitor(name, self)
            self.famID[reqid] = name
            self.directories.append(name)

    def AddEntry(self, name, event):
        '''Add new entry to FAM structures'''
        try:
            sdata = stat(name)[ST_MODE]
        except OSError:
            return

        if S_ISDIR(sdata):
            self.AddDirectoryMonitor(name)
        else:
            # file entries shouldn't contain path-to-repo
            shortname = '/'+ '/'.join(name[len(self.data)+1:].split('/')[:-1])
            repodir = '/' + '/'.join(name.split('/')[:-1])
            if not self.entries.has_key(shortname):
                self.entries[shortname] = ConfigFileEntry(shortname, repodir)
                self.Entries['ConfigFile'][shortname] = self.entries[shortname].GetConfigFile
            self.entries[shortname].AddEntry(name)
            self.entries[shortname].HandleEvent(event)

    def HandleEvent(self, event):
        '''Handle FAM updates'''
        action = event.code2str()
        if self.tempfile.match(event.filename):
            syslog(LOG_INFO, "Cfg: Suppressed event for file %s" % event.filename)
            return
        if event.filename[0] != '/':
            filename = "%s/%s" % (self.famID[event.requestID], event.filename)
        else:
            filename = event.filename
        configfile = filename[len(self.data):-(len(event.filename)+1)]

        if ((action in ['exists', 'created']) and (filename != self.data)):
            self.AddEntry(filename, event)
        elif action == 'changed':
            # pass the event down the chain to the ConfigFileEntry
            if self.entries.has_key(configfile):
                self.entries[configfile].HandleEvent(event)
            else:
                if filename != self.data:
                    self.AddEntry(filename, event)
                else:
                    self.LogError("Ignoring event for %s"%(configfile))
        elif action == 'deleted':
            if self.entries.has_key(configfile):
                self.entries[configfile].HandleEvent(event)
        elif action in ['exists', 'endExist']:
            pass
        else:
            self.LogError("Got unknown event %s %s:%s" % (action, event.requestID, event.filename))