#!/usr/bin/python -t

# 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 2 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 Library General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
# Copyright 2002 Duke University 

"""
Configuration parser and default values for yum.
"""

import os
import warnings
import rpm
import copy
import urlparse
from parser import ConfigPreProcessor
from iniparse import INIConfig
from iniparse.compat import NoSectionError, NoOptionError, ConfigParser
from iniparse.compat import ParsingError
import rpmUtils.transaction
import rpmUtils.arch
import Errors

class Option(object):
    '''
    This class handles a single Yum configuration file option. Create
    subclasses for each type of supported configuration option.
    
    Python descriptor foo (__get__ and __set__) is used to make option
    definition easy and consise.
    '''

    def __init__(self, default=None):
        self._setattrname()
        self.inherit = False
        self.default = default

    def _setattrname(self):
        '''Calculate the internal attribute name used to store option state in
        configuration instances.
        '''
        self._attrname = '__opt%d' % id(self)

    def __get__(self, obj, objtype):
        '''Called when the option is read (via the descriptor protocol). 

        @param obj: The configuration instance to modify.
        @param objtype: The type of the config instance (not used).
        @return: The parsed option value or the default value if the value
            wasn't set in the configuration file.
        '''
        if obj is None:
            return self

        return getattr(obj, self._attrname, None)

    def __set__(self, obj, value):
        '''Called when the option is set (via the descriptor protocol). 

        @param obj: The configuration instance to modify.
        @param value: The value to set the option to.
        @return: Nothing.
        '''
        # Only try to parse if its a string
        if isinstance(value, basestring):
            try:
                value = self.parse(value)
            except ValueError, e:
                # Add the field name onto the error
                raise ValueError('Error parsing %r: %s' % (value, str(e)))

        setattr(obj, self._attrname, value)

    def setup(self, obj, name):
        '''Initialise the option for a config instance. 
        This must be called before the option can be set or retrieved. 

        @param obj: BaseConfig (or subclass) instance.
        @param name: Name of the option.
        '''
        setattr(obj, self._attrname, copy.copy(self.default))

    def clone(self):
        '''Return a safe copy of this Option instance
        '''
        new = copy.copy(self)
        new._setattrname()
        return new

    def parse(self, s):
        '''Parse the string value to the Option's native value.

        @param s: Raw string value to parse.
        @return: Validated native value.
    
        Will raise ValueError if there was a problem parsing the string.
        Subclasses should override this.
        '''
        return s

    def tostring(self, value):
        '''Convert the Option's native value to a string value.

        @param value: Native option value.
        @return: String representation of input.

        This does the opposite of the parse() method above.
        Subclasses should override this.
        '''
        return str(value)

def Inherit(option_obj):
    '''Clone an Option instance for the purposes of inheritance. The returned
    instance has all the same properties as the input Option and shares items
    such as the default value. Use this to avoid redefinition of reused
    options.

    @param option_obj: Option instance to inherit.
    @return: New Option instance inherited from the input.
    '''
    new_option = option_obj.clone()
    new_option.inherit = True
    return new_option

class ListOption(Option):

    """
    An option containing a list of strings.
    """

    def __init__(self, default=None):
        if default is None:
            default = []
        super(ListOption, self).__init__(default)

    def parse(self, s):
        """Converts a string from the config file to a workable list

        Commas and spaces are used as separators for the list
        """
        # we need to allow for the '\n[whitespace]' continuation - easier
        # to sub the \n with a space and then read the lines
        s = s.replace('\n', ' ')
        s = s.replace(',', ' ')
        return s.split()

    def tostring(self, value):
        return '\n '.join(value)

class UrlOption(Option):
    '''
    This option handles lists of URLs with validation of the URL scheme.
    '''

    def __init__(self, default=None, schemes=('http', 'ftp', 'file', 'https'), 
            allow_none=False):
        super(UrlOption, self).__init__(default)
        self.schemes = schemes
        self.allow_none = allow_none

    def parse(self, url):
        url = url.strip()

        # Handle the "_none_" special case
        if url.lower() == '_none_':
            if self.allow_none:
                return None
            else:
                raise ValueError('"_none_" is not a valid value')

        # Check that scheme is valid
        (s,b,p,q,f,o) = urlparse.urlparse(url)
        if s not in self.schemes:
            raise ValueError('URL must be %s not "%s"' % (self._schemelist(), s))

        return url

    def _schemelist(self):
        '''Return a user friendly list of the allowed schemes
        '''
        if len(self.schemes) < 1:
            return 'empty'
        elif len(self.schemes) == 1:
            return self.schemes[0]
        else:
            return '%s or %s' % (', '.join(self.schemes[:-1]), self.schemes[-1])

class UrlListOption(ListOption):
    '''
    Option for handling lists of URLs with validation of the URL scheme.
    '''

    def __init__(self, default=None, schemes=('http', 'ftp', 'file', 'https')):
        super(UrlListOption, self).__init__(default)

        # Hold a UrlOption instance to assist with parsing
        self._urloption = UrlOption(schemes=schemes)
        
    def parse(self, s):
        out = []
        for url in super(UrlListOption, self).parse(s):
            out.append(self._urloption.parse(url))
        return out


class IntOption(Option):

    """
    An option representing an integer value.
    """

    def __init__(self, default=None, range_min=None, range_max=None):
        super(IntOption, self).__init__(default)
        self._range_min = range_min
        self._range_max = range_max
        
    def parse(self, s):
        try:
            val = int(s)
        except (ValueError, TypeError), e:
            raise ValueError('invalid integer value')
        if self._range_max is not None and val > self._range_max:
            raise ValueError('out of range integer value')
        if self._range_min is not None and val < self._range_min:
            raise ValueError('out of range integer value')
        return val

class PositiveIntOption(IntOption):

    """
    An option representing a positive integer value, where 0 can have a special
    represention.
    """

    def __init__(self, default=None, range_min=0, range_max=None,
                 names_of_0=None):
        super(PositiveIntOption, self).__init__(default, range_min, range_max)
        self._names0 = names_of_0

    def parse(self, s):
        if s in self._names0:
            return 0
        return super(PositiveIntOption, self).parse(s)

class SecondsOption(Option):

    """
    An option representing an integer value of seconds, or a human readable
    variation specifying days, hours, minutes or seconds until something
    happens. Works like BytesOption.
    Note that due to historical president -1 means "never", so this accepts
    that and allows the word never too.

    Valid inputs: 100, 1.5m, 90s, 1.2d, 1d, 0xF, 0.1, -1, never
    Invalid inputs: -10, -0.1, 45.6Z, 1d6h, 1day, 1y

    Return value will always be an integer
    """
    MULTS = {'d': 60 * 60 * 24, 'h' : 60 * 60, 'm' : 60, 's': 1}

    def parse(self, s):
        if len(s) < 1:
            raise ValueError("no value specified")

        if s == "-1" or s == "never": # Special cache timeout, meaning never
            return -1
        if s[-1].isalpha():
            n = s[:-1]
            unit = s[-1].lower()
            mult = self.MULTS.get(unit, None)
            if not mult:
                raise ValueError("unknown unit '%s'" % unit)
        else:
            n = s
            mult = 1

        try:
            n = float(n)
        except (ValueError, TypeError), e:
            raise ValueError('invalid value')

        if n < 0:
            raise ValueError("seconds value may not be negative")

        return int(n * mult)

class BoolOption(Option):

    """
    An option representing a boolean value.

    The value can be one of 0, 1, yes, no, true, or false.
    """

    def parse(self, s):
        s = s.lower()
        if s in ('0', 'no', 'false'):
            return False
        elif s in ('1', 'yes', 'true'):
            return True
        else:
            raise ValueError('invalid boolean value')

    def tostring(self, value):
        if value:
            return "1"
        else:
            return "0"

class FloatOption(Option):
    """
    An option representing a numeric float value.
    """
    def parse(self, s):
        try:
            return float(s.strip())
        except (ValueError, TypeError):
            raise ValueError('invalid float value')

class SelectionOption(Option):
    '''Handles string values where only specific values are allowed
    '''
    def __init__(self, default=None, allowed=()):
        super(SelectionOption, self).__init__(default)
        self._allowed = allowed
        
    def parse(self, s):
        if s not in self._allowed:
            raise ValueError('"%s" is not an allowed value' % s)
        return s

class BytesOption(Option):

    """
    An option representing a value in bytes.

    The value may be given in bytes, kilobytes, megabytes, or gigabytes.
    """
    # Multipliers for unit symbols
    MULTS = {
        'k': 1024,
        'm': 1024*1024,
        'g': 1024*1024*1024,
    }

    def parse(self, s):
        """Parse a friendly bandwidth option to bytes

        The input should be a string containing a (possibly floating point)
        number followed by an optional single character unit. Valid units are
        'k', 'M', 'G'. Case is ignored.
       
        Valid inputs: 100, 123M, 45.6k, 12.4G, 100K, 786.3, 0
        Invalid inputs: -10, -0.1, 45.6L, 123Mb

        Return value will always be an integer

        1k = 1024 bytes.

        ValueError will be raised if the option couldn't be parsed.
        """
        if len(s) < 1:
            raise ValueError("no value specified")

        if s[-1].isalpha():
            n = s[:-1]
            unit = s[-1].lower()
            mult = self.MULTS.get(unit, None)
            if not mult:
                raise ValueError("unknown unit '%s'" % unit)
        else:
            n = s
            mult = 1
             
        try:
            n = float(n)
        except ValueError:
            raise ValueError("couldn't convert '%s' to number" % n)

        if n < 0:
            raise ValueError("bytes value may not be negative")

        return int(n * mult)

class ThrottleOption(BytesOption):

    """
    An option representing a bandwidth throttle value. See
    ThrottleOption.parse for acceptable input values.
    """

    def parse(self, s):
        """Get a throttle option. 

        Input may either be a percentage or a "friendly bandwidth value" as
        accepted by the BytesOption.

        Valid inputs: 100, 50%, 80.5%, 123M, 45.6k, 12.4G, 100K, 786.0, 0
        Invalid inputs: 100.1%, -4%, -500

        Return value will be a int if a bandwidth value was specified or a
        float if a percentage was given.

        ValueError will be raised if input couldn't be parsed.
        """
        if len(s) < 1:
            raise ValueError("no value specified")

        if s[-1] == '%':
            n = s[:-1]
            try:
                n = float(n)
            except ValueError:
                raise ValueError("couldn't convert '%s' to number" % n)
            if n < 0 or n > 100:
                raise ValueError("percentage is out of range")
            return n / 100.0
        else:
            return BytesOption.parse(self, s)


class BaseConfig(object):
    '''
    Base class for storing configuration definitions. Subclass when creating
    your own definitons.
    '''

    def __init__(self):
        self._section = None

        for name in self.iterkeys():
            option = self.optionobj(name)
            option.setup(self, name)

    def __str__(self):
        out = []
        out.append('[%s]' % self._section)
        for name, value in self.iteritems():
            out.append('%s: %r' % (name, value))
        return '\n'.join(out)

    def populate(self, parser, section, parent=None):
        '''Set option values from a INI file section.

        @param parser: ConfParser instance (or subclass)
        @param section: INI file section to read use.
        @param parent: Optional parent BaseConfig (or subclass) instance to use
            when doing option value inheritance.
        '''
        self.cfg = parser
        self._section = section

        for name in self.iterkeys():
            option = self.optionobj(name)
            value = None
            try:
                value = parser.get(section, name)
            except (NoSectionError, NoOptionError):
                # No matching option in this section, try inheriting
                if parent and option.inherit:
                    value = getattr(parent, name)
               
            if value is not None:
                setattr(self, name, value)

    def optionobj(cls, name):
        '''Return the Option instance for the given name
        '''
        obj = getattr(cls, name, None)
        if isinstance(obj, Option):
            return obj
        else:
            raise KeyError
    optionobj = classmethod(optionobj)

    def isoption(cls, name):
        '''Return True if the given name refers to a defined option 
        '''
        try:
            cls.optionobj(name)
            return True
        except KeyError:
            return False
    isoption = classmethod(isoption)

    def iterkeys(self):
        '''Yield the names of all defined options in the instance.
        '''
        for name, item in self.iteritems():
            yield name

    def iteritems(self):
        '''Yield (name, value) pairs for every option in the instance.

        The value returned is the parsed, validated option value.
        '''
        # Use dir() so that we see inherited options too
        for name in dir(self):
            if self.isoption(name):
                yield (name, getattr(self, name))

    def write(self, fileobj, section=None, always=()):
        '''Write out the configuration to a file-like object

        @param fileobj: File-like object to write to
        @param section: Section name to use. If not-specified the section name
            used during parsing will be used.
        @param always: A sequence of option names to always write out.
            Options not listed here will only be written out if they are at
            non-default values. Set to None to dump out all options.
        '''
        # Write section heading
        if section is None:
            if self._section is None:
                raise ValueError("not populated, don't know section")
            section = self._section

        # Updated the ConfigParser with the changed values    
        cfgOptions = self.cfg.options(section)
        for name,value in self.iteritems():
            option = self.optionobj(name)
            if always is None or name in always or option.default != value or name in cfgOptions :
                self.cfg.set(section,name, option.tostring(value))
        # write the updated ConfigParser to the fileobj.
        self.cfg.write(fileobj)

    def getConfigOption(self, option, default=None):
        warnings.warn('getConfigOption() will go away in a future version of Yum.\n'
                'Please access option values as attributes or using getattr().',
                DeprecationWarning)
        if hasattr(self, option):
            return getattr(self, option)
        return default

    def setConfigOption(self, option, value):
        warnings.warn('setConfigOption() will go away in a future version of Yum.\n'
                'Please set option values as attributes or using setattr().',
                DeprecationWarning)
        if hasattr(self, option):
            setattr(self, option, value)
        else:
            raise Errors.ConfigError, 'No such option %s' % option

class StartupConf(BaseConfig):
    '''
    Configuration option definitions for yum.conf's [main] section that are
    required early in the initialisation process or before the other [main]
    options can be parsed. 
    '''
    debuglevel = IntOption(2, 0, 10)
    errorlevel = IntOption(2, 0, 10)

    distroverpkg = Option('redhat-release')
    installroot = Option('/')
    config_file_path = Option('/etc/yum/yum.conf')
    plugins = BoolOption(False)
    pluginpath = ListOption(['/usr/share/yum-plugins', '/usr/lib/yum-plugins'])
    pluginconfpath = ListOption(['/etc/yum/pluginconf.d'])
    gaftonmode = BoolOption(False)

class YumConf(StartupConf):
    '''
    Configuration option definitions for yum.conf\'s [main] section.

    Note: see also options inherited from StartupConf
    '''
    retries = PositiveIntOption(10, names_of_0=["<forever>"])
    recent = IntOption(7, range_min=0)

    cachedir = Option('/var/cache/yum')
    persistdir = Option('/var/lib/yum')
    keepcache = BoolOption(True)
    logfile = Option('/var/log/yum.log')
    reposdir = ListOption(['/etc/yum/repos.d', '/etc/yum.repos.d'])
    syslog_ident = Option()
    syslog_facility = Option('LOG_DAEMON')

    commands = ListOption()
    exclude = ListOption()
    failovermethod = Option('roundrobin')
    proxy = UrlOption(schemes=('http', 'ftp', 'https'), allow_none=True)
    proxy_username = Option()
    proxy_password = Option()
    installonlypkgs = ListOption(['kernel', 'kernel-bigmem',
            'kernel-enterprise','kernel-smp', 'kernel-modules', 'kernel-debug',
            'kernel-unsupported', 'kernel-source', 'kernel-devel', 'kernel-PAE',
            'kernel-PAE-debug'])
    # NOTE: If you set this to 2, then because it keeps the current kernel it
    # means if you ever install an "old" kernel it'll get rid of the newest one
    # so you probably want to use 3 as a minimum ... if you turn it on.
    installonly_limit = PositiveIntOption(0, range_min=2,
                                          names_of_0=["0", "<off>"])
    kernelpkgnames = ListOption(['kernel','kernel-smp', 'kernel-enterprise',
            'kernel-bigmem', 'kernel-BOOT', 'kernel-PAE', 'kernel-PAE-debug'])
    exactarchlist = ListOption(['kernel', 'kernel-smp', 'glibc',
            'kernel-hugemem', 'kernel-enterprise', 'kernel-bigmem',
            'kernel-devel', 'kernel-PAE', 'kernel-PAE-debug'])
    tsflags = ListOption()

    assumeyes = BoolOption(False)
    alwaysprompt = BoolOption(True)
    exactarch = BoolOption(True)
    tolerant = BoolOption(True)
    diskspacecheck = BoolOption(True)
    overwrite_groups = BoolOption(False)
    keepalive = BoolOption(True)
    gpgcheck = BoolOption(False)
    obsoletes = BoolOption(False)
    showdupesfromrepos = BoolOption(False)
    enabled = BoolOption(True)
    enablegroups = BoolOption(True)
    enable_group_conditionals = BoolOption(True)
    group_package_types = ListOption(['mandatory', 'default'])
    
    timeout = FloatOption(30.0) # FIXME: Should use variation of SecondsOption

    bandwidth = BytesOption(0)
    throttle = ThrottleOption(0)

    http_caching = SelectionOption('all', ('none', 'packages', 'all'))
    #  Time in seconds (1.5h), yum-updatesd runs once per. hour by default
    # this time means we don't do interactive network checks/updates if
    # yum-updatesd is running.
    metadata_expire = SecondsOption(60 * 90)
    mirrorlist_expire = SecondsOption(86400) # time in seconds (1 day)
    rpm_check_debug = BoolOption(True)
    disable_excludes = ListOption()    
    skip_broken = BoolOption(False)
    #  Note that "instant" is the old behaviour, but group:primary is very
    # similar but better :).
    mdpolicy = SelectionOption('group:primary',
                               ('instant', 'group:all', 'group:main',
                                'group:small', 'group:primary'))
    multilib_policy = SelectionOption('all',('best', 'all'))
                 # all == install any/all arches you can
                 # best == use the 'best  arch' for the system
                 

    
    _reposlist = []

class RepoConf(BaseConfig):
    '''
    Option definitions for repository INI file sections.
    '''
    name = Option()
    enabled = Inherit(YumConf.enabled)
    baseurl = UrlListOption()
    mirrorlist = UrlOption()
    mediaid = Option()
    gpgkey = UrlListOption()
    exclude = ListOption() 
    includepkgs = ListOption() 

    proxy = Inherit(YumConf.proxy)
    proxy_username = Inherit(YumConf.proxy_username)
    proxy_password = Inherit(YumConf.proxy_password)
    retries = Inherit(YumConf.retries)
    failovermethod = Inherit(YumConf.failovermethod)

    gpgcheck = Inherit(YumConf.gpgcheck)
    keepalive = Inherit(YumConf.keepalive)
    enablegroups = Inherit(YumConf.enablegroups)

    bandwidth = Inherit(YumConf.bandwidth)
    throttle = Inherit(YumConf.throttle)
    timeout = Inherit(YumConf.timeout)
    http_caching = Inherit(YumConf.http_caching)
    metadata_expire = Inherit(YumConf.metadata_expire)
    mirrorlist_expire = Inherit(YumConf.mirrorlist_expire)
    mdpolicy = Inherit(YumConf.mdpolicy)
    cost = IntOption(1000)
    
def readStartupConfig(configfile, root):
    '''
    Parse Yum's main configuration file and return a StartupConf instance.
    
    This is required in order to access configuration settings required as Yum
    starts up.

    @param configfile: The path to yum.conf.
    @param root: The base path to use for installation (typically '/')
    @return: A StartupConf instance.

    May raise Errors.ConfigError if a problem is detected with while parsing.
    '''

    StartupConf.installroot.default = root
    startupconf = StartupConf()
    startupconf.config_file_path = configfile
    parser = ConfigParser()
    confpp_obj = ConfigPreProcessor(configfile)
    try:
        parser.readfp(confpp_obj)
    except ParsingError, e:
        raise Errors.ConfigError("Parsing file failed: %s" % e)
    startupconf.populate(parser, 'main')

    # Check that plugin paths are all absolute
    for path in startupconf.pluginpath:
        if not path[0] == '/':
            raise Errors.ConfigError("All plugin search paths must be absolute")

    # Stuff this here to avoid later re-parsing
    startupconf._parser = parser

    return startupconf

def readMainConfig(startupconf):
    '''
    Parse Yum's main configuration file

    @param startupconf: StartupConf instance as returned by readStartupConfig()
    @return: Populated YumConf instance.
    '''
    
    # Set up substitution vars
    yumvars = _getEnvVar()
    yumvars['basearch'] = rpmUtils.arch.getBaseArch()          # FIXME make this configurable??
    yumvars['arch'] = rpmUtils.arch.getCanonArch()             # FIXME make this configurable??
    yumvars['releasever'] = _getsysver(startupconf.installroot, startupconf.distroverpkg)

    # Read [main] section
    yumconf = YumConf()
    yumconf.populate(startupconf._parser, 'main')

    # Apply the installroot to directory options
    for option in ('cachedir', 'logfile', 'persistdir'):
        path = getattr(yumconf, option)
        setattr(yumconf, option, yumconf.installroot + path)
    
    # Add in some extra attributes which aren't actually configuration values 
    yumconf.yumvar = yumvars
    yumconf.uid = 0
    yumconf.cache = 0
    yumconf.progess_obj = None
    
    # items related to the originating config file
    yumconf.config_file_path = startupconf.config_file_path
    if os.path.exists(startupconf.config_file_path):
        yumconf.config_file_age = os.stat(startupconf.config_file_path)[8]
    else:
        yumconf.config_file_age = 0
    
    # propagate the debuglevel and errorlevel values:
    yumconf.debuglevel = startupconf.debuglevel
    yumconf.errorlevel = startupconf.errorlevel
    
    return yumconf

def getOption(conf, section, name, option):
    '''Convenience function to retrieve a parsed and converted value from a
    ConfigParser.

    @param conf: ConfigParser instance or similar
    @param section: Section name
    @param name: Option name
    @param option: Option instance to use for conversion.
    @return: The parsed value or default if value was not present.

    Will raise ValueError if the option could not be parsed.
    '''
    try: 
        val = conf.get(section, name)
    except (NoSectionError, NoOptionError):
        return option.default
    return option.parse(val)

def _getEnvVar():
    '''Return variable replacements from the environment variables YUM0 to YUM9

    The result is intended to be used with parser.varReplace()
    '''
    yumvar = {}
    for num in range(0, 10):
        env = 'YUM%d' % num
        val = os.environ.get(env, '')
        if val:
            yumvar[env.lower()] = val
    return yumvar

def _getsysver(installroot, distroverpkg):
    '''Calculate the release version for the system.

    @param installroot: The value of the installroot option.
    @param distroverpkg: The value of the distroverpkg option.
    @return: The release version as a string (eg. '4' for FC4)
    '''
    ts = rpmUtils.transaction.initReadOnlyTransaction(root=installroot)
    ts.pushVSFlags(~(rpm._RPMVSF_NOSIGNATURES|rpm._RPMVSF_NODIGESTS))
    idx = ts.dbMatch('provides', distroverpkg)
    # we're going to take the first one - if there is more than one of these
    # then the user needs a beating
    if idx.count() == 0:
        releasever = '$releasever'
    else:
        hdr = idx.next()
        releasever = hdr['version']
        del hdr
    del idx
    del ts
    return releasever

def writeRawRepoFile(repo,only=None):
    """
    Writes changes in a repo object back to a .repo file.
    @param repo: Repo Object
    @param only: List of attributes to work on (None = All)
    It work by reading the repo file, changes the values there shall be changed and write it back to disk.
    """
    ini = INIConfig(open(repo.repofile))
    # Updated the ConfigParser with the changed values    
    cfgOptions = repo.cfg.options(repo.id)
    for name,value in repo.iteritems():
        option = repo.optionobj(name)
        if option.default != value or name in cfgOptions :
            if only == None or name in only:
                ini[repo.id][name] = option.tostring(value)
    fp =file(repo.repofile,"w")               
    fp.write(str(ini))
    fp.close()

#def main():
#    mainconf = readMainConfig(readStartupConfig('/etc/yum/yum.conf', '/'))
#    print mainconf.cachedir
#
#if __name__ == '__main__':
#    main()
