"""Handles differences between different distributions

Authors: Dave Malcolm <dmalcolm@redhat.com>, Zack Cerza <zcerza@redhat.com>"""
__author__ = "Dave Malcolm <dmalcolm@redhat.com>, Zack Cerza <zcerza@redhat.com>"

import os
import re
from version import Version
from logging import debugLogger as logger

class DistributionNotSupportedError(Exception):
    """
    This distribution is not supported.
    """
    PATCH_MESSAGE = "Please send patches to dogtail-devel-list@gnome.org"

    def __init__(self, distro):
        self.distro = distro

    def __str__(self):
        return self.distro + ". " + DistributionNotSupportedError.PATCH_MESSAGE

class PackageNotFoundError(Exception):
    """
    Error finding the requested package.
    """
    pass

global packageDb
global distro

class PackageDb:
    """
    Class to abstract the details of whatever software package database is in
    use (RPM, APT, etc)
    """
    def __init__(self):
        self.prefix = '/usr'
        self.localePrefixes = [self.prefix + '/share/locale']

    def getVersion(self, packageName):
        """
        Method to get the version of an installed package as a Version 
        instance (or raise an exception if not found)
        
        Note: does not know about distributions' internal revision numbers.
        """
        raise NotImplementedError

    def getFiles(self, packageName):
        """
        Method to get a list of filenames owned by the package, or raise an 
        exception if not found.
        """
        raise NotImplementedError

    def getMoFiles(self, locale = None):
        """
        Method to get a list of all .mo files on the system, optionally for a
        specific locale.
        """
        moFiles = {}

        def appendIfMoFile(moFiles, dirName, fNames):
            import re
            for fName in fNames:
                if re.match('(.*)\\.mo', fName):
                    moFiles[dirName + '/' + fName] = None

        for localePrefix in self.localePrefixes:
            if locale: localePrefix = localePrefix + '/' + locale
            os.path.walk(localePrefix, appendIfMoFile, moFiles)

        return moFiles.keys()

    def getDependencies(self, packageName):
        """
        Method to get a list of unique package names that this package
        is dependent on, or raise an exception if the package is not
        found.
        """
        raise NotImplementedError

class _RpmPackageDb(PackageDb):
    def __init__(self):
        PackageDb.__init__(self)

    def getVersion(self, packageName):
        import rpm
        ts = rpm.TransactionSet()
        for header in ts.dbMatch("name", packageName):
            return Version.fromString(header["version"])
        raise PackageNotFoundError, packageName

    def getFiles(self, packageName):
        import rpm
        ts = rpm.TransactionSet()
        for header in ts.dbMatch("name", packageName):
            return header["filenames"]
        raise PackageNotFoundError, packageName

    def getDependencies(self, packageName):
        import rpm
        ts = rpm.TransactionSet()
        for header in ts.dbMatch("name", packageName):
            # Simulate a set using a hash (to a dummy value);
            # sets were only added in Python 2.4
            result = {}

            # Get the list of requirements; these are
            # sometimes package names, but can also be
            # so-names of libraries, and invented virtual
            # ids
            for requirement in header[rpm.RPMTAG_REQUIRES]:
                # Get the name of the package providing
                # this requirement:
                for depPackageHeader in ts.dbMatch("provides", requirement):
                    depName = depPackageHeader['name']
                    if depName!=packageName:
                        # Add to the Hash with a dummy value
                        result[depName]=None
            return result.keys()
        raise PackageNotFoundError, packageName

class _AptPackageDb(PackageDb):
    def __init__(self):
        PackageDb.__init__(self)
        self.cache = None

    def getVersion(self, packageName):
        if not self.cache:
            import apt_pkg
            apt_pkg.init()
            self.cache = apt_pkg.Cache()
        packages = self.cache.packages
        for package in packages:
            if package.name == packageName:
                import re
                verString = re.match('.*Ver:\'(.*)-.*\' Section:', str(package.current_ver)).group(1)
                return Version.fromString(verString)
        raise PackageNotFoundError, packageName

    def getFiles(self, packageName):
        files = []
        list = os.popen('dpkg -L %s' % packageName).readlines()
        if not list:
            raise PackageNotFoundError, packageName
        else:
            for line in list:
                file = line.strip()
                if file: files.append(file)
            return files

    def getDependencies(self, packageName):
        # Simulate a set using a hash (to a dummy value);
        # sets were only added in Python 2.4
        result = {}
        if not self.cache:
            import apt_pkg
            apt_pkg.init()
            self.cache = apt_pkg.Cache()
        packages = self.cache.packages
        for package in packages:
            if package.name == packageName:
                current = package.current_ver
                if not current:
                    raise PackageNotFoundError, packageName
                depends = current.depends_list
                list = depends['Depends']
                for dependency in list:
                    name = dependency[0].target_pkg.name
                    # Add to the hash using a dummy value
                    result[name] = None
        return result.keys()

class _UbuntuAptPackageDb(_AptPackageDb):
    def __init__(self):
        _AptPackageDb.__init__(self)
        self.localePrefixes.append(self.prefix + '/share/locale-langpack')

class _PortagePackageDb(PackageDb):
    def __init__(self):
        PackageDb.__init__(self)

    def getVersion(self, packageName):
        # the portage utilities are almost always going to be in 
        # /usr/lib/portage/pym
        import sys
        sys.path.append ('/usr/lib/portage/pym')
        import portage
        # FIXME: this takes the first package returned in the list, in the 
        # case that there are slotted packages, and removes the leading 
        # category such as 'sys-apps'
        gentooPackageName = portage.db["/"]["vartree"].dbapi.match(packageName)[0].split('/')[1];
        # this removes the distribution specific versioning returning only the
        # upstream version
        upstreamVersion = portage.pkgsplit(gentooPackageName)[1]
        #print "Version of package is: " + upstreamVersion
        return Version.fromString(upstreamVersion);

class _ConaryPackageDb(PackageDb):
    def __init__(self):
        PackageDb.__init__(self)

    def getVersion(self, packageName):
        import conary
        from conaryclient import ConaryClient
        client = ConaryClient()
        dbVersions = client.db.getTroveVersionList(packageName)
        if not len(dbVersions):
            raise PackageNotFoundError, packageName
        return dbVersions[0].trailingRevision().asString().split("-")[0]

# getVersion not implemented because on Solaris multiple modules are installed
# in single packages, so it is hard to tell what version number of a specific
# module.
class _SolarisPackageDb(PackageDb):
    def __init__(self):
        PackageDb.__init__(self)

class JhBuildPackageDb(PackageDb):
    def __init__(self):
        PackageDb.__init__(self)
        prefixes = []
        prefixes.append(os.environ['LD_LIBRARY_PATH'])
        prefixes.append(os.environ['XDG_CONFIG_DIRS'])
        prefixes.append(os.environ['PKG_CONFIG_PATH'])
        self.prefix = os.path.commonprefix(prefixes)
        self.localePrefixes.append(self.prefix + '/share/locale')

    def getDependencies(self, packageName):
        result = {}
        lines = os.popen('jhbuild list ' + packageName).readlines()
        for line in lines:
            if line:
                result[line.strip()] = None
        return result.keys()

class Distro:
    """
    Class representing a distribution.

    Scripts may want to do arbitrary logic based on whichever distro is in use
    (e.g. handling differences in names of packages, distribution-specific 
    patches, etc.)

    We can either create methods in the Distro class to handle these, or we 
    can use constructs like isinstance(distro, Ubuntu) to handle this. We can
    even create hierarchies of distro subclasses to handle this kind of thing
    (could get messy fast though)
    """

class Fedora(Distro):
    def __init__(self):
        self.packageDb = _RpmPackageDb()

class RHEL(Fedora):
    pass

class Debian(Distro):
    def __init__(self):
        self.packageDb = _AptPackageDb()

class Ubuntu(Debian):
    def __init__(self):
        self.packageDb = _UbuntuAptPackageDb()

class Suse(Distro):
    def __init__(self):
        self.packageDb = _RpmPackageDb()

class Gentoo(Distro):
    def __init__(self):
        self.packageDb = _PortagePackageDb()

class Conary(Distro):
    def __init__(self):
        self.packageDb = _ConaryPackageDb()

class Solaris(Distro):
    def __init__(self):
        self.packageDb = _SolarisPackageDb()

class JHBuild(Distro):
    def __init__(self):
        self.packageDb = JhBuildPackageDb()

def detectDistro():
    logger.log("Detecting distribution:", newline = False)

    if os.environ.get("CERTIFIED_GNOMIE", "no") == "yes":
        distro = JHBuild()
    elif os.path.exists("/etc/SuSE-release"):
        distro = Suse()
    elif os.path.exists("/etc/fedora-release"):
        distro = Fedora()
    elif os.path.exists("/etc/redhat-release"):
        distro = RHEL()
    elif os.path.exists("/usr/share/doc/ubuntu-minimal"):
        distro = Ubuntu()
    elif os.path.exists("/etc/debian_version"):
        distro = Debian()
    elif os.path.exists("/etc/gentoo-release"):
        distro = Gentoo()
    elif os.path.exists("/etc/slackware-version"):
        raise DistributionNotSupportedError("Slackware")
    elif os.path.exists("/var/lib/conarydb/conarydb"):
        distro = Conary()
    elif os.path.exists ("/etc/release") and \
            re.match(".*Solaris", open ("/etc/release").readline()):
        distro = Solaris()
    else:
        raise DistributionNotSupportedError("Unknown")
    logger.log(distro.__class__.__name__)
    return distro

distro = detectDistro()
packageDb = distro.packageDb