#!/usr/bin/python
#
# Copyright (C) 2006 Mandriva; 2009-2014 Red Hat, Inc.
# Authors: Frederic Lepied, Florian Festi
#
# 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 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
#
# This library and program is heavily based on rpmdiff from the rpmlint package
# It was modified to be used as standalone library for the Koji project.

import rpm
import os
import itertools

import sys, getopt


class Rpmdiff:

    # constants

    TAGS = ( rpm.RPMTAG_NAME, rpm.RPMTAG_SUMMARY,
             rpm.RPMTAG_DESCRIPTION, rpm.RPMTAG_GROUP,
             rpm.RPMTAG_LICENSE, rpm.RPMTAG_URL,
             rpm.RPMTAG_PREIN, rpm.RPMTAG_POSTIN,
             rpm.RPMTAG_PREUN, rpm.RPMTAG_POSTUN)

    PRCO = ( 'REQUIRES', 'PROVIDES', 'CONFLICTS', 'OBSOLETES')

    #{fname : (size, mode, mtime, flags, dev, inode,
    #          nlink, state, vflags, user, group, digest)}
    __FILEIDX = [ ['S', 0],
                  ['M', 1],
                  ['5', 11],
                  ['D', 4],
                  ['N', 6],
                  ['L', 7],
                  ['V', 8],
                  ['U', 9],
                  ['G', 10],
                  ['F', 3],
                  ['T', 2] ]

    try:
        if rpm.RPMSENSE_SCRIPT_PRE:
            PREREQ_FLAG=rpm.RPMSENSE_PREREQ|rpm.RPMSENSE_SCRIPT_PRE|\
                rpm.RPMSENSE_SCRIPT_POST|rpm.RPMSENSE_SCRIPT_PREUN|\
                rpm.RPMSENSE_SCRIPT_POSTUN
    except AttributeError:
        try:
            PREREQ_FLAG=rpm.RPMSENSE_PREREQ
        except:
            #(proyvind): This seems ugly, but then again so does
            #            this whole check as well.
            PREREQ_FLAG=False

    DEPFORMAT = '%-12s%s %s %s %s'
    FORMAT = '%-12s%s'

    ADDED   = 'added'
    REMOVED = 'removed'

    # code starts here

    def __init__(self, old, new, ignore=None):
        self.result = []
        self.ignore = ignore
        if self.ignore is None:
            self.ignore = []

        FILEIDX = self.__FILEIDX
        for tag in self.ignore:
            for entry in FILEIDX:
                if tag == entry[0]:
                    entry[1] = None
                    break

        old = self.__load_pkg(old)
        new = self.__load_pkg(new)

        # Compare single tags
        for tag in self.TAGS:
            old_tag = old[tag]
            new_tag = new[tag]
            if old_tag != new_tag:
                tagname = rpm.tagnames[tag]
                if old_tag == None:
                    self.__add(self.FORMAT, (self.ADDED, tagname))
                elif new_tag == None:
                    self.__add(self.FORMAT, (self.REMOVED, tagname))
                else:
                    self.__add(self.FORMAT, ('S.5........', tagname))

        # compare Provides, Requires, ...
        for  tag in self.PRCO:
            self.__comparePRCOs(old, new, tag)

        # compare the files

        old_files_dict = self.__fileIteratorToDict(old.fiFromHeader())
        new_files_dict = self.__fileIteratorToDict(new.fiFromHeader())
        files = list(set(itertools.chain(old_files_dict.iterkeys(),
                                         new_files_dict.iterkeys())))
        files.sort()

        for f in files:
            diff = 0

            old_file = old_files_dict.get(f)
            new_file = new_files_dict.get(f)

            if not old_file:
                self.__add(self.FORMAT, (self.ADDED, f))
            elif not new_file:
                self.__add(self.FORMAT, (self.REMOVED, f))
            else:
                format = ''
                for entry in FILEIDX:
                    if entry[1] != None and \
                            old_file[entry[1]] != new_file[entry[1]]:
                        format = format + entry[0]
                        diff = 1
                    else:
                        format = format + '.'
                if diff:
                    self.__add(self.FORMAT, (format, f))

    # return a report of the differences
    def textdiff(self):
        return '\n'.join((format % data for format, data in self.result))

    # do the two rpms differ
    def differs(self):
        return bool(self.result)

    # add one differing item
    def __add(self, format, data):
        self.result.append((format, data))

    # load a package from a file or from the installed ones
    def __load_pkg(self, filename):
        ts = rpm.ts()
        f = os.open(filename, os.O_RDONLY)
        hdr = ts.hdrFromFdno(f)
        os.close(f)
        return hdr

    # output the right string according to RPMSENSE_* const
    def sense2str(self, sense):
        s = ""
        for tag, char in ((rpm.RPMSENSE_LESS, "<"),
                          (rpm.RPMSENSE_GREATER, ">"),
                          (rpm.RPMSENSE_EQUAL, "=")):
            if sense & tag:
                s += char
        return s

    # compare Provides, Requires, Conflicts, Obsoletes
    def __comparePRCOs(self, old, new, name):
        oldflags = old[name[:-1]+'FLAGS']
        newflags = new[name[:-1]+'FLAGS']
        # fix buggy rpm binding not returning list for single entries
        if not isinstance(oldflags, list): oldflags = [ oldflags ]
        if not isinstance(newflags, list): newflags = [ newflags ]

        o = zip(old[name], oldflags, old[name[:-1]+'VERSION'])
        n = zip(new[name], newflags, new[name[:-1]+'VERSION'])

        if name == 'PROVIDES': # filter our self provide
            oldNV = (old['name'], rpm.RPMSENSE_EQUAL,
                     "%s-%s" % (old['version'], old['release']))
            newNV = (new['name'], rpm.RPMSENSE_EQUAL,
                     "%s-%s" % (new['version'], new['release']))
            o = [entry for entry in o if entry != oldNV]
            n = [entry for entry in n if entry != newNV]

        for oldentry in o:
            if not oldentry in n:
                if name == 'REQUIRES' and oldentry[1] & self.PREREQ_FLAG:
                    tagname = 'PREREQ'
                else:
                    tagname = name
                self.__add(self.DEPFORMAT,
                           (self.REMOVED, tagname, oldentry[0],
                            self.sense2str(oldentry[1]), oldentry[2]))
        for newentry in n:
            if not newentry in o:
                if name == 'REQUIRES' and newentry[1] & self.PREREQ_FLAG:
                    tagname = 'PREREQ'
                else:
                    tagname = name
                self.__add(self.DEPFORMAT,
                           (self.ADDED, tagname, newentry[0],
                            self.sense2str(newentry[1]), newentry[2]))

    def __fileIteratorToDict(self, fi):
        result = {}
        for filedata in fi:
            result[filedata[0]] = filedata[1:]
        return result

def _usage(exit=1):
    print("Usage: %s [<options>] <old package> <new package>" % sys.argv[0])
    print("Options:")
    print("  -h, --help            Output this message and exit")
    print("  -i, --ignore          Tag to ignore when calculating differences")
    print("                          (may be used multiple times)")
    print("                        Valid values are: SM5DNLVUGFT")
    sys.exit(exit)

def main():

    ignore_tags = []
    try:
        opts, args = getopt.getopt(sys.argv[1:], "hi:", ["help", "ignore="])
    except getopt.GetoptError, e:
        print("Error: %s" % e)
        _usage()

    for option, argument in opts:
        if option in ("-h", "--help"):
            _usage(0)
        if option in ("-i", "--ignore"):
            ignore_tags.append(argument)

    if len(args) != 2:
        _usage()

    d = Rpmdiff(args[0], args[1], ignore=ignore_tags)
    print(d.textdiff())
    sys.exit(int(d.differs()))

if __name__ == '__main__':
    main()

# rpmdiff ends here