#!/usr/bin/env python

import sys
import os
import re
import shutil
import getopt
from stat import *

#------------------------------------------------------------------------------

# Command Line Args
doit = True
verbose = False
quiet = False
warn = False
force = False
print_mapping = False
remove_files = False
remove_installation = False

# Scan Results
existing_files = {}
non_existing_files = {}

# Directory and File mappings

# This is the complete directory map, it includes both data files
# and run-time files
dir_map = {
    '/var/mailman'				: '/var/lib/mailman',
    '/var/mailman/Mailman'			: '/usr/lib/mailman/Mailman',
    '/var/mailman/archives'			: '/var/lib/mailman/archives',
    '/var/mailman/bin'				: '/usr/lib/mailman/bin',
    '/var/mailman/cgi-bin'			: '/usr/lib/mailman/cgi-bin',
    '/var/mailman/cron'				: '/usr/lib/mailman/cron',
    '/var/mailman/data'				: '/var/lib/mailman/data',
    '/var/mailman/lists'			: '/var/lib/mailman/lists',
    '/var/mailman/locks'			: '/var/lock/mailman',
    '/var/mailman/logs'				: '/var/log/mailman',
    '/var/mailman/mail'				: '/usr/lib/mailman/mail',
    '/var/mailman/messages'			: '/usr/lib/mailman/messages',
    '/var/mailman/pythonlib'			: '/usr/lib/mailman/pythonlib',
    '/var/mailman/qfiles'			: '/var/spool/mailman',
    '/var/spool/mailman/qfiles'			: '/var/spool/mailman',
    '/var/mailman/scripts'			: '/usr/lib/mailman/scripts',
    '/var/mailman/spam'				: '/var/lib/mailman/spam',
    '/var/mailman/templates'			: '/usr/lib/mailman/templates',
    '/var/mailman/tests'			: '/usr/lib/mailman/tests'
}

# These are directories that contain data files the user may
# want to preserve from an old installation and should be copied
# into the new directory location.
data_dir_map = {
    '/var/mailman/archives'			: '/var/lib/mailman/archives',
    '/var/mailman/data'				: '/var/lib/mailman/data',
    '/var/mailman/lists'			: '/var/lib/mailman/lists',
    '/var/mailman/logs'				: '/var/log/mailman',
    '/var/mailman/qfiles'			: '/var/spool/mailman',
    '/var/spool/mailman/qfiles'			: '/var/spool/mailman',
    '/var/mailman/spam'				: '/var/lib/mailman/spam',
}

# These are mappings for individual files. They represent files that
# cannot be mapped via their parent dirctories, they must be treated
# individually.
file_map = {
    '/var/mailman/data/adm.pw'			: '/etc/mailman/adm.pw',
    '/var/mailman/data/creator.pw'		: '/etc/mailman/creator.pw',
    '/var/mailman/data/aliases'			: '/etc/mailman/aliases',
    '/var/mailman/data/virtual-mailman'		: '/etc/mailman/virtual-mailman',
    '/var/mailman/data/sitelist.cfg'		: '/etc/mailman/sitelist.cfg',
    '/var/mailman/data/master-qrunner.pid'	: '/var/run/mailman/master-qrunner.pid'
}

#------------------------------------------------------------------------------

def DumpMapping():
    '''Print out the directory and file mappings'''
    print "Directory Mapping:"
    for key in dir_map.keys():
        print "%s --> %s" %(key, dir_map[key])

    print "\nFile Mapping:"
    for key in file_map.keys():
        print "%s --> %s" %(key, file_map[key])

def RecordFile(src, dst):
    '''If the src files (old) exists record this as a potential
    file operation. File operations are grouped into two sets,
    those where the dst (new) files exists and those where it does not
    exist. This is done to prevent overwriting files'''
    
    global existing_files, non_existing_files

    if not os.path.exists(src):
        return

    if existing_files.has_key(src):
        if warn:
            print "WARNING: src file already seen (%s) and has dst match: (%s)" % (src, dst)
        return

    if non_existing_files.has_key(src):
        if warn:
            print "WARNING: src file already seen (%s) does not have dst match" % (src)
        return

    if os.path.exists(dst):
        existing_files[src] = dst
    else:
        non_existing_files[src] = dst

def GetCopyFiles(old_root, new_root):
    '''Recursively generate a list of src files (old) in the old_root
    and pair each of them with their new dst path name'''
    
    prefix_re = re.compile("^(%s)/*(.*)" % re.escape(old_root))
    dst_files_existing = []
    dst_files_non_existing = []
    for root, dirs, files in os.walk(old_root):
        match = prefix_re.match(root)
        subdir = match.group(2)
        for name in files:
            oldpath = os.path.join(root, name)
            newpath = os.path.join(new_root, subdir, name)
            RecordFile(oldpath, newpath)

def CopyFile(src_path, dst_path):
    '''Copy file, preserve its mode and ownership. If the dst directory
    does not exist, create it preserving the mode and ownership of the
    src direcotry'''
    
    if not doit:
        print "cp %s %s" % (src_path, dst_path)
        return
    
    src_dir = os.path.dirname(src_path)
    dst_dir = os.path.dirname(dst_path)

    if not os.path.isdir(dst_dir):
        if os.path.exists(dst_dir):
            print "ERROR: dst dir exists, but is not directory (%s)" % dst_dir
            return
        st = os.stat(src_dir)
        os.makedirs(dst_dir, st[ST_MODE])
        os.chown(dst_dir, st[ST_UID], st[ST_GID])
    
    shutil.copy2(src_path, dst_path)
    st = os.stat(src_path)
    os.chown(dst_path, st[ST_UID], st[ST_GID])

def RemoveFile(path):
    '''Remove the file'''
    
    if not os.path.exists(path):
        if warn:
            print "WARNING: attempt to remove non-existent file (%s)" % path
        return

    if not os.path.isfile(path):
        if warn:
            print "WARNING: attempt to remove non-plain file (%s)" % path
        return

    if not doit:
        print "rm %s" % (path)
        return

    os.unlink(path)
    
def RemoveDirs(top):
    '''Delete everything reachable from the directory named in 'top',
    assuming there are no symbolic links.
    CAUTION:  This is dangerous!  For example, if top == '/', it
    could delete all your disk files.'''
    for root, dirs, files in os.walk(top, topdown=False):
        for name in files:
            path = os.path.join(root, name)
            if not doit:
                print "rm %s" % (path)
            else:
                os.remove(path)
        for name in dirs:
            path = os.path.join(root, name)
            if not doit:
                print "rmdir %s" % (path)
            else:
                os.rmdir(path)

def Usage():
    print """
This script will help you copy mailman data files from the old
directory structure to the new FHS directory structure.

Mailman should not be running when you perform this!
/sbin/service mailman stop

This script is conservative, by default it will not overwrite
any file in the new directory on the assumption it is most recent
and most correct. If you want to force overwrites use -f.

Files are copied to the new directories, if you want to remove the
old data files use -r. Hint: copy first and test, once everything is
working remove the old files with -r. If you want to remove the entire
old installation use -R

migrate [-f] [-n] [-q] [-v] [-w] [-m] [-r] [-R]
-n don't execute, but show what would be done
-f force destination overwrites
-m print mapping
-r remove old data files
-R remove entire old installation
-q be quiet
-v be verbose
-w print warnings
-h help
"""

#------------------------------------------------------------------------------

try:
    opts, args = getopt.getopt(sys.argv[1:], "nfvmqwhrR")
    for o, a in opts:
        if o == "-n":
            doit = False
        elif o == "-f":
            force = True
        elif o == "-v":
            verbose = True
        elif o == "-m":
            print_mapping = True
        elif o == "-q":
            quiet = True
        elif o == "-w":
            warn = True
        elif o == "-r":
            remove_files = True
        elif o == "-R":
            remove_installation = True
        elif o == "-h":
            Usage()
            sys.exit(1)
except getopt.GetoptError, err:
    print err
    Usage()
    sys.exit(1)


if print_mapping:
    DumpMapping()
    sys.exit(0)

# Generate file list
for src_dir in data_dir_map.keys():
    GetCopyFiles(src_dir, dir_map[src_dir])

for src_file in file_map.keys():
    RecordFile(src_file, file_map[src_file])


# Copy files
for src in non_existing_files:
    dst = non_existing_files[src]
    CopyFile(src, dst)

if force:
    for src in existing_files:
        dst = existing_files[src]
        CopyFile(src, dst)
else:
    if len(existing_files) > 0 and not quiet:
        print "\nThe following files already exist in the destination, they will NOT be copied"
        print "To force overwriting invoke with -f\n"
        for src in existing_files:
            dst = existing_files[src]
            print "# cp %s %s" %(src, dst)

# Remove old files
if remove_files:
    for src in existing_files:
        RemoveFile(src)
    for src in non_existing_files:
        RemoveFile(src)

if remove_installation:
    for old_dir in dir_map.keys():
        RemoveDirs(old_dir)


sys.exit(0)