#!/usr/bin/python
"""Maintain mailman-xmail integration automatically.

Read cmdalias symlinks to mailman-template.tab and the available mailman lists,
and keep them in sync.

"""

MAILMAN_HOME = '/usr/local/mailman'
XMAIL_HOME = '/var/MailRoot'
CMD_ALIAS_TEMPLATE = XMAIL_HOME + '/bin/mailman-template.tab'

import os, sys
SUFFIXES = ('admin', 'bounces', 'confirm', 'join', 'leave', 'owner',
            'request', 'subscribe', 'unsubscribe')

def readAliasDomains():
    """Read the aliasdomains.tab file

    Returns a dictionary with alias -> real domain entries

    """
    alias_domains = {}
    for line in open(XMAIL_HOME + '/aliasdomain.tab').readlines():
        alias, orig = line.strip().split('\t')
        alias = alias.strip().strip('"')
        orig = orig.strip().strip('"')
        alias_domains[alias] = orig

    return alias_domains

def getMailmanLists():
    """List available Mailman lists
    
    Return a dictionary of virtual hosts, each entry with a list of
    mailinglists for the given domain. 

    """
    # Insert the Mailman path into the module search path
    sys.path.insert(0, MAILMAN_HOME)

    from Mailman import Utils, MailList

    # Lists, grouped by their virtual domain
    domain_lists = {}
    aliases = readAliasDomains()

    for name in Utils.list_names():
        list = MailList.MailList(name, lock=0)
        host = list.host_name
        host = aliases.get(host, host)
        lists = domain_lists.setdefault(host, [])
        lists.append(list.internal_name())

    return domain_lists

def stripSuffix(name):
    """Return the list name, stripped of any alias suffix"""
    if name.endswith('.tab'):
       name = name[:-4]

    for suffix in SUFFIXES:
        if name.endswith(suffix) and name[-(len(suffix) + 1)] == '-':
            return name[:-(len(suffix) + 1)]

    return name

def getSymlinkedLists():
    """List listnames to which cmdalias symlinks exist.

    Return a dictionary of virtual hosts, each entry with a list of
    mailinglists for the given domain. 

    """

    domains = ()
    alias_dir = XMAIL_HOME + '/cmdaliases'
    for entry in os.listdir(alias_dir):
        if os.path.isdir(alias_dir + '/' + entry):
            domains += (entry,)

    # Lists, grouped by their virtual domain
    domain_lists = {}

    for domain in domains:
        lists = domain_lists[domain] = []
        domain_dir = alias_dir + '/' + domain

        for entry in os.listdir(domain_dir):
            if not os.path.islink(domain_dir + '/' + entry):
                continue
            if os.readlink(domain_dir + '/' + entry) != CMD_ALIAS_TEMPLATE:
                continue

            name = stripSuffix(entry)
            if name not in lists:
               lists.append(name)

    return domain_lists

def createLinks(domain, listname):
    """Create cmdalias entries for a given domain and listname"""

    base = '%s/cmdaliases/%s/%s' % (XMAIL_HOME, domain, listname)

    try:
        os.symlink(CMD_ALIAS_TEMPLATE, base + '.tab')
    except OSError:
        pass
    for suffix in SUFFIXES:
        try:
            os.symlink(CMD_ALIAS_TEMPLATE, '%s-%s.tab' % (base, suffix))
        except OSError:
            pass

def removeLinks(domain, listname):
    """Remove cmdalias entries for a given domain and listname"""

    base = '%s/cmdaliases/%s/%s' % (XMAIL_HOME, domain, listname)

    try:
        os.unlink(base + '.tab')
    except OSError:
        pass

    for suffix in SUFFIXES:
        try:
            os.unlink('%s-%s.tab' % (base, suffix))
        except OSError:
            pass

def checkLinks(domain, listname):
    """Verify that all aliases for a give list are symlinked
    
    Return 1 when all are there.

    """
    domain_dir = '%s/cmdaliases/%s' % (XMAIL_HOME, domain)

    entries = os.listdir(domain_dir)

    if listname + '.tab' not in entries:
        return 0

    for suffix in SUFFIXES:
        filename = '%s-%s.tab' % (listname, suffix)
        if filename not in entries:
            return 0
    return 1

def findDeltas(mailmanLists, configuredLists):
    """Find those mailman lists that are removed or added

    Returns three lists; one for adding, one for removing, one remainders.
    Each lists consist of (domain, listname) tuples.

    """
    add = []       # (domain, list) tuples to add links for
    remove = []    # (domain, list) tuples to remove links for
    remainder = [] # (domain, list) tuples of lists that remain

    addDomains = [domain for domain in mailmanLists
                        if domain not in configuredLists]
    removeDomains = [domain for domain in configuredLists
                            if domain not in mailmanLists]
    remainingDomains = [domain for domain in configuredLists
                               if domain in mailmanLists]

    for domain in addDomains:
        add.extend([(domain, list) for list in mailmanLists[domain]])

    for domain in removeDomains:
        remove.extend([(domain, list) for list in configuredLists[domain]])

    for domain in remainingDomains:
        add.extend([(domain, list) for list in mailmanLists[domain]
                                   if list not in configuredLists[domain]])
        remove.extend([(domain, list) for list in configuredLists[domain]
                                      if list not in mailmanLists[domain]])
        remainder.extend([(domain, list) for list in mailmanLists[domain]
                                         if list in configuredLists[domain]])

    return add, remove, remainder

def usage(exit=0):
    print """\
Usage: %s [options]

  Keep XMail cmdaliases up-to-date with available mailman lists.

  Options:

  -a, --add     Only add missing cmdaliases, don't remove any.
  -r, --remove  Only remove cmdaliases for non-existant lists, don't add any.
  -f, --fix     Repair missing cmdaliases for existing lists.
  -d, --dryrun  Only state what we'd be doing, don't make any real changes.
  -q, --quiet   Don't print anything, just do the job.
  -h, --help    This message
""" % sys.argv[0]
    sys.exit(exit)

if __name__ == '__main__':
    import getopt
    opts, args = getopt.getopt(sys.argv[1:], 'arfdqh',
                               ('add', 'remove', 'fix' 'dryrun', 'quiet',
                                'help'))

    if args:
       usage(2)

    quiet = 0
    dryrun = 0
    do_add = 1
    do_remove = 1
    do_fix = 0

    for opt, val in opts:
        if opt in ('-h', '--help'):
            usage(1)
        if opt in ('-a', '--add'):
            do_add, do_remove = 1, 0
        if opt in ('-r', '--remove'):
            do_add, do_remove = 0, 1
        if opt in ('-f', '--fix'):
            do_fix = 1
        if opt in ('-d', '--dryrun'):
            dryrun = 1
        if opt in ('-q', '--quiet'):
            quiet = 1

    if quiet and dryrun:
        sys.exit(0)

    mailmanLists = getMailmanLists()
    configuredLists = getSymlinkedLists()

    add, remove, remainder = findDeltas(mailmanLists, configuredLists)

    if not do_add:
        add = []

    if not do_remove:
        remove = []

    if not add and not remove and not do_fix:
        if not quiet:
            print "Nothing to do."
        sys.exit(0)

    for domain, list in remove:
        if not quiet:
            print "Removing %s@%s list" % (list, domain)
        if not dryrun:
            removeLinks(domain, list)

    for domain, list in add:
        if not quiet:
            print "Adding %s@%s list" % (list, domain)
        if not dryrun:
            createLinks(domain, list)

    if do_fix:
        repairs = 0
        for domain, list in remainder:
            if checkLinks(domain, list):
                continue
            repairs += 1
            if not quiet:
                print "Repairing %s@%s list" % (list, domain)
            if not dryrun:
                createLinks(domain, list)
        if repairs:
            if not quiet:
                print "Fixed %d lists" % repairs
        else:
            if not quiet:
                print "List cmdalias entries were in good shape."