#!/usr/bin/env python

"""

Remove expired events from quota journals.

Copyright (C) 2014, 2015, 2016 Paul Boddie <paul@boddie.org.uk>

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 3 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, see <http://www.gnu.org/licenses/>.

"""

from os.path import split

import sys

# Find the modules.

try:

    import imiptools

except ImportError:

    parent = split(split(__file__)[0])[0]

    if split(parent)[1] == "imip-agent":

        sys.path.append(parent)

from codecs import getwriter

from imiptools.dates import get_datetime, get_default_timezone, get_time, \

                            to_utc_datetime

from imip_store import FileJournal

def remove_expired_entries(entries, expiry):

    "Remove from 'entries' events that end at or before 'expiry'."

    removed = []

    i = 0

    while i < len(entries):

        period = entries[i]

        if period.get_end_point() <= expiry:

            removed.append(period)

            del entries[i]

        else:

            i += 1

    return removed

def update_entries(journal, quota, expiry, store, verbose):

    """

    Using the given 'journal' process quota records for the given 'quota', with

    the given 'expiry' time used to expire events ending before or at this time,

    with None meaning the current time.

    If 'store' is set, the stored details will be updated; otherwise, the

    details will be written to standard output.

    If 'verbose' is set, messages will be written to standard error.

    """

    if not store:

        stdout = getwriter("utf-8")(sys.stdout)

    if verbose:

        stderr = getwriter("utf-8")(sys.stderr)

    if not expiry:

        expiry = get_time()

    journal.acquire_lock(quota)

    try:

        for user in journal.get_quota_users(quota):

            if verbose:

                print >>stderr, user

            entries = journal.get_entries(quota, user)

            removed = remove_expired_entries(entries, expiry)

            if verbose:

                for period in removed:

                    print >>stderr, "\t".join(("Removed",) + period.as_tuple(strings_only=True))

            # Store the processed entries.

            if store:

                journal.set_entries(quota, user, entries)

            # Alternatively, just write the entries to standard output.

            else:

                for period in entries:

                    print >>stdout, "\t".join(period.as_tuple(strings_only=True))

    finally:

        journal.release_lock(quota)

# Main program.

if __name__ == "__main__":

    # Interpret the command line arguments.

    quotas = []

    args = []

    journal_dir = []

    expiry = []

    ignored = []

    # Collect quota details first, switching to other arguments when encountering

    # switches.

    l = quotas

    for arg in sys.argv[1:]:

        if arg in ("-s", "-v"):

            args.append(arg)

            l = ignored

        elif arg == "-j":

            l = journal_dir

        elif arg == "-e":

            l = expiry

        else:

            l.append(arg)

    try:

        quota = quotas[0]

    except IndexError:

        print >>sys.stderr, """\

Usage: %s <quota> <options>

Need a quota along with the -s option if updating the journal.

Specify -v for additional messages on standard error.

General options:

-e  indicate an expiry time for events (default is now)

-j  indicate the journal directory location

""" % split(sys.argv[0])[1]

        sys.exit(1)

    # Define any other options.

    store = "-s" in args

    verbose = "-v" in args

    # Override defaults if indicated.

    journal_dir = journal_dir and journal_dir[0] or None

    expiry = expiry and expiry[0] or None

    if expiry:

        expiry = to_utc_datetime(get_datetime(expiry), get_default_timezone())

        if not expiry:

            print >>sys.stderr, "Expiry time must be a valid datetime."

            sys.exit(1)

    # Obtain store-related objects.

    journal = FileJournal(journal_dir)

    # Obtain a list of users for processing.

    if quota in ("*", "all"):

        quotas = journal.get_quotas()

    # Process the given users.

    if verbose:

        stderr = getwriter("utf-8")(sys.stderr)

    for quota in quotas:

        if verbose:

            print >>stderr, quota

        update_entries(journal, quota, expiry, store, verbose)

# vim: tabstop=4 expandtab shiftwidth=4