#!/usr/bin/env python3.6
#
# Copyright (C) 2016,2017 The University of Sheffield, 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/>.
#

import getopt
import glob
import os
import sys
import logging
import re

from ExtensionCrawler import config


def print_help():
    print("""extfind [OPTION]""")
    print("""  -h                  print this help text""")
    print("""  -a <DIR>            archive directory""")
    print("""  -g <GLOB>           glob on the extension id, don't use with -e """)
    print("""  -e <EXTIDFILELIST>  file with extension ids, don't use with -g""")
    print("""  -n <TASKID>         process chunk n where n in [1,N]""")
    print("""  -N <MAXTASKID>      """)


def split(l, n, N):
    if n < 1 or n > N:
        raise ValueError("n must be between 1 and N")
    chunksize = int(len(l) / N) + 1

    # Slicing beyond the list contents returns the empty list
    return l[chunksize * (n - 1):chunksize * n]


def iter_extension_paths_from_file(archive, n, N, extidlistfile):
    paths = []
    with open(extidlistfile, 'r') as f:
        for line in f.readlines():
            path = os.path.join(archive, "data", line[:3], line + ".tar")
            if re.fullmatch("[a-p]{32}", line) and os.path.exists(path):
                paths += [path]
            else:
                logging.warning("WARNING: {} is not a valid extension path!".format(path))
    return split(paths, n, N)


def iter_extension_paths(archive, n, N, extidglob="[a-p]"*32):
    paths = glob.glob(os.path.join(archive, "data", "[a-p]" * 3, extidglob + ".tar"))
    return split(paths, n, N)


def main(argv):
    archive = config.const_basedir()
    extidglob = None
    extidlistfile = None
    taskid = 1
    maxtaskid = 1

    try:
        opts, args = getopt.getopt(argv, "ha:g:e:n:N:", [
            "archive=", "glob=", "extidlistfile=", "taskid=",
            "maxtaskid=", "help"
        ])
    except getopt.GetoptError:
        print_help()
        sys.exit(2)
    for opt, arg in opts:
        if opt in ("-h", "--help"):
            print_help()
            sys.exit()
        elif opt in ("-a", "--archive"):
            archive = arg
        elif opt in ("-g", "--glob"):
            extidglob = arg
        elif opt in ("-e", "--extidlistfile"):
            extidlistfile = arg
        elif opt in ("-n", "--taskid"):
            taskid = int(arg)
        elif opt in ("-N", "--maxtaskid"):
            maxtaskid = int(arg)

    if extidglob is None and extidlistfile is None:
        paths = iter_extension_paths(archive, taskid, maxtaskid)
    elif extidglob is None and extidlistfile is not None:
        paths = iter_extension_paths_from_file(archive, taskid, maxtaskid, extidlistfile)
    elif extidglob is not None and extidlistfile is None:
        paths = iter_extension_paths(archive, taskid, maxtaskid, extidglob)
    else:
        print_help()
        sys.exit(2)

    for path in paths:
        print(path)


if __name__ == "__main__":
    main(sys.argv[1:])