'''
retrieve and display the max page id for a given wiki
'''
import sys
import getopt
from dumps.utils import PageAndEditStats
from dumps.WikiDump import Wiki, Config


class DbStatsRetriever(object):
    '''
    retrieve various stats from the db for the specific wiki
    '''
    def __init__(self, configfile, wikiname):
        config = Config(configfile)
        config.parse_conffile_per_project(wikiname)
        self.wiki = Wiki(config, wikiname)
        self.stats = PageAndEditStats(self.wiki, wikiname)

    def get_max_pageid(self):
        '''
        return the results from select MAX(page_id) from page
        if the command was not successful, None is returned
        '''
        return self.stats.get_total_pages()


def usage(message):
    '''
    display a message about how to use this script, along with an optional
    leading sentence or two, and exit with 1
    '''
    if message:
        sys.stderr.write(message + "\n")
    usage_message = """Usage: python get_max_pageid.py [options]

This script writes MAX(pageid) to stdout, for the specified
wiki.

--configfile  (-c): path to configuration file
--wiki        (-w): name of wiki for which to retrieve the max page id;
                    this should be the name of the wiki database, for
                    example, elwiki
--help        (-h): display this message
"""
    sys.stderr.write(usage_message)
    sys.exit(1)


def check_args(configfile, wikiname, remainder):
    '''
    whine about any missing/extra args and exit with 1
    '''
    if remainder:
        usage("Unknown option(s) specified: <%s>" % remainder[0])
    if configfile is None:
        usage("mandatory arg 'configfile' is missing")
        sys.exit(1)
    if wikiname is None:
        usage("mandatory arg 'wiki' is missing")
        sys.exit(1)


def do_main():
    '''
    Either displays max page id on stdout or
    exits with 1 on error. No stack trace if things
    go wrong though :-P
    '''
    configfile = None
    wikiname = None

    try:
        (options, remainder) = getopt.gnu_getopt(
            sys.argv[1:], "c:w:vh",
            ['configfile=', 'wiki=', 'help'])

    except getopt.GetoptError as err:
        print str(err)
        usage("Unknown option specified")

    for (opt, val) in options:
        if opt in ["-c", "--configfile"]:
            configfile = val
        elif opt in ["-w", "--wiki"]:
            wikiname = val
        elif opt in ["-h", "--help"]:
            usage("Help for this script:")

    check_args(configfile, wikiname, remainder)

    retriever = DbStatsRetriever(configfile, wikiname)
    maxid = retriever.get_max_pageid()
    if maxid is not None:
        print maxid
    else:
        sys.exit(1)


if __name__ == '__main__':
    do_main()