#!/usr/bin/python

"""
Find the total population contained within a geometric object.
"""

"""
Our input is an OGC Well-Known Text[1] string. This string is used as
part of a database query that finds the population contained within
(i.e. 'underneath') the geometric object corresponding to the WKT
string.

[1] http://en.wikipedia.org/wiki/Well-known_text
"""

import sys
import os
import site
from optparse import OptionParser

# Basically, add '../src' to our path.
# Needed for the imports that follow.
site.addsitedir(os.path.dirname(os.path.abspath(sys.argv[0])) + '/../src')

import Census
import Configuration.Defaults
import ExitCodes

usage = '%prog [options] <well-known text representation>'

# -h (help) Conflicts with -h HOSTNAME
parser = OptionParser(usage=usage, add_help_option = False)

# Use this module's docstring as the description.
parser.description = __doc__.strip()

parser.add_option('-h',
                  '--host',
                  help='The hostname/address where the database is located.',
                  default=Configuration.Defaults.DATABASE_HOST)

parser.add_option('-d',
                  '--database',
                  help='The database in which the population data are stored.',
                  default=Configuration.Defaults.DATABASE_NAME)

parser.add_option('-U',
                  '--username',
                  help='The username who has access to the database.',
                  default=Configuration.Defaults.DATABASE_USERNAME)

parser.add_option('-s',
                  '--srid',
                  type="int",
                  help="SRID of the input geometry. Defaults to %s." % Configuration.Defaults.SRID,
                  default=Configuration.Defaults.SRID)


(options, args) = parser.parse_args()

if len(args) < 1:
    print "\nERROR: You must supply a geometric object in Well-Known Text format.\n"
    parser.print_help()
    print '' # Print a newline.
    raise SystemExit(ExitCodes.NOT_ENOUGH_ARGS)


cdb = Census.Database(options.host,
                      options.database,
                      options.username,
                      options.srid)

population = cdb.find_contained_population(args[0])

if (population != None):
    print population
else:
    print 'Error: No rows returned.'
    raise SystemExit(ExitCodes.NO_RESULTS)