#!/usr/bin/env python

"""
We take a Well-Known Text string and one or more KML files as
parameters. We convert the WKT string to a polygon, and drag that
polygon along the paths defined within the KML files. For each path,
the result is another (longer) polygon, whose contained population is
output.
"""

import os
import site
import sys


# 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 CLI
import Configuration.Defaults
import ExitCodes
import Geometry
import KML

usage = '%prog [options] <well-known text> <kml file #1>, [kml file #2,...]'

# -h (help) Conflicts with -h HOSTNAME
parser = CLI.default_option_parser(usage)

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

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) < 2:
    print """
ERROR: You must supply both a Well-Known Text string, and a KML file
       containing a linestring.
"""
    parser.print_help()
    print '' # Print a newline
    raise SystemExit(ExitCodes.NOT_ENOUGH_ARGS)


wkt_string = args[0]
paths = args[1:]

for path in paths:
    f = open(path, 'r')
    kml = f.read()
    f.close()

    coords = KML.LineString.tuples_from_kml(kml)
    p = Geometry.Polygon.from_wkt(wkt_string)

    death_tube = None

    for i in range(len(coords) - 1):
        # For each coordinate (except the last), we want to:
        # a) Translate our polygon to the coordinate.
        # b) Drag the polygon to the next coordinate.
        this_coord = Geometry.TwoVector(coords[i][0], coords[i][1])
        next_coord = Geometry.TwoVector(coords[i+1][0], coords[i+1][1])
        drag_vector = (next_coord - this_coord)
        tp = p.translate(this_coord)

        if (death_tube == None):
            death_tube = tp.drag(drag_vector)
        else:
            death_tube = death_tube.union(tp.drag(drag_vector))

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

    pop = cdb.find_contained_population(death_tube.wkt())

    print "Path: %s; Population: %d" % (path, pop)