"""
standalone WSGI application for serving plaintext and xml suitable
for the Adobe Flex "Getting Started" tutorial, "Part II. Exchanging Data"

For the plaintext data flex app, set the HTTPService url to:

    http://<hostname>:<port>/text

For the xml data flex app, set the HTTPService url to:
    
    http://<hostname>:<port>/xml

"""
from __future__ import print_function

import sys
import cgi
import optparse
from wsgiref.simple_server import make_server

__author__ = 'Dan Buch dbuch@ag.com'
__license__ = 'AGI'

USAGE = """\
%prog [options]
Run a standalone WSGI app for the Adobe Flex Tutorial
"Getting Started", "Part II. Exchanging Data"
"""


def main(sysargs=sys.argv[:]):
    parser = optparse.OptionParser(usage=USAGE)
    parser.add_option('-p', '--port', dest='port', type='int',
        help='port number on which to serve app, default=%default',
        default=18080)
    parser.add_option('-i', '--interface', dest='interface',
        help='interface on which to serve app, default=%default',
        default='0.0.0.0')

    opts = parser.parse_args(sysargs[1:])[0]

    server = make_server(opts.interface, opts.port, ShippingCostApp())
    print('serving {0.__name__} on '
          'port {1}'.format(ShippingCostApp, opts.port))
    server.serve_forever()
    return 0


class NotFoundError(ValueError):
    pass


class ShippingCostApp(object):

    def __call__(self, environ, start_response):
        try:
            return ShippingCostHandler(environ, start_response).handle()
        except NotFoundError:
            return self._handle_404(environ, start_response)

    @classmethod
    def _handle_404(cls, environ, start_response):
        ret = 'nothin at {0!r}'.format(environ.get('PATH_INFO', '/'))
        start_response('404 Not Found', [
            ('content-type', 'text/plain'),
            ('content-length', str(len(ret)))
        ])
        return [ret]


class ShippingCostHandler(object):
    _shipping_options = None
    _zipcode = 0
    _pounds = 0
    _handler_method = ''

    def __init__(self, environ, start_response):
        self.environ = environ
        self.start_response = start_response
        self._path_info = self.environ.get('PATH_INFO', '').strip('/')
        self._handler_method = \
            '_handle_{0}'.format(self._path_info.replace('.', '_'))

    def _get_params(self):
        """some dumb param fetching, ignores multiple values for
        same var name, e.g. query of "zipcode=12345&zipcode=90210"
        would effectively discard the 90210 value
        """
        params = cgi.parse_qs(self.environ.get('QUERY_STRING', ''))

        for intvar in ('zipcode', 'pounds'):
            if params.get(intvar):
                value = int(float(params.get(intvar)[0]))
                setattr(self, '_{0}'.format(intvar), value)

    def _get_shipping_options(self):
        base_cost = (float(self._zipcode) / 10000.0) + (self._pounds * 5.0)
        self._shipping_options = {
            "Next Day": int(base_cost * 4),
            "Two Day Air": int(base_cost * 2),
            "Saver Ground": int(base_cost)
        }

    def handle(self):
        if hasattr(self, self._handler_method):
            self._get_params()
            self._get_shipping_options()
            return getattr(self, self._handler_method)()
        else:
            raise NotFoundError

    def _handle_xml(self):
        response = XMLShippingOptionsResponse(self._shipping_options)
        return response(self.environ, self.start_response)

    def _handle_text(self):
        response = PlaintextShippingOptionsResponse(self._shipping_options)
        return response(self.environ, self.start_response)

    def _handle_crossdomain_xml(self):
        response = CrossdomainXMLResponse()
        return response(self.environ, self.start_response)


class PlaintextShippingOptionsResponse(object):
    _head = ''
    _record = '{service}: {price} USD'
    _tail = ''
    _content_type = 'text/plain'

    def __init__(self, shipping_options):
        self._shipping_options = shipping_options

    def __call__(self, environ, start_response):
        body = str(self)
        start_response('200 OK', [
            ('content-type', self._content_type),
            ('content-length', str(len(body))),
        ])
        return [body]

    def __str__(self):
        ret = [self._head]
        for service, price in self._shipping_options.iteritems():
            ret.append(self._record.format(service=service, price=price))
        ret.append(self._tail)
        return '\n'.join(ret)


class XMLShippingOptionsResponse(PlaintextShippingOptionsResponse):
    _head = '<options>'
    _record = ('<option><service>{service}</service>'
               '<price>{price}</price></option>')
    _tail = '</options>'
    _content_type = 'text/xml'


class CrossdomainXMLResponse(PlaintextShippingOptionsResponse):
    _content_type = 'text/xml'

    def __init__(self):
        pass

    def __str__(self):
        return (
            '<cross-domain-policy>'
                '<allow-access-from domain="*"/>'
            '</cross-domain-policy>'
        )


if __name__ == '__main__':
    sys.exit(main())

# vim:filetype=python