#!/usr/bin/env python
# DT WSGI Robots
#
# Douglas Thrift
#
# $Id$

#  Copyright 2010 Douglas Thrift
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

from cStringIO import StringIO
import urlparse

class Robots(object):
	def __init__(self, disallows = None, sitemaps = None):
		self.disallows = disallows
		self.sitemaps = sitemaps

	def __iter__(self):
		yield '# $Id$\n'

		if self.disallows:
			if isinstance(self.disallows, str):
				yield self._agent('*', [self.disallows])
			elif isinstance(self.disallows, (list, tuple)) and isinstance(self.disallows[0], str):
				yield self._agent('*', self.disallows)
			else:
				for agent, disallows in self.disallows.iteritems() if isinstance(self.disallows, dict) else self.disallows:
					yield self._agent(agent, [disallows] if isinstance(disallows, str) else disallows)

		if self.sitemaps:
			robots = StringIO()

			robots.write('\n')

			for sitemap in [self.sitemaps] if isinstance(self.sitemaps, str) else self.sitemaps:
				robots.write('Sitemap: %s\n' % sitemap)

			yield robots.getvalue()

	def __str__(self):
		return ''.join(self)

	@staticmethod
	def _agent(agent, disallows):
		robots = StringIO()

		robots.write('\nUser-agent: %s\n' % agent)

		for disallow in disallows:
			robots.write('Disallow: %s\n' % disallow)

		return robots.getvalue()

def robots(disallows = None, sitemaps = None, string = False):
	robots = Robots(disallows, sitemaps)

	return str(robots) if string else robots

def wsgi(function = None, string = False):
	class WSGI(object):
		def __init__(self, function):
			self.function = function
			self.__name__ = function.__name__
			self.__module__ = function.__module__
			self.__doc__ = function.__doc__

		def __call__(self, *args, **kwargs):
			value = self.function(*args, **kwargs)

			if isinstance(value, dict):
				return robots(value.get('disallows'), value.get('sitemaps'), string = string)

			return value

	return WSGI(function) if function is not None else WSGI

def bottle(function):
	@wsgi
	def _bottle(*args, **kwargs):
		import bottle

		value = function(*args, **kwargs)

		if isinstance(value, dict):
			if 'sitemaps' in value:
				url = urlparse.urlsplit(bottle.request.url)

				def _url(value):
					value = urlparse.urlsplit(value)

					if value.scheme and value.netloc:
						return value.geturl()

					return urlparse.urlunsplit(url[:2] + value[2:])

				sitemaps = value['sitemaps']
				value['sitemaps'] = map(_url, [sitemaps] if isinstance(sitemaps, str) else sitemaps)

			bottle.response.content_type = 'text/plain'

		return value

	return _bottle