#!/usr/bin/env python

import os
import sys
import dbus
import dbus.exceptions
import json
import logging
from xml.etree import ElementTree
from rocket import Rocket
from bottle import Bottle, abort, request, response, JSONPlugin, HTTPError
import OpenBMCMapper
from OpenBMCMapper import Mapper, PathTree, IntrospectionNodeParser, ListMatch
import spwd
import grp
import crypt

DBUS_UNKNOWN_INTERFACE = 'org.freedesktop.UnknownInterface'
DBUS_UNKNOWN_METHOD = 'org.freedesktop.DBus.Error.UnknownMethod'
DBUS_INVALID_ARGS = 'org.freedesktop.DBus.Error.InvalidArgs'
DBUS_TYPE_ERROR = 'org.freedesktop.DBus.Python.TypeError'
DELETE_IFACE = 'org.openbmc.Object.Delete'

_4034_msg = "The specified %s cannot be %s: '%s'"

def valid_user(session, *a, **kw):
	''' Authorization plugin callback that checks that the user is logged in. '''
	if session is None:
		abort(403, 'Login required')

class UserInGroup:
	''' Authorization plugin callback that checks that the user is logged in
	and a member of a group. '''
	def __init__(self, group):
		self.group = group

	def __call__(self, session, *a, **kw):
		valid_user(session, *a, **kw)
		res = False

		try:
			res = session['user'] in grp.getgrnam(self.group)[3]
		except KeyError:
			pass

		if not res:
			abort(403, 'Insufficient access')

def find_case_insensitive(value, lst):
	return next((x for x in lst if x.lower() == value.lower()), None)

def makelist(data):
	if isinstance(data, list):
		return data
	elif data:
		return [data]
	else:
		return []

class RouteHandler(object):
	_require_auth = makelist(valid_user)
	def __init__(self, app, bus, verbs, rules):
		self.app = app
		self.bus = bus
		self.mapper = Mapper(bus)
		self._verbs = makelist(verbs)
		self._rules = rules

	def _setup(self, **kw):
		request.route_data = {}
		if request.method in self._verbs:
			return self.setup(**kw)
		else:
			self.find(**kw)
			raise HTTPError(405, "Method not allowed.",
					Allow=','.join(self._verbs))

	def __call__(self, **kw):
		return getattr(self, 'do_' + request.method.lower())(**kw)

	def install(self):
		self.app.route(self._rules, callback = self,
				method = ['GET', 'PUT', 'PATCH', 'POST', 'DELETE'])

	@staticmethod
	def try_mapper_call(f, callback = None, **kw):
		try:
			return f(**kw)
		except dbus.exceptions.DBusException, e:
			if e.get_dbus_name() != OpenBMCMapper.MAPPER_NOT_FOUND:
				raise
			if callback is None:
				def callback(e, **kw):
					abort(404, str(e))

			callback(e, **kw)

	@staticmethod
	def try_properties_interface(f, *a):
		try:
			return f(*a)
		except dbus.exceptions.DBusException, e:
			if DBUS_UNKNOWN_INTERFACE in e.get_dbus_message():
				# interface doesn't have any properties
				return None
			if DBUS_UNKNOWN_METHOD == e.get_dbus_name():
				# properties interface not implemented at all
				return None
			raise

class DirectoryHandler(RouteHandler):
	verbs = 'GET'
	rules = '<path:path>/'

	def __init__(self, app, bus):
		super(DirectoryHandler, self).__init__(
				app, bus, self.verbs, self.rules)

	def find(self, path = '/'):
		return self.try_mapper_call(
				self.mapper.get_subtree_paths,
				path = path, depth = 1)

	def setup(self, path = '/'):
		request.route_data['map'] = self.find(path)

	def do_get(self, path = '/'):
		return request.route_data['map']

class ListNamesHandler(RouteHandler):
	verbs = 'GET'
	rules = ['/list', '<path:path>/list']

	def __init__(self, app, bus):
		super(ListNamesHandler, self).__init__(
				app, bus, self.verbs, self.rules)

	def find(self, path = '/'):
		return self.try_mapper_call(
				self.mapper.get_subtree, path = path).keys()

	def setup(self, path = '/'):
		request.route_data['map'] = self.find(path)

	def do_get(self, path = '/'):
		return request.route_data['map']

class ListHandler(RouteHandler):
	verbs = 'GET'
	rules = ['/enumerate', '<path:path>/enumerate']

	def __init__(self, app, bus):
		super(ListHandler, self).__init__(
				app, bus, self.verbs, self.rules)

	def find(self, path = '/'):
		return self.try_mapper_call(
				self.mapper.get_subtree, path = path)

	def setup(self, path = '/'):
		request.route_data['map'] = self.find(path)

	def do_get(self, path = '/'):
		objs = {}
		mapper_data = request.route_data['map']
		tree = PathTree()
		for x,y in mapper_data.iteritems():
			tree[x] = y

		try:
			# Check to see if the root path implements
			# enumerate in addition to any sub tree
			# objects.
			root = self.try_mapper_call(self.mapper.get_object,
					path = path)
			mapper_data[path] = root
		except:
			pass

		have_enumerate = [ (x[0], self.enumerate_capable(*x)) \
				for x in mapper_data.iteritems() \
					if self.enumerate_capable(*x) ]

		for x,y in have_enumerate:
			objs.update(self.call_enumerate(x, y))
			tmp = tree[x]
			# remove the subtree
			del tree[x]
			# add the new leaf back since enumerate results don't
			# include the object enumerate is being invoked on
			tree[x] = tmp

		# make dbus calls for any remaining objects
		for x,y in tree.dataitems():
			objs[x] = self.app.instance_handler.do_get(x)

		return objs

	@staticmethod
	def enumerate_capable(path, bus_data):
		busses = []
		for name, ifaces in bus_data.iteritems():
			if OpenBMCMapper.ENUMERATE_IFACE in ifaces:
				busses.append(name)
		return busses

	def call_enumerate(self, path, busses):
		objs = {}
		for b in busses:
			obj = self.bus.get_object(b, path, introspect = False)
			iface = dbus.Interface(obj, OpenBMCMapper.ENUMERATE_IFACE)
			objs.update(iface.enumerate())
		return objs

class MethodHandler(RouteHandler):
	verbs = 'POST'
	rules = '<path:path>/action/<method>'
	request_type = list

	def __init__(self, app, bus):
		super(MethodHandler, self).__init__(
				app, bus, self.verbs, self.rules)

	def find(self, path, method):
		busses = self.try_mapper_call(self.mapper.get_object,
				path = path)
		for items in busses.iteritems():
			m = self.find_method_on_bus(path, method, *items)
			if m:
				return m

		abort(404, _4034_msg %('method', 'found', method))

	def setup(self, path, method):
		request.route_data['method'] = self.find(path, method)

	def do_post(self, path, method):
		try:
			if request.parameter_list:
				return request.route_data['method'](*request.parameter_list)
			else:
				return request.route_data['method']()

		except dbus.exceptions.DBusException, e:
			if e.get_dbus_name() == DBUS_INVALID_ARGS:
				abort(400, str(e))
			if e.get_dbus_name() == DBUS_TYPE_ERROR:
				abort(400, str(e))
			raise

	@staticmethod
	def find_method_in_interface(method, obj, interface, methods):
		if methods is None:
			return None

		method = find_case_insensitive(method, methods.keys())
		if method is not None:
			iface = dbus.Interface(obj, interface)
			return iface.get_dbus_method(method)

	def find_method_on_bus(self, path, method, bus, interfaces):
		obj = self.bus.get_object(bus, path, introspect = False)
		iface = dbus.Interface(obj, dbus.INTROSPECTABLE_IFACE)
		data = iface.Introspect()
		parser = IntrospectionNodeParser(
				ElementTree.fromstring(data),
				intf_match = ListMatch(interfaces))
		for x,y in parser.get_interfaces().iteritems():
			m = self.find_method_in_interface(method, obj, x,
					y.get('method'))
			if m:
				return m

class PropertyHandler(RouteHandler):
	verbs = ['PUT', 'GET']
	rules = '<path:path>/attr/<prop>'

	def __init__(self, app, bus):
		super(PropertyHandler, self).__init__(
				app, bus, self.verbs, self.rules)

	def find(self, path, prop):
		self.app.instance_handler.setup(path)
		obj = self.app.instance_handler.do_get(path)
		try:
			obj[prop]
		except KeyError, e:
			if request.method == 'PUT':
				abort(403, _4034_msg %('property', 'created', str(e)))
			else:
				abort(404, _4034_msg %('property', 'found', str(e)))

		return { path: obj }

	def setup(self, path, prop):
		request.route_data['obj'] = self.find(path, prop)

	def do_get(self, path, prop):
		return request.route_data['obj'][path][prop]

	def do_put(self, path, prop, value = None):
		if value is None:
			value = request.parameter_list

		prop, iface, properties_iface = self.get_host_interface(
				path, prop, request.route_data['map'][path])
		try:
			properties_iface.Set(iface, prop, value)
		except ValueError, e:
			abort(400, str(e))
		except dbus.exceptions.DBusException, e:
			if e.get_dbus_name() == DBUS_INVALID_ARGS:
				abort(403, str(e))
			raise

	def get_host_interface(self, path, prop, bus_info):
		for bus, interfaces in bus_info.iteritems():
			obj = self.bus.get_object(bus, path, introspect = True)
			properties_iface = dbus.Interface(
				obj, dbus_interface=dbus.PROPERTIES_IFACE)

			info = self.get_host_interface_on_bus(
					path, prop, properties_iface,
					bus, interfaces)
			if info is not None:
				prop, iface = info
				return prop, iface, properties_iface

	def get_host_interface_on_bus(self, path, prop, iface, bus, interfaces):
		for i in interfaces:
			properties = self.try_properties_interface(iface.GetAll, i)
			if properties is None:
				continue
			prop = find_case_insensitive(prop, properties.keys())
			if prop is None:
				continue
			return prop, i

class InstanceHandler(RouteHandler):
	verbs = ['GET', 'PUT', 'DELETE']
	rules = '<path:path>'
	request_type = dict

	def __init__(self, app, bus):
		super(InstanceHandler, self).__init__(
				app, bus, self.verbs, self.rules)

	def find(self, path, callback = None):
		return { path: self.try_mapper_call(
			self.mapper.get_object,
			callback,
			path = path) }

	def setup(self, path):
		callback = None
		if request.method == 'PUT':
			def callback(e, **kw):
				abort(403, _4034_msg %('resource',
					'created', path))

		if request.route_data.get('map') is None:
			request.route_data['map'] = self.find(path, callback)

	def do_get(self, path):
		properties = {}
		for item in request.route_data['map'][path].iteritems():
			properties.update(self.get_properties_on_bus(
				path, *item))

		return properties

	@staticmethod
	def get_properties_on_iface(properties_iface, iface):
		properties = InstanceHandler.try_properties_interface(
				properties_iface.GetAll, iface)
		if properties is None:
			return {}
		return properties

	def get_properties_on_bus(self, path, bus, interfaces):
		properties = {}
		obj = self.bus.get_object(bus, path, introspect = False)
		properties_iface = dbus.Interface(
				obj, dbus_interface=dbus.PROPERTIES_IFACE)
		for i in interfaces:
			properties.update(self.get_properties_on_iface(
				properties_iface, i))

		return properties

	def do_put(self, path):
		# make sure all properties exist in the request
		obj = set(self.do_get(path).keys())
		req = set(request.parameter_list.keys())

		diff = list(obj.difference(req))
		if diff:
			abort(403, _4034_msg %('resource', 'removed',
				'%s/attr/%s' %(path, diff[0])))

		diff = list(req.difference(obj))
		if diff:
			abort(403, _4034_msg %('resource', 'created',
				'%s/attr/%s' %(path, diff[0])))

		for p,v in request.parameter_list.iteritems():
			self.app.property_handler.do_put(
					path, p, v)

	def do_delete(self, path):
		for bus_info in request.route_data['map'][path].iteritems():
			if self.bus_missing_delete(path, *bus_info):
				abort(403, _4034_msg %('resource', 'removed',
					path))

		for bus in request.route_data['map'][path].iterkeys():
			self.delete_on_bus(path, bus)

	def bus_missing_delete(self, path, bus, interfaces):
		return DELETE_IFACE not in interfaces

	def delete_on_bus(self, path, bus):
		obj = self.bus.get_object(bus, path, introspect = False)
		delete_iface = dbus.Interface(
				obj, dbus_interface = DELETE_IFACE)
		delete_iface.Delete()

class SessionHandler(MethodHandler):
	''' Handles the /login and /logout routes, manages server side session store and
	session cookies.  '''

	rules = ['/login', '/logout']
	login_str = "User '%s' logged %s"
	bad_passwd_str = "Invalid username or password"
	no_user_str = "No user logged in"
	bad_json_str = "Expecting request format { 'data': [<username>, <password>] }, got '%s'"
	_require_auth = None
	MAX_SESSIONS = 16

	def __init__(self, app, bus):
		super(SessionHandler, self).__init__(
				app, bus)
		self.hmac_key = os.urandom(128)
		self.session_store = []

	@staticmethod
	def authenticate(username, clear):
		try:
			encoded = spwd.getspnam(username)[1]
			return encoded == crypt.crypt(clear, encoded)
		except KeyError:
			return False

	def invalidate_session(self, session):
		try:
			self.session_store.remove(session)
		except ValueError:
			pass

	def new_session(self):
		sid = os.urandom(32)
		if self.MAX_SESSIONS <= len(self.session_store):
			self.session_store.pop()
		self.session_store.insert(0, {'sid': sid})

		return self.session_store[0]

	def get_session(self, sid):
		sids = [ x['sid'] for x in self.session_store ]
		try:
			return self.session_store[sids.index(sid)]
		except ValueError:
			return None

	def get_session_from_cookie(self):
		return self.get_session(
				request.get_cookie('sid',
					secret = self.hmac_key))

	def do_post(self, **kw):
		if request.path == '/login':
			return self.do_login(**kw)
		else:
			return self.do_logout(**kw)

	def do_logout(self, **kw):
		session = self.get_session_from_cookie()
		if session is not None:
			user = session['user']
			self.invalidate_session(session)
			response.delete_cookie('sid')
			return self.login_str %(user, 'out')

		return self.no_user_str

	def do_login(self, **kw):
		session = self.get_session_from_cookie()
		if session is not None:
			return self.login_str %(session['user'], 'in')

		if len(request.parameter_list) != 2:
			abort(400, self.bad_json_str %(request.json))

		if not self.authenticate(*request.parameter_list):
			return self.bad_passwd_str

		user = request.parameter_list[0]
		session = self.new_session()
		session['user'] = user
		response.set_cookie('sid', session['sid'], secret = self.hmac_key,
				secure = True,
				httponly = True)
		return self.login_str %(user, 'in')

	def find(self, **kw):
		pass

	def setup(self, **kw):
		pass

class AuthorizationPlugin(object):
	''' Invokes an optional list of authorization callbacks. '''

	name = 'authorization'
	api = 2

	class Compose:
		def __init__(self, validators, callback, session_mgr):
			self.validators = validators
			self.callback = callback
			self.session_mgr = session_mgr

		def __call__(self, *a, **kw):
			sid = request.get_cookie('sid', secret = self.session_mgr.hmac_key)
			session = self.session_mgr.get_session(sid)
			for x in self.validators:
				x(session, *a, **kw)

			return self.callback(*a, **kw)

	def apply(self, callback, route):
		undecorated = route.get_undecorated_callback()
		if not isinstance(undecorated, RouteHandler):
			return callback

		auth_types = getattr(undecorated,
				'_require_auth', None)
		if not auth_types:
			return callback

		return self.Compose(auth_types, callback,
				undecorated.app.session_handler)

class JsonApiRequestPlugin(object):
	''' Ensures request content satisfies the OpenBMC json api format. '''
	name = 'json_api_request'
	api = 2

	error_str = "Expecting request format { 'data': <value> }, got '%s'"
	type_error_str = "Unsupported Content-Type: '%s'"
	json_type = "application/json"
	request_methods = ['PUT', 'POST', 'PATCH']

	@staticmethod
	def content_expected():
		return request.method in JsonApiRequestPlugin.request_methods

	def validate_request(self):
		if request.content_length > 0 and \
				request.content_type != self.json_type:
			abort(415, self.type_error_str %(request.content_type))

		try:
			request.parameter_list = request.json.get('data')
		except ValueError, e:
			abort(400, str(e))
		except (AttributeError, KeyError, TypeError):
			abort(400, self.error_str %(request.json))

	def apply(self, callback, route):
		verbs = getattr(route.get_undecorated_callback(),
				'_verbs', None)
		if verbs is None:
			return callback

		if not set(self.request_methods).intersection(verbs):
			return callback

		def wrap(*a, **kw):
			if self.content_expected():
				self.validate_request()
			return callback(*a, **kw)

		return wrap

class JsonApiRequestTypePlugin(object):
	''' Ensures request content type satisfies the OpenBMC json api format. '''
	name = 'json_api_method_request'
	api = 2

	error_str = "Expecting request format { 'data': %s }, got '%s'"

	def apply(self, callback, route):
		request_type = getattr(route.get_undecorated_callback(),
				'request_type', None)
		if request_type is None:
			return callback

		def validate_request():
			if not isinstance(request.parameter_list, request_type):
				abort(400, self.error_str %(str(request_type), request.json))

		def wrap(*a, **kw):
			if JsonApiRequestPlugin.content_expected():
				validate_request()
			return callback(*a, **kw)

		return wrap

class JsonApiResponsePlugin(object):
	''' Emits normal responses in the OpenBMC json api format. '''
	name = 'json_api_response'
	api = 2

	def apply(self, callback, route):
		def wrap(*a, **kw):
			resp = { 'data': callback(*a, **kw) }
			resp['status'] = 'ok'
			resp['message'] = response.status_line
			return resp
		return wrap

class JsonApiErrorsPlugin(object):
	''' Emits error responses in the OpenBMC json api format. '''
	name = 'json_api_errors'
	api = 2

	def __init__(self, **kw):
		self.app = None
		self.function_type = None
		self.original = None
		self.json_opts = { x:y for x,y in kw.iteritems() \
			if x in ['indent','sort_keys'] }

	def setup(self, app):
		self.app = app
		self.function_type = type(app.default_error_handler)
		self.original = app.default_error_handler
		self.app.default_error_handler = self.function_type(
			self.json_errors, app, Bottle)

	def apply(self, callback, route):
		return callback

	def close(self):
		self.app.default_error_handler = self.function_type(
				self.original, self.app, Bottle)

	def json_errors(self, res, error):
		response_object = {'status': 'error', 'data': {} }
		response_object['message'] = error.status_line
		response_object['data']['description'] = str(error.body)
		if error.status_code == 500:
			response_object['data']['exception'] = repr(error.exception)
			response_object['data']['traceback'] = error.traceback.splitlines()

		json_response = json.dumps(response_object, **self.json_opts)
		response.content_type = 'application/json'
		return json_response

class RestApp(Bottle):
	def __init__(self, bus):
		super(RestApp, self).__init__(autojson = False)
		self.bus = bus
		self.mapper = Mapper(bus)

		self.install_hooks()
		self.install_plugins()
		self.create_handlers()
		self.install_handlers()

	def install_plugins(self):
		# install json api plugins
		json_kw = {'indent': 2, 'sort_keys': True}
		self.install(JSONPlugin(**json_kw))
		self.install(JsonApiErrorsPlugin(**json_kw))
		self.install(AuthorizationPlugin())
		self.install(JsonApiResponsePlugin())
		self.install(JsonApiRequestPlugin())
		self.install(JsonApiRequestTypePlugin())

	def install_hooks(self):
		self.real_router_match = self.router.match
		self.router.match = self.custom_router_match
		self.add_hook('before_request', self.strip_extra_slashes)

	def create_handlers(self):
		# create route handlers
		self.session_handler = SessionHandler(self, self.bus)
		self.directory_handler = DirectoryHandler(self, self.bus)
		self.list_names_handler = ListNamesHandler(self, self.bus)
		self.list_handler = ListHandler(self, self.bus)
		self.method_handler = MethodHandler(self, self.bus)
		self.property_handler = PropertyHandler(self, self.bus)
		self.instance_handler = InstanceHandler(self, self.bus)

	def install_handlers(self):
		self.session_handler.install()
		self.directory_handler.install()
		self.list_names_handler.install()
		self.list_handler.install()
		self.method_handler.install()
		self.property_handler.install()
		# this has to come last, since it matches everything
		self.instance_handler.install()

	def custom_router_match(self, environ):
		''' The built-in Bottle algorithm for figuring out if a 404 or 405 is
                    needed doesn't work for us since the instance rules match everything.
                    This monkey-patch lets the route handler figure out which response is
                    needed.  This could be accomplished with a hook but that would require
		    calling the router match function twice.
		'''
		route, args = self.real_router_match(environ)
		if isinstance(route.callback, RouteHandler):
			route.callback._setup(**args)

		return route, args

	@staticmethod
	def strip_extra_slashes():
		path = request.environ['PATH_INFO']
		trailing = ("","/")[path[-1] == '/']
		parts = filter(bool, path.split('/'))
		request.environ['PATH_INFO'] = '/' + '/'.join(parts) + trailing

if __name__ == '__main__':
	log = logging.getLogger('Rocket.Errors')
	log.setLevel(logging.INFO)
	log.addHandler(logging.StreamHandler(sys.stdout))

	bus = dbus.SystemBus()
	app = RestApp(bus)
	default_cert = os.path.join(sys.prefix, 'share',
			os.path.basename(__file__), 'cert.pem')

	server = Rocket(('0.0.0.0',
			443,
			default_cert,
			default_cert),
		'wsgi', {'wsgi_app': app},
		min_threads = 1,
		max_threads = 1)
	server.start()