#!/usr/bin/env python

# Contributors Listed Below - COPYRIGHT 2015
# [+] International Business Machines Corp.
#
#
# 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 xml.etree import ElementTree
import dbus

MAPPER_NAME = 'org.openbmc.objectmapper'
MAPPER_IFACE = MAPPER_NAME + '.ObjectMapper'
MAPPER_PATH = '/org/openbmc/objectmapper/objectmapper'

class Path:
	def __init__(self, path):
		self.parts = filter(bool, path.split('/'))

	def rel(self, first = None, last = None):
		# relative
		return self.get('', first, last)

	def fq(self, first = None, last = None):
		# fully qualified
		return self.get('/', first, last)

	def depth(self):
		return len(self.parts)

	def get(self, prefix = '/', first = None, last = None):
		if not first:
			first = 0
		if not last:
			last = self.depth()
		return prefix + '/'.join(self.parts[first:last])

def org_dot_openbmc_match(name):
	return 'org.openbmc' in name

class TagListMatch(object):
	def __init__(self, tag_list):
		self.tag_list = tag_list

	def __call__(self, tag):
		return tag in self.tag_list

class IntrospectionNodeParser:
	def __init__(self, data, tag_match = bool, intf_match = bool):
		self.data = data
		self.cache = {}
		self.tag_match = tag_match
		self.intf_match = intf_match

	def parse_args(self):
		return [ x.attrib for x in self.data.findall('arg') ]

	def parse_children(self):
		return [ x.attrib['name'] for x in self.data.findall('node') ]

	def parse_method_or_signal(self):
		name = self.data.attrib['name']
		return name, self.parse_args()

	def parse_interface(self):
		iface = {}
		iface['method'] = {}
		iface['signal'] = {}

		for node in self.data:
			if node.tag not in ['method', 'signal']:
				continue
			if not self.tag_match(node.tag):
				continue
			p = IntrospectionNodeParser(
					node, self.tag_match, self.intf_match)
			n, element = p.parse_method_or_signal()
			iface[node.tag][n] = element

		return iface

	def parse_node(self):
		if self.cache:
			return self.cache

		self.cache['interfaces'] = {}
		self.cache['children'] = []

		for node in self.data:
			if node.tag == 'interface':
				p = IntrospectionNodeParser(
						node, self.tag_match, self.intf_match)
				name = p.data.attrib['name']
				if not self.intf_match(name):
					continue
				self.cache['interfaces'][name] = p.parse_interface()
			elif node.tag == 'node':
				self.cache['children'] = self.parse_children()

		return self.cache

	def get_interfaces(self):
		return self.parse_node()['interfaces']

	def get_children(self):
		return self.parse_node()['children']

	def recursive_binding(self):
		return any('/' in s for s in self.get_children())

class IntrospectionParser:
	def __init__(self, name, bus, tag_match = bool, intf_match = bool):
		self.name = name
		self.bus = bus
		self.tag_match = tag_match
		self.intf_match = intf_match

	def _introspect(self, path):
		try:
			obj = self.bus.get_object(self.name, path)
			iface = dbus.Interface(obj, dbus.BUS_DAEMON_IFACE + '.Introspectable')
			data = iface.Introspect()
		except dbus.DBusException:
			return None

		return IntrospectionNodeParser(
				ElementTree.fromstring(data),
				self.tag_match,
				self.intf_match)

	def _discover_flat(self, path, parser):
		items = {}
		interfaces = parser.get_interfaces().keys()
		if interfaces:
			items[path] = {}
			items[path]['interfaces'] = interfaces

		return items

	def introspect(self, path = '/', parser = None):
		items = {}
		if not parser:
			parser = self._introspect(path)
		if not parser:
			return {}
		items.update(self._discover_flat(path, parser))

		if path != '/':
			path += '/'

		if parser.recursive_binding():
			callback = self._discover_flat
		else:
			callback = self.introspect

		for k in parser.get_children():
			parser = self._introspect(path + k)
			if not parser:
				continue
			items.update(callback(path + k, parser))

		return items

class PathTreeItemIterator(object):
	def __init__(self, path_tree, subtree, depth):
		self.path_tree = path_tree
		self.path = []
		self.itlist = []
		self.subtree = ['/'] + filter(bool, subtree.split('/'))
		self.depth = depth
		d = path_tree.root
		for k in self.subtree:
			try:
				d = d[k]['children']
			except KeyError:
				raise KeyError(subtree)
		self.it = d.iteritems()

	def __iter__(self):
		return self

	def __next__(self):
		return super(PathTreeItemIterator, self).next()

	def next(self):
		key, value = self._next()
		path = self.subtree[0] + '/'.join(self.subtree[1:] + self.path)
		return path, value.get('data')

	def _next(self):
		try:
			while True:
				x = self.it.next()
				depth_exceeded = len(self.path) +1 > self.depth
				if self.depth and depth_exceeded:
					continue
				self.itlist.append(self.it)
				self.path.append(x[0])
				self.it = x[1]['children'].iteritems()
				break;

		except StopIteration:
			if not self.itlist:
				raise StopIteration

			self.it = self.itlist.pop()
			self.path.pop()
			x = self._next()
		
		return x

class PathTreeKeyIterator(PathTreeItemIterator):
	def __init__(self, path_tree, subtree, depth):
		super(PathTreeKeyIterator, self).__init__(path_tree, subtree, depth)

	def next(self):
		return super(PathTreeKeyIterator, self).next()[0]

class PathTree:
	def __init__(self):
		self.root = {}

	def _try_delete_parent(self, elements):
		if len(elements) == 1:
			return False

		kids = 'children'
		elements.pop()
		d = self.root
		for k in elements[:-1]:
			d = d[k][kids]

		if 'data' not in d[elements[-1]] and not d[elements[-1]][kids]:
			del d[elements[-1]]
			self._try_delete_parent(elements)

	def _get_node(self, key):
		kids = 'children'
		elements = ['/'] + filter(bool, key.split('/'))
		d = self.root
		for k in elements[:-1]:
			try:
				d = d[k][kids]
			except KeyError:
				raise KeyError(key)
		
		return d[elements[-1]]

	def __iter__(self):
		return self

	def __missing__(self, key):
		for x in self.iterkeys():
			if key == x:
				return False
		return True

	def __delitem__(self, key):
		kids = 'children'
		elements = ['/'] + filter(bool, key.split('/'))
		d = self.root
		for k in elements[:-1]:
			try:
				d = d[k][kids]
			except KeyError:
				raise KeyError(key)

		del d[elements[-1]]
		self._try_delete_parent(elements)

	def __setitem__(self, key, value):
		kids = 'children'
		elements = ['/'] + filter(bool, key.split('/'))
		d = self.root
		for k in elements[:-1]:
			d = d.setdefault(k, {kids: {}})[kids]

		children = d.setdefault(elements[-1], {kids: {}})[kids]
		d[elements[-1]].update({kids: children, 'data': value})

	def __getitem__(self, key):
		return self._get_node(key).get('data')

	def setdefault(self, key, default):
		if not self.get(key):
			self.__setitem__(key, default)

		return self.__getitem__(key)

	def get(self, key, default = None):
		try:
			x = self.__getitem__(key)
		except KeyError:
			x = default

		return x

	def get_children(self, key):
		return [ x for x in self._get_node(key)['children'].iterkeys() ]

	def demote(self, key):
		n = self._get_node(key)
		if 'data' in n:
			del n['data']

	def keys(self, subtree = '/', depth = None):
		return [ x for x in self.iterkeys(subtree, depth) ]

	def values(self, subtree = '/', depth = None):
		return [ x[1] for x in self.iteritems(subtree, depth) ]

	def items(self, subtree = '/', depth = None):
		return [ x for x in self.iteritems(subtree, depth) ]

	def dataitems(self, subtree = '/', depth = None):
		return [ x for x in self.iteritems(subtree, depth) \
				if x[1] is not None ]

	def iterkeys(self, subtree = '/', depth = None):
		if not self.root:
			return {}.iterkeys()
		return PathTreeKeyIterator(self, subtree, depth)

	def iteritems(self, subtree = '/', depth = None):
		if not self.root:
			return {}.iteritems()
		return PathTreeItemIterator(self, subtree, depth)