#!/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'
ENUMERATE_IFACE = 'org.openbmc.Object.Enumerate'
MAPPER_NOT_FOUND = 'org.openbmc.objectmapper.Error.NotFound'


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 ListMatch(object):
    def __init__(self, l):
        self.l = l

    def __call__(self, match):
        return match in self.l


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, introspect=False)
            iface = dbus.Interface(obj, dbus.INTROSPECTABLE_IFACE)
            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)


class Mapper:
    def __init__(self, bus):
        self.bus = bus
        obj = bus.get_object(MAPPER_NAME, MAPPER_PATH, introspect=False)
        self.iface = dbus.Interface(
            obj, dbus_interface=MAPPER_IFACE)

    def get_object(self, path):
        return self.iface.GetObject(path)

    def get_subtree_paths(self, path='/', depth=0):
        return self.iface.GetSubTreePaths(path, depth)

    def get_subtree(self, path='/', depth=0):
        return self.iface.GetSubTree(path, depth)