#
# Support for XML representation
#
# Copyright (C) 2019  Red Hat, Inc.  All rights reserved.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
# USA
#
# For more info about DBus specification see:
# https://dbus.freedesktop.org/doc/dbus-specification.html#introspection-format
#
from xml.etree import ElementTree
from xml.dom import minidom

__all__ = [
    "XMLParser",
    "XMLGenerator"
]


class XMLParser(object):
    """Class for parsing XML."""

    @staticmethod
    def xml_to_element(xml):
        return ElementTree.fromstring(xml)

    @staticmethod
    def is_member(member_node):
        return member_node.tag in ("method", "signal", "property")

    @staticmethod
    def is_interface(member_node):
        return member_node.tag == "interface"

    @staticmethod
    def is_signal(member_node):
        return member_node.tag == "signal"

    @staticmethod
    def is_method(member_node):
        return member_node.tag == "method"

    @staticmethod
    def is_property(member_node):
        return member_node.tag == "property"

    @staticmethod
    def is_parameter(member_node):
        return member_node.tag == "arg"

    @staticmethod
    def has_name(node, node_name):
        return node.attrib.get("name", "") == node_name

    @staticmethod
    def get_name(node):
        return node.attrib["name"]

    @staticmethod
    def get_type(node):
        return node.attrib["type"]

    @staticmethod
    def get_access(node):
        return node.attrib["access"]

    @staticmethod
    def get_direction(node):
        return node.attrib["direction"]

    @staticmethod
    def get_interfaces_from_node(node_element):
        """Return a dictionary of interfaces defined in a node element."""
        interfaces = dict()

        for element in node_element.iterfind("interface"):
            interfaces[element.attrib["name"]] = element

        return interfaces


class XMLGenerator(XMLParser):
    """Class for generating XML."""

    @staticmethod
    def element_to_xml(element):
        """Return XML of the element."""
        return ElementTree.tostring(
            element,
            method="xml",
            encoding="unicode"
        )

    @staticmethod
    def prettify_xml(xml):
        """Return pretty printed normalized XML.

        Python 3.8 changed the order of the attributes and introduced
        the function canonicalize that should be used to normalize XML.
        """
        # Remove newlines and extra whitespaces,
        xml_line = "".join([line.strip() for line in xml.splitlines()])

        # Generate pretty xml.
        xml = minidom.parseString(xml_line).toprettyxml(indent="  ")

        # Normalize attributes.
        canonicalize = getattr(
            ElementTree, "canonicalize", lambda xml, *args, **kwargs: xml
        )

        return canonicalize(xml, with_comments=True)

    @staticmethod
    def add_child(parent_element, child_element):
        """Append the child element to the parent element."""
        parent_element.append(child_element)

    @staticmethod
    def add_comment(element, comment):
        element.append(ElementTree.Comment(text=comment))

    @staticmethod
    def create_node():
        """Create a node element called node."""
        return ElementTree.Element("node")

    @staticmethod
    def create_interface(name):
        """Create an interface element."""
        return ElementTree.Element("interface", {"name": name})

    @staticmethod
    def create_signal(name):
        """Create a signal element."""
        return ElementTree.Element("signal", {"name": name})

    @staticmethod
    def create_method(name):
        """Create a method element."""
        return ElementTree.Element("method", {"name": name})

    @staticmethod
    def create_parameter(name, param_type, direction):
        """Create a parameter element."""
        tag = "arg"
        attr = {
            "name": name,
            "type": param_type,
            "direction": direction
        }
        return ElementTree.Element(tag, attr)

    @staticmethod
    def create_property(name, property_type, access):
        """Create a property element."""
        tag = "property"
        attr = {
            "name": name,
            "type": property_type,
            "access": access
        }
        return ElementTree.Element(tag, attr)