# -*- coding: utf-8 -*-

# Copyright 2011 Tomo Krajina
#
# 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 __future__ import print_function

import pdb

import re as mod_re
import logging as mod_logging
import datetime as mod_datetime
import xml.dom.minidom as mod_minidom

try:
    import lxml.etree as mod_etree
except:
    mod_etree = None
    pass # LXML not available

from . import gpx as mod_gpx
from . import utils as mod_utils
from . import gpxfield as mod_gpxfield


class XMLParser:
    """
    Used when lxml is not available. Uses standard minidom.
    """

    def __init__(self, xml):
        self.xml = xml
        self.dom = mod_minidom.parseString(xml)

    def get_first_child(self, node=None, name=None):
        # TODO: Remove find_first_node from utils!
        if not node:
            node = self.dom

        children = node.childNodes
        if not children:
            return None

        if not name:
            return children[0]

        for tmp_node in children:
            if tmp_node.nodeName == name:
                return tmp_node

        return None

    def get_node_name(self, node):
        if not node:
            return None
        return node.nodeName

    def get_children(self, node=None):
        if not node:
            node = self.dom

        return list(filter(lambda node : node.nodeType == node.ELEMENT_NODE, node.childNodes))

    def get_node_data(self, node):
        if node is None:
            return None

        child_nodes = node.childNodes
        if not child_nodes or len(child_nodes) == 0:
            return None

        return child_nodes[0].nodeValue

    def get_node_attribute(self, node, attribute):
        if (not hasattr(node, 'attributes')) or (not node.attributes):
            return None
        if attribute in node.attributes.keys():
            return node.attributes[attribute].nodeValue
        return None


class LXMLParser:
    """
    Used when lxml is available.
    """

    def __init__(self, xml):
        if not mod_etree:
            raise Exception('Cannot use LXMLParser without lxml installed')

        if mod_utils.PYTHON_VERSION[0] == '3':
            # In python 3 all strings are unicode and for some reason lxml
            # don't like unicode strings with XMLs declared as UTF-8:
            self.xml = xml.encode('utf-8')
        else:
            self.xml = xml

        self.dom = mod_etree.XML(self.xml)
        # get the namespace
        self.ns = self.dom.nsmap.get(None)

    def get_first_child(self, node=None, name=None):
        if node is None:
            if name:
                if self.get_node_name(self.dom) == name:
                    return self.dom
            return self.dom

        children = node.getchildren()

        if not children:
            return None

        if name:
            for node in children:
                if self.get_node_name(node) == name:
                    return node
            return None

        return children[0]

    def get_node_name(self, node):
        if '}' in node.tag:
            return node.tag.split('}')[1]
        return node.tag

    def get_children(self, node=None):
        if node is None:
            node = self.dom
        return node.getchildren()

    def get_node_data(self, node):
        if node is None:
            return None

        return node.text

    def get_node_attribute(self, node, attribute):
        if node is None:
            return None
        return node.attrib.get(attribute)


class GPXParser:
    def __init__(self, xml_or_file=None, parser=None):
        """
        Parser may be lxml of minidom. If you set to None then lxml will be used if installed
        otherwise minidom.
        """
        self.init(xml_or_file)
        self.gpx = mod_gpx.GPX()
        self.xml_parser_type = parser
        self.xml_parser = None

    def init(self, xml_or_file):
        text = xml_or_file.read() if hasattr(xml_or_file, 'read') else xml_or_file
        self.xml = mod_utils.make_str(text)
        self.gpx = mod_gpx.GPX()

    def parse(self):
        """
        Parses the XML file and returns a GPX object.

        It will throw GPXXMLSyntaxException if the XML file is invalid or
        GPXException if the XML file is valid but something is wrong with the
        GPX data.
        """
        try:
            if self.xml_parser_type is None:
                if mod_etree:
                    self.xml_parser = LXMLParser(self.xml)
                else:
                    self.xml_parser = XMLParser(self.xml)
            elif self.xml_parser_type == 'lxml':
                self.xml_parser = LXMLParser(self.xml)
            elif self.xml_parser_type == 'minidom':
                self.xml_parser = XMLParser(self.xml)
            else:
                raise mod_gpx.GPXException('Invalid parser type: %s' % self.xml_parser_type)

            self.__parse_dom()

            return self.gpx
        except Exception as e:
            # The exception here can be a lxml or minidom exception.
            mod_logging.debug('Error in:\n%s\n-----------\n' % self.xml)
            mod_logging.exception(e)

            # The library should work in the same way regardless of the
            # underlying XML parser that's why the exception thrown
            # here is GPXXMLSyntaxException (instead of simply throwing the
            # original minidom or lxml exception e).
            #
            # But, if the user need the original exception (lxml or minidom)
            # it is available with GPXXMLSyntaxException.original_exception:
            raise mod_gpx.GPXXMLSyntaxException('Error parsing XML: %s' % str(e), e)

    def __parse_dom(self):
        node = self.xml_parser.get_first_child(name='gpx')

        if node is None:
            raise mod_gpx.GPXException('Document must have a `gpx` root node.')

        version = self.xml_parser.get_node_attribute(node, 'version')

        mod_gpxfield.gpx_fields_from_xml(self.gpx, self.xml_parser, node, version)
