#!/usr/bin/env python2
# -*- coding: utf-8 -*-
#
# Copyright 2004-2007 Zuza Software Foundation
#
# This file is part of translate.
#
# translate is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# translate 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>.
#

"""module that provides modified DOM functionality for our needs

Note that users of ourdom should ensure that no code might still use classes
directly from minidom, like minidom.Element, minidom.Document or methods such
as minidom.parseString, since the functionality provided here will not be in
those objects.
"""

from xml.dom import minidom
from xml.dom import expatbuilder

# helper functions we use to do xml the way we want, used by modified
# classes below


def writexml_helper(self, writer, indent="", addindent="", newl=""):
    """A replacement for writexml that formats it like typical XML files.
    Nodes are intendented but text nodes, where whitespace can be
    significant, are not indented."""
    # indent = current indentation
    # addindent = indentation to add to higher levels
    # newl = newline string
    writer.write(indent + "<" + self.tagName)

    attrs = self._get_attributes()
    a_names = attrs.keys()
    a_names.sort()

    for a_name in a_names:
        writer.write(" %s=\"" % a_name)
        minidom._write_data(writer, attrs[a_name].value)
        writer.write("\"")
    if self.childNodes:
        # We need to write text nodes without newline and indentation, so
        # we handle them differently. Note that we here assume that "empty"
        # text nodes can be done away with (see the strip()). Note also that
        # nested tags in a text node (like ph tags in xliff) should also not
        # have newlines and indentation or an extra newline, since that will
        # alter the text node.
        haveText = False
        for childNode in self.childNodes:
            if childNode.nodeType == self.TEXT_NODE and childNode.data.strip():
                haveText = True
                break
        if haveText:
            writer.write(">")
            for node in self.childNodes:
                node.writexml(writer, "", "", "")
            writer.write("</%s>%s" % (self.tagName, newl))
        else:
            # This is the normal case that we do with pretty layout
            writer.write(">%s" % (newl))
            for node in self.childNodes:
                if node.nodeType != self.TEXT_NODE:
                    node.writexml(writer, (indent + addindent), addindent, newl)
            writer.write("%s</%s>%s" % (indent, self.tagName, newl))
    else:
        writer.write("/>%s" % (newl))


def getElementsByTagName_helper(parent, name, dummy=None):
    """A reimplementation of getElementsByTagName as an iterator.

    Note that this is not compatible with getElementsByTagName that returns a
    list, therefore, the class below exposes this through yieldElementsByTagName"""

    for node in parent.childNodes:
        if (node.nodeType == minidom.Node.ELEMENT_NODE and
            (name == "*" or node.tagName == name)):
            yield node
        if node.hasChildNodes():
            for othernode in node.getElementsByTagName(name):
                yield othernode


def searchElementsByTagName_helper(parent, name, onlysearch):
    """limits the search to within tags occuring in onlysearch"""
    for node in parent.childNodes:
        if (node.nodeType == minidom.Node.ELEMENT_NODE and
            (name == "*" or node.tagName == name)):
            yield node
        if (node.nodeType == minidom.Node.ELEMENT_NODE and
            node.tagName in onlysearch):
            for node in node.searchElementsByTagName(name, onlysearch):
                yield node


def getFirstElementByTagName(node, name):
    results = node.yieldElementsByTagName(name)
#  if isinstance(results, list):
#    if len(results) == 0:
#      return None
#    else:
#      return results[0]
    try:
        result = results.next()
        return result
    except StopIteration:
        return None


def getnodetext(node):
    """returns the node's text by iterating through the child nodes"""
    if node is None:
        return ""
    return "".join([t.data for t in node.childNodes if t.nodeType == t.TEXT_NODE])

# various modifications to minidom classes to add functionality we like


class DOMImplementation(minidom.DOMImplementation):

    def _create_document(self):
        return Document()


class Element(minidom.Element):

    def yieldElementsByTagName(self, name):
        return getElementsByTagName_helper(self, name)

    def searchElementsByTagName(self, name, onlysearch):
        return searchElementsByTagName_helper(self, name, onlysearch)

    def writexml(self, writer, indent, addindent, newl):
        return writexml_helper(self, writer, indent, addindent, newl)


class Document(minidom.Document):
    implementation = DOMImplementation()

    def yieldElementsByTagName(self, name):
        return getElementsByTagName_helper(self, name)

    def searchElementsByTagName(self, name, onlysearch):
        return searchElementsByTagName_helper(self, name, onlysearch)

    def createElement(self, tagName):
        e = Element(tagName)
        e.ownerDocument = self
        return e

    def createElementNS(self, namespaceURI, qualifiedName):
        prefix, localName = _nssplit(qualifiedName)
        e = Element(qualifiedName, namespaceURI, prefix)
        e.ownerDocument = self
        return e

theDOMImplementation = DOMImplementation()

# an ExpatBuilder that allows us to use the above modifications


class ExpatBuilderNS(expatbuilder.ExpatBuilderNS):

    def reset(self):
        """Free all data structures used during DOM construction."""
        self.document = theDOMImplementation.createDocument(
          expatbuilder.EMPTY_NAMESPACE, None, None)
        self.curNode = self.document
        self._elem_info = self.document._elem_info
        self._cdata = False
        self._initNamespaces()

    def start_element_handler(self, name, attributes):
        # All we want to do is construct our own Element instead of
        # minidom.Element, unfortunately the only way to do this is to
        # copy this whole function from expatbuilder.py
        if ' ' in name:
            uri, localname, prefix, qname = expatbuilder._parse_ns_name(self, name)
        else:
            uri = expatbuilder.EMPTY_NAMESPACE
            qname = name
            localname = None
            prefix = expatbuilder.EMPTY_PREFIX
        node = Element(qname, uri, prefix, localname)
        node.ownerDocument = self.document
        expatbuilder._append_child(self.curNode, node)
        self.curNode = node

        if self._ns_ordered_prefixes:
            for prefix, uri in self._ns_ordered_prefixes:
                if prefix:
                    a = minidom.Attr(expatbuilder._intern(self,
                                                          'xmlns:' + prefix),
                             expatbuilder.XMLNS_NAMESPACE, prefix, "xmlns")
                else:
                    a = minidom.Attr("xmlns", expatbuilder.XMLNS_NAMESPACE,
                             "xmlns", expatbuilder.EMPTY_PREFIX)
                d = a.childNodes[0].__dict__
                d['data'] = d['nodeValue'] = uri
                d = a.__dict__
                d['value'] = d['nodeValue'] = uri
                d['ownerDocument'] = self.document
                expatbuilder._set_attribute_node(node, a)
            del self._ns_ordered_prefixes[:]

        if attributes:
            _attrs = node._attrs
            _attrsNS = node._attrsNS
            for i in range(0, len(attributes), 2):
                aname = attributes[i]
                value = attributes[i+1]
                if ' ' in aname:
                    uri, localname, prefix, qname = expatbuilder._parse_ns_name(self, aname)
                    a = minidom.Attr(qname, uri, localname, prefix)
                    _attrs[qname] = a
                    _attrsNS[(uri, localname)] = a
                else:
                    a = minidom.Attr(aname, expatbuilder.EMPTY_NAMESPACE,
                             aname, expatbuilder.EMPTY_PREFIX)
                    _attrs[aname] = a
                    _attrsNS[(expatbuilder.EMPTY_NAMESPACE, aname)] = a
                d = a.childNodes[0].__dict__
                d['data'] = d['nodeValue'] = value
                d = a.__dict__
                d['ownerDocument'] = self.document
                d['value'] = d['nodeValue'] = value
                d['ownerElement'] = node

    if __debug__:
        # This only adds some asserts to the original
        # end_element_handler(), so we only define this when -O is not
        # used.  If changing one, be sure to check the other to see if
        # it needs to be changed as well.

        def end_element_handler(self, name):
            curNode = self.curNode
            if ' ' in name:
                uri, localname, prefix, qname = expatbuilder._parse_ns_name(self, name)
                assert (curNode.namespaceURI == uri
                    and curNode.localName == localname
                    and curNode.prefix == prefix), \
                    "element stack messed up! (namespace)"
            else:
                assert curNode.nodeName == name, \
                     "element stack messed up - bad nodeName"
                assert curNode.namespaceURI == expatbuilder.EMPTY_NAMESPACE, \
                     "element stack messed up - bad namespaceURI"
            self.curNode = curNode.parentNode
            self._finish_end_element(curNode)

# parser methods that use our modified xml classes


def parse(file, parser=None, bufsize=None):
    """Parse a file into a DOM by filename or file object."""
    builder = ExpatBuilderNS()
    if isinstance(file, basestring):
        fp = open(file, 'rb')
        try:
            result = builder.parseFile(fp)
        finally:
            fp.close()
    else:
        result = builder.parseFile(file)
    return result


def parseString(string, parser=None):
    """Parse a file into a DOM from a string."""
    builder = ExpatBuilderNS()
    return builder.parseString(string)
