#
# diffoscope: in-depth comparison of files, archives, and directories
#
# Copyright © 2017 Juliana Rodrigues <juliana.orod@gmail.com>
# Copyright © 2017-2020 Chris Lamb <lamby@debian.org>
#
# diffoscope 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 3 of the License, or
# (at your option) any later version.
#
# diffoscope 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 diffoscope.  If not, see <https://www.gnu.org/licenses/>.

from xml.parsers.expat import ExpatError

from diffoscope.comparators.utils.file import File
from diffoscope.difference import Difference
from diffoscope.tools import python_module_missing

from .missing_file import MissingFile

try:
    defusedxml = True
    from defusedxml import minidom
except ImportError:
    defusedxml = False
    python_module_missing("defusedxml")
    from xml.dom import minidom


def _format(node):
    """
    Removes *inplace* spaces from minidom.Document

    Args:
        node -- A xml.dom.minidom.Document object

    Returns:
        void
    """
    for n in node.childNodes:
        if n.nodeType == n.TEXT_NODE:
            if n.nodeValue:
                n.nodeValue = n.nodeValue.strip()
        elif n.nodeType == n.ELEMENT_NODE:
            _format(n)


def _parse(file):
    """
    Formats a minidom.Document file and returns XML as string.

    Args:
        file -- An io.TextIOWrapper object

    Returns:
        str: formated string object
    """

    if defusedxml:
        xml = minidom.parse(file, forbid_entities=False, forbid_external=False)
    else:
        xml = minidom.parse(file)

    _format(xml)
    xml.normalize()

    return xml.toprettyxml(indent=2 * " ", encoding="utf-8").decode("utf-8")


class XMLFile(File):
    """
    XML Files Comparison class

    Attributes:
        FILE_EXTENSION_SUFFIX (str): xml file extension suffix
    """

    DESCRIPTION = "XML files"
    FILE_EXTENSION_SUFFIX = {".xml"}

    @classmethod
    def recognizes(cls, file):
        """
        Identifies if a given file has XML extension

        Args:
            file - a diffoscope.comparators.utils.file.File object

        Returns:
            False if file is not a XML File, True otherwise
        """
        if not super().recognizes(file):
            return False

        with open(file.path) as f:
            try:
                file.parsed = _parse(f)
            except (ExpatError, UnicodeDecodeError):
                return False

        return True

    def compare_details(self, other, source=None):
        """
        Compares self.object with another, returning a Difference object

        Args:
            other    -- A XMLFile object
            source

        Returns:
            A diffoscope.difference.Difference object
        """
        if isinstance(other, MissingFile):
            return [
                Difference(
                    None,
                    self.name,
                    other.name,
                    comment="Trying to compare two non-existing files.",
                )
            ]

        return [
            Difference.from_text(
                self.dumps(self), self.dumps(other), self.name, other.name
            )
        ]

    def dumps(self, file):
        """
        Opens a XMLFile and returns its parsed content

        Args:
            file -- XMLFile object

        Returns:
            str -- Formatted XML content from file
        """
        if file.parsed:
            return file.parsed

        with open(file.path) as f:
            return _parse(f)
