# coding: utf-8
from os.path import join, isfile, basename, isdir
from os import listdir
#from io import BytesIO

from lxml.etree import DTD, parse, tostring  # , XMLParser

from .i18n import _
from .error import DictConsistencyError

HIGH_COMPATIBILITY = True

class XMLReflector(object):
    """Helper class for loading the Creole XML file,
    parsing it, validating against the Creole DTD,
    writing the xml result on the disk
    """
    def __init__(self):
        self.dtd = None

    def parse_dtd(self, dtdfilename):
        """Loads the Creole DTD

        :raises IOError: if the DTD is not found

        :param dtdfilename: the full filename of the Creole DTD
        """
        if not isfile(dtdfilename):
            raise IOError(_("no such DTD file: {}").format(dtdfilename))
        with open(dtdfilename, 'r') as dtdfd:
            self.dtd = DTD(dtdfd)

    def parse_xmlfile(self, xmlfile):
        """Parses and validates some Creole XML against the Creole DTD

        :returns: the root element tree object
        """
        # document = parse(BytesIO(xmlfile), XMLParser(remove_blank_text=True))
        document = parse(xmlfile)
        if not self.dtd.validate(document):
            raise DictConsistencyError(_("not a valid xml file: {}").format(xmlfile))
        return document.getroot()

    def load_xml_from_folders(self, xmlfolders):
        """Loads all the XML files located in the xmlfolders' list

        :param xmlfolders: list of full folder's name
        """
        documents = []
        if not isinstance(xmlfolders, list):
            xmlfolders = [xmlfolders]
        for xmlfolder in xmlfolders:
            if isinstance(xmlfolder, list) or isinstance(xmlfolder, tuple):
                # directory group : collect files from each
                # directory and sort them before loading
                group_files = []
                for idx, subdir in enumerate(xmlfolder):
                    if isdir(subdir):
                        for filename in listdir(subdir):
                            group_files.append((filename, idx, subdir))
                    else:
                        group_files.append(basename(subdir), idx, dirname(subdir))
                def sort_group(file1, file2):
                    if file1[0] == file2[0]:
                        # sort by initial xmlfolder order if same name
                        return file1[1].__cmp__(file2[1])
                    # sort by filename
                    elif file1[0] > file2[0]:
                        return 1
                    else:
                        return -1
                group_files.sort(sort_group)
                filenames = [join(f[2], f[0]) for f in group_files]
            elif isdir(xmlfolder):
                filenames = []
                for filename in listdir(xmlfolder):
                    filenames.append(join(xmlfolder, filename))
                filenames.sort()
            else:
                filenames = [xmlfolder]
            for xmlfile in filenames:
                if xmlfile.endswith('.xml'):
                    #xmlfile_path = join(xmlfolder, xmlfile)
                    documents.append((xmlfile, self.parse_xmlfile(xmlfile)))
        return documents

    def save_xmlfile(self, xmlfilename, xml):  # pylint: disable=R0201
        """Write a bunch of XML on the disk
        """
        with open(xmlfilename, 'w') as xmlfh:
            xmlfh.write(tostring(xml, pretty_print=True, encoding="UTF-8", xml_declaration=True).decode('utf8'))