# -*- coding: utf-8 -*-
#
# This file is part of Librarian, licensed under GNU Affero GPLv3 or later.
# Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
#
from __future__ import with_statement

import os
import re
import shutil
import urllib

from util import makedirs


class UnicodeException(Exception):
    def __str__(self):
        """ Dirty workaround for Python Unicode handling problems. """
        return unicode(self).encode('utf-8')

    def __unicode__(self):
        """ Dirty workaround for Python Unicode handling problems. """
        args = self.args[0] if len(self.args) == 1 else self.args
        try:
            message = unicode(args)
        except UnicodeDecodeError:
            message = unicode(args, encoding='utf-8', errors='ignore')
        return message

class ParseError(UnicodeException):
    pass

class ValidationError(UnicodeException):
    pass

class NoDublinCore(ValidationError):
    """There's no DublinCore section, and it's required."""
    pass

class NoProvider(UnicodeException):
    """There's no DocProvider specified, and it's needed."""
    pass

class XMLNamespace(object):
    '''A handy structure to repsent names in an XML namespace.'''

    def __init__(self, uri):
        self.uri = uri

    def __call__(self, tag):
        return '{%s}%s' % (self.uri, tag)

    def __contains__(self, tag):
        return tag.startswith('{' + str(self) + '}')

    def __repr__(self):
        return 'XMLNamespace(%r)' % self.uri

    def __str__(self):
        return '%s' % self.uri

class EmptyNamespace(XMLNamespace):
    def __init__(self):
        super(EmptyNamespace, self).__init__('')

    def __call__(self, tag):
        return tag

# some common namespaces we use
XMLNS = XMLNamespace('http://www.w3.org/XML/1998/namespace')
RDFNS = XMLNamespace('http://www.w3.org/1999/02/22-rdf-syntax-ns#')
DCNS = XMLNamespace('http://purl.org/dc/elements/1.1/')
XINS = XMLNamespace("http://www.w3.org/2001/XInclude")
XHTMLNS = XMLNamespace("http://www.w3.org/1999/xhtml")
NCXNS = XMLNamespace("http://www.daisy.org/z3986/2005/ncx/")
OPFNS = XMLNamespace("http://www.idpf.org/2007/opf")
PLMETNS = XMLNamespace("http://dl.psnc.pl/schemas/plmet/")

WLNS = EmptyNamespace()


class WLURI(object):
    """Represents a WL URI. Extracts slug from it."""
    slug = None

    example = 'http://wolnelektury.pl/katalog/lektura/template/'
    _re_wl_uri = re.compile(r'http://(www\.)?wolnelektury.pl/katalog/lektura/'
            '(?P<slug>[-a-z0-9]+)/?$')

    def __init__(self, uri):
        uri = unicode(uri)
        self.uri = uri
        self.slug = uri.rstrip('/').rsplit('/', 1)[-1]

    @classmethod
    def strict(cls, uri):
        match = cls._re_wl_uri.match(uri)
        if not match:
            raise ValidationError(u'Invalid URI (%s). Should match: %s' % (
                        uri, cls._re_wl_uri.pattern))
        return cls(uri)

    @classmethod
    def from_slug(cls, slug):
        """Contructs an URI from slug.

        >>> WLURI.from_slug('a-slug').uri
        u'http://wolnelektury.pl/katalog/lektura/a-slug/'

        """
        uri = 'http://wolnelektury.pl/katalog/lektura/%s/' % slug
        return cls(uri)

    def __unicode__(self):
        return self.uri

    def __str__(self):
        return self.uri

    def __eq__(self, other):
        return self.slug == other.slug


class DocProvider(object):
    """Base class for a repository of XML files.

    Used for generating joined files, like EPUBs.
    """

    def by_slug(self, slug):
        """Should return a file-like object with a WL document XML."""
        raise NotImplementedError

    def by_uri(self, uri, wluri=WLURI):
        """Should return a file-like object with a WL document XML."""
        wluri = wluri(uri)
        return self.by_slug(wluri.slug)


class DirDocProvider(DocProvider):
    """ Serve docs from a directory of files in form <slug>.xml """

    def __init__(self, dir_):
        self.dir = dir_
        self.files = {}

    def by_slug(self, slug):
        fname = slug + '.xml'
        return open(os.path.join(self.dir, fname))


import lxml.etree as etree
import dcparser

DEFAULT_BOOKINFO = dcparser.BookInfo(
        { RDFNS('about'): u'http://wiki.wolnepodreczniki.pl/Lektury:Template'},
        { DCNS('creator'): [u'Some, Author'],
          DCNS('title'): [u'Some Title'],
          DCNS('subject.period'): [u'Unknown'],
          DCNS('subject.type'): [u'Unknown'],
          DCNS('subject.genre'): [u'Unknown'],
          DCNS('date'): ['1970-01-01'],
          DCNS('language'): [u'pol'],
          # DCNS('date'): [creation_date],
          DCNS('publisher'): [u"Fundacja Nowoczesna Polska"],
          DCNS('description'):
          [u"""Publikacja zrealizowana w ramach projektu
             Wolne Lektury (http://wolnelektury.pl). Reprodukcja cyfrowa
             wykonana przez Bibliotekę Narodową z egzemplarza
             pochodzącego ze zbiorów BN."""],
          DCNS('identifier.url'): [WLURI.example],
          DCNS('rights'):
            [u"Domena publiczna - zm. [OPIS STANU PRAWNEGO TEKSTU]"] })

def xinclude_forURI(uri):
    e = etree.Element(XINS("include"))
    e.set("href", uri)
    return etree.tostring(e, encoding=unicode)

def wrap_text(ocrtext, creation_date, bookinfo=DEFAULT_BOOKINFO):
    """Wrap the text within the minimal XML structure with a DC template."""
    bookinfo.created_at = creation_date

    dcstring = etree.tostring(bookinfo.to_etree(), \
        method='xml', encoding=unicode, pretty_print=True)

    return u'<utwor>\n' + dcstring + u'\n<plain-text>\n' + ocrtext + \
        u'\n</plain-text>\n</utwor>'


def serialize_raw(element):
    b = u'' + (element.text or '')

    for child in element.iterchildren():
        e = etree.tostring(child, method='xml', encoding=unicode,
                pretty_print=True)
        b += e

    return b

SERIALIZERS = {
    'raw': serialize_raw,
}

def serialize_children(element, format='raw'):
    return SERIALIZERS[format](element)

def get_resource(path):
    return os.path.join(os.path.dirname(__file__), path)


class OutputFile(object):
    """Represents a file returned by one of the converters."""

    _string = None
    _filename = None

    def __del__(self):
        if self._filename:
            os.unlink(self._filename)

    def __nonzero__(self):
        return self._string is not None or self._filename is not None

    @classmethod
    def from_string(cls, string):
        """Converter returns contents of a file as a string."""

        instance = cls()
        instance._string = string
        return instance

    @classmethod
    def from_filename(cls, filename):
        """Converter returns contents of a file as a named file."""

        instance = cls()
        instance._filename = filename
        return instance

    def get_string(self):
        """Get file's contents as a string."""

        if self._filename is not None:
            with open(self._filename) as f:
                return f.read()
        else:
            return self._string

    def get_file(self):
        """Get file as a file-like object."""

        if self._string is not None:
            from StringIO import StringIO
            return StringIO(self._string)
        elif self._filename is not None:
            return open(self._filename)

    def get_filename(self):
        """Get file as a fs path."""

        if self._filename is not None:
            return self._filename
        elif self._string is not None:
            from tempfile import NamedTemporaryFile
            temp = NamedTemporaryFile(prefix='librarian-', delete=False)
            temp.write(self._string)
            temp.close()
            self._filename = temp.name
            return self._filename
        else:
            return None

    def save_as(self, path):
        """Save file to a path. Create directories, if necessary."""

        dirname = os.path.dirname(os.path.abspath(path))
        makedirs(dirname)
        shutil.copy(self.get_filename(), path)


class URLOpener(urllib.FancyURLopener):
    version = 'FNP Librarian (http://github.com/fnp/librarian)'
urllib._urlopener = URLOpener()