# vim: set fileencoding=UTF-8:
# Copyright 2013 Red Hat, Inc.
# Author: Jan Pokorný <jpokorny at redhat dot com>
# Licensed under LGPL v2.1 (the same as original ns-schema.xsl)

from sys import modules, stdout, stderr
from datetime import date
from textwrap import TextWrapper, dedent
from os import extsep, getcwd, mkdir, symlink, remove
from os.path import basename, dirname, exists, isdir, islink, join, splitext, \
                    sep as pathsep
from subprocess import call
from shlex import split
#import codecs

import logging

logging.basicConfig()
log = logging.getLogger(__name__)


#VERSIONSEP = sep  # non-unix paths -> problems
VERSIONSEP = '/'
ONTSEP = '#'
INDEX = 'index.html'

TEMPLATE_GENSHI = join(dirname(__file__), 'ontogen.template')
TEMPLATE_XSLT = join(dirname(__file__), 'ns-schema.xsl')
TEXT_INDENT = '      '
TW = TextWrapper(initial_indent=TEXT_INDENT, subsequent_indent=TEXT_INDENT)
tw = lambda x: TW.fill(x)
twd = lambda x: tw(dedent(x))
norm = lambda x: reduce(
    lambda a, b: a and a + (b.islower() and b or '-' + b.lower()) or b.lower(),
    x,
    ''
).replace('_', '-')


#
# Helpers
#


# classics: http://stackoverflow.com/a/1383402
class ClassProperty(property):
    def __get__(self, this, owner):
        return self.fget.__get__(None, owner)()


# another common fixer (adjusted): http://stackoverflow.com/a/13937525
class InheritDocstring(type):
    """Allows docstrings to be inherited (restricted to external classes)"""
    def __init__(this, name, bases, attrs):
        if __name__ not in (this.__module__, this.__base__.__module__):
            if not getattr(this, '__doc__', None):
                this.__doc__ = super(this, this).__doc__
        super(InheritDocstring, InheritDocstring).__init__(this, name,
                                                           bases, attrs)


def custom_symlink(source, link_name, report=False):
    """symlink + overwriting (unlink-new) of existing symlinks"""
    if exists(link_name):
        if islink(link_name):
            remove(link_name)
        else:
            raise RuntimeError('{0} is in our way'.format(link_name))
    if report is not False:
        print '{0}: {1}'.format(report, link_name)
    symlink(source, link_name)


#
# Pure documentation level
#


class Example(object):
    """Important data regarding examples"""
    @ClassProperty
    @classmethod
    def comment(this):
        return tw('\n'.join(this.__doc__.strip().splitlines()[:1]))

    @ClassProperty
    @classmethod
    def pfx(this):
        return ''

    @ClassProperty
    @classmethod
    def code(this):
        return '\n'.join(map(str.rstrip, this.__doc__.strip().splitlines()[2:]))

    @ClassProperty
    @classmethod
    def image(this):
        return ''


# combine this "example" with Makefile to trigger the magic
class ExampleSelfFigureProto(type):
    def __new__(self, ontology):
        base = ontology.base

        class ExampleSelfFigure(Example):
            """Illustrative figure of the vocabulary"""
            image_full = ontology.version + VERSIONSEP + base + extsep + 'svg'
            image = base + extsep + 'svg'  # referenced from html
            symlink = base + extsep + 'svg'

        return ExampleSelfFigure


#
# Abstract RDF level
#


class RDFEntity(object):
    """Common base for property, class and ontology"""

    __metaclass__ = InheritDocstring

    @ClassProperty
    @classmethod
    def id(this):
        return ONTSEP + norm(this.__name__)

    @ClassProperty
    @classmethod
    def namespaces(this):
        return {}

    @ClassProperty
    @classmethod
    def documentation(this):
        return this.__doc__

    @ClassProperty
    @classmethod
    def label(this):
        return '\n'.join(this.documentation.strip().splitlines()[:1]).strip()

    @ClassProperty
    @classmethod
    def comment(this):
        return '\n\n'.join(
            map(
                twd,
                '\n'.join(map(
                    str.rstrip,
                    this.documentation.strip().splitlines()[2:])).split('\n\n')
            )
        )

    @ClassProperty
    @classmethod
    def status(this):
        return ''


#
# RDF entities
#


class Class(RDFEntity):
    """Important data regarding RDF class"""

    # decorators

    @classmethod
    def inDomainOf(this, prop):
        """Tells that decorated Property has decorating Class as a domain"""
        assert issubclass(prop, Property)
        if not prop.domain:
            prop.domain = this.id
        else:
            log.warning('{0} already has domain set'
                        .format(prop))
        return prop

    @classmethod
    def inRangeOf(this, prop):
        """Tells that decorated Property has decorating Class as a range"""
        assert issubclass(prop, Property)
        if not prop.range:
            prop.range = this.id
        else:
            log.warning('{0} already has range set'
                        .format(prop))
        return prop

    # members

    @ClassProperty
    @classmethod
    def subClassOf(this):
        return '' if this.__base__ == Class else this.__base__.id


class Property(RDFEntity):
    """Important data regarding RDF property"""

    # members

    @ClassProperty
    @classmethod
    def domain(this):
        return ''

    @ClassProperty
    @classmethod
    def range(this):
        return ''

    @ClassProperty
    @classmethod
    def subPropertyOf(this):
        return '' if this.__base__ == Property else this.__base__.id


class Ontology(RDFEntity):
    """Important data regarding ontology"""

    # decorators

    @classmethod
    def supersededBy(this, onto):
        """Tells that decorated Ontology supersedes the decorating Ontology"""
        assert issubclass(onto, Ontology)
        if onto.priorVersion is None:
            onto.priorVersion = this
        else:
            log.warning('{0} already has priorVersion set'.format(onto))
        return onto

    # members - override

    @ClassProperty
    @classmethod
    def documentation(this):
        ret = getattr(this, '__doc__', '') or modules[this.__module__].__doc__
        return ret

    # members

    @ClassProperty
    @classmethod
    def base_uri(this):
        module = modules[this.__module__]
        if hasattr(module, 'base_uri'):
            return module.base_uri
        raise NotImplementedError

    @ClassProperty
    @classmethod
    def version(this):
        # sorting key
        raise NotImplementedError

    @ClassProperty
    @classmethod
    def base_uri_full(this):
        return this.base_uri + VERSIONSEP + this.version

    @ClassProperty
    @classmethod
    def base(this):
        # TODO: cache me please?
        return this.base_uri.rpartition('/')[2]

    @ClassProperty
    @classmethod
    def creator(this):
        module = modules[this.__module__]
        if hasattr(module, '__author__'):
            return module.__author__
        return ''

    @ClassProperty
    @classmethod
    def issued(this):
        return ''

    @ClassProperty
    @classmethod
    def modified(this):
        return date.today().isoformat()

    @ClassProperty
    @classmethod
    def priorVersion(this):
        return None

    @ClassProperty
    @classmethod
    def classes(this):
        return []

    @ClassProperty
    @classmethod
    def properties(this):
        return []

    @ClassProperty
    @classmethod
    def examples(this):
        return []

    # extras

    @classmethod
    def valid(this):
        proper_subclasses = all((
            all(issubclass(c, Class) for c in this.classes),
            all(issubclass(p, Property) for p in this.properties),
            all(issubclass(e, Example) for e in this.examples),
        ))
        if not proper_subclasses:
            log.warning('Not proper subclasses used')

        ids = [
            x.id for x in
                reduce(lambda a, b: a + b,
                       (getattr(this, ent_name) for ent_name in ('classes',
                                                                 'properties')))
        ]
        unique_ids = len(ids) == len(set(ids))
        if not unique_ids:
            log.warning('Not unique IDs used')

        return proper_subclasses and unique_ids

    @classmethod
    def _prepare_targets(this):
        base = this.base
        version = this.version
        if not exists(version):
            mkdir(version)
        elif not isdir(version):
            raise RuntimeError('{0} is not a directory'.format(version))
        return (version + VERSIONSEP + base + extsep + 'rdf',
                base + extsep + 'rdf')

    @classmethod
    def gendoc(this, infile, outfile, template=TEMPLATE_XSLT):
        """Generate HTML as per RDF (ns-schema.xsl wrapper)"""
        cmd = 'xsltproc --stringparam xmlfile {reference} -o {outfile}' \
              ' {template} {infile}'.format(
                  reference=basename(infile),
                  infile=infile,
                  outfile=outfile,
                  template=template
              )
        log.debug('running {0}'.format(split(cmd)))
        if call(split(cmd)):
            raise RuntimeError('Something went wrong while running {0}; pwd={1}'
                               .format(cmd, getcwd()))

    @classmethod
    def generate(this, ontologies=(), template=None, outfile='-', gendoc=True):
        """Generate RDF as per declarations"""
        from genshi.template import MarkupTemplate

        namespaces = {}
        for ns, ns_uri in reduce(
                lambda a, b: a + b.namespaces.items(),
                [this] + this.classes + this.properties,
                []
        ):
            if namespaces.setdefault('xmlns:' + ns, ns_uri) != ns_uri:
                print >>stderr, 'NS clash: {0} vs {1}'.format(
                                namespaces['xmlns:' + ns], ns_uri)

        tmpl_filename = template or TEMPLATE_GENSHI
        tmpl_fileobj = open(tmpl_filename)
        #tmpl_fileobj = codecs.open(tmpl_filename, encoding='UTF-8')
        tmpl = MarkupTemplate(tmpl_fileobj, tmpl_filename)
        tmpl_fileobj.close()

        symfile = None
        if outfile is '-':
            outobj = stdout
        else:
            if outfile == 'AUTO':
                outfile, symfile = this._prepare_targets()
            outobj = open(outfile, "w")

        tmpldict = dict(Ontology=this, namespaces=namespaces)
        print >>outobj, \
              tmpl.generate(**tmpldict).render('xml', strip_whitespace=False)
        outobj.flush()  # usually failing without this

        # htmldoc
        htmlfile = None
        if gendoc and outfile != '-':
            htmlfile = join(dirname(outfile), INDEX)
            this.gendoc(outfile, htmlfile)

        # symlink to base (non-versioned) only for the newest ontology
        if ontologies[-1] is this and symfile:
            custom_symlink(outfile, symfile, 'output')
            if htmlfile:
                custom_symlink(htmlfile, splitext(symfile)[0] + extsep + 'html',
                               'html')
                for ex in [e for e in this.examples if e.image]:
                    img = ex.image
                    if ex.__name__ == 'ExampleSelfFigure':
                        custom_symlink(ex.image_full, ex.symlink, 'self-figure')
                    elif not pathsep in img:
                        custom_symlink(join(this.base, img), img, 'image')

        if outobj is not stdout:
            outobj.close()

    @classmethod
    def __str__(this):
        this.generate()


class PrependFigure(InheritDocstring):
    """Attaches self-figure (to be provided externally) as a first example"""
    def __new__(this, name, bases, attrs):
        ret = super(PrependFigure, PrependFigure).__new__(this, name, bases,
                                                          attrs)
        if attrs['__module__'] == __name__:
            return ret  # nothing more to do here for internal classes
        try:
            if all(map(lambda x: isinstance(x, basestring),
                       map(lambda x: getattr(ret, x, None),
                           ('base_uri_full',))
            )):
                setattr(ret, 'examples', [ExampleSelfFigureProto(ret)]
                                         + list(getattr(ret, 'examples', ())))
        except NotImplementedError:
            pass
        finally:
            return ret


class OntologyWithFigure(Ontology):
    __metaclass__ = PrependFigure


#
# Generalized view
#

class Ontologies(object):
    """Groups multiple versions of ontologies (presumably of the same base)"""
    def __init__(self, ontologies=()):
        self._ontologies = []
        if ontologies:
            self.include(*ontologies)

    # decorators

    def include(self, *ontologies):
        assert all(map(lambda o: o.valid(), ontologies))
        assert reduce(lambda a, b: issubclass(a, b) or issubclass(b, a),
                      ontologies)
        map(lambda a: setattr(a, '_final', True), ontologies)
        merge = self._ontologies + list(ontologies)
        self._ontologies = list(sorted(set(merge), key=lambda o: o.version))
        # make it decorator-compatible
        return (lambda first=None, *others: first)(*ontologies)

    # members

    def generate_latest(self, **kwargs):
        self._ontologies[-1].generate(tuple(self._ontologies), **kwargs)