"""mime type transformation engine for cubicweb, based on mtconverter

:organization: Logilab
:copyright: 2001-2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""
__docformat__ = "restructuredtext en"

from logilab import mtconverter

from logilab.mtconverter.engine import TransformEngine
from logilab.mtconverter.transform import Transform
from logilab.mtconverter import (register_base_transforms,
                                 register_pil_transforms,
                                 register_pygments_transforms)

from cubicweb.utils import UStringIO
from cubicweb.common.uilib import rest_publish, html_publish

HTML_MIMETYPES = ('text/html', 'text/xhtml', 'application/xhtml+xml')

# CubicWeb specific transformations

class rest_to_html(Transform):
    inputs = ('text/rest', 'text/x-rst')
    output = 'text/html'
    def _convert(self, trdata):
        return rest_publish(trdata.appobject, trdata.decode())

class html_to_html(Transform):
    inputs = HTML_MIMETYPES
    output = 'text/html'
    def _convert(self, trdata):
        return html_publish(trdata.appobject, trdata.data)


# Instantiate and configure the transformation engine

mtconverter.UNICODE_POLICY = 'replace'

ENGINE = TransformEngine()
ENGINE.add_transform(rest_to_html())
ENGINE.add_transform(html_to_html())

try:
    from cubicweb.ext.tal import CubicWebContext, compile_template
except ImportError:
    HAS_TAL = False
    from cubicweb import schema
    schema.NEED_PERM_FORMATS.remove('text/cubicweb-page-template')

else:
    HAS_TAL = True

    class ept_to_html(Transform):
        inputs = ('text/cubicweb-page-template',)
        output = 'text/html'
        output_encoding = 'utf-8'
        def _convert(self, trdata):
            context = CubicWebContext()
            appobject = trdata.appobject
            context.update({'self': appobject, 'rset': appobject.rset,
                            'req': appobject.req,
                            '_' : appobject.req._,
                            'user': appobject.req.user})
            output = UStringIO()
            template = compile_template(trdata.encode(self.output_encoding))
            template.expand(context, output)
            return output.getvalue()

    ENGINE.add_transform(ept_to_html())

if register_pil_transforms(ENGINE, verb=False):
    HAS_PIL_TRANSFORMS = True
else:
    HAS_PIL_TRANSFORMS = False

try:
    from logilab.mtconverter.transforms import pygmentstransforms
    for mt in ('text/plain',) + HTML_MIMETYPES:
        try:
            pygmentstransforms.mimetypes.remove(mt)
        except ValueError:
            continue
    register_pygments_transforms(ENGINE, verb=False)

    def patch_convert(cls):
        def _convert(self, trdata, origconvert=cls._convert):
            try:
                trdata.appobject.req.add_css('pygments.css')
            except AttributeError: # session has no add_css, only http request
                pass
            return origconvert(self, trdata)
        cls._convert = _convert
    patch_convert(pygmentstransforms.PygmentsHTMLTransform)

    HAS_PYGMENTS_TRANSFORMS = True
except ImportError:
    HAS_PYGMENTS_TRANSFORMS = False

register_base_transforms(ENGINE, verb=False)