from django.template.backends.utils import csrf_input_lazy, csrf_token_lazy
import django.template.backends.base
import genshi.template
import genshi.template.loader
import genshi.template.base


class GenshiEngine(django.template.backends.base.BaseEngine):
    app_dirname = 'genshi'

    def __init__(self, params):
        params = params.copy()
        options = params.pop('OPTIONS').copy()
        self.app_dirname = options.get('app_dirname', self.app_dirname)
        super(GenshiEngine, self).__init__(params)
        loader = genshi.template.TemplateLoader(self.template_dirs, auto_reload=options['auto_reload'])
        self.loader = loader


    def from_string(self, template_code):
        try:
            template = genshi.template.MarkupTemplate(template_code)
            return GenshiTemplateWrapper(template)
        except genshi.template.base.TemplateSyntaxError as exc:
            raise django.template.TemplateSyntaxError(exc.args)


    def get_template(self, template_name):
        try:
            template = self.loader.load(template_name)
            return GenshiTemplateWrapper(template)
        except genshi.template.loader.TemplateNotFound as exc:
            raise django.template.TemplateDoesNotExist(exc.args)
        except genshi.template.base.TemplateSyntaxError as exc:
            raise django.template.TemplateSyntaxError(exc.args)


class GenshiTemplateWrapper(object):
    def __init__(self, template):
        self.template = template

    def render(self, context=None, request=None):
        if context is None:
            context = {}
        if request is not None:
            context['request'] = request
            context['csrf_input'] = csrf_input_lazy(request)
            context['csrf_token'] = csrf_token_lazy(request)
        stream = self.template.generate(**context)
        return stream.render()