# -*- coding: utf-8 -*-
#
# Copyright (C) 2006 Edgewall Software
# Copyright (C) 2006 Matthew Good
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://markup.edgewall.org/wiki/License.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at http://markup.edgewall.org/log/.

"""Basic support for the template engine plugin API used by TurboGears and
CherryPy/Buffet.
"""

import os
from pkg_resources import resource_filename

from markup.template import Context, Template, TemplateLoader
from markup.core import Stream, QName

def ET(element):
    tag_name = element.tag
    if tag_name.startswith('{'):
        tag_name = tag_name[1:]
    tag_name = QName(tag_name)

    yield (Stream.START, (tag_name, element.items()),
           ('<string>', 0, 0))
    if element.text:
        yield Stream.TEXT, element.text, ('<string>', 0, 0)
    for child in element.getchildren():
        for item in ET(child):
            yield item
    yield Stream.END, tag_name, ('<string>', 0, 0)
    if element.tail:
        yield Stream.TEXT, element.tail, ('<string>', 0, 0)


class TemplateEnginePlugin(object):
    """Implementation of the plugin API."""

    def __init__(self, extra_vars_func=None, options=None):
        if options is None:
            options = {}
        # TODO get loader_args from the options dict

        self.loader = TemplateLoader(auto_reload=True)
        self.options = options
        self.get_extra_vars = extra_vars_func

    def load_template(self, templatename):
        """Find a template specified in python 'dot' notation."""
        divider = templatename.rfind('.')
        if divider >= 0:
            package = templatename[:divider]
            basename = templatename[divider + 1:] + '.html'
            templatename = resource_filename(package, basename)

        return self.loader.load(templatename)

    def render(self, info, format='html', fragment=False, template=None):
        """Render the template to a string using the provided info."""
        return self.transform(info, template).render(method=format)

    def transform(self, info, template):
        """Render the output to an event stream."""
        if not isinstance(template, Template):
            template = self.load_template(template)

        data = {'ET': ET}
        if self.get_extra_vars:
            data.update(self.get_extra_vars())
        data.update(info)

        ctxt = Context(**data)
        return template.generate(ctxt)