# -*- coding: utf-8 -*-
"""
    flask.templating
    ~~~~~~~~~~~~~~~~

    Implements the bridge to Jinja2.

    :copyright: (c) 2010 by Armin Ronacher.
    :license: BSD, see LICENSE for more details.
"""
from jinja2 import BaseLoader, FileSystemLoader, TemplateNotFound

from .globals import _request_ctx_stack


def _default_template_ctx_processor():
    """Default template context processor.  Injects `request`,
    `session` and `g`.
    """
    reqctx = _request_ctx_stack.top
    return dict(
        request=reqctx.request,
        session=reqctx.session,
        g=reqctx.g
    )


class _DispatchingJinjaLoader(BaseLoader):
    """A loader that looks for templates in the application and all
    the module folders.
    """

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

    def get_source(self, environment, template):
        try:
            module, name = template.split('/', 1)
            loader = self.app.modules[module].jinja_loader
            if loader is None:
                raise ValueError()
        except (ValueError, KeyError):
            loader = self.app.jinja_loader
            if loader is not None:
                return loader.get_source(environment, template)
        else:
            try:
                return loader.get_source(environment, name)
            except TemplateNotFound:
                pass
        # raise the exception with the correct fileame here.
        # (the one that includes the prefix)
        raise TemplateNotFound(template)

    def list_templates(self):
        result = self.app.jinja_loader.list_templates()
        for name, module in self.app.modules.iteritems():
            if module.jinja_loader is not None:
                for template in module.jinja_loader.list_templates():
                    result.append('%s/%s' % (name, template))
        return result


def render_template(template_name, **context):
    """Renders a template from the template folder with the given
    context.

    :param template_name: the name of the template to be rendered
    :param context: the variables that should be available in the
                    context of the template.
    """
    ctx = _request_ctx_stack.top
    ctx.app.update_template_context(context)
    return ctx.app.jinja_env.get_template(template_name).render(context)


def render_template_string(source, **context):
    """Renders a template from the given template source string
    with the given context.

    :param template_name: the sourcecode of the template to be
                          rendered
    :param context: the variables that should be available in the
                    context of the template.
    """
    ctx = _request_ctx_stack.top
    ctx.app.update_template_context(context)
    return ctx.app.jinja_env.from_string(source).render(context)