# -*- coding: utf-8 -*-
"""
    flaskext_compat
    ~~~~~~~~~~~~~~~

    Implements the ``flask.ext`` virtual package for versions of Flask
    older than 0.7.  This module is a noop if Flask 0.8 was detected.

    Usage::

        import flaskext_compat
        from flask.ext import foo

    :copyright: (c) 2011 by Armin Ronacher.
    :license: BSD, see LICENSE for more details.
"""


class _ExtensionImporter(object):
    """This importer redirects imports from this submodule to other locations.
    This makes it possible to transition from the old flaskext.name to the
    newer flask_name without people having a hard time.
    """
    _module_choices = ['flask_%s', 'flaskext.%s']

    def __init__(self):
        from sys import meta_path
        self.prefix = __name__ + '.'
        self.prefix_cutoff = __name__.count('.') + 1

        # since people might reload the flask.ext module (by accident or
        # intentionally) we have to make sure to not add more than one
        # import hook.  We can't check class types here either since a new
        # class will be created on reload.  As a result of that we check
        # the name of the class and remove stale instances.
        def _name(x):
            cls = type(x)
            return cls.__module__ + '.' + cls.__name__
        this = _name(self)
        meta_path[:] = [x for x in meta_path if _name(x) != this] + [self]

    def find_module(self, fullname, path=None):
        if fullname.startswith(self.prefix):
            return self

    def load_module(self, fullname):
        from sys import modules
        if fullname in modules:
            return modules[fullname]
        modname = fullname.split('.', self.prefix_cutoff)[self.prefix_cutoff]
        for path in self._module_choices:
            realname = path % modname
            try:
                __import__(realname)
            except ImportError:
                continue
            module = modules[fullname] = modules[realname]
            if '.' not in modname:
                setattr(modules[__name__], modname, module)
            return module
        raise ImportError(fullname)


import sys
import flask
try:
    __import__('flask.ext')
except ImportError:
    sys.modules['flask.ext'] = flask.ext = sys.modules[__name__]
    __name__ = __package__ = 'flask.ext'
    __path__ = []
    _ExtensionImporter()
del _ExtensionImporter, sys, flask