import os

from dispatcher import Dispatcher
from paste.httpexceptions import HTTPExceptionHandler
from paste.urlparser import StaticURLParser
from pkg_resources import resource_filename

class PassthroughFileserver(object):
    """serve files if they exist"""

    def __init__(self, app, *directories):
        self.app = app
        missing = [i for i in directories
                   if not os.path.exists(i) or not os.path.isdir(i)]
        assert not missing, "Missing directories: %s" % missing
        self.directories = [(directory, StaticURLParser(directory))
                             for directory in directories]

    def __call__(self, environ, start_response):
        path = environ['PATH_INFO'].strip('/')
        for directory, fileserver in self.directories:
            if path and os.path.exists(os.path.join(directory, path)):
                return fileserver(environ, start_response)
        return self.app(environ, start_response)

def factory(**app_conf):
    """create a webob view and wrap it in middleware"""
    directory = app_conf['directory']
    app = Dispatcher(**app_conf)
    return PassthroughFileserver(app, resource_filename(__name__, 'static'))

if __name__ == '__main__':
    import shutil
    import tempfile
    from wsgiref import simple_server
    tempdir = tempfile.mkdtemp()
    try:
        app = factory(directory=tempdir)
        server = simple_server.make_server(host='0.0.0.0', port=8080, app=app)
        server.serve_forever()
    finally:
        shutil.rmtree(tempdir)