"""
request dispatcher
"""

from handlers import Get, Post
from webob import Request, exc

class Dispatcher(object):

    ### class level variables
    defaults = { 'app': None}

    def __init__(self, **kw):
        for key in self.defaults:
            setattr(self, key, kw.get(key, self.defaults[key]))
        self.handlers = [ Get, Post ]
        if self.app:
            assert hasattr(self.app, '__call__')

    ### methods dealing with HTTP
    def __call__(self, environ, start_response):
        request = Request(environ)
        for h in self.handlers:
            if h.match(request):
                handler = h(request)
                break
        else:
            if self.app:
                return self.app(environ, start_response)
            handler = exc.HTTPNotFound
        res = handler()
        return res(environ, start_response)