from paste.util import import_string
from paste.wsgilib import catch_errors
from paste.deploy.converters import asbool
from cherrypy._cpwsgi import wsgiApp
import cherrypy
import cherrypy.filters
import threadobject

cherrypy_installed = False

def install():
    global cherrypy_installed, default_config
    if cherrypy_installed:
        return
    import cherrypy
    import cherrypy.config
    import cherrypy._cputil
    cherrypy.server.start(initOnly=True, serverClass=None)
    try:
        default_config = cherrypy.config.configs
    except AttributeError:
        # CP 2.1
        default_config = cherrypy.config.configMap
    cherrypy.root = FAKE_ROOT
    cherrypy.config.configs = FAKE_CONFIG
    cherrypy.config.configMap = FAKE_CONFIG
    cherrypy_installed = True
    cherrypy._cputil._cp_filters.insert(
        0, PathFixingFilter())

class PathFixingFilter(object):

    def on_start_resource(self):
        script_name = FAKE_CONFIG.get('cherrypaste.real_script_name')
        path = cherrypy.request.object_path
        if path.startswith(script_name):
            if path == script_name:
                new_path = '/'
            else:
                new_path = path[len(script_name):]
            cherrypy.request.object_path = new_path
            cherrypy.request.app_path = script_name
            callbacks = FAKE_CONFIG.get('cherrypaste.set_script_name_callbacks')
            if callbacks:
                for callback in callbacks:
                    callback(script_name, new_path)
        else:
            # @@: For some reason this error messages isn't getting
            # through...?
            exc = cherrypy.NotFound(path)
            exc.args = (
                ('%s: Root path did not match WSGI SCRIPT_NAME of %r (got %r)'
                 % (str(exc), script_name, path)), )
            exc.message = exc.args[0]
            raise exc

FAKE_ROOT = threadobject.FakeObject('cherrypy.root')
FAKE_CONFIG = threadobject.FakeObject('cherrypy.config.configs')

class CherryDispatcher(object):
    def __init__(self, conf, root_object):
        self.conf = default_config.copy()
        self.conf.update(conf)
        self.root_object = root_object

    def __call__(self, environ, start_response):
        def deregister(exc_info=None):
            FAKE_ROOT._FAKE_detach()
            FAKE_CONFIG._FAKE_detach()
        conf = self.conf.copy()
        conf.setdefault('cherrypaste.real_script_name',
                        environ['SCRIPT_NAME'])
        if environ.get('paste.throw_errors'):
            conf['server.throw_errors'] = True
        FAKE_ROOT._FAKE_attach(self.root_object)
        FAKE_CONFIG._FAKE_attach(conf)
        
        return catch_errors(wsgiApp, environ, start_response,
                                    deregister, deregister)
        
def make_app(
    global_conf,
    root_object,
    lazy_fake=False,
    **local_conf):
    lazy_fake = asbool(lazy_fake)
    if not lazy_fake:
        install()
    if isinstance(root_object, basestring):
        root_object = import_string.eval_import(root_object)
    if lazy_fake:
        install()
    complete_conf = global_conf.copy()
    complete_conf.update(local_conf)
    app = CherryDispatcher(complete_conf, root_object)
    return app