try:
    import json
except ImportError:
    import simplejson as json  # noqa

import functools
import sys

import cherrypy
import webob
from turbogears import expose, util
import turbogears.view

from wsme.rest import validate as wsvalidate
import wsme.api
import wsme.rest
import wsme.rest.args
import wsme.rest.json
from wsme.utils import is_valid_code

import inspect

APIPATH_MAXLEN = 50

__all__ = ['wsexpose', 'wsvalidate']


def wsexpose(*args, **kwargs):
    tg_json_expose = expose(
        'wsmejson:',
        accept_format='application/json',
        content_type='application/json',
        tg_format='json'
    )
    tg_altjson_expose = expose(
        'wsmejson:',
        accept_format='text/javascript',
        content_type='application/json'
    )
    tg_xml_expose = expose(
        'wsmexml:',
        accept_format='text/xml',
        content_type='text/xml',
        tg_format='xml'
    )
    sig = wsme.signature(*args, **kwargs)

    def decorate(f):
        sig(f)
        funcdef = wsme.api.FunctionDefinition.get(f)

        @functools.wraps(f)
        def callfunction(self, *args, **kwargs):
            args, kwargs = wsme.rest.args.get_args(
                funcdef, args, kwargs,
                cherrypy.request.params, None,
                cherrypy.request.body,
                cherrypy.request.headers['Content-Type']
            )
            if funcdef.pass_request:
                kwargs[funcdef.pass_request] = cherrypy.request
            try:
                result = f(self, *args, **kwargs)
            except Exception:
                try:
                    exception_info = sys.exc_info()
                    orig_exception = exception_info[1]
                    if isinstance(orig_exception, cherrypy.HTTPError):
                        orig_code = getattr(orig_exception, 'status', None)
                    else:
                        orig_code = getattr(orig_exception, 'code', None)
                    data = wsme.api.format_exception(exception_info)
                finally:
                    del exception_info

                cherrypy.response.status = 500
                if data['faultcode'] == 'client':
                    cherrypy.response.status = 400
                elif orig_code and is_valid_code(orig_code):
                    cherrypy.response.status = orig_code

                accept = cherrypy.request.headers.get('Accept', "").lower()
                accept = util.simplify_http_accept_header(accept)

                decorators = {'text/xml': wsme.rest.xml.encode_error}
                return decorators.get(
                    accept,
                    wsme.rest.json.encode_error
                )(None, data)

            return dict(
                datatype=funcdef.return_type,
                result=result
            )

        callfunction = tg_xml_expose(callfunction)
        callfunction = tg_altjson_expose(callfunction)
        callfunction = tg_json_expose(callfunction)
        callfunction._wsme_original_function = f
        return callfunction

    return decorate


class AutoJSONTemplate(object):
    def __init__(self, extra_vars_func=None, options=None):
        pass

    def render(self, info, format="json", fragment=False, template=None):
        "Renders the template to a string using the provided info."
        return wsme.rest.json.encode_result(
            info['result'], info['datatype']
        )

    def get_content_type(self, user_agent):
        return "application/json"


class AutoXMLTemplate(object):
    def __init__(self, extra_vars_func=None, options=None):
        pass

    def render(self, info, format="json", fragment=False, template=None):
        "Renders the template to a string using the provided info."
        return wsme.rest.xml.encode_result(
            info['result'], info['datatype']
        )

    def get_content_type(self, user_agent):
        return "text/xml"


turbogears.view.engines['wsmejson'] = AutoJSONTemplate(turbogears.view.stdvars)
turbogears.view.engines['wsmexml'] = AutoXMLTemplate(turbogears.view.stdvars)


class Controller(object):
    def __init__(self, wsroot):
        self._wsroot = wsroot

    @expose()
    def default(self, *args, **kw):
        req = webob.Request(cherrypy.request.wsgi_environ)
        res = self._wsroot._handle_request(req)
        cherrypy.response.header_list = res.headerlist
        cherrypy.response.status = res.status
        return res.body


def _scan_api(controller, path=[], objects=[]):
    """
    Recursively iterate a controller api entries.
    """
    for name in dir(controller):
        if name.startswith('_'):
            continue
        a = getattr(controller, name)
        if a in objects:
            continue
        if inspect.ismethod(a):
            if wsme.api.iswsmefunction(a):
                yield path + [name], a._wsme_original_function, [controller]
        elif inspect.isclass(a):
            continue
        else:
            if len(path) > APIPATH_MAXLEN:
                raise ValueError("Path is too long: " + str(path))
            for i in _scan_api(a, path + [name], objects + [a]):
                yield i


def scan_api(root=None):
    return _scan_api(cherrypy.root)