import json
import logging

from mechanize import ParseResponseEx
from mechanize._form import AmbiguityError
from mechanize._form import ControlNotFoundError
from mechanize._form import ListControl
from urlparse import urlparse


__author__ = "rohe0002"

logger = logging.getLogger(__name__)


class FlowException(Exception):
    def __init__(self, function="", content="", url=""):
        Exception.__init__(self)
        self.function = function
        self.content = content
        self.url = url

    def __str__(self):
        return json.dumps(self.__dict__)


class DResponse:
    """A Response class that behaves in the way that mechanize expects it"""

    def __init__(self, **kwargs):
        self.status = 200  # default
        self.index = 0
        self._message = ""
        self.url = ""
        if kwargs:
            for key, val in kwargs.items():
                if val:
                    self.__setitem__(key, val)

    def __setitem__(self, key, value):
        setattr(self, key, value)

    def __getitem__(self, item):
        if item == "content-location":
            return self.url
        elif item == "content-length":
            return len(self._message)
        else:
            return getattr(self, item)

    def geturl(self):
        """
        The base url for the response

        :return: The url
        """
        return self.url

    def read(self, size=0):
        """
        Read from the content of the response. The class remembers what has
        been read so it's possible to read small consecutive parts of the
        content.

        :param size: The number of bytes to read
        :return: Somewhere between zero and 'size' number of bytes depending
            on how much it left in the content buffer to read.
        """
        if size:
            if self._len < size:
                return self._message
            else:
                if self._len == self.index:
                    part = None
                elif self._len - self.index < size:
                    part = self._message[self.index :]
                    self.index = self._len
                else:
                    part = self._message[self.index : self.index + size]
                    self.index += size
                return part
        else:
            return self._message

    def write(self, message):
        """
        Write the message into the content buffer

        :param message: The message
        """
        self._message = message
        self._len = len(message)


def do_request(client, url, method, body="", headers=None):
    """
    Sends a HTTP request.

    :param client: The client instance
    :param url: Where to send the request
    :param method: The HTTP method to use for the request
    :param body: The request body
    :param headers: The requset headers
    :return: A tuple of
        url - the url the request was sent to
        response - the response to the request
        content - the content of the response if any
    """
    if headers is None:
        headers = {}

    logger.info("--> URL: %s", url)
    logger.info("--> BODY: %s", body)
    logger.info("--> Headers: %s", headers)

    response = client.http_request(url, method=method, data=body, headers=headers)

    logger.info("<-- RESPONSE: %s", response)
    logger.info("<-- CONTENT: %s", response.text)
    if response.cookies:
        logger.info("<-- COOKIES: %s", response.cookies)

    return url, response, response.text


def pick_form(response, content, url=None, **kwargs):
    """
    Picks which form in a web-page that should be used

    :param response: A HTTP request response. A DResponse instance
    :param content: The HTTP response content
    :param url: The url the request was sent to
    :return: The picked form or None of no form matched the criteria.
    """

    forms = ParseResponseEx(response)
    if not forms:
        raise FlowException(content=content, url=url)

    # if len(forms) == 1:
    #    return forms[0]
    # else:

    _form = None
    # ignore the first form for now
    forms = forms[1:]
    if len(forms) == 1:
        _form = forms[0]
    else:
        if "pick" in kwargs:
            _dict = kwargs["pick"]
            for form in forms:
                if _form:
                    break
                for key, _ava in _dict.items():
                    if key == "form":
                        _keys = form.attrs.keys()
                        for attr, val in _ava.items():
                            if attr in _keys and val == form.attrs[attr]:
                                _form = form
                    elif key == "control":
                        prop = _ava["id"]
                        _default = _ava["value"]
                        try:
                            orig_val = form[prop]
                            if isinstance(orig_val, str):
                                if orig_val == _default:
                                    _form = form
                            elif _default in orig_val:
                                _form = form
                        except KeyError:
                            pass
                    elif key == "method":
                        if form.method == _ava:
                            _form = form
                    else:
                        _form = None

                    if not _form:
                        break
        elif "index" in kwargs:
            _form = forms[int(kwargs["index"])]

    return _form


def do_click(client, form, **kwargs):
    """
    Emulates the user clicking submit on a form.

    :param client: The Client instance
    :param form: The form that should be submitted
    :return: What do_request() returns
    """

    if "click" in kwargs:
        request = None
        _name = kwargs["click"]
        try:
            _ = form.find_control(name=_name)
            request = form.click(name=_name)
        except AmbiguityError:
            # more than one control with that name
            _val = kwargs["set"][_name]
            _nr = 0
            while True:
                try:
                    cntrl = form.find_control(name=_name, nr=_nr)
                    if cntrl.value == _val:
                        request = form.click(name=_name, nr=_nr)
                        break
                    else:
                        _nr += 1
                except ControlNotFoundError:
                    raise Exception(f"No submit control with the name='{_name}' and value='{_val}' could be found")
    else:
        request = form.click()

    headers = {}
    for key, val in request.unredirected_hdrs.items():
        headers[key] = val

    url = request._Request__original

    if form.method == "POST":
        return do_request(client, url, "POST", request.data, headers)
    else:
        return do_request(client, url, "GET", headers=headers)


def select_form(client, orig_response, content, **kwargs):
    """
    Pick a form on a web page, possibly enter some information and submit
    the form.

    :param client: The Client
    :param orig_response: The original response (as returned by httplib2)
    :param content: The content of the response
    :return: The response do_click() returns
    """
    try:
        _url = orig_response.url
    except KeyError:
        _url = kwargs["location"]

    # content is a form to be filled in and returned
    response = DResponse(status=orig_response.status_code, url=_url)
    response.write(content)

    form = pick_form(response, content, _url, **kwargs)
    # form.backwards_compatible = False
    if not form:
        raise Exception("Can't pick a form !!")

    if "set" in kwargs:
        for key, val in kwargs["set"].items():
            if key.startswith("_"):
                continue
            if "click" in kwargs and kwargs["click"] == key:
                continue

            try:
                form[key] = val
            except ControlNotFoundError:
                pass
            except TypeError:
                cntrl = form.find_control(key)
                if isinstance(cntrl, ListControl):
                    form[key] = [val]
                else:
                    raise

    return do_click(client, form, **kwargs)


# noinspection PyUnusedLocal
def chose(client, orig_response, content, path, **kwargs):
    """
    Sends a HTTP GET to a url given by the present url and the given
    relative path.

    :param orig_response: The original response
    :param content: The content of the response
    :param path: The relative path to add to the base URL
    :return: The response do_click() returns
    """

    if not path.startswith("http"):
        try:
            _url = orig_response.url
        except KeyError:
            _url = kwargs["location"]

        part = urlparse(_url)
        url = f"{part[0]}://{part[1]}{path}"
    else:
        url = path

    return do_request(client, url, "GET")


def post_form(client, orig_response, content, **kwargs):
    """
    The same as select_form but with no possibility of change the content
    of the form.

    :param client: The Client instance
    :param orig_response: The original response (as returned by httplib2)
    :param content: The content of the response
    :return: The response do_click() returns
    """
    _url = orig_response.url
    # content is a form to be filled in and returned
    response = DResponse(status=orig_response.status_code, url=_url)
    response.write(content)

    form = pick_form(response, content, _url, **kwargs)

    return do_click(client, form, **kwargs)


def NoneFunc():
    return None


def interaction(args):
    _type = args["type"]
    if _type == "form":
        return select_form
    elif _type == "link":
        return chose
    else:
        return NoneFunc


# ========================================================================


class Operation:
    def __init__(self, conv, args=None, features=None):
        if args:
            self.function = interaction(args)

        self.args = args or {}
        self.request = None
        self.conv = conv
        self.features = features
        self.cconf = conv.client_config

    def update(self, dic):
        self.args.update(dic)

    # noinspection PyUnusedLocal
    def post_op(self, result, environ, args):
        pass

    def __call__(self, location, response, content, feature=None):
        try:
            _args = self.args.copy()
        except (KeyError, AttributeError):
            _args = {}

        _args["location"] = location

        logger.info("--> FUNCTION: %s", self.function.__name__)
        logger.info("--> ARGS: %s", _args)

        result = self.function(self.conv.client, response, content, **_args)
        self.post_op(result, self.conv, _args)
        return result