import requests

from time import time
from .util import xml_to_dict, sha256_hex
from ...util import validate_ipv4
from ...http import HTTPMethod
from typing import Optional, Union


class ResponseError(RuntimeError):
    pass


class AuthError(ResponseError):
    pass


class ISAPIClient:
    def __init__(self, host):
        self.host = host
        self.cookies = {}

    def call(self,
             path: str,
             method: HTTPMethod = HTTPMethod.GET,
             data: Optional[Union[dict, str, bytes]] = None,
             raise_for_status=True,
             check_put_response=False):
        f = getattr(requests, method.value.lower())

        headers = {
            'X-Requested-With': 'XMLHttpRequest',
        }
        if method in (HTTPMethod.PUT, HTTPMethod.POST):
            headers['Content-Type'] = 'application/x-www-form-urlencoded; charset=UTF-8'

        kwargs = {}
        if data:
            kwargs['data' if method is not HTTPMethod.GET else 'params'] = data
        if len(self.cookies) > 0:
            kwargs['cookies'] = self.cookies

        r = f(f'http://{self.host}/ISAPI/{path}', headers=headers, **kwargs)

        if raise_for_status or check_put_response:
            r.raise_for_status()

        parsed_xml = None
        if check_put_response:
            parsed_xml = xml_to_dict(r.text)
            resp = parsed_xml['ResponseStatus']
            status_code = int(resp['statusCode'][0])
            status_string = resp['statusString'][0]
            if status_code != 1 or status_string.lower() != 'ok':
                raise ResponseError('response status looks bad')

        self.cookies.update(r.cookies.get_dict())

        if parsed_xml is None:
            parsed_xml = xml_to_dict(r.text)

        return parsed_xml

    def auth(self, username: str, password: str):
        xml = self.call('Security/sessionLogin/capabilities', data={'username': username})
        caps = xml['SessionLoginCap']
        is_irreversible = caps['isIrreversible'][0].lower() == 'true'

        # https://github.com/JakeVincet/nvt/blob/master/2018/hikvision/gb_hikvision_ip_camera_default_credentials.nasl
        # also look into webAuth.js and utils.js

        if 'salt' in caps and is_irreversible:
            p = sha256_hex(username + caps['salt'][0] + password)
            p = sha256_hex(p + caps['challenge'][0])
            for i in range(int(caps['iterations'][0])-2):
                p = sha256_hex(p)
        else:
            p = sha256_hex(password) + caps['challenge'][0]
            for i in range(int(caps['iterations'][0])-1):
                p = sha256_hex(p)

        data = '<SessionLogin>'
        data += f'<userName>{username}</userName>'
        data += f'<password>{p}</password>'
        data += f'<sessionID>{caps["sessionID"][0]}</sessionID>'
        data += '<isSessionIDValidLongTerm>false</isSessionIDValidLongTerm>'
        data += f'<sessionIDVersion>{caps["sessionIDVersion"][0]}</sessionIDVersion>'
        data += '</SessionLogin>'

        resp = self.call(f'Security/sessionLogin?timeStamp={int(time())}', HTTPMethod.POST, data=data)['SessionLogin']
        status_value = int(resp['statusValue'][0])
        status_string = resp['statusString'][0]
        if status_value != 200:
            raise AuthError(f'{status_value}: {status_string}')

    def get_ntp_server(self) -> str:
        try:
            # works on newer 1080p cams
            xml = self.call('System/time/ntpServers/capabilities')
            ntp_server = xml['NTPServerList']['NTPServer'][0]
            if ntp_server['addressingFormatType'][0]['#text'] == 'hostname':
                ntp_host = ntp_server['hostName'][0]
            else:
                ntp_host = ntp_server['ipAddress'][0]

        except requests.exceptions.HTTPError:
            # works on older 720p cams
            ntp_server = self.call('System/time/ntpServers/1')['NTPServer']
            if ntp_server['addressingFormatType'][0] == 'hostname':
                ntp_host = ntp_server['hostName'][0]
            else:
                ntp_host = ntp_server['ipAddress'][0]

        return ntp_host

    def set_timezone(self):
        data = '<?xml version="1.0" encoding="UTF-8"?>'
        data += '<Time><timeMode>NTP</timeMode><timeZone>CST-3:00:00</timeZone></Time>'
        self.call('System/time', HTTPMethod.PUT, data=data, check_put_response=True)

    def set_ntp_server(self,
                       ntp_host: str,
                       ntp_port: int = 123):
        format = 'ipaddress' if validate_ipv4(ntp_host) else 'hostname'

        # test ntp server first
        data = f'<?xml version="1.0" encoding="UTF-8"?><NTPTestDescription><addressingFormatType>{format}</addressingFormatType><ipAddress>{ntp_host}</ipAddress><portNo>{ntp_port}</portNo></NTPTestDescription>'
        resp = self.call('System/time/ntpServers/test', HTTPMethod.POST, data=data)['NTPTestResult']
        error_code = int(resp['errorCode'][0])
        error_description = resp['errorDescription'][0]
        if error_code != 0 or error_description.lower() != 'ok':
            raise ResponseError('response status looks bad')

        # then set it
        data = '<?xml version="1.0" encoding="UTF-8"?>'
        data += f'<NTPServer><id>1</id><addressingFormatType>{format}</addressingFormatType><ipAddress>{ntp_host}</ipAddress><portNo>{ntp_port}</portNo><synchronizeInterval>1440</synchronizeInterval></NTPServer>'
        self.call('System/time/ntpServers/1', HTTPMethod.PUT, data=data, check_put_response=True)