"""
"""

import random

from datetime import timedelta
from time import time
from uuid import uuid4

from wheezy.core.collections import last_item_adapter
from wheezy.core.uuid import shrink_uuid
from wheezy.http import CacheProfile
from wheezy.http import HTTPResponse
from wheezy.http import accept_method
from wheezy.http import bad_request
from wheezy.http import response_cache


class FileAdapter(object):

    def __init__(self, response):
        self.write = response.write_bytes


class CaptchaContext(object):

    def __init__(self, image,
                 cache, prefix='captcha:', namespace=None,
                 timeout=5 * 60, profile=None,
                 chars='ABCDEFGHJKLMNPQRSTUVWXYZ23456789',
                 max_chars=4, wait_timeout=2,
                 challenge_key='c', turing_key='turing_number',
                 enabled=True):
        self.image = image
        self.cache = cache
        self.prefix = prefix
        self.namespace = namespace
        self.timeout = timeout
        self.chars = chars
        self.wait_timeout = wait_timeout
        self.max_chars = max_chars
        self.challenge_key = challenge_key
        self.turing_key = turing_key
        self.enabled = enabled
        if profile:
            self.profile = profile
        else:
            self.profile = CacheProfile(
                'server',
                vary_query=[challenge_key],
                duration=timedelta(seconds=wait_timeout),
                no_store=True,
                namespace=namespace)

    def create_handler(self, content_type='image/jpg', format='JPEG',
                       **options):
        @accept_method('GET')
        @response_cache(self.profile)
        def handler(request):
            if self.challenge_key not in request.query:
                return bad_request()
            challenge_code = last_item_adapter(
                request.query)[self.challenge_key]
            turing_number = ''.join(random.sample(self.chars, self.max_chars))
            if not self.cache.set(self.prefix + challenge_code,
                                  (int(time()), turing_number),
                                  self.timeout, self.namespace):
                return bad_request()
            response = HTTPResponse(content_type)
            self.image(turing_number).save(
                FileAdapter(response), format, **options)
            return response
        return handler

    def get_challenge_code(self, request):
        if self.challenge_key not in request.query:
            return shrink_uuid(uuid4())
        else:
            return request.query[self.challenge_key][0]

    def validate(self, request, errors, gettext):
        if not self.enabled:
            return True
        if self.challenge_key not in request.form:
            self.append_error(errors, gettext(
                'The challenge code is not available.'))
            return False
        if self.turing_key not in request.form:
            self.append_error(errors, gettext(
                'The turing number is not available.'))
            return False
        form = last_item_adapter(request.form)
        challenge_code = form[self.challenge_key]
        if len(challenge_code) != 22:
            self.append_error(errors, gettext(
                'The challenge code is invalid.'))
            return False
        entered_turing_number = form[self.turing_key]
        if len(entered_turing_number) != self.max_chars:
            self.append_error(errors, gettext(
                'The turing number is invalid.'))
            return False

        key = self.prefix + challenge_code
        data = self.cache.get(key, self.namespace)
        if not data:
            self.append_error(errors, gettext(
                'The code you typed has expired after %d seconds.')
                % self.timeout)
            return False
        self.cache.delete(key, 0, self.namespace)
        issued, turing_number = data
        if issued + self.wait_timeout > int(time()):
            self.append_error(errors, gettext(
                'The code was typed too quickly. Wait at least %d seconds.')
                % self.wait_timeout)
            return False
        if turing_number != entered_turing_number.upper():
            self.append_error(
                errors, gettext('The code you typed has no match.'))
            return False
        return True

    def append_error(self, errors, message):
        errors.setdefault(self.turing_key, []).append(message)