import hashlib
import json
import re
import uuid
from datetime import datetime
from six import text_type as unicodestr
from transmeta import TransMeta

from django.conf import settings
from django.contrib.contenttypes.fields import GenericForeignKey
from django.contrib.contenttypes.models import ContentType
from django.db import models
from django.db.models.signals import post_save
from django.utils.translation import ugettext_lazy as _
from django.urls import reverse

from . import QuestionChoices
from .utils import split_numal
from .parsers import parse_checks, ParseException

_numre = re.compile("(\d+)([a-z]+)", re.I)

class Subject(models.Model):
    STATE_CHOICES = [
        ("active", _("Active")),
        ("inactive", _("Inactive")),
        # Can be changed from elsewhere with
        # Subject.STATE_CHOICES[:] = [ ('blah', 'Blah') ]
    ]
    state = models.CharField(max_length=16, default="inactive",
        choices = STATE_CHOICES, verbose_name=_('State'))
    anonymous = models.BooleanField(default=False)
    ip_address = models.GenericIPAddressField(null=True, blank=True)
    surname = models.CharField(max_length=64, blank=True, null=True,
        verbose_name=_('Surname'))
    givenname = models.CharField(max_length=64, blank=True, null=True,
        verbose_name=_('Given name'))
    email = models.EmailField(null=True, blank=True, verbose_name=_('Email'))
    gender = models.CharField(max_length=8, default="unset", blank=True,
        verbose_name=_('Gender'),
        choices = ( ("unset", _("Unset")),
                    ("male", _("Male")),
                    ("female", _("Female")),
        )
    )
    nextrun = models.DateField(verbose_name=_('Next Run'), blank=True, null=True)
    formtype = models.CharField(max_length=16, default='email',
        verbose_name = _('Form Type'),
        choices = (
            ("email", _("Subject receives emails")),
            ("paperform", _("Subject is sent paper form"),))
    )
    language = models.CharField(max_length=5, default=settings.LANGUAGE_CODE,
        verbose_name = _('Language'), choices = settings.LANGUAGES)

    def __unicode__(self):
        if self.anonymous:
            return self.ip_address
        else:
            return u'%s, %s (%s)' % (self.surname, self.givenname, self.email)

    __str__ = __unicode__

    def next_runid(self):
        "Return the string form of the runid for the upcoming run"
        return str(self.nextrun.year)

    def last_run(self):
        "Returns the last completed run or None"
        try:
            query = RunInfoHistory.objects.filter(subject=self)
            return query.order_by('-completed')[0]
        except IndexError:
            return None

    def history(self):
        return RunInfoHistory.objects.filter(subject=self).order_by('run__runid')

    def pending(self):
        return RunInfo.objects.filter(subject=self).order_by('run__runid')

    class Meta:
        index_together = [
            ["givenname", "surname"],
            ]
                   
class GlobalStyles(models.Model):
    content = models.TextField()

class Questionnaire(models.Model):
    name = models.CharField(max_length=128)
    redirect_url = models.CharField(max_length=128, help_text="URL to redirect to when Questionnaire is complete. Macros: $SUBJECTID, $RUNID, $LANG. Leave blank to render the 'complete.$LANG.html' template.", default="", blank=True)
    html = models.TextField(u'Html', blank=True)
    parse_html = models.BooleanField("Render html instead of name for questionnaire?", null=False, default=False)
    admin_access_only = models.BooleanField("Only allow access to logged in users? (This allows entering paper questionnaires without allowing new external submissions)", null=False, default=False)

    def __unicode__(self):
        return self.name

    __str__ = __unicode__

    def questionsets(self):
        if not hasattr(self, "__qscache"):
            self.__qscache = \
              QuestionSet.objects.filter(questionnaire=self).order_by('sortid')
        return self.__qscache

    def questions(self):
        questions = []
        for questionset in self.questionsets():
            questions += questionset.questions()
        return questions

    class Meta:
        permissions = (
            ("export", "Can export questionnaire answers"),
            ("management", "Management Tools")
        )

class Landing(models.Model):
    # defines an entry point to a Feedback session
    nonce =  models.CharField(max_length=32, null=True,blank=True)
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE, null=True,blank=True, related_name='landings')
    object_id = models.PositiveIntegerField(null=True,blank=True)
    content_object = GenericForeignKey('content_type', 'object_id') 
    label = models.CharField(max_length=64, blank=True)
    questionnaire = models.ForeignKey(Questionnaire, on_delete=models.CASCADE, null=True, blank=True, related_name='landings')
    def _hash(self):
        return uuid.uuid4().hex 
    
    def __str__(self):
        return self.label
        
    def url(self):
        try:
            return  settings.BASE_URL_SECURE + reverse('landing', args=[self.nonce])
        except AttributeError:
            # not using sites
            return  reverse('landing', args=[self.nonce])
            

def config_landing(sender, instance, created,  **kwargs):
    if created:
        instance.nonce=instance._hash()
        instance.save()

post_save.connect(config_landing,sender=Landing)

class DBStylesheet(models.Model):
    #Questionnaire max length of name is 128; Questionset max length of heading 
    #is 64, and Question associative information is id which is less than 128 
    #in length
    inclusion_tag = models.CharField(max_length=128) 
    content = models.TextField()

    def __unicode__(self):
        return self.inclusion_tag

    __str__ = __unicode__


class QuestionSet(models.Model, metaclass=TransMeta):

    "Which questions to display on a question page"
    questionnaire = models.ForeignKey(Questionnaire, on_delete=models.CASCADE)
    sortid = models.IntegerField() # used to decide which order to display in
    heading = models.CharField(max_length=64)
    checks = models.CharField(max_length=256, blank=True,
        help_text = """Current options are 'femaleonly' or 'maleonly' and shownif="QuestionNumber,Answer" which takes the same format as <tt>requiredif</tt> for questions.""")
    text = models.TextField(u'Text', help_text="HTML or Text",  default="",)

    parse_html = models.BooleanField("Render html in heading?", null=False, default=False)

    def questions(self):
        if not hasattr(self, "__qcache"):
            def numeric_number(val):
                matches = re.findall(r'^\d+', val)
                return int(matches[0]) if matches else 0

            questions_with_sort_id = sorted(Question.objects.filter(questionset=self.id).exclude(sort_id__isnull=True), key=lambda q: q.sort_id)

            questions_with_out_sort_id = sorted(Question.objects.filter(questionset=self.id, sort_id__isnull=True), key=lambda q: (numeric_number(q.number), q.number))
            self.__qcache = questions_with_sort_id + questions_with_out_sort_id
        return self.__qcache

    def sorted_questions(self):
        questions = self.questions()
        return sorted(questions, key = lambda question : (question.sort_id, question.number))

    def next(self):
        qs = self.questionnaire.questionsets()
        retnext = False
        for q in qs:
            if retnext:
                return q
            if q == self:
                retnext = True
        return None

    __next__ = next

    def prev(self):
        qs = self.questionnaire.questionsets()
        last = None
        for q in qs:
            if q == self:
                return last
            last = q

    def is_last(self):
        try:
            return self.questionnaire.questionsets()[-1] == self
        except NameError:
            # should only occur if not yet saved
            return True

    def is_first(self):
        try:
            return self.questionnaire.questionsets()[0] == self
        except NameError:
            # should only occur if not yet saved
            return True

    def __unicode__(self):
        return u'%s: %s' % (self.questionnaire.name, self.heading)

    __str__ = __unicode__

    class Meta:
        translate = ('text',)
        index_together = [
            ["questionnaire", "sortid"],
            ["sortid",]
            ]
class Run(models.Model):
    runid = models.CharField(max_length=32, null=True)

class RunInfo(models.Model):
    "Store the active/waiting questionnaire runs here"
    subject = models.ForeignKey(Subject, on_delete=models.CASCADE)
    random = models.CharField(max_length=32) # probably a randomized md5sum
    run = models.ForeignKey(Run, on_delete=models.CASCADE, related_name='run_infos')
    landing = models.ForeignKey(Landing, on_delete=models.CASCADE, null=True, blank=True)
    # questionset should be set to the first QuestionSet initially, and to null on completion
    # ... although the RunInfo entry should be deleted then anyway.
    questionset = models.ForeignKey(QuestionSet, on_delete=models.CASCADE, blank=True, null=True) # or straight int?
    emailcount = models.IntegerField(default=0)

    created = models.DateTimeField(auto_now_add=True)
    emailsent = models.DateTimeField(null=True, blank=True)

    lastemailerror = models.CharField(max_length=64, null=True, blank=True)

    state = models.CharField(max_length=16, null=True, blank=True)
    cookies = models.TextField(null=True, blank=True)

    tags = models.TextField(
            blank=True,
            help_text=u"Tags active on this run, separated by commas"
        )

    skipped = models.TextField(
            blank=True,
            help_text=u"A comma sepearted list of questions to skip"
        )

    def save(self, **kwargs):
        self.random = (self.random or '').lower()
        super(RunInfo, self).save(**kwargs)

    def add_tags(self, tags):
        for tag in tags:
            if self.tags:
                self.tags += ','
            self.tags += tag

    def remove_tags(self, tags):
        if not self.tags:
            return

        current_tags = self.tags.split(',')

        for tag in tags:
            try:
                current_tags.remove(tag)
            except ValueError:
                pass
        self.tags = ",".join(current_tags)

    def set_cookie(self, key, value):
        "runinfo.set_cookie(key, value). If value is None, delete cookie"
        key = key.lower().strip()
        cookies = self.get_cookiedict()
        if type(value) not in (int, float, unicodestr, type(None)):
            raise Exception("Can only store cookies of type integer or string")
        if value is None:
            if key in cookies:
                del cookies[key]
        else:
            if type(value) in ('int', 'float'):
                value=str(value)
            cookies[key] = value
        cstr = json.dumps(cookies)
        self.cookies=cstr
        self.save()
        self.__cookiecache = cookies

    def get_cookie(self, key, default=None):
        if not self.cookies:
            return default
        d = self.get_cookiedict()
        return d.get(key.lower().strip(), default)

    def get_cookiedict(self):
        if not self.cookies:
            return {}
        if not hasattr(self, '__cookiecache'):
            self.__cookiecache = json.loads(self.cookies)
        return self.__cookiecache

    def __unicode__(self):
        return "%s: %s, %s" % (self.run.runid, self.subject.surname, self.subject.givenname)

    __str__ = __unicode__

    class Meta:
        verbose_name_plural = 'Run Info'
        index_together = [
            ["random"],
            ]

class RunInfoHistory(models.Model):
    subject = models.ForeignKey(Subject, on_delete=models.CASCADE)
    run = models.ForeignKey(Run, on_delete=models.CASCADE, related_name='run_info_histories')
    completed = models.DateTimeField()
    landing = models.ForeignKey(Landing, on_delete=models.CASCADE, null=True, blank=True)
    tags = models.TextField(
            blank=True,
            help_text=u"Tags used on this run, separated by commas"
        )
    skipped = models.TextField(
            blank=True,
            help_text=u"A comma sepearted list of questions skipped by this run"
        )
    questionnaire = models.ForeignKey(Questionnaire, on_delete=models.CASCADE)

    def __unicode__(self):
        return "%s: %s on %s" % (self.run.runid, self.subject, self.completed)    
        
    __str__ = __unicode__

    def answers(self):
        "Returns the query for the answers."
        return Answer.objects.filter(subject=self.subject, run=self.run)

    class Meta:
        verbose_name_plural = 'Run Info History'


class Question(models.Model, metaclass=TransMeta):

    questionset = models.ForeignKey(QuestionSet, on_delete=models.CASCADE)
    number = models.CharField(max_length=8, help_text=
        "eg. <tt>1</tt>, <tt>2a</tt>, <tt>2b</tt>, <tt>3c</tt><br /> "
        "Number is also used for ordering questions.")
    sort_id = models.IntegerField(null=True, blank=True, help_text="Questions within a questionset are sorted by sort order first, question number second")
    text = models.TextField(blank=True, default="", verbose_name=_("Text"))
    type = models.CharField(u"Type of question", max_length=32,
        choices = QuestionChoices,
        help_text = u"Determines the means of answering the question. " \
        "An open question gives the user a single-line textfield, " \
        "multiple-choice gives the user a number of choices he/she can " \
        "choose from. If a question is multiple-choice, enter the choices " \
        "this user can choose from below'.")
    extra = models.CharField(u"Extra information", max_length=512, blank=True, null=True, help_text=u"Extra information (use  on question type)")
    checks = models.CharField(u"Additional checks", max_length=512, blank=True,
        null=True, help_text="Additional checks to be performed for this "
        "value (space separated)  <br /><br />"
        "For text fields, <tt>required</tt> is a valid check.<br />"
        "For yes/no choice, <tt>required</tt>, <tt>required-yes</tt>, "
        "and <tt>required-no</tt> are valid.<br /><br />"
        "If this question is required only if another question's answer is "
        'something specific, use <tt>requiredif="QuestionNumber,Value"</tt> '
        'or <tt>requiredif="QuestionNumber,!Value"</tt> for anything but '
        "a specific value.  "
        "You may also combine tests appearing in <tt>requiredif</tt> "
        "by joining them with the words <tt>and</tt> or <tt>or</tt>, "
        'eg. <tt>requiredif="Q1,A or Q2,B"</tt>')
    footer = models.TextField(u"Footer", help_text="Footer rendered below the question", default="", null=True, blank=True)

    parse_html = models.BooleanField("Render html in Footer?", null=False, default=False)

    def questionnaire(self):
        return self.questionset.questionnaire

    def getcheckdict(self):
        """getcheckdict returns a dictionary of the values in self.checks"""
        if(hasattr(self, '__checkdict_cached')):
            return self.__checkdict_cached
        try:
            self.__checkdict_cached = d = parse_checks(self.sameas().checks or '')
        except ParseException:
            raise Exception("Error Parsing Checks for Question %s: %s" % (
                self.number, self.sameas().checks))
        return d

    def __unicode__(self):
        return u'{%s} (%s) %s' % (unicodestr(self.questionset), self.number, self.text)

    __str__ = __unicode__


    def sameas(self):
        if self.type == 'sameas':
            try:
                kwargs = {}
                for check, value in parse_checks(self.checks):
                    if check == 'sameasid':
                        kwargs['id'] = value
                        break
                    elif check == 'sameas':
                        kwargs['number'] = value
                        kwargs['questionset__questionnaire'] = self.questionset.questionnaire
                        break

                self.__sameas = res = getattr(self, "__sameas", Question.objects.get(**kwargs))
                return res
            except Question.DoesNotExist:
                return Question(type='comment') # replace with something benign
        return self

    def display_number(self):
        "Return either the number alone or the non-number part of the question number indented"
        m = _numre.match(self.number)
        if m:
            sub = m.group(2)
            return "&nbsp;&nbsp;&nbsp;" + sub
        return self.number

    def choices(self):
        if self.type == 'sameas':
            return self.sameas().choices()

        res = None
        if 'samechoicesas' in parse_checks(self.checks):
            number_to_grab_from = parse_checks(self.checks)['samechoicesas']
            choicesource = Question.objects.get(number=number_to_grab_from)
            if not choicesource == None:
                res = Choice.objects.filter(question=choicesource).order_by('sortid')
        else:        
            res = Choice.objects.filter(question=self).order_by('sortid')
        return res

    def is_custom(self):
        return "custom" == self.sameas().type

    def get_type(self):
        "Get the type name, treating sameas and custom specially"
        t = self.sameas().type
        if t == 'custom':
            cd = self.sameas().getcheckdict()
            if 'type' not in cd:
                raise Exception("When using custom types, you must have type=<name> in the additional checks field")
            return cd.get('type')
        return t

    def questioninclude(self):
        return "questionnaire/" + self.get_type() + ".html"

    @property
    def is_comment(self):
        return self.type == 'comment'

    def get_value_for_run_question(self, runid):
        runanswer = Answer.objects.filter(run__runid=runid, question=self)
        if len(runanswer) > 0:
            return runanswer[0].answer
        else:
            return None

    class Meta:
        translate = ('text', 'extra', 'footer')
        index_together = [
            ["number", "questionset"],
            ]

class Choice(models.Model, metaclass=TransMeta):

    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    sortid = models.IntegerField()
    value = models.CharField(u"Short Value", max_length=64, default="")
    text = models.CharField(u"Choice Text", max_length=200, default="")
    tags = models.CharField(u"Tags", max_length=64, blank=True)

    def __unicode__(self):
        return u'(%s) %d. %s' % (self.question.number, self.sortid, self.text)

    __str__ = __unicode__


    class Meta:
        translate = ('text',)
        index_together = [
            ['value'],
            ]

class Answer(models.Model):
    subject = models.ForeignKey(Subject, on_delete=models.CASCADE, help_text = u'The user who supplied this answer')
    question = models.ForeignKey(Question, on_delete=models.CASCADE, help_text = u"The question that this is an answer to")
    run = models.ForeignKey(Run, on_delete=models.CASCADE, related_name='answers')
    answer = models.TextField()

    def __unicode__(self):
        return "Answer(%s: %s, %s)" % (self.question.number, self.subject.surname, self.subject.givenname)

    __str__ = __unicode__

    def split_answer(self):
        """
        Decode stored answer value and return as a list of choices.
        Any freeform value will be returned in a list as the last item.

        Calling code should be tolerant of freeform answers outside
        of additional [] if data has been stored in plain text format
        """
        try:
            return json.loads(self.answer)
        except ValueError:
            # this was likely saved as plain text, try to guess what the
            # value(s) were
            if 'multiple' in self.question.type:
                return self.answer.split('; ')
            else:
                return [self.answer]

    def check_answer(self):
        "Confirm that the supplied answer matches what we expect"
        return True

    def save(self, runinfo=None, **kwargs):
        self._update_tags(runinfo)
        super(Answer, self).save(**kwargs)

    def _update_tags(self, runinfo):
        if not runinfo:
            return

        tags_to_add = []

        for choice in self.question.choices():
            tags = choice.tags
            if not tags:
                continue
            tags = tags.split(',')
            runinfo.remove_tags(tags)

            for split_answer in self.split_answer():
                if unicodestr(split_answer) == choice.value:
                    tags_to_add.extend(tags)

        runinfo.add_tags(tags_to_add)
        runinfo.save()

    class Meta:
        index_together = [
            ['subject', 'run'],
            ['subject', 'run', 'id'],
            ]