import hashlib
import json
import re
import uuid
from datetime import datetime
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.core.urlresolvers 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)

    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

    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


class QuestionSet(models.Model):
    __metaclass__ = TransMeta

    "Which questions to display on a question page"
    questionnaire = models.ForeignKey(Questionnaire)
    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")

    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

    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)

    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)
    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, str, unicode, 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)

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

class RunInfoHistory(models.Model):
    subject = models.ForeignKey(Subject)
    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)

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

    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)
    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, 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", 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' % (unicode(self.questionset), self.number, self.text)

    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)
    sortid = models.IntegerField()
    value = models.CharField(u"Short Value", max_length=64)
    text = models.CharField(u"Choice Text", max_length=200)
    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)

    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)

    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 unicode(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'],
            ]