import datetime

from django.conf import settings
from django.core.exceptions import ValidationError
from django.db import models
from django.db.models.signals import post_init, post_save
from django.urls import reverse
from django.utils.translation import ugettext_lazy as _

from django.contrib.auth import get_user_model

from symposion.conference.models import Conference
from symposion.sponsorship.managers import SponsorManager

User = get_user_model()


# The benefits we track as individual fields on sponsors
# Names are the names in the database as defined by organizers.
# Field names are the benefit names, lowercased, with
# spaces changed to _, and with "_benefit" appended.
# Column titles are arbitrary.

# "really just care about the ones we have today: print logo, web logo, print description, web description and the ad."

BENEFITS = [
    {
        'name': 'Web logo',
        'field_name': 'web_logo_benefit',
        'column_title': _(u"Web Logo"),
    }, {
        'name': 'Print logo',
        'field_name': 'print_logo_benefit',
        'column_title': _(u"Print Logo"),
    }, {
        'name': 'Company Description',
        'field_name': 'company_description_benefit',
        'column_title': _(u"Web Desc"),
    }, {
        'name': 'Print Description',
        'field_name': 'print_description_benefit',
        'column_title': _(u"Print Desc"),
    }
]


class SponsorLevel(models.Model):

    conference = models.ForeignKey(
        Conference,
        verbose_name=_("Conference"),
        on_delete=models.CASCADE,
    )
    name = models.CharField(_("Name"), max_length=100)
    order = models.IntegerField(_("Order"), default=0)
    cost = models.PositiveIntegerField(_("Cost"))
    description = models.TextField(_("Description"), blank=True, help_text=_("This is private."))

    class Meta:
        ordering = ["conference", "order"]
        verbose_name = _("Sponsor level")
        verbose_name_plural = _("Sponsor levels")

    def __str__(self):
        return "%s %s" % (self.conference, self.name)

    def sponsors(self):
        return self.sponsor_set.filter(active=True).order_by("added")


class Sponsor(models.Model):

    applicant = models.ForeignKey(
        User,
        related_name="sponsorships",
        verbose_name=_("Applicant"),
        null=True,
        on_delete=models.CASCADE,
    )

    name = models.CharField(_("Sponsor Name"), max_length=100)
    display_url = models.URLField(_("display URL"), blank=True)
    external_url = models.URLField(_("External URL"))
    annotation = models.TextField(_("Annotation"), blank=True)
    contact_name = models.CharField(_("Contact Name"), max_length=100)
    contact_email = models.EmailField(_("Contact Email"))
    level = models.ForeignKey(
        SponsorLevel,
        verbose_name=_("level"),
        on_delete=models.CASCADE,
    )
    added = models.DateTimeField(_("added"), default=datetime.datetime.now)
    active = models.BooleanField(_("active"), default=False)

    # Denormalization (this assumes only one logo)
    sponsor_logo = models.ForeignKey(
        "SponsorBenefit",
        related_name="+",
        null=True,
        blank=True,
        editable=False,
        verbose_name=_("Sponsor logo"),
        on_delete=models.CASCADE,
    )

    # Whether things are complete
    # True = complete, False = incomplate, Null = n/a for this sponsor level
    web_logo_benefit = models.NullBooleanField(_("Web logo benefit"), help_text=_(u"Web logo benefit is complete"))
    print_logo_benefit = models.NullBooleanField(_("Print logo benefit"), help_text=_(u"Print logo benefit is complete"))
    print_description_benefit = models.NullBooleanField(_("Print description benefit"), help_text=_(u"Print description benefit is complete"))
    company_description_benefit = models.NullBooleanField(_("Company description benefit"), help_text=_(u"Company description benefit is complete"))

    objects = SponsorManager()

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = _("Sponsor")
        verbose_name_plural = _("Sponsors")
        ordering = ['name']

    def save(self, *args, **kwargs):
        # Set fields related to benefits being complete
        for benefit in BENEFITS:
            field_name = benefit['field_name']
            benefit_name = benefit['name']
            setattr(self, field_name, self.benefit_is_complete(benefit_name))
            super(Sponsor, self).save(*args, **kwargs)

    def get_absolute_url(self):
        if self.active:
            return reverse("sponsor_detail", kwargs={"pk": self.pk})
        return reverse("sponsor_list")

    def get_display_url(self):
        if self.display_url:
            return self.display_url
        else:
            return self.external_url

    @property
    def website_logo(self):
        if self.sponsor_logo is None:
            benefits = self.sponsor_benefits.filter(
                benefit__type="weblogo", upload__isnull=False)[:1]
            if benefits.count():
                if benefits[0].upload:
                    self.sponsor_logo = benefits[0]
                    self.save()
        return self.sponsor_logo.upload

    @property
    def listing_text(self):
        if not hasattr(self, "_listing_text"):
            self._listing_text = ""
            # @@@ better than hard-coding a pk but still not good
            benefits = self.sponsor_benefits.filter(benefit__name="Sponsor Description")
            if benefits.count():
                self._listing_text = benefits[0].text
        return self._listing_text

    def reset_benefits(self):
        """
        Reset all benefits for this sponsor to the defaults for their
        sponsorship level.
        """
        level = None

        try:
            level = self.level
        except SponsorLevel.DoesNotExist:
            pass

        allowed_benefits = []
        if level:
            for benefit_level in level.benefit_levels.all():
                # Create all needed benefits if they don't exist already
                sponsor_benefit, created = SponsorBenefit.objects.get_or_create(
                    sponsor=self, benefit=benefit_level.benefit)

                # and set to default limits for this level.
                sponsor_benefit.max_words = benefit_level.max_words
                sponsor_benefit.other_limits = benefit_level.other_limits

                # and set to active
                sponsor_benefit.active = True

                # @@@ We don't call sponsor_benefit.clean here. This means
                # that if the sponsorship level for a sponsor is adjusted
                # downwards, an existing too-long text entry can remain,
                # and won't raise a validation error until it's next
                # edited.
                sponsor_benefit.save()

                allowed_benefits.append(sponsor_benefit.pk)

        # Any remaining sponsor benefits that don't normally belong to
        # this level are set to inactive
        self.sponsor_benefits.exclude(pk__in=allowed_benefits)\
            .update(active=False, max_words=None, other_limits="")

    def send_coordinator_emails(self):
        pass  # @@@ should this just be done centrally?

    def benefit_is_complete(self, name):
        """Return True - benefit is complete, False - benefit is not complete,
         or None - benefit not applicable for this sponsor's level """
        if BenefitLevel.objects.filter(level=self.level, benefit__name=name).exists():
            try:
                benefit = self.sponsor_benefits.get(benefit__name=name)
            except SponsorBenefit.DoesNotExist:
                return False
            else:
                return benefit.is_complete
        else:
            return None   # Not an applicable benefit for this sponsor's level


def _store_initial_level(sender, instance, **kwargs):
    if instance:
        instance._initial_level_id = instance.level_id


post_init.connect(_store_initial_level, sender=Sponsor)


def _check_level_change(sender, instance, created, **kwargs):
    if instance and (created or instance.level_id != instance._initial_level_id):
        instance.reset_benefits()


post_save.connect(_check_level_change, sender=Sponsor)


BENEFIT_TYPE_CHOICES = [
    ("text", _("Text")),
    ("file", _("File")),
    ("richtext", _("Rich Text")),
    ("weblogo", _("Web Logo")),
    ("simple", _("Simple")),
    ("option", _("Option"))
]

CONTENT_TYPE_CHOICES = [
    ("simple", "Simple"),
] + [
    ("listing_text_%s" % lang, "Listing Text (%s)" % label) for lang, label in settings.LANGUAGES
]


class Benefit(models.Model):

    name = models.CharField(_("Name"), max_length=100)
    description = models.TextField(_("Description"), blank=True)
    type = models.CharField(_("Type"), choices=BENEFIT_TYPE_CHOICES, max_length=10,
                            default="simple")
    content_type = models.CharField(_("content type"), choices=CONTENT_TYPE_CHOICES,
                                    max_length=20, default="simple")

    def __str__(self):
        return self.name


class BenefitLevel(models.Model):

    benefit = models.ForeignKey(
        Benefit,
        related_name="benefit_levels",
        verbose_name=_("Benefit"),
        on_delete=models.CASCADE,
    )
    level = models.ForeignKey(
        SponsorLevel,
        related_name="benefit_levels",
        verbose_name=_("Level"),
        on_delete=models.CASCADE,
    )

    # default limits for this benefit at given level
    max_words = models.PositiveIntegerField(_("Max words"), blank=True, null=True)
    other_limits = models.CharField(_("Other limits"), max_length=200, blank=True)

    class Meta:
        ordering = ["level"]
        verbose_name = _("Benefit level")
        verbose_name_plural = _("Benefit levels")

    def __str__(self):
        return "%s - %s" % (self.level, self.benefit)


class SponsorBenefit(models.Model):

    sponsor = models.ForeignKey(
        Sponsor,
        related_name="sponsor_benefits",
        verbose_name=_("Sponsor"),
        on_delete=models.CASCADE,
    )
    benefit = models.ForeignKey(
        Benefit,
        related_name="sponsor_benefits",
        verbose_name=_("Benefit"),
        on_delete=models.CASCADE,
    )
    active = models.BooleanField(default=True, verbose_name=_("Active"))

    # Limits: will initially be set to defaults from corresponding BenefitLevel
    max_words = models.PositiveIntegerField(_("Max words"), blank=True, null=True)
    other_limits = models.CharField(_("Other limits"), max_length=200, blank=True)

    # Data: zero or one of these fields will be used, depending on the
    # type of the Benefit (text, file, or simple)
    text = models.TextField(_("Text"), blank=True)
    upload = models.FileField(_("File"), blank=True, upload_to="sponsor_files")

    # Whether any assets required from the sponsor have been provided
    # (e.g. a logo file for a Web logo benefit).
    is_complete = models.NullBooleanField(_("Complete?"), help_text=_(u"True - benefit complete; False - benefit incomplete; Null - n/a"))

    class Meta:
        ordering = ["-active"]
        verbose_name = _("Sponsor benefit")
        verbose_name_plural = _("Sponsor benefits")

    def __str__(self):
        return "%s - %s (%s)" % (self.sponsor, self.benefit, self.benefit.type)

    def save(self, *args, **kwargs):
        # Validate - save() doesn't clean your model by default, so call
        # it explicitly before saving
        self.full_clean()
        self.is_complete = self._is_complete()
        super(SponsorBenefit, self).save(*args, **kwargs)

    def clean(self):
        num_words = len(self.text.split())
        if self.max_words and num_words > self.max_words:
            raise ValidationError(
                _("Sponsorship level only allows for %(word)s words, you provided %(num)d.") % {
                    "word": self.max_words, "num": num_words})

    def data_fields(self):
        """
        Return list of data field names which should be editable for
        this ``SponsorBenefit``, depending on its ``Benefit`` type.
        """
        if self.benefit.type == "file" or self.benefit.type == "weblogo":
            return ["upload"]
        elif self.benefit.type in ("text", "richtext", "simple", "option"):
            return ["text"]
        return []

    def _is_text_benefit(self):
        return self.benefit.type in ["text", "richtext", "simple"] and bool(self.text)

    def _is_upload_benefit(self):
        return self.benefit.type in ["file", "weblogo"] and bool(self.upload)

    def _is_complete(self):
        return self.active and (self._is_text_benefit() or self._is_upload_benefit())


def _denorm_weblogo(sender, instance, created, **kwargs):
    if instance:
        if instance.benefit.type == "weblogo" and instance.upload:
            sponsor = instance.sponsor
            sponsor.sponsor_logo = instance
            sponsor.save()


post_save.connect(_denorm_weblogo, sender=SponsorBenefit)