from django.db import models
from django.contrib.auth.models import User

from email.utils import parseaddr

# Reason a message was hidden.
# We're intentionally putting the prefix text in the array here, since
# we might need that flexibility in the future.
hide_reasons = [
    None,                                # placeholder for 0
    'This message has been hidden because a virus was found in the message.',  # 1
    'This message has been hidden because the message violated policies.',     # 2
    'This message has been hidden because for privacy reasons.',               # 3
    'This message was corrupt',                                                # 4
]


class Message(models.Model):
    threadid = models.IntegerField(null=False, blank=False)
    mailfrom = models.TextField(null=False, db_column='_from')
    to = models.TextField(null=False, db_column='_to')
    cc = models.TextField(null=False)
    subject = models.TextField(null=False)
    date = models.DateTimeField(null=False)
    messageid = models.TextField(null=False)
    bodytxt = models.TextField(null=False)
    # rawtxt is a bytea field, which django doesn't support (easily)
    parentid = models.IntegerField(null=False, blank=False)
    has_attachment = models.BooleanField(null=False, default=False)
    hiddenstatus = models.IntegerField(null=True)
    # fti is a tsvector field, which django doesn't support (easily)

    class Meta:
        db_table = 'messages'

    @property
    def printdate(self):
        return self.date.strftime("%Y-%m-%d %H:%M:%S")

    @property
    def shortdate(self):
        return self.date.strftime("%Y%m%d%H%M")

    @property
    def dateonly(self):
        return self.date.strftime("%Y%m%d")

    def from_name_only(self):
        try:
            return parseaddr(self.mailfrom)[0]
        except Exception:
            return ''

    # We explicitly cache the attachments here, so we can use them
    # multiple times from templates without generating multiple queries
    # to the database.
    _attachments = None

    @property
    def attachments(self):
        if not self._attachments:
            self._attachments = self.attachment_set.extra(select={'len': 'length(attachment)'}).all()
        return self._attachments

    @property
    def hiddenreason(self):
        if not self.hiddenstatus:
            return None
        try:
            return hide_reasons[self.hiddenstatus]
        except Exception:
            # Weird value
            return 'This message has been hidden.'


class ListGroup(models.Model):
    groupid = models.IntegerField(null=False, primary_key=True)
    groupname = models.CharField(max_length=200, null=False, blank=False)
    sortkey = models.IntegerField(null=False)

    class Meta:
        db_table = 'listgroups'


class List(models.Model):
    listid = models.IntegerField(null=False, primary_key=True)
    listname = models.CharField(max_length=200, null=False, blank=False, unique=True)
    shortdesc = models.TextField(null=False, blank=False)
    description = models.TextField(null=False, blank=False)
    active = models.BooleanField(null=False, blank=False)
    group = models.ForeignKey(ListGroup, db_column='groupid', on_delete=models.CASCADE)
    subscriber_access = models.BooleanField(null=False, blank=False, default=False, help_text="Subscribers can access contents (default is admins only)")

    @property
    def maybe_shortdesc(self):
        if self.shortdesc:
            return self.shortdesc
        return self.listname

    class Meta:
        db_table = 'lists'


class Attachment(models.Model):
    message = models.ForeignKey(Message, null=False, blank=False, db_column='message', on_delete=models.CASCADE)
    filename = models.CharField(max_length=1000, null=False, blank=False)
    contenttype = models.CharField(max_length=1000, null=False, blank=False)
    # attachment = bytea, not supported by django at this point

    class Meta:
        db_table = 'attachments'
        # Predictable same-as-insert order
        ordering = ('id',)

    def inlineable(self):
        # Return True if this image should be inlined
        if self.contenttype in ('image/png', 'image/gif', 'image/jpg', 'image/jpeg'):
            # Note! len needs to be set with extra(select=)
            if self.len < 75000:
                return True
        return False


class ListSubscriber(models.Model):
    # Only used when public access is not allowed.
    # We set the username of the community account instead of a
    # foreign key, because the user might not exist.
    list = models.ForeignKey(List, null=False, blank=False, on_delete=models.CASCADE)
    username = models.CharField(max_length=30, null=False, blank=False)

    class Meta:
        unique_together = (('list', 'username'), )
        db_table = 'listsubscribers'


class ResendMessage(models.Model):
    message = models.ForeignKey(Message, null=False, blank=False, on_delete=models.CASCADE)
    sendto = models.ForeignKey(User, null=False, blank=False, on_delete=models.CASCADE)
    registeredat = models.DateTimeField(null=False, blank=False)

    class Meta:
        unique_together = (('message', 'sendto'), )


class LastResentMessage(models.Model):
    sentto = models.OneToOneField(User, null=False, blank=False, primary_key=True, on_delete=models.CASCADE)
    sentat = models.DateTimeField(null=False, blank=False)