# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import models
from django.core.exceptions import ValidationError, NON_FIELD_ERRORS
from django.db.utils import IntegrityError
from django.utils.text import Truncator
import re

#import logging
#logger = logging.getLogger('console')

unique_constraint_re = re.compile(r'^UNIQUE\s+constraint\s+failed:(.*)$', re.IGNORECASE)

class ModelEx(models.Model):
    class Meta:
        abstract = True

    def get_duplicate_key_error_dict(self, fields):
        return {NON_FIELD_ERRORS: 'Duplicate value for %s' % ', '.join(fields)}

    def save(self, *args, **kwargs):
        try:
            super(ModelEx, self).save(*args, **kwargs)
        except IntegrityError as e:
            match = unique_constraint_re.search(e.message)
            if match:
                fields = [x.strip().split('.')[-1] for x in match.group(1).split(',')]
                raise ValidationError(self.get_duplicate_key_error_dict(fields))
            else:
                raise

class FeedCategory(ModelEx):
    name = models.CharField(max_length=50, unique=True)
    description = models.CharField(max_length=255, blank=True)
    days_required = models.PositiveIntegerField(default=366)

    class Meta:
        verbose_name = 'Category'
        verbose_name_plural = 'Categories'

    def get_duplicate_key_error_dict(self, fields):
        if fields[0] == 'name':
            return {'name': 'There is already a category with this name'}
        else:
            return super(FeedCategory, self).get_duplicate_key_error_dict(fields)

    @property
    def status(self):
        last_day = 0
        total_missing = 0
        missing_days = []

        for item in FeedItem.objects.filter(feed_category=self).order_by('feed_category_id', 'day_number'):
            day = item.day_number
            missing_count = day - last_day - 1
            total_missing += missing_count

            # The unique key and order_by on FeedItem ensure that missing_count
            # cannot be less than 0.
            if missing_count == 1:
                missing_days.append(str(day - 1))
            elif missing_count > 1:
                missing_days.append('{0}-{1}'.format(last_day + 1, day - 1))

            last_day = day

        missing_count = self.days_required - last_day
        if missing_count > 0:
            total_missing += missing_count
            if missing_count == 1:
                missing_days.append(str(self.days_required))
            elif missing_count > 1:
                missing_days.append('{0}-{1}'.format(last_day + 1, self.days_required))

        if missing_days:
            return "WARNING: Missing {0} day{1}: {2}".format(total_missing, '' if total_missing == 1 else 's', ', '.join(missing_days))
        else:
            return "Complete"

    def __unicode__(self):
        return self.name

class FeedItem(ModelEx):
    feed_category = models.ForeignKey(FeedCategory, on_delete=models.CASCADE)
    day_number = models.PositiveIntegerField()
    message_text = models.CharField(max_length=160)

    class Meta:
        verbose_name = 'Item'
        verbose_name_plural = 'Items'
        unique_together = ('feed_category', 'day_number')

    def get_duplicate_key_error_dict(self, fields):
        return {'day_number': 'There is already an item with this day number'}

    def __unicode__(self):
        return u'{0}: {1}'.format(self.day_number, Truncator(self.message_text).chars(20))