from django.db import models
from django.utils import timezone

from django.core.files.storage import FileSystemStorage
from django.conf import settings
from django.utils.html import format_html

from django.urls import reverse

from django.utils.translation import ugettext_lazy as _

from sortedm2m.fields import SortedManyToManyField


class Category(models.Model):
    category = models.CharField(max_length=200)

    def __str__(self):
        return self.category

class Question(models.Model):
    stem = models.TextField(
        blank=False,
        help_text="Stem of the question",
    )

    a = models.TextField(
        blank=False,
        help_text="The question text",
    )
    a_answer = models.BooleanField(
        help_text="Answer (check for true)", default=True
    )

    b = models.TextField(
        blank=False,
        help_text="The question text",
    )
    b_answer = models.BooleanField(
        help_text="Answer", default=True
    )

    c = models.TextField(
        blank=False,
        help_text="The question text",
    )
    c_answer = models.BooleanField(
        help_text="Answer", default=True
    )

    d = models.TextField(
        blank=False,
        help_text="The question text",
    )
    d_answer = models.BooleanField(
        help_text="Answer", default=True
    )

    e = models.TextField(
        blank=False,
        help_text="The question text",
    )
    e_answer = models.BooleanField(
        help_text="Answer", default=True
    )

    created_date = models.DateTimeField(default=timezone.now)

    author = models.ManyToManyField(
        settings.AUTH_USER_MODEL,
        blank=True,
        help_text="Author(s) of question",
        related_name="physics_authored_questions",
    )

    category = models.ForeignKey(
        Category, on_delete=models.SET_NULL, null=True, blank=True
    )

    def __str__(self):
        return self.stem

    def clean(self):
        if self.a:
            self.a = self.a.strip()
        if self.b:
            self.b = self.b.strip()
        if self.c:
            self.c = self.c.strip()
        if self.d:
            self.d = self.d.strip()
        if self.e:
            self.e = self.e.strip()

class Exam(models.Model):
    name = models.CharField(max_length=200)
    exam_questions = SortedManyToManyField(
        Question, related_name="exams", blank="true"
    )

    active = models.BooleanField(
        help_text="If an exam should be available", default=True
    )

    publish_results = models.BooleanField(
        help_text="If an exams results should be available", default=True
    )

    def __str__(self):
        return self.name

    def get_exam_name(self):
        return self.name

    def get_json_url(self):
        return reverse("anatomy:exam_json", args=(self.pk,))

    def get_question_index(self, question):
        return list(self.exam_questions.all()).index(question)


class CidUserAnswer(models.Model):
    """User answers by candidate"""

    question = models.ForeignKey(
        Question, related_name="cid_user_answers", on_delete=models.CASCADE
    )
    a = models.BooleanField(blank=False)
    b = models.BooleanField(blank=False)
    c = models.BooleanField(blank=False)
    d = models.BooleanField(blank=False)
    e = models.BooleanField(blank=False)

    cid = models.IntegerField(blank=True, null=True)

    # Each user answer is associated with a particular exam
    exam = models.ForeignKey(
        Exam, related_name="cid_user_answers", on_delete=models.CASCADE, null=True
    )

    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)

    def __str__(self):
        return "{}/{}/{}".format(self.cid, self.exam, self.question.pk)