penracourses/generic/models.py

from collections import defaultdict
import datetime
import json
import os
from typing import Optional, Self, Tuple
from django.contrib.auth.mixins import LoginRequiredMixin
from django.db import models
from django.forms import ValidationError
from django.http import Http404, HttpRequest
from django.utils import timezone
from django.core.validators import MaxValueValidator, MinValueValidator
from smtplib import SMTPException

from django.urls import reverse
from django.views.generic.edit import CreateView
from reversion.views import RevisionMixin

from django.conf import settings

from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
from django.contrib.contenttypes.models import ContentType

from django.core.mail import send_mail
from django.core.mail import EmailMessage

from django.contrib.auth.models import User

from django.db.models.signals import post_save
from django.dispatch import receiver
from generic.mixins import AuthorMixin, QuestionMixin
from helpers.images import get_image_hash, pretty_print_dicom
from rad.settings import REMOTE_URL
from django.utils.html import format_html

from easy_thumbnails.files import get_thumbnailer
from easy_thumbnails.exceptions import InvalidImageFormatError


import pydicom
import dicognito.anonymizer
from django.contrib.auth.models import User
from django.forms.models import model_to_dict
from django.forms.utils import from_current_timezone, to_current_timezone


def findMiddle(input_list):
    """Returns the middle element of a list"""
    middle = float(len(input_list)) / 2
    if middle % 2 != 0:
        return input_list[int(middle - 0.5)]
    else:
        return input_list[int(middle)]


class Modality(models.Model):
    modality = models.CharField(max_length=200, unique=True)
    short_code = models.CharField(max_length=5, unique=True, null=True)

    def __str__(self):
        return f"{self.modality} ({self.short_code})"


class Plane(models.Model):
    plane = models.CharField(max_length=200, unique=True)

    def __str__(self):
        return self.plane

    class Meta:
        ordering = ("plane",)


class Contrast(models.Model):
    contrast = models.CharField(max_length=200, unique=True)

    def __str__(self):
        return self.contrast

    class Meta:
        ordering = ("contrast",)


class Examination(models.Model):
    """

    Currently used for
    - Atlas series
    - Longs series
    - Anatomy questions

    Not used for rapids - yet??
    """

    examination = models.CharField(max_length=200, unique=True)

    modality = models.ForeignKey(Modality, on_delete=models.SET_NULL, null=True)

    class Meta:
        ordering = ("examination",)

    def __str__(self):
        return self.examination

    def merge_into(self, examination_to_merge_into: Self, delete: bool = True) -> bool:
        """Merges the current examination into another

        To do so it replaces all associations (many to many and foreign key relations)

        Returns True if successful
        """
        # Get all atlas series with the examination
        atlas_series = self.atlas_series_examination.all()
        longs_series = self.series_examination.all()
        anatomy_questions = self.anatomyquestion_set.all()

        # Reassign them to the new object
        for series in atlas_series:
            series.examination = examination_to_merge_into
            series.save()

        for series in longs_series:
            series.examination = examination_to_merge_into
            series.save()

        for question in anatomy_questions:
            question.examination = examination_to_merge_into
            question.save()

        # quick check to make sure nothing has gone wrong and we have hanging
        # associations
        querysets = (
            self.atlas_series_examination.all(),
            self.series_examination.all(),
            self.anatomyquestion_set.all(),
        )

        for q in querysets:
            if q.count() > 0:
                return False

        if delete:
            self.delete()
        return True


class Site(models.Model):
    """Model to hold site details"""

    full_name = models.CharField(
        max_length=255, blank=True, help_text="Name of the site"
    )
    short_code = models.CharField(
        max_length=255, blank=True, help_text="Shortcode/name of the site"
    )

    def __str__(self):
        return self.short_code


class QuestionBase(models.Model, AuthorMixin, QuestionMixin):
    authors_only = models.BooleanField(
        help_text="If true only question authors will be able to view.",
        default=False,
    )

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

    open_access = models.BooleanField(
        help_text="If a question should be freely available to browse", default=True
    )

    feedback = models.TextField(null=True, blank=True, help_text="Question Feedback")

    notes = GenericRelation("generic.QuestionNote")

    class Meta:
        abstract = True

    def get_unanswered_mark_and_text(self) -> tuple[int, str]:
        """
        Override in models if needed
        """
        return (0, "Not answered")

    def get_primary_answer(self):
        """If this makes sense in the question/answer context override"""
        return None

    def can_edit(self, user: User) -> bool:
        """Returns True if the user can edit the question"""
        if user.is_superuser:
            return True

        if user in self.get_author_objects():
            return True

        return False


class SeriesImageBase(models.Model):
    """
    Series Images may be modified (usually downsampled to save space), in this case the
    (larger) original file will be deleted but the model object will be persisted so that
    the duplicate check continues to function.
    """

    position = models.IntegerField(default=0)
    upload_filename = models.CharField(max_length=255, blank=True)
    series = models.ForeignKey(
        "Series", related_name="images", on_delete=models.SET_NULL, null=True
    )
    dicom_tags_ohif = models.JSONField(
        help_text="Holds the dicom tags required for the OHIF viewer",
        blank=True,
        null=True,
    )

    # We store two hashes of the dicom data to uniquely identify the file
    # and allow duplicate detection

    # The first is a md5 hash of the pixel array data
    # this is used because I can't get the direct pixel data to match from cornerstone
    # (and struggle to get blake3 working in the browser)
    image_md5_hash = models.CharField(max_length=32, null=True, blank=True)

    # The second is a blake3 hash of the direct pixel data
    # This is much faster when using pydicom
    image_blake3_hash = models.CharField(max_length=64, null=True, blank=True)

    is_dicom = models.BooleanField(default=False)

    removed = models.BooleanField(
        default=False,
        help_text="Set to true if the file this object refers to has been removed (either from series truncation or merging)",
    )

    class Meta:
        ordering = ["position"]
        abstract = True

    def get_dicom_json(self):
        try:
            json = pydicom.read_file(self.image).to_json()
        except pydicom.errors.InvalidDicomError:
            return {}
        return json

    def get_dicom_info(self):
        try:
            info = pretty_print_dicom(pydicom.read_file(self.image))
        except pydicom.errors.InvalidDicomError:
            info = "File is not a dicom."
        return info

    def generate_md5_hash(self):
        if not self.removed:
            image_hash, is_dicom = get_image_hash(
                self.image, hash_type="md5", direct_pixel_data=False
            )

            self.is_dicom = is_dicom
            self.image_md5_hash = image_hash

            self.save()

    def generate_blake3_hash(self):
        if not self.removed:
            image_blake3_hash, is_dicom = get_image_hash(
                self.image, hash_type="blake3", direct_pixel_data=True
            )
            self.is_dicom = is_dicom
            self.image_blake3_hash = image_blake3_hash

            self.save()

    def save(self, *args, **kwargs):
        """Override save method to add image hash"""
        if self.image:
            # if not self.image_md5_hash:
            #    image_hash, is_dicom = get_image_hash(self.image, hash_type="md5", direct_pixel_data=False)

            #    self.is_dicom = is_dicom
            #    self.image_md5_hash = image_hash

            if not self.image_blake3_hash:
                image_blake3_hash, is_dicom = get_image_hash(
                    self.image, hash_type="blake3", direct_pixel_data=True
                )
                self.is_dicom = is_dicom
                self.image_blake3_hash = image_blake3_hash

                ## Hack for tests
                # if image_hash != "12345ABCD":
                #    super().save(*args, **kwargs)  # Call the "real" save() method.

        super().save(*args, **kwargs)  # Call the "real" save() method.


class SeriesBase(models.Model):
    info = models.TextField(
        blank=True,
        help_text="Description of stack, for admin organisation, will not be visible when taking",
    )

    description = models.CharField(
        null=True,
        blank=True,
        max_length=255,
        help_text="Description of the series. This is usually visable to the user (as the name of the stack)",
    )

    open_access = models.BooleanField(
        help_text="If a series should be freely available to browse", default=True
    )

    created_date = models.DateTimeField(auto_now_add=True)
    modified_date = models.DateTimeField(auto_now=True)

    class SeriesModifiedChocies(models.TextChoices):
        NO = (
            "NO",
            "Not modified",
        )
        TR = (
            "TR",
            "Truncated",
        )
        RE = (
            "RE",
            "Resliced/resampled",
        )

    modified = models.CharField(
        max_length=2,
        default=SeriesModifiedChocies.NO,
        choices=SeriesModifiedChocies.choices,
    )

    class Meta:
        abstract = True

    def __str__(self):
        return f"{self.pk}:{self.description}"

    def check_user_can_edit(self, user: User):
        if user.is_superuser:
            return True

        if user in self.get_author_objects():
            return True

        return False

    def get_author_objects(self):
        """Returns a list of authors"""
        if self.author:
            return self.author.all()
        else:
            return ["None"]

    def get_author_display(self):
        return ", ".join([i.username for i in self.get_author_objects()])

    def get_examination(self):
        """Returns a comma seperated text list of regions"""
        return str(self.examination)

    def get_examination_full(self):
        examination = ""
        plane = ""
        contrast = ""

        if self.examination:
            examination = self.examination
        if self.plane:
            plane = " {}".format(self.plane)
        if self.contrast:
            contrast = " {}".format(self.contrast)
        return "{}{}{}".format(examination, plane, contrast)

    def get_images(self, include_removed=False):
        if include_removed:
            return self.images.all()
        else:
            return self.images.filter(removed=False)

    def get_image_count(self):
        return self.images.filter(removed=False).count()

    def get_image_urls(self):
        images = [
            f"{REMOTE_URL}{i.image.url}" for i in self.images.filter(removed=False)
        ]

        return ",".join(images)

    def get_image_url_array_not_json(self):
        return self.get_image_url_array(json_output=False)

    def get_image_url_array_and_count(self, json_output=True):
        return self.get_image_url_array(json_output=json_output, count=True)

    def get_image_url_array(self, json_output=True, count=False):
        images = [
            f"{REMOTE_URL}{i.image.url}" for i in self.images.filter(removed=False)
        ]

        if json_output:
            if count:
                return (json.dumps(images), len(images))
            else:
                return json.dumps(images)
        else:
            # This is a mess...
            if count:
                return (format_html('", "'.join(images)), len(images))
            else:
                return format_html('", "'.join(images))

    def get_thumbnail(self, recreate=False):
        images = self.images.filter(removed=False)

        if len(images) < 1:
            return "No images", 0

        img = findMiddle(images).image
        try:
            thumbnailer = get_thumbnailer(img)
            if recreate:
                thumbnailer.delete_thumbnails()
            thumbnail = thumbnailer["exam-list"]
        except InvalidImageFormatError:
            return format_html(
                '<img title="{}" src="/static/not-found-image.jpg" />', img
            ), len(images)
        return format_html('<img src="/media/{}" />', thumbnail), len(images)

    def get_thumbnail_link(self):
        return format_html(
            "<a href='{}'>{}<a/>", self.get_absolute_url(), self.get_thumbnail()[0]
        )

    def get_block(self, series_number: None | int = None):
        examination = self.get_examination_full()
        thumb, image_number = self.get_thumbnail()

        series_html = ""
        if series_number is not None:
            series_html = format_html(
                "<span class='series-block-series-number'>Series {}</span>{}<br>",
                series_number,
            )
        description = ""
        if self.description:
            description = format_html("{}<br/>", self.description)

        return format_html(
            """{}{}
            <span>
            <span class='series-block-examination'>{}</span><br/>
            <span class='series-block-thumbnail'>{}</span><br/>
            <span class='series-block-image-number'>Images: <span class='series-block-image-number-count'>{}</span></span>
            </span>""",
            series_html,
            description,
            examination,
            thumb,
            image_number,
        )

    def order_by_upload_filename(self):
        images = self.images.filter(removed=False)

        filenames = []
        map = {}

        for i in images:
            filenames.append(i.upload_filename)
            map[i.upload_filename] = i

        filenames = sorted(filenames)

        n = 1
        for f in filenames:
            i = map[f]
            i.position = n
            i.save()
            n = n + 1

    def order_by_dicom(self, field="SliceLocation"):
        images = self.images.filter(removed=False)

        files = []

        for i in images:
            files.append((i, pydicom.dcmread(i.image.path)))

        # print("file count: {}".format(len(files)))

        # skip files with no SliceLocation (eg scout views)
        slices = []
        map = {}
        skipcount = 0
        for i, f in files:
            if hasattr(f, field):
                slices.append(f)
                # map[f.SliceLocation] = i
                map[f[field].value] = i
            else:
                skipcount = skipcount + 1

        print("skipped, no {}: {}".format(field, skipcount))

        if not slices:
            return

        # ensure they are in the correct order
        slices = sorted(slices, key=lambda s: s[field].value)

        # print(slices)
        n = 1
        for f in slices:
            i = map[f[field].value]
            i.position = n
            i.save()
            n = n + 1

    def get_total_image_size(self):
        images = self.images.filter(removed=False)

        size = 0

        for i in images:
            size += i.image.size

        return size

    def anonymise_images(self):
        # NOTE: this will not maintain the correct hashed filename
        # but that doesn't matter as we will never get the same anonymisation
        # even with the same dicom...
        anonymizer = dicognito.anonymizer.Anonymizer()

        for series_image in self.images.filter(removed=False):
            file_path = os.path.join(settings.MEDIA_ROOT, series_image.image.name)

            try:
                with pydicom.dcmread(file_path) as dataset:
                    anonymizer.anonymize(dataset)
                    dataset.save_as(file_path)
            except pydicom.errors.InvalidDicomError:
                pass


class ExamOrCollectionGenericBase(models.Model, AuthorMixin):
    """Holds functions that relate to both case and other exams

    e.g. user management

    """

    # Is this actually used? It is but should be replaced on the inherited class
    cid_users = GenericRelation("generic.CidUserExam")

    name = models.CharField(max_length=200, help_text="Name of the exam/collection")

    start_date = models.DateTimeField(
        help_text="Date (and time) the exam/collection starts", null=True, blank=True
    )
    end_date = models.DateTimeField(
        help_text="Date (and time) the exam/collection ends", null=True, blank=True
    )
    restrict_to_dates = models.BooleanField(
        default=False,
        help_text="If the exam/collection should only be taken between the start and end date times",
    )

    active = models.BooleanField(
        help_text="If an exam/collection should be available to take", default=False
    )
    publish_results = models.BooleanField(
        help_text="If an exam/collections results should be available", default=False
    )

    archive = models.BooleanField(
        help_text="Archived exams/collections will remain on the test system but will not be displayed by default",
        default=False,
    )

    open_access = models.BooleanField(
        help_text="If the exam/collection is freely accessible (to view and edit on the test system)",
        default=False,
    )

    candidates_only = models.BooleanField(
        help_text="If the exam/collection is only available to candidates who have been added",
        default=True,
    )

    authors_only = models.BooleanField(
        help_text="If true only exam/collection authors will be able to view.",
        default=False,
    )

    class Meta:
        abstract = True

    def save(self, *args, **kwargs):
        self.full_clean()
        return super().save(*args, **kwargs)

    def clean(self, *args, **kwargs):
        if self.restrict_to_dates:
            if self.start_date is None:
                raise ValidationError(
                    "If restrict to dates is set, a start date must be set"
                )

            if self.end_date is not None and self.end_date <= self.start_date:
                raise ValidationError({"end_date": "End date must be after start date"})

        return super().clean(*args, **kwargs)

    def get_app_name(self):
        raise NotImplementedError(
            "You must implement get_app_name in the derived class"
        )

    def get_base_template(self):
        return f"{self.get_app_name()}/exams.html"

    def get_link_headers(self):
        return "generic/exam_link_headers.html"

    def check_user_can_edit(self, user: User):
        if user.is_superuser:
            return True

        if user in self.get_author_objects():
            return True

        return False

    def check_logged_in_user(self, request: HttpRequest):
        """Helper to check if the logged in user can access the exam"""
        return self.check_cid_user(user=request.user, user_id=request.user.id)

    def check_user_can_review(
        self, cid, passcode, request: HttpRequest, active_only=False
    ):
        return self.check_user_can_take(cid, passcode, request.user, active_only)

    def check_user_can_take(self, cid, passcode, user=None, active_only=True):
        """
        Helper to check if a user is allowed to access an exam/collection

        Args:
            cid (_type_): _description_
            passcode (_type_): _description_
            request (_type_): _description_

        Raises:
            Http404: If user does not have access
        """
        # If we are limiting by dates check that the current date is within the range
        if self.restrict_to_dates:
            if self.start_date >= timezone.now() or (
                self.end_date is not None and self.end_date <= timezone.now()
            ):
                raise Http404("Exam not found")
        # If it is not active no one can take
        elif active_only and not self.active:
            raise Http404("Exam not found")

        # If candidates only check they have access
        if self.candidates_only:
            if not self.check_cid_user(cid, passcode, user):
                raise Http404("Error accessing exam")
            return

        # Otherwise check that they are a valid user.
        if user is None:
            raise Http404("Error accessing exam")

        if not user.is_active:
            raise Http404("Error accessing exam")

        return

    def check_cid_user(
        self,
        cid: int | None = None,
        passcode: str | None = None,
        user: User | None = None,
        # request: HttpRequest | None = None,
        user_id: int | None = None,
        allow_authors: bool = True,
    ):
        print(f"Check cid user: {cid=}, {passcode=}, exam_id={self.pk}")
        if user is not None and user.is_superuser:
            return True

        if user_id is not None:
            if allow_authors:
                if self.author.filter(pk=user_id).exists():
                    return True

        if not self.valid_cid_users.exists() and not self.valid_user_users.exists():
            return False

        if cid is None and user_id is None:
            if user is not None:
                user_id = user.id
            else:
                return False

        # Start by checking if the logged in user can access
        if user_id is not None:
            if self.valid_user_users.filter(pk=user_id).exists():
                return True

        # Then test CID data
        if self.valid_cid_users.exists():
            cid_user = self.valid_cid_users.filter(cid=cid).first()

            if cid_user and cid_user.passcode == passcode:
                return True

            return False

        return False

    def get_or_create_cid_user_exam(
        self,
        cid: int | None = None,
        cid_user: "CidUser | None" = None,
        user_user: User | None = None,
        start_time=None,
    ):
        content_type = ContentType.objects.get_for_model(self)

        if cid is not None:
            cid_user = CidUser.objects.filter(cid=cid).first()

        if cid_user is not None:
            c = CidUserExam.objects.filter(
                content_type=content_type, object_id=self.pk, cid_user=cid_user
            ).first()
            if c:
                return c

        elif user_user is not None:
            c = CidUserExam.objects.filter(
                content_type=content_type, object_id=self.pk, user_user=user_user
            ).first()
            if c:
                return c
        else:
            raise ValueError("Invalid cid / cid_user / user_user")

        if start_time is None:
            start_time = timezone.now()

        if cid_user is not None:
            new = CidUserExam(
                content_type=content_type,
                object_id=self.pk,
                cid_user=cid_user,
                start_time=start_time,
            )

        elif user_user is not None:
            new = CidUserExam(
                content_type=content_type,
                object_id=self.pk,
                user_user=user_user,
                start_time=start_time,
            )
        else:
            raise ValueError("Invalid cid / cid_user / user_user")

        new.save()
        return new

    def get_question_cid_user_answer(self, question_index, cid):
        raise NotImplementedError

    def get_question_user_user_answer(self, question_index, user):
        raise NotImplementedError

    def get_cid_user_exams(
        self, cid_user: Optional["CidUser"] = None, user_user: User | None = None
    ) -> "CidUserExam":
        content_type = ContentType.objects.get_for_model(self)
        if cid_user is None and user_user is None:
            return CidUserExam.objects.filter(
                content_type=content_type,
                object_id=self.pk,
            )
        else:
            if cid_user is not None:
                return CidUserExam.objects.filter(
                    content_type=content_type, object_id=self.pk, cid_user=cid_user
                )
            else:
                return CidUserExam.objects.filter(
                    content_type=content_type, object_id=self.pk, user_user=user_user
                )

    def clone_model(self):
        M2M_fields = (
            "exam_questions",
            "author",
            "valid_cid_users",
            "valid_user_users",
            "cid_user_groups",
            "user_user_groups",
        )
        FK_fields = ("examcollection",)

        model_dict = model_to_dict(self)

        m2m_to_update = {}
        for field in M2M_fields:
            m2m_to_update[field] = model_dict[field]
            del model_dict[field]
        fk_to_update = {}
        for field in FK_fields:
            fk_to_update[field] = model_dict[field]
            del model_dict[field]

        cloned_model = self.__class__(**model_dict)
        cloned_model.pk = None

        for field in fk_to_update:
            setattr(cloned_model, f"{field}_id", fk_to_update[field])

        cloned_model.save()

        for field in m2m_to_update:
            rel = getattr(cloned_model, field)
            rel.clear()
            for item in m2m_to_update[field]:
                rel.add(item)

        return cloned_model


class ExamBase(ExamOrCollectionGenericBase):
    exam_mode = models.BooleanField(
        help_text="If an exam should be taken in exam mode (users results will be submited to the server for marking)",
        default=False,
    )

    # randomise_question_order = models.BooleanField(
    #    help_text="If an exam should randomise the order of questions in RTS.",
    # )

    include_history = models.BooleanField(
        help_text="If an exam should include history when taking",
        default=False,
    )

    recreate_json = models.BooleanField(
        help_text="If the json cache needs updating", default=False
    )

    json_creation_time = models.DateTimeField(blank=True, default=None, null=True)
    exam_json_id = models.IntegerField(
        default=1, help_text="auto incrementing field when json recreated"
    )

    stats_mean = models.FloatField(default=0)
    stats_mode = models.CharField(default=0, max_length=25)
    stats_median = models.FloatField(default=0)

    stats_candidates = models.FloatField(default=0)

    stats_min = models.FloatField(default=0)
    stats_max = models.FloatField(default=0)

    stats_max_possible = models.FloatField(default=0)

    stats_graph = models.TextField(default=0)

    user_scores = models.JSONField(default=dict, blank=True)

    exam_results_emailed = models.DateTimeField(default=None, null=True, blank=True)

    class Meta:
        abstract = True

    def __str__(self):
        if self.start_date and self.start_date is not None:
            print(self.start_date)
            print(to_current_timezone(self.start_date))
            return f"{self.name} ({to_current_timezone(self.start_date):%d %B %Y})"
        else:
            return self.name

    def save(self, *args, recreate_json=True, **kwargs):
        self.recreate_json = recreate_json

        super().save(*args, **kwargs)

    # def clean(self, *args, **kwargs):
    #    if self.user_scores is None:
    #        self.user_scores = {}
    #    return super().clean(*args, **kwargs)

    def get_questions(self):
        """Returns a list of questions in the exam in the correct order

        This should be used in preference to exam_questions.all() as it
        will order the questions correctly"""
        return self.exam_questions.all().order_by("examquestiondetail__sort_order")

    def order_questions(self):
        """Modifies the examquestiondetail sort_order to sequentially order the cases"""
        for n, c in enumerate(self.examquestiondetail_set.all().order_by("sort_order")):
            c.sort_order = n
            c.save()

    def get_exam_stats(self, name=True):
        if self.stats_candidates < int(4):
            return f"- Candidates: {int(self.stats_candidates)} (too few to generate stats)"

        text = f"""- Candidates: {int(self.stats_candidates)}
- Mean: {self.stats_mean:.2f} Median: {self.stats_median} Mode: {self.stats_mode} [Min: {self.stats_min} / Max: {self.stats_max}]
"""
        if name:
            text = f"""{self.name}
{"-"*len(self.name)}
{text}
"""
        return text

    def get_absolute_url(self):
        return reverse("{}:exam_overview".format(self.app_name), kwargs={"pk": self.pk})

    def get_cid_edit_url(self):
        return reverse(
            "{}:exam_cids_edit".format(self.app_name), kwargs={"exam_id": self.pk}
        )

    def get_user_edit_url(self):
        return reverse(
            "{}:exam_users_edit".format(self.app_name), kwargs={"exam_id": self.pk}
        )

    def get_take_url(self):
        return f"{settings.REMOTE_URL}/rts"

    def get_exam_name(self):
        return str(self)

    def get_json_url(self, cid=None, passcode=None):
        if cid is None:
            return reverse("{}:exam_json".format(self.app_name), args=(self.pk,))
        else:
            return reverse(
                "{}:exam_json_cid".format(self.app_name), args=(self.pk, cid, passcode)
            )

    def get_time_limit(self):
        """Returns a human readable time limit"""
        if self.time_limit is None:
            return "No time limit set"
        h, m, s = str(datetime.timedelta(seconds=self.time_limit)).split(":")

        time_limit = ""
        if s != "0" and s != "00":
            time_limit = f" {s} second(s)"
        if m != "0":
            time_limit = f"{m} minute(s) {time_limit}"
        if h != "0":
            time_limit = f"{h} hour(s) {time_limit}"

        return time_limit.strip()

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

    def get_question_by_index(self, index: int):
        # There must be a better way to do this
        return list(self.get_questions())[index]

    def get_cid_user_score(self, cid_user):
        c = "c/" + str(cid_user)
        if c in self.user_scores:
            return self.user_scores[c]
        else:
            return False

    def generate_user_report(self, user):
        exam_text = [f"Candidate {user.first_name} [{user.email}]"]

        exam_name = self.name

        exam_text.append(f"{'='*len(exam_name)}\n{exam_name}\n{'='*len(exam_name)}")

        try:
            user_score = self.user_scores["u/" + str(user.pk)]["score"]

            if self.app_name == "rapids":
                callstate = self.user_scores["u/" + str(user.pk)]["callstates"]
        except KeyError:
            user_score = "Score not generated"

        try:
            percentage = f" ({user_score / int(self.stats_max_possible) * 100:.2f}%)"
        except TypeError:
            percentage = ""

        exam_text.append(
            f"""Results\n{'-'*len('Results')}
# Score: {user_score} / {int(self.stats_max_possible)}{percentage}
"""
        )
        stats = self.get_exam_stats(name=False)
        exam_text.append(f"Stats\n{'-'*len('Stats')}\n{stats}")

        rapids_extra = ""
        if self.app_name == "rapids":
            rapids_extra = f"Answers breakdown: {callstate}"
            exam_text.append(rapids_extra)

        msg = "\n\n".join(exam_text)

        html_msg = f"""
        <p>Candidate: {user.first_name} [{user.email}]</p>
        <h2>{exam_name}</h2>

        <h3>Results</h3>
        Score: {user_score} / {int(self.stats_max_possible)} {percentage}

        <h3>Stats</h3>
        {stats}<br/>
        <a href="{settings.REMOTE_URL}{reverse("{}:exam_stats".format(self.app_name), args=(self.pk,))}">View all stats (including graph) here</a>

"""
        if self.app_name == "rapids":
            html_msg = f"{html_msg}<br/>{rapids_extra}"

        return msg, html_msg

    def email_user_results(self, user, resend=False, additional_emails=None):
        # if self.results_email_sent and not resend:
        #    return False, "Already sent."

        # Get a list of taken exams
        msg, html_msg = self.generate_user_report(user)

        if not user.email:
            return [False, "User has no email"]

        emails = [user.email]

        extra = ""

        if user.userprofile.supervisor is not None:
            supervisor_email = user.userprofile.supervisor.email
            emails.append(supervisor_email)
        else:
            extra = "No supervisor"

        if additional_emails is not None:
            emails.extend(additional_emails)

        try:
            send_mail(
                f"{self.name} results",
                msg,
                "no-reply@penracourses.org.uk",
                emails,
                fail_silently=False,
                html_message=html_msg,
            )
        except SMTPException as e:
            return [False, e]

        # self.results_email_sent = True
        # self.save()
        return [True, extra]


class ExamUserStatus(models.Model):
    datetime = models.DateTimeField(auto_now_add=True)
    # cid_user: "CidUser" = models.ForeignKey(
    #    "CidUser", blank=True, null=True, on_delete=models.SET_NULL
    # )
    # user_user = models.ForeignKey(
    #    settings.AUTH_USER_MODEL, blank=True, null=True, on_delete=models.SET_NULL
    # )
    status = models.CharField(max_length=255)
    extra = models.CharField(max_length=255)

    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    exam = GenericForeignKey("content_type", "object_id")

    cid_user_exam = models.ForeignKey(
        "CidUserExam", blank=True, null=True, on_delete=models.SET_NULL
    )

    def __str__(self):
        self.cid_user_exam: "CidUserExam"
        if self.cid_user_exam.cid_user:
            user = self.cid_user_exam.cid_user.cid
            email = self.cid_user_exam.cid_user.email
            return f"{self.datetime:%Y-%m-%d %H:%M:%S}: [CID] {user} ({email}) - {self.status} ({self.extra})"
        else:
            user = self.cid_user_exam.user_user.username
            return f"{self.datetime:%Y-%m-%d %H:%M:%S}: [USER] {user} - {self.status} ({self.extra})"


class UserAnswerBase(models.Model):
    cid = models.BigIntegerField(
        blank=True,
        null=True,
        help_text="Candidate ID (limitied by BigIntegerField size)",
    )

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

    class Meta:
        abstract = True
        ordering = ["cid"]

    def __str__(self) -> str:
        return "{}/{}/{}".format(self.get_candidate_name(), self.exam, self.question.pk)

    def get_candidate_name(self) -> str:
        if self.cid is not None:
            return str(self.cid)
        else:
            return self.user.username

    def get_candidate_masked(self) -> str:
        if self.cid is not None:
            return str(self.cid)
        else:
            return str(self.user.id)

    def get_absolute_url(self):
        return reverse(f"{self.app_name}:user_answer_view", kwargs={"pk": self.pk})

    def get_answer(self):
        """might need overriding"""
        return self.answer


class NoteType(models.Model):
    note_type = models.CharField(max_length=200)

    def __str__(self):
        return self.note_type


class QuestionNote(models.Model):
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    question = GenericForeignKey("content_type", "object_id")

    author = models.CharField(max_length=200, blank=True)

    user_author = models.ForeignKey(
        settings.AUTH_USER_MODEL, on_delete=models.CASCADE, blank=True, null=True
    )

    note = models.TextField(blank=True)
    created_on = models.DateTimeField(auto_now_add=True)

    complete = models.BooleanField(default=False)

    note_type = models.ForeignKey(
        NoteType, on_delete=models.CASCADE, null=True, blank=True
    )

    # def get_absolute_url(self):
    #    self.pk = self.rapid_id
    #    return reverse('rapids:question_detail', kwargs={'pk': self.pk})

    def __str__(self):
        return "{}: {} [{}] {} / {}".format(
            self.content_type,
            self.get_author_str(),
            self.created_on,
            self.note_type,
            self.note,
        )

    def get_absolute_url(self):
        # TODO: return to question if logged in
        return "/"

    def get_object_url(self):
        return self.question.get_absolute_url()

    def get_author_str(self):
        if self.user_author is not None:
            return self.user_author.username
        else:
            return self.author

    def get_short_str(self):
        return f"{self.note_type} - {self.note}"


EXAM_TYPES = (
    ("physics", "physics_exams"),
    ("rapids", "rapid_exams"),
    ("sbas", "sba_exams"),
    ("anatomy", "anatomy_exams"),
    ("longs", "longs_exams"),
    ("casecollection", "casecollection_exams"),
)


class CidUser(models.Model):
    cid = models.IntegerField(blank=True, null=True, unique=True)
    passcode = models.CharField(blank=True, max_length=50)
    active = models.BooleanField(default=True)
    internal_candidate = models.BooleanField(default=False)
    name = models.CharField(blank=True, max_length=255)
    email = models.EmailField(blank=True)
    supervisor = models.ForeignKey(
        "Supervisor",
        on_delete=models.SET_NULL,
        blank=True,
        null=True,
        related_name="cid_user",
    )

    login_email_sent = models.BooleanField(default=False)
    results_email_sent = models.BooleanField(default=False)

    group = models.ForeignKey(
        "CidUserGroup", on_delete=models.SET_NULL, null=True, blank=True
    )

    class Meta:
        indexes = [models.Index(fields=["cid"])]

    def __str__(self) -> str:
        return str(self.cid)

    def get_absolute_url(self):
        return reverse("generic:manage_cids")

    def check_passcode(self, passcode) -> bool:
        return self.passcode == passcode

    def get_cid_exams(self, include_case_collections=True):
        available_exams = []

        for n, t in EXAM_TYPES:
            if not include_case_collections and n == "casecollection":
                continue
            exam_rel = getattr(self, t)
            if exam_rel.exists():
                exams = exam_rel.filter(exam_mode=True, archive=False).order_by("name")
                available_exams.append((n, exams))

        return available_exams

    def generate_exam_report(self):
        exam_list = self.get_cid_exams()

        name = ""
        if self.name:
            name = f"{self.name} "

        exam_text = [f"Candidate {self.cid} {name}[{self.email}]"]

        for exam_type, exams in exam_list:
            exam_text.append(f"{'='*len(exam_type)}\n{exam_type}\n{'='*len(exam_type)}")

            for exam in exams:
                try:
                    user_score = exam.user_scores["c/" + str(self.cid)]
                except KeyError:
                    user_score = "Score not generated"
                t = exam.get_exam_stats()

                try:
                    percentage = (
                        f" ({user_score / int(exam.stats_max_possible) * 100:.2f}%)"
                    )
                except TypeError:
                    percentage = ""

                exam_text.append(
                    f"""{t}
# Score: {user_score} / {int(exam.stats_max_possible)}{percentage}
"""
                )

        msg = "\n\n".join(exam_text)

        return msg

        html_msg = f""""""

    def email_results(self, resend=False, additional_emails=[]):
        """Emails a CID candidate results (internal candidates)

        ***DEPRECATED***
        """
        if not self.internal_candidate:
            return False, "Not internal candidate."

        if self.results_email_sent and not resend:
            return False, "Already sent."

        # Get a list of taken exams
        msg = self.generate_exam_report()

        emails = [self.email, self.supervisor.email]

        if additional_emails:
            emails.extend(additional_emails)

        try:
            send_mail(
                f"{self.group} results",
                msg,
                "test@xkjq.uk",
                emails,
                fail_silently=False,
                # html_message=html_msg,
            )
        except SMTPException as e:
            return False, e

        self.results_email_sent = True
        self.save()
        return True, ""

    def email_details(self, resend: bool = False) -> Tuple[bool, str]:
        """Email candidate details to the CID user

        Args:
            resend (bool, optional): Force sending details (even if sent previously). Defaults to False.

        Returns:
            Tuple[bool, str]: Tuple containing the email status and any error message
        """
        if self.login_email_sent and not resend:
            return False, "Already sent."

        login_url = reverse("cid_selector")

        msg = f"""
        See below for your details for: {self.group}

        ---------
        CID: {self.cid}
        Passcode: {self.passcode}
        ---------

        You will need these to access to the test system.

        Direct link to login:
        {settings.REMOTE_URL}{login_url}?cid={self.cid}&passcode={self.passcode}

        The above details are unique to you. Please do not share as otherwise others will be able to access and submit your results.



        Please note this inbox is not monitored. Direct all enquiries to plh-tr.radiology-academy@nhs.net
        """

        try:
            # send_mail(
            #    "Candidate Details",
            #    msg,
            #    "test@xkjq.uk",
            #    [self.email],
            #    fail_silently=False,
            # )
            email = EmailMessage(
                "Candidate Details",
                msg,
                "no-reply@penracourses.org.uk",
                [self.email],
                # ["ross.kruger@nhs.net"],
            )
            email.send(fail_silently=False)
        except SMTPException as e:
            return False, e

        self.login_email_sent = True
        self.save()
        return True, ""

    def get_email_details_url(self):
        return reverse("generic:candidate_email_details", kwargs={"cid": self.cid})

    def get_email_results_url(self):
        return reverse("generic:candidate_email_results", kwargs={"cid": self.cid})

    def get_email_results_resend_url(self):
        return reverse(
            "generic:candidate_email_results_resend", kwargs={"cid": self.cid}
        )


def get_next_cid():
    """Returns the next available CID"""
    return CidUser.objects.order_by("-cid").first().cid + 1


class CidUserExam(models.Model):
    """This holds the current status of the exam for a candidate

    Contrast with ExamUserStatus which holds the status changes for a candidate
    (and should be merged into here)
    """

    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    exam = GenericForeignKey("content_type", "object_id")

    start_time = models.DateTimeField(blank=True, null=True)
    end_time = models.DateTimeField(blank=True, null=True)

    completed = models.BooleanField(
        default=False,
        help_text="If a exam has been completed. This will usually lock the exam to further reponses.",
    )

    cid_user = models.ForeignKey(
        CidUser,
        on_delete=models.CASCADE,
        blank=True,
        null=True,
        related_name="cid_userexam",
    )
    user_user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        blank=True,
        null=True,
        related_name="user_userexam",
    )

    manual_submission = models.BooleanField(default=False)

    # TODO switch to json field?
    results_emailed_status = models.CharField(max_length=255, blank=True)

    def __str__(self) -> str:
        if self.cid_user is None:
            try:
                user = self.user_user.username
            except AttributeError:
                user = "None"
        else:
            user = self.cid_user.cid

        if self.start_time is None:
            start_time = ""
        else:
            start_time = f"{ self.start_time:%Y-%m-%d %H:%M }"

        if self.end_time is None:
            end_time = ""
        else:
            end_time = f"{ self.end_time:%Y-%m-%d %H:%M }"

        return f"{self.exam} / {user}: {start_time} {end_time}"


CID_GROUP_EXAMS = (
    ("SBAs", "sba_cid_user_groups"),
    ("Physics", "physics_cid_user_groups"),
    ("Anatomy", "anatomy_cid_user_groups"),
    ("Rapids", "rapid_cid_user_groups"),
    ("Longs", "longs_cid_user_groups"),
)


class BaseUserGroup(models.Model):
    name = models.CharField(blank=True, max_length=50, help_text="Name of the Group")
    archive = models.BooleanField(
        default=False,
        help_text="Archived groups remain on the test system but are not displayed by default",
    )

    open_access = models.BooleanField(
        default=False, help_text="If the group is freely accessible to use"
    )

    class Meta:
        abstract = True


class CidUserGroup(BaseUserGroup):

    def __str__(self) -> str:
        return str(self.name)

    def GetGroupUsers(self):
        cid_users = self.ciduser_set.all()

        s = ", ".join([f"{user.id} - {user.name}" for user in cid_users])
        return s

    def GetGroupExams(self):
        exams = defaultdict(list)
        for t, rel in CID_GROUP_EXAMS:
            exam_rel = getattr(self, rel)
            if exam_rel.exists():
                exams[t].extend(exam_rel.all())

        return dict(exams)

    def get_absolute_url(self):
        return reverse("generic:cid_group_update", kwargs={"pk": self.pk})


USER_GROUP_EXAMS = (
    ("SBAs", "sba_user_user_groups"),
    ("Physics", "physics_user_user_groups"),
    ("Anatomy", "anatomy_user_user_groups"),
    ("Rapids", "rapid_user_user_groups"),
    ("Longs", "longs_user_user_groups"),
)


class UserUserGroup(BaseUserGroup):
    users = models.ManyToManyField(
        settings.AUTH_USER_MODEL,
        blank=True,
        related_name="user_groups",
    )

    def __str__(self) -> str:
        return str(self.name)

    def GetGroupUsers(self):
        users = self.users.all()

        s = ", ".join([f"{user.id} - {user.username} ({user.email})" for user in users])
        return s

    def GetGroupExams(self):
        exams = defaultdict(list)
        for t, rel in USER_GROUP_EXAMS:
            exam_rel = getattr(self, rel)
            if exam_rel.exists():
                exams[t].extend(exam_rel.all())

        return dict(exams)

    def get_absolute_url(self):
        return reverse("generic:user_group_update", kwargs={"pk": self.pk})


class UserGrades(models.Model):
    name = models.CharField(max_length=100)

    def __str__(self):
        return self.name


USER_EXAM_TYPES = (
    ("Physics", "user_physics_exams"),
    ("Rapids", "user_rapid_exams"),
    ("SBAs", "user_sba_exams"),
    ("Anatomy", "user_anatomy_exams"),
    ("Longs", "user_longs_exams"),
    # ("CaseCollection", "user_casecollection_exams"),
)


class UserProfile(models.Model):
    user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    supervisor = models.ForeignKey(
        "Supervisor",
        on_delete=models.SET_NULL,
        blank=True,
        null=True,
        related_name="trainee",
    )
    registration_number = models.CharField(max_length=25, blank=True)
    grade = models.ForeignKey(
        UserGrades,
        null=True,
        blank=True,
        help_text="User grade",
        on_delete=models.CASCADE,
    )
    peninsula_trainee = models.BooleanField(default=False)
    site = models.ForeignKey(
        "Site",
        on_delete=models.SET_NULL,
        blank=True,
        null=True,
        help_text="Primary site / rotation location",
    )

    def getusername(self):
        return self.user.username

    def __str__(self):
        return f"Userprofile {self.user}"

    username = property(getusername)

    def get_exams(self):
        available_exams = defaultdict(list)

        for n, t in USER_EXAM_TYPES:
            exam_rel = getattr(self.user, t)
            if exam_rel.exists():
                exams = exam_rel.filter(exam_mode=True, archive=False).order_by("name")
                available_exams[n].extend(exams)

        return dict(available_exams)


class Supervisor(models.Model):
    """Model to hold individual supervisor details (email and name)

    This can be linked with a user account.
    """

    email = models.EmailField(
        unique=True, help_text="The (nhs.net) email address of the supervisor"
    )
    name = models.CharField(max_length=255, help_text="Name of the supervisor")
    user = models.OneToOneField(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        help_text="If the supervisor has an account on the test system that can be associated here",
    )
    site = models.ForeignKey(
        "Site",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        help_text="Hospital site at which the supervisor is based",
    )
    active = models.BooleanField(default=True)

    def __str__(self) -> str:
        return f"{self.name} ({self.email})"

    def get_absolute_url(self):
        return reverse("generic:supervisor_detail", kwargs={"pk": self.pk})

    def clean(self):
        self.email = self.email.strip()
        self.name = self.name.strip()


@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
    if created:
        UserProfile.objects.create(user=instance)


@receiver(post_save, sender=User)
def save_user_profile(sender, instance, **kwargs):
    instance.userprofile.save()


class ExamCollection(models.Model, AuthorMixin):
    name = models.CharField(max_length=255)

    date = models.DateField(blank=True, null=True)

    archive = models.BooleanField(default=False)

    author = models.ManyToManyField(
        settings.AUTH_USER_MODEL,
        blank=True,
        help_text="Author/Manager(s) of the exam collection",
    )

    def __str__(self):
        return f"{self.name} [{self.date}]"

    def get_absolute_url(self):
        return reverse("generic:examcollection_detail", kwargs={"pk": self.pk})