from RIGS.models import Profile, filter_by_pk
from reversion import revisions as reversion
from django.core.exceptions import ValidationError
from django.db import models
from django.db.models import Q
from django.urls import reverse
from django.utils.safestring import mark_safe
from versioning.versioning import RevisionMixin
from queryable_properties.properties import queryable_property
from queryable_properties.managers import QueryablePropertiesManager


class TraineeManager(models.Manager):
    def get_queryset(self):
        return super().get_queryset().filter(is_active=True, is_approved=True)

    def search(self, query=None):
        qs = self.get_queryset()
        if query is not None:
            or_lookup = Q(first_name__icontains=query) | Q(last_name__icontains=query) | Q(initials__icontains=query)
            or_lookup = filter_by_pk(or_lookup, query)
            qs = qs.filter(or_lookup).distinct()  # distinct() is often necessary with Q lookups
        return qs


@reversion.register(for_concrete_model=False, fields=["is_supervisor"])
class Trainee(Profile, RevisionMixin):
    class Meta:
        proxy = True

    objects = TraineeManager()

    # FIXME use queryset
    def started_levels(self):
        return [
            level
            for level in TrainingLevel.objects.all()
            if level.percentage_complete(self) > 0
            and level.pk not in self.level_qualifications.values_list("level", flat=True)
        ]

    @property
    def confirmed_levels(self):
        return self.level_qualifications.exclude(confirmed_on=None).select_related("level")

    @property
    def is_technician(self):
        return (
            self.confirmed_levels.filter(level__level=TrainingLevel.TECHNICIAN)
            .exclude(level__department=TrainingLevel.HAULAGE)
            .exclude(level__department__isnull=True)
            .exists()
        )

    @property
    def is_driver(self):
        return self.confirmed_levels.filter(level__department=TrainingLevel.HAULAGE).exists()

    def get_records_of_depth(self, depth):
        return self.qualifications_obtained.filter(depth=depth).select_related("item", "trainee", "supervisor")

    def is_user_qualified_in(self, item, required_depth):
        return (
            self.qualifications_obtained.values("item", "depth")
            .filter(item=item)
            .filter(depth__gte=required_depth)
            .exists()
        )

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

    @property
    def display_id(self):
        return str(self)


class TrainingCategory(models.Model):
    reference_number = models.IntegerField(unique=True)
    name = models.CharField(max_length=50)
    training_level = models.ForeignKey(
        "TrainingLevel",
        on_delete=models.CASCADE,
        null=True,
        help_text="If this is set, any user with the selected level may pass out users within this category, regardless of other status",
    )

    def __str__(self):
        return f"{self.reference_number}. {self.name}"

    class Meta:
        verbose_name_plural = "Training Categories"
        ordering = ["reference_number"]


class TrainingItemManager(QueryablePropertiesManager):
    def search(self, query=None):
        qs = self.get_queryset()
        if query is not None:
            or_lookup = Q(name__icontains=query) | Q(description__icontains=query) | Q(display_id=query)
            qs = qs.filter(or_lookup).distinct()  # distinct() is often necessary with Q lookups
        return qs


@reversion.register
class TrainingItem(models.Model):
    reference_number = models.IntegerField()
    category = models.ForeignKey("TrainingCategory", related_name="items", on_delete=models.CASCADE)
    name = models.CharField(max_length=50)
    description = models.TextField(blank=True)
    active = models.BooleanField(default=True)
    prerequisites = models.ManyToManyField("self", symmetrical=False, blank=True)

    objects = TrainingItemManager()

    @queryable_property
    def display_id(self):
        return f"{self.category.reference_number}.{self.reference_number}"

    @property
    def display_name(self):
        return f"{self.display_id} | {self.name}"

    @display_id.filter
    @classmethod
    def display_id(cls, lookup, value):
        if "." in str(value):
            try:
                category_number, number = value.split(".", 2)
                if category_number and number:
                    return Q(category__reference_number=int(category_number), reference_number=int(number))
            except ValueError:
                pass
        return models.Q()

    def __str__(self):
        name = f"{self.display_id} {self.name}"
        if not self.active:
            name += " (inactive)"
        return name

    def get_absolute_url(self):
        return reverse("item_list")

    def has_prereqs(self):
        return self.prerequisites.all().exists()

    def user_has_requirements(self, user):
        # Always true if there are no prerequisites, otherwise get a set of prerequsite IDs and check if they are a subset of the set of qualification IDs
        return not self.has_prereqs() or set(self.prerequisites.values_list("pk", flat=True)).issubset(
            set(user.qualifications_obtained.values_list("item", flat=True))
        )

    @staticmethod
    def user_has_qualification(item, user, depth):
        return user.qualifications_obtained.only("item", "depth").filter(item=item, depth__gte=depth).exists()

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=["reference_number", "active", "category"], name="unique_reference_number_active_category"
            )
        ]
        ordering = ["category__reference_number", "reference_number"]


class TrainingItemQualificationManager(QueryablePropertiesManager):
    def search(self, query=None):
        qs = self.get_queryset().select_related("item", "supervisor", "item__category")
        if query is not None:
            or_lookup = (
                Q(item__name__icontains=query)
                | Q(supervisor__first_name__icontains=query)
                | Q(supervisor__last_name__icontains=query)
                | Q(item__category__name__icontains=query)
                | Q(item__display_id=query)
            )

            try:
                or_lookup = Q(item__category__reference_number=int(query)) | or_lookup
            except:  # noqa
                pass

            qs = qs.filter(or_lookup).distinct()
        return qs


@reversion.register
class TrainingItemQualification(models.Model, RevisionMixin):
    STARTED = 0
    COMPLETE = 1
    PASSED_OUT = 2
    CHOICES = (
        (STARTED, "Training Started"),
        (COMPLETE, "Training Complete"),
        (PASSED_OUT, "Passed Out"),
    )
    item = models.ForeignKey("TrainingItem", on_delete=models.CASCADE)
    depth = models.IntegerField(choices=CHOICES)
    trainee = models.ForeignKey("Trainee", related_name="qualifications_obtained", on_delete=models.CASCADE)
    date = models.DateField()
    # TODO Remember that some training is external. Support for making an organisation the trainer?
    supervisor = models.ForeignKey("Trainee", related_name="qualifications_granted", on_delete=models.CASCADE)
    notes = models.TextField(blank=True)
    # TODO Maximum depth - some things stop at Complete and you can't be passed out in them

    objects = TrainingItemQualificationManager()

    def clean(self):
        errdict = {}
        # Validate supervisor can train in this item
        if hasattr(self, "supervisor"):  # This will be false if form validation fails
            if self.item.category.training_level:
                if not self.supervisor.level_qualifications.filter(level=self.item.category.training_level):
                    errdict["supervisor"] = (
                        "Selected supervising person is missing requisite training level to train in this department"
                    )
            elif not self.supervisor.is_supervisor:
                errdict["supervisor"] = "Selected supervisor must actually *be* a supervisor..."
        # Item requirements only apply to being passed out
        if self.depth == TrainingItemQualification.PASSED_OUT and not self.item.user_has_requirements(self.trainee):
            errdict["item"] = "Missing prerequisites"
        if errdict != {}:  # If there was an error when validation
            raise ValidationError(errdict)

    def __str__(self):
        return f"{self.get_depth_display()} in {self.item} on {self.date.strftime('%b %d %Y')}"

    @property
    def activity_feed_string(self):
        return f"{self.trainee} {self.get_depth_display().lower()} in {self.item}"

    @classmethod
    def get_colour_from_depth(cls, depth):
        if depth == 0:
            return "warning"
        if depth == 1:
            return "success"

        return "info"

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

    class Meta:
        constraints = [models.UniqueConstraint(fields=["trainee", "item", "depth"], name="unique_trainee_item_depth")]
        order_with_respect_to = "item"


# Levels
@reversion.register(follow=["requirements"])
class TrainingLevel(models.Model, RevisionMixin):
    description = models.TextField(blank=True)
    TA = 0
    TECHNICIAN = 1
    SUPERVISOR = 2
    CHOICES = (
        (TA, "Technical Assistant"),
        (TECHNICIAN, "Technician"),
        (SUPERVISOR, "Supervisor"),
    )
    SOUND = 0
    LIGHTING = 1
    POWER = 2
    RIGGING = 3
    HAULAGE = 4
    DEPARTMENTS = (
        (SOUND, "Sound"),
        (LIGHTING, "Lighting"),
        (POWER, "Power"),
        (RIGGING, "Rigging"),
        (HAULAGE, "Haulage"),
    )
    department = models.IntegerField(
        choices=DEPARTMENTS, null=True, blank=True
    )  # N.B. Technical Assistant does not have a department
    level = models.IntegerField(choices=CHOICES)
    prerequisite_levels = models.ManyToManyField("self", related_name="prerequisites", symmetrical=False, blank=True)
    icon = models.CharField(null=True, blank=True, max_length=20)

    class Meta:
        ordering = ["department", "level"]

    @property
    def department_colour(self):
        if self.department == self.SOUND:
            return "info"
        if self.department == self.LIGHTING:
            return "dark"
        if self.department == self.POWER:
            return "danger"
        if self.department == self.RIGGING:
            return "warning"
        if self.department == self.HAULAGE:
            return "light"

        return "primary"

    def get_requirements_of_depth(self, depth):
        return self.requirements.filter(depth=depth)

    @property
    def is_common_competencies(self):
        return self.department is None and self.level > 0

    @property
    def started_requirements(self):
        return self.get_requirements_of_depth(TrainingItemQualification.STARTED)

    @property
    def complete_requirements(self):
        return self.get_requirements_of_depth(TrainingItemQualification.COMPLETE)

    @property
    def passed_out_requirements(self):
        return self.get_requirements_of_depth(TrainingItemQualification.PASSED_OUT)

    def percentage_complete(self, user):
        needed_qualifications = self.requirements.all().select_related("item")
        relavant_qualifications = 0.0
        # TODO Efficiency...
        for req in needed_qualifications:
            if user.is_user_qualified_in(req.item, req.depth):
                relavant_qualifications += 1.0

        if len(needed_qualifications) > 0:
            return int(relavant_qualifications / float(len(needed_qualifications)) * 100)

        return 0

    def user_has_requirements(self, user):
        has_required_items = all(
            TrainingItem.user_has_qualification(req.item, user, req.depth) for req in self.requirements.all()
        )
        # Always true if there are no prerequisites, otherwise get a set of prerequsite IDs and check if they are a subset of the set of qualification IDs
        has_required_levels = not self.prerequisite_levels.all().exists() or set(
            self.prerequisite_levels.values_list("pk", flat=True)
        ).issubset(set(user.level_qualifications.values_list("level", flat=True)))
        return has_required_items and has_required_levels

    def __str__(self):
        if self.department is None:
            if self.level == self.TA:
                return self.get_level_display()
            else:
                return f"{self.get_level_display()} Common Competencies"
        else:
            return f"{self.get_department_display()} {self.get_level_display()}"

    @property
    def activity_feed_string(self):
        return str(self)

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

    @property
    def get_icon(self):
        if self.icon is not None:
            icon = f"<span class='fas fa-{self.icon}'></span>"
        else:
            icon = "".join([w[0] for w in str(self).split()])
        return mark_safe(
            f"<span class='badge badge-{self.department_colour} badge-pill' data-toggle='tooltip' title='{str(self)}'>{icon}</span>"
        )


@reversion.register
class TrainingLevelRequirement(models.Model, RevisionMixin):
    level = models.ForeignKey("TrainingLevel", related_name="requirements", on_delete=models.CASCADE)
    item = models.ForeignKey("TrainingItem", on_delete=models.CASCADE)
    depth = models.IntegerField(choices=TrainingItemQualification.CHOICES)

    reversion_hide = True

    def __str__(self):
        depth = TrainingItemQualification.CHOICES[self.depth][1]
        return f"{depth} in {self.item}"

    class Meta:
        constraints = [models.UniqueConstraint(fields=["level", "item"], name="unique_level_item")]


@reversion.register
class TrainingLevelQualification(models.Model, RevisionMixin):
    trainee = models.ForeignKey("Trainee", related_name="level_qualifications", on_delete=models.CASCADE)
    level = models.ForeignKey("TrainingLevel", on_delete=models.CASCADE)
    confirmed_on = models.DateTimeField(null=True)
    confirmed_by = models.ForeignKey("Trainee", related_name="confirmer", on_delete=models.CASCADE, null=True)

    @property
    def get_icon(self):
        return self.level.get_icon

    def clean(self):
        if self.level.level >= TrainingLevel.SUPERVISOR and self.level.department != TrainingLevel.HAULAGE:
            self.trainee.is_supervisor = True
            self.trainee.save()

    def __str__(self):
        if self.level.is_common_competencies:
            return f"{self.trainee} is qualified in the {self.level}"
        return f"{self.trainee} is qualified as a {self.level}"

    @property
    def activity_feed_string(self):
        return str(self)

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

    class Meta:
        constraints = [models.UniqueConstraint(fields=["trainee", "level"], name="unique_trainee_level")]
        ordering = ["-confirmed_on"]