import abc
import uuid

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

from .managers import ExampleManager, ExampleStateManager

DOCUMENT_CLASSIFICATION = 'DocumentClassification'
SEQUENCE_LABELING = 'SequenceLabeling'
SEQ2SEQ = 'Seq2seq'
SPEECH2TEXT = 'Speech2text'
IMAGE_CLASSIFICATION = 'ImageClassification'
INTENT_DETECTION_AND_SLOT_FILLING = 'IntentDetectionAndSlotFilling'
PROJECT_CHOICES = (
    (DOCUMENT_CLASSIFICATION, 'document classification'),
    (SEQUENCE_LABELING, 'sequence labeling'),
    (SEQ2SEQ, 'sequence to sequence'),
    (INTENT_DETECTION_AND_SLOT_FILLING, 'intent detection and slot filling'),
    (SPEECH2TEXT, 'speech to text'),
    (IMAGE_CLASSIFICATION, 'image classification')
)


class Project(PolymorphicModel):
    name = models.CharField(max_length=100)
    description = models.TextField(default='')
    guideline = models.TextField(default='', blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    created_by = models.ForeignKey(
        User,
        on_delete=models.SET_NULL,
        null=True,
    )
    project_type = models.CharField(max_length=30, choices=PROJECT_CHOICES)
    random_order = models.BooleanField(default=False)
    collaborative_annotation = models.BooleanField(default=False)
    single_class_classification = models.BooleanField(default=False)

    @property
    @abc.abstractmethod
    def is_text_project(self) -> bool:
        return False

    @property
    def can_define_label(self) -> bool:
        """Whether or not the project can define label(ignoring the type of label)"""
        return False

    @property
    def can_define_relation(self) -> bool:
        """Whether or not the project can define relation."""
        return False

    @property
    def can_define_category(self) -> bool:
        """Whether or not the project can define category."""
        return False

    @property
    def can_define_span(self) -> bool:
        """Whether or not the project can define span."""
        return False

    def __str__(self):
        return self.name


class TextClassificationProject(Project):

    @property
    def is_text_project(self) -> bool:
        return True

    @property
    def can_define_label(self) -> bool:
        return True

    @property
    def can_define_category(self) -> bool:
        return True


class SequenceLabelingProject(Project):
    allow_overlapping = models.BooleanField(default=False)
    grapheme_mode = models.BooleanField(default=False)

    @property
    def is_text_project(self) -> bool:
        return True

    @property
    def can_define_label(self) -> bool:
        return True

    @property
    def can_define_span(self) -> bool:
        return True


class Seq2seqProject(Project):

    @property
    def is_text_project(self) -> bool:
        return True


class IntentDetectionAndSlotFillingProject(Project):

    @property
    def is_text_project(self) -> bool:
        return True

    @property
    def can_define_label(self) -> bool:
        return True

    @property
    def can_define_category(self) -> bool:
        return True

    @property
    def can_define_span(self) -> bool:
        return True


class Speech2textProject(Project):

    @property
    def is_text_project(self) -> bool:
        return False


class ImageClassificationProject(Project):

    @property
    def is_text_project(self) -> bool:
        return False

    @property
    def can_define_label(self) -> bool:
        return True

    @property
    def can_define_category(self) -> bool:
        return True


class Example(models.Model):
    objects = ExampleManager()

    uuid = models.UUIDField(default=uuid.uuid4, editable=False, db_index=True, unique=True)
    meta = models.JSONField(default=dict)
    filename = models.FileField(default='.', max_length=1024)
    project = models.ForeignKey(
        to=Project,
        on_delete=models.CASCADE,
        related_name='examples'
    )
    annotations_approved_by = models.ForeignKey(
        to=User,
        on_delete=models.SET_NULL,
        null=True,
        blank=True
    )
    text = models.TextField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True, db_index=True)
    updated_at = models.DateTimeField(auto_now=True)

    @property
    def comment_count(self):
        return Comment.objects.filter(example=self.id).count()

    @property
    def data(self):
        if self.project.is_text_project:
            return self.text
        else:
            return str(self.filename)

    class Meta:
        ordering = ['created_at']


class ExampleState(models.Model):
    objects = ExampleStateManager()
    example = models.ForeignKey(
        to=Example,
        on_delete=models.CASCADE,
        related_name='states'
    )
    confirmed_by = models.ForeignKey(
        to=User,
        on_delete=models.CASCADE
    )
    confirmed_at = models.DateTimeField(auto_now=True)

    class Meta:
        unique_together = (('example', 'confirmed_by'),)


class Comment(models.Model):
    text = models.TextField()
    example = models.ForeignKey(
        to=Example,
        on_delete=models.CASCADE,
        related_name='comments'
    )
    user = models.ForeignKey(
        to=User,
        on_delete=models.CASCADE,
        null=True
    )
    created_at = models.DateTimeField(auto_now_add=True, db_index=True)
    updated_at = models.DateTimeField(auto_now=True)

    @property
    def username(self):
        return self.user.username

    class Meta:
        ordering = ['created_at']


class Tag(models.Model):
    text = models.TextField()
    project = models.ForeignKey(
        to=Project,
        on_delete=models.CASCADE,
        related_name='tags'
    )

    def __str__(self):
        return self.text