import json
from django.db import models, transaction
from django.core.validators import MinValueValidator
from django.core.exceptions import ValidationError
from django.urls import reverse
from apps.users.models import User

import pyconcept


class CstType(models.TextChoices):
    ''' Type of constituenta '''
    BASE = 'basic'
    CONSTANT = 'constant'
    STRUCTURED = 'structure'
    AXIOM = 'axiom'
    TERM = 'term'
    FUNCTION = 'function'
    PREDICATE = 'predicate'
    THEOREM = 'theorem'


class Syntax(models.TextChoices):
    ''' Syntax types '''
    UNDEF = 'undefined'
    ASCII = 'ascii'
    MATH = 'math'


def _empty_forms():
    return []


class RSForm(models.Model):
    ''' RSForm is a math form of capturing conceptual schema '''
    owner = models.ForeignKey(
        verbose_name='Владелец',
        to=User,
        on_delete=models.SET_NULL,
        null=True
    )
    title = models.TextField(
        verbose_name='Название'
    )
    alias = models.CharField(
        verbose_name='Шифр',
        max_length=255,
        blank=True
    )
    comment = models.TextField(
        verbose_name='Комментарий',
        blank=True
    )
    is_common = models.BooleanField(
        verbose_name='Общая',
        default=False
    )
    time_create = models.DateTimeField(
        verbose_name='Дата создания',
        auto_now_add=True
    )
    time_update = models.DateTimeField(
        verbose_name='Дата изменения',
        auto_now=True
    )

    class Meta:
        verbose_name = 'Схема'
        verbose_name_plural = 'Схемы'

    def constituents(self) -> models.QuerySet:
        ''' Get QuerySet containing all constituents of current RSForm '''
        return Constituenta.objects.filter(schema=self)

    @transaction.atomic
    def insert_at(self, position: int, alias: str, type: CstType) -> 'Constituenta':
        ''' Insert new constituenta at given position. All following constituents order is shifted by 1 position '''
        if position <= 0:
            raise ValidationError('Invalid position: should be positive integer')
        update_list = Constituenta.objects.only('id', 'order', 'schema').filter(schema=self, order__gte=position)
        for cst in update_list:
            cst.order += 1
        Constituenta.objects.bulk_update(update_list, ['order'])

        result = Constituenta.objects.create(
            schema=self,
            order=position,
            alias=alias,
            cst_type=type
        )
        self._update_from_core()
        self.save()
        result.refresh_from_db()
        return result

    @transaction.atomic
    def insert_last(self, alias: str, type: CstType) -> 'Constituenta':
        ''' Insert new constituenta at last position '''
        position = 1
        if self.constituents().exists():
            position += self.constituents().only('order').aggregate(models.Max('order'))['order__max']
        result = Constituenta.objects.create(
            schema=self,
            order=position,
            alias=alias,
            cst_type=type
        )
        self._update_from_core()
        self.save()
        result.refresh_from_db()
        return result

    @transaction.atomic
    def move_cst(self, listCst: list['Constituenta'], target: int):
        ''' Move list of constituents to specific position '''
        count_moved = 0
        count_top = 0
        count_bot = 0
        size = len(listCst)
        update_list = []
        for cst in self.constituents():
            if cst not in listCst:
                if count_top + 1 < target:
                    cst.order = count_top + 1
                    count_top += 1
                else:
                    cst.order = target + size + count_bot
                    count_bot += 1
            else:
                cst.order = target + count_moved
                count_moved += 1
            update_list.append(cst)
        Constituenta.objects.bulk_update(update_list, ['order'])
        self._update_from_core()
        self.save()

    @transaction.atomic
    def delete_cst(self, listCst):
        ''' Delete multiple constituents. Do not check if listCst are from this schema '''
        for cst in listCst:
            cst.delete()
        self._update_from_core()
        self.save()

    @staticmethod
    @transaction.atomic
    def import_json(owner: User, data: dict, is_common: bool = True) -> 'RSForm':
        schema = RSForm.objects.create(
            title=data.get('title', 'Без названия'),
            owner=owner,
            alias=data.get('alias', ''),
            comment=data.get('comment', ''),
            is_common=is_common
        )
        schema._create_cst_from_json(data['items'])
        return schema

    def to_json(self) -> str:
        ''' Generate JSON string containing all data from RSForm '''
        result = self._prepare_json_rsform()
        items = self.constituents().order_by('order')
        for cst in items:
            result['items'].append(cst.to_json())
        return result

    def __str__(self):
        return self.title

    def get_absolute_url(self):
        return reverse('rsform-detail', kwargs={'pk': self.pk})

    def _prepare_json_rsform(self: 'Constituenta') -> dict:
        return {
            'type': 'rsform',
            'title': self.title,
            'alias': self.alias,
            'comment': self.comment,
            'items': []
        }

    def _update_from_core(self) -> dict:
        checked = json.loads(pyconcept.check_schema(json.dumps(self.to_json())))
        update_list = self.constituents().only('id', 'order')
        if (len(checked['items']) != update_list.count()):
            raise ValidationError
        order = 1
        for cst in checked['items']:
            id = cst['entityUID']
            for oldCst in update_list:
                if oldCst.id == id:
                    oldCst.order = order
                    order += 1
                    break
        Constituenta.objects.bulk_update(update_list, ['order'])
        return checked

    def _create_cst_from_json(self, items):
        order = 1
        for cst in items:
            Constituenta.import_json(cst, self, order)
            order += 1


class Constituenta(models.Model):
    ''' Constituenta is the base unit for every conceptual schema '''
    schema = models.ForeignKey(
        verbose_name='Концептуальная схема',
        to=RSForm,
        on_delete=models.CASCADE
    )
    order = models.PositiveIntegerField(
        verbose_name='Позиция',
        validators=[MinValueValidator(1)],
        default=-1,
    )
    alias = models.CharField(
        verbose_name='Имя',
        max_length=8,
        default='undefined'
    )
    cst_type = models.CharField(
        verbose_name='Тип',
        max_length=10,
        choices=CstType.choices,
        default=CstType.BASE
    )
    convention = models.TextField(
        verbose_name='Комментарий/Конвенция',
        default='',
        blank=True
    )
    term_raw = models.TextField(
        verbose_name='Термин (с отсылками)',
        default='',
        blank=True
    )
    term_resolved = models.TextField(
        verbose_name='Термин',
        default='',
        blank=True
    )
    term_forms = models.JSONField(
        verbose_name='Словоформы',
        default=_empty_forms
    )
    definition_formal = models.TextField(
        verbose_name='Родоструктурное определение',
        default='',
        blank=True
    )
    definition_raw = models.TextField(
        verbose_name='Текстовое определние (с отсылками)',
        default='',
        blank=True
    )
    definition_resolved = models.TextField(
        verbose_name='Текстовое определние',
        default='',
        blank=True
    )

    class Meta:
        verbose_name = 'Конституета'
        verbose_name_plural = 'Конституенты'

    def get_absolute_url(self):
        return reverse('constituenta-detail', kwargs={'pk': self.pk})

    def __str__(self):
        return self.alias

    @staticmethod
    def import_json(data: dict, schema: RSForm, order: int) -> 'Constituenta':
        cst = Constituenta(
            alias=data['alias'],
            schema=schema,
            order=order,
            cst_type=data['cstType'],
            convention=data.get('convention', 'Без названия')
        )
        if 'definition' in data:
            if 'formal' in data['definition']:
                cst.definition_formal = data['definition']['formal']
            if 'text' in data['definition']:
                cst.definition_raw = data['definition']['text'].get('raw', '')
                cst.definition_resolved = data['definition']['text'].get('resolved', '')
        if 'term' in data:
            cst.term_raw = data['term'].get('raw', '')
            cst.term_resolved = data['term'].get('resolved', '')
            cst.term_forms = data['term'].get('forms', [])
        cst.save()
        return cst

    def to_json(self) -> str:
        return {
            'entityUID': self.id,
            'type': 'constituenta',
            'cstType': self.cst_type,
            'alias': self.alias,
            'convention': self.convention,
            'term': {
                'raw': self.term_raw,
                'resolved': self.term_resolved,
                'forms': self.term_forms,
            },
            'definition': {
                'formal': self.definition_formal,
                'text': {
                    'raw': self.definition_raw,
                    'resolved': self.definition_resolved,
                },
            },
        }