from django.db import models
from django.utils.translation import gettext_lazy as _
from django.utils.text import slugify
from django.conf import settings
from typing import Optional
from utils.mixins import ColorPaletteMixin, LowercaseSlugMixin

class BookSubjectArea(models.Model):
    title =  models.JSONField(default = list  , verbose_name=_('Title'))
    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_('updated at'))

    class Meta:
        ordering = ('-created_at', '-id')
        verbose_name = _('Subject Area')
        verbose_name_plural = _('Subject Areas')
    
    def __str__(self):
        if self.title and isinstance(self.title, list) and len(self.title) > 0 and isinstance(self.title[0], dict):
            return self.title[0].get('text') or self.title[0].get('title') or str(self.id)
        return str(self.id)

    def get_title(self,lang):
        """
            Get title for a specific language
        """

        if not self.title or not isinstance(self.title, list):
            return None

        for tr in self.title:
            if isinstance(tr, dict) and tr.get('language_code') == lang:
                return tr.get('text', '') or tr.get('title', '')

        for tr in self.title:
            if isinstance(tr, dict) and tr.get('language_code') == 'en':
                return tr.get('text', '') or tr.get('title', '')
        return None


class BookTag(models.Model):
    """
    Model for book reference tags
    """
    title = models.JSONField(default=list, verbose_name=_('Title'))
    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_('updated at'))

    class Meta:
        verbose_name = _('Book Tag')
        verbose_name_plural = _('Book Tags')

    def __str__(self):
        if self.title and isinstance(self.title, list) and len(self.title) > 0 and isinstance(self.title[0], dict):
            return self.title[0].get('text') or self.title[0].get('title') or f"Tag {self.id}"
        return f"Tag {self.id}"

class BookType(models.Model):
    class Sect(models.TextChoices):
        SHIA = 'shia', _('Shia')
        SUNNI = 'sunni', _('Sunni')

    title =  models.JSONField(default = list  , verbose_name=_('Title'))
    sect = models.CharField(
        max_length=10, 
        choices=Sect.choices, 
        default=Sect.SHIA, 
        verbose_name=_('Sect')
    )
    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_('updated at'))
    
    def __str__(self):
        if self.title and isinstance(self.title, list) and len(self.title) > 0 and isinstance(self.title[0], dict):
            return self.title[0].get('text') or self.title[0].get('title') or str(self.id)
        return str(self.id)

    def get_title(self,lang):
        """
            Get title for a specific language
        """

        if not self.title or not isinstance(self.title, list):
            return None

        for tr in self.title:
            if isinstance(tr, dict) and tr.get('language_code') == lang:
                return tr.get('text', '') or tr.get('title', '')

        for tr in self.title:
            if isinstance(tr, dict) and tr.get('language_code') == 'en':
                return tr.get('text', '') or tr.get('title', '')
        return None

class BookReference(LowercaseSlugMixin, models.Model):
    slug_source_field = 'title'
    """
    Model for hadis book references with detailed information
    This is different from library books - these are reference books for hadis
    """
    legacy_id = models.CharField(max_length=255, unique=True, null=True, blank=True, db_index=True)
    title =  models.JSONField(default = list  , verbose_name=_('Title'))
    description =  models.JSONField(default = list  , verbose_name=_('Description'))
    language =  models.JSONField(default = list  , verbose_name=_('Language'))
    number_page = models.PositiveIntegerField(verbose_name=_('number of pages'), blank=True, null=True)
    slug = models.SlugField(max_length=255, verbose_name=_('slug'), blank=True,unique=True, allow_unicode=True)
    subject_area = models.ManyToManyField(
        'BookSubjectArea',
        verbose_name=_('Subject Area'),
        blank=True
    )
    tag = models.ForeignKey(
        'BookTag',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='book_references',
        verbose_name=_('Tag')
    )
    type = models.ForeignKey('BookType', on_delete=models.SET_NULL, null=True, blank=True, verbose_name=_('Type'))
    author = models.ForeignKey(
        'BookAuthor',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='book_references',
        verbose_name=_('Author')
    )
    order = models.IntegerField(default=0, verbose_name=_('Order'))
    priority = models.PositiveIntegerField(
        default=0,
        db_index=True,
        verbose_name=_('Priority'),
        help_text=_('Display order priority. Lower numbers appear first.')
    )
    rate = models.DecimalField(
        max_digits=3,
        decimal_places=2,
        verbose_name=_('rate'),
        blank=True,
        null=True,
        help_text=_('Rating from 0 to 5')
    )
    has_editions = models.BooleanField(
        default=False,
        verbose_name=_('Has Editions Structure'),
        help_text=_('True if this reference has one or more editions, False for direct volumes without edition structure')
    )

    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_('updated at'))
    normalized_text = models.TextField(blank=True, null=True, verbose_name=_('normalized text for search'))

    class Meta:
        indexes = [
            models.Index(fields=['id']),  # Already indexed (PK)
            models.Index(fields=['priority']),
        ]
        verbose_name = _('Book Reference')
        verbose_name_plural = _('Book References')
        ordering = ('priority', 'id')

    def __str__(self):
        if self.title and isinstance(self.title, list) and len(self.title) > 0 and isinstance(self.title[0], dict):
            return self.title[0].get('text') or self.title[0].get('title') or f"Reference {self.id}"
        return f"Reference {self.id}"

    def save(self, *args, **kwargs):
        from utils.text_normalizer import build_search_blob
        author_name = self.author.name if self.author else ""
        self.normalized_text = build_search_blob(
            self.title,
            self.description,
            author_name
        )
        super().save(*args, **kwargs)

    def _get_json_field(self, field_name: str, lang: Optional[str]=None , fallback: str = "en"):
        """
        Generic getter for JSONField in our [{text, language_code}] format.
        Usage: self._get_json_field('title', 'fa')
        """
        if lang is None:
            lang = fallback

        value = getattr(self, field_name, None)
        if not value or not isinstance(value, list):
            return None

        # 1) exact language
        for item in value:
            if isinstance(item, dict) and item.get("language_code") == lang:
                return item.get("text", "")

        # 2) fallback language
        if fallback and fallback != lang:
            for item in value:
                if isinstance(item, dict) and item.get("language_code") == fallback:
                    return item.get("text", "")

        # 3) first available
        item = value[0]
        print(item)
        return item.get("text", "") if isinstance(item, dict) else None

    @property
    def share_link(self):
        if self.slug:
            return f"{settings.DOVODI_DOMAIN}/arguments/sources/{self.slug}"
        return None

    @property
    def authors(self):
        """
        Backward compatibility helper returning a queryset/list of authors.
        Allows serializers calling obj.authors.all() to function correctly without hitting DB if author is already cached.
        """
        if hasattr(self, '_state') and hasattr(self._state, 'fields_cache') and 'author' in self._state.fields_cache:
            author_obj = self._state.fields_cache['author']
            class InMemAuthorList(list):
                def all(self):
                    return self
                def first(self):
                    return self[0] if self else None
                def exists(self):
                    return bool(self)
                def count(self):
                    return len(self)
                def filter(self, *args, **kwargs):
                    return self
            return InMemAuthorList([author_obj] if author_obj else [])

        if self.author_id:
            return BookAuthor.objects.filter(id=self.author_id)
        return BookAuthor.objects.none()

    def get_title(self,lang):
        return self._get_json_field("title" , lang)

    def get_description(self, lang):
        return self._get_json_field("description" , lang)

    def get_language(self, lang):
        return self._get_json_field("language" , lang)





class BookPublisher(LowercaseSlugMixin, models.Model):
    slug_source_field = 'title'

    title = models.JSONField(default=list, verbose_name=_('Title'))
    slug = models.SlugField(max_length=255, verbose_name=_('slug'), blank=True, null=True, allow_unicode=True)
    city = models.ForeignKey(
        'hadis.City',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='publishers',
        verbose_name=_('City')
    )
    country = models.ForeignKey(
        'hadis.Country',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='publishers',
        verbose_name=_('Country')
    )
    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_('updated at'))

    class Meta:
        ordering = ('-created_at', '-id')
        verbose_name = _('Book Publisher')
        verbose_name_plural = _('Book Publishers')

    def __str__(self):
        if self.title and isinstance(self.title, list) and len(self.title) > 0 and isinstance(self.title[0], dict):
            return self.title[0].get('text') or self.title[0].get('title') or str(self.id)
        return str(self.id)

    def get_title(self, lang: str = 'en') -> Optional[str]:
        if not self.title or not isinstance(self.title, list):
            return None
        for tr in self.title:
            if isinstance(tr, dict) and tr.get('language_code') == lang:
                return tr.get('text', '') or tr.get('title', '')
        for tr in self.title:
            if isinstance(tr, dict) and tr.get('language_code') == 'en':
                return tr.get('text', '') or tr.get('title', '')
        if isinstance(self.title[0], dict):
            return self.title[0].get('text', '') or self.title[0].get('title', '')
        return None

    def save(self, *args, **kwargs):
        super().save(*args, **kwargs)
        self.editions.all().update(publisher=self.title or [])


class BookEdition(models.Model):
    """
    Model representing a specific edition or print of a book reference.
    """
    title = models.JSONField(default=list, blank=True, verbose_name=_('Edition Title'))
    book_reference = models.ForeignKey(BookReference, on_delete=models.CASCADE, related_name='editions', verbose_name=_('book reference'), null=True, blank=True)
    books = models.ManyToManyField(
        BookReference,
        related_name='editions_list',
        blank=True,
        verbose_name=_('Connected Books/Works')
    )
    publisher = models.JSONField(default=list, blank=True, verbose_name=_('Publisher'))
    publisher_item = models.ForeignKey(
        'hadis.BookPublisher',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='editions',
        verbose_name=_('Publisher Entity')
    )
    city_of_publication = models.JSONField(default=list, blank=True, verbose_name=_('City of Publication'))
    city_of_publication_city = models.ForeignKey(
        'hadis.City',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='publication_editions',
        verbose_name=_('City of Publication (City)'),
    )
    country_of_publication = models.JSONField(default=list, blank=True, verbose_name=_('Country of Publication'))
    country_of_publication_country = models.ForeignKey(
        'hadis.Country',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='publication_editions',
        verbose_name=_('Country of Publication (Country)'),
    )
    edition_number = models.CharField(max_length=100, blank=True, null=True, verbose_name=_('Edition Number'))
    year_of_publication = models.CharField(max_length=50, blank=True, null=True, verbose_name=_('year of publication'))
    number_of_volumes = models.PositiveIntegerField(null=True, blank=True, verbose_name=_('Total Number of Volumes'))
    source_url = models.URLField(max_length=1000, null=True, blank=True, verbose_name=_('Online Source URL'))
    isbn = models.CharField(max_length=100, verbose_name=_('ISBN'), blank=True, null=True)
    notes = models.JSONField(default=list, blank=True, verbose_name=_('Notes'))
    tag = models.ForeignKey(
        'BookTag',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='book_editions',
        verbose_name=_('Tag')
    )
    
    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_('updated at'))

    class Meta:
        verbose_name = _('Book Edition')
        verbose_name_plural = _('Book Editions')
        ordering = ['-created_at']

    def __str__(self):
        t_str = ""
        if self.title and isinstance(self.title, list):
            for item in self.title:
                if isinstance(item, dict) and (item.get('text') or item.get('title')):
                    t_str = (item.get('text') or item.get('title')).strip()
                    break
        if t_str:
            return f"{t_str} ({self.edition_number or 'Ed. ' + str(self.id)})"
        return f"{self.book_reference} - {self.edition_number or 'Edition ' + str(self.id)}"

    def save(self, *args, **kwargs):
        if self.publisher_item_id and self.publisher_item:
            self.publisher = self.publisher_item.title or []
        if self.city_of_publication_city_id and self.city_of_publication_city:
            self.city_of_publication = self.city_of_publication_city.title or []
        if self.country_of_publication_country_id and self.country_of_publication_country:
            self.country_of_publication = self.country_of_publication_country.title or []
        super().save(*args, **kwargs)
        if self.book_reference and not self.books.filter(id=self.book_reference_id).exists():
            self.books.add(self.book_reference)

class BookVolume(models.Model):
    """
    Model representing a single volume, which can belong to an edition or directly to the book.
    """
    book_reference = models.ForeignKey(BookReference, on_delete=models.CASCADE, related_name='volumes', verbose_name=_('book reference'))
    edition = models.ForeignKey(BookEdition, on_delete=models.CASCADE, related_name='volumes', verbose_name=_('edition'), null=True, blank=True)
    title = models.CharField(max_length=255, verbose_name=_('Title'), help_text=_('e.g., Volume 1'), blank=True, null=True)
    image = models.ImageField(
        upload_to='hadis/volume_images/',
        null=True,
        blank=True,
        verbose_name=_('Image')
    )
    file = models.FileField(
        upload_to='hadis/volume_files/',
        null=True,
        blank=True,
        verbose_name=_('File')
    )
    
    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_('updated at'))

    class Meta:
        verbose_name = _('Book Volume')
        verbose_name_plural = _('Book Volumes')
        ordering = ['title']

    def __str__(self):
        return f"{self.book_reference} - {self.title or 'Vol ' + str(self.id)}"

class BookReferenceImage(models.Model):
    """
    Model for book reference images - multiple images per book reference
    """
    book_reference = models.ForeignKey(
        BookReference,
        on_delete=models.CASCADE,
        related_name='images',
        verbose_name=_('book reference')
    )
    book_volume = models.ForeignKey(
        BookVolume,
        on_delete=models.CASCADE,
        related_name='images',
        verbose_name=_('book volume'),
        null=True, 
        blank=True
    )
    image = models.ImageField(upload_to='hadis/book_reference_images/', verbose_name=_('image'))
    order = models.PositiveIntegerField(default=0, verbose_name=_('order'))
    description =  models.JSONField(default = list  , verbose_name=_('Description'))

    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))

    class Meta:
        verbose_name = _('Book Reference Image')
        verbose_name_plural = _('Book Reference Images')
        ordering = ['order', '-created_at']

    def save(self, *args, **kwargs):
        from utils.watermark import apply_watermark_to_field_file
        apply_watermark_to_field_file(self.image, position="bottom_left")
        super().save(*args, **kwargs)

    def get_description(self,lang):
        """
            Get title for a specific language
        """

        if not self.description or not isinstance(self.description, list):
            return None

        for tr in self.description:
            if isinstance(tr, dict) and tr.get('language_code') == lang:
                return tr.get('text', '')

        for tr in self.description:
            if isinstance(tr, dict) and tr.get('language_code') == 'en':
                return tr.get('text', '')
        return None

    def __str__(self):
        return f"{self.book_reference} - Image {self.order}"

class BookReferenceDocument(models.Model):
    """
    Model for handling multiple PDF files per book (e.g., different volumes).
    """
    book_reference = models.ForeignKey(
        BookReference, 
        on_delete=models.CASCADE, 
        related_name='documents',
        verbose_name=_('book reference')
    )
    book_volume = models.ForeignKey(
        BookVolume,
        on_delete=models.CASCADE,
        related_name='documents',
        verbose_name=_('book volume'),
        null=True,
        blank=True
    )
    file = models.FileField(upload_to='hadis/book_reference_documents/', verbose_name=_('Document File'))
    title = models.CharField(max_length=255, blank=True, null=True, help_text=_('e.g., Volume 1, 01.pdf'))
    order = models.PositiveIntegerField(default=0, verbose_name=_('order'))
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        verbose_name = _('Book Reference Document')
        verbose_name_plural = _('Book Reference Documents')
        ordering = ['order', '-created_at']

    def __str__(self):
        return f"{self.book_reference} - {self.title or 'Doc ' + str(self.id)}"


class BookAuthorRutba(ColorPaletteMixin, LowercaseSlugMixin, models.Model):
    slug_source_field = 'title'

    title = models.JSONField(default=list, verbose_name=_('Title'))
    slug = models.SlugField(max_length=255, verbose_name=_('slug'), blank=True, null=True, allow_unicode=True)
    description = models.JSONField(default=list, verbose_name=_('Description'))

    def __str__(self):
        if self.title and isinstance(self.title, list) and len(self.title) > 0 and isinstance(self.title[0], dict):
            return self.title[0].get('text') or self.title[0].get('title') or str(self.id)
        return str(self.id)

    def get_title(self, lang):
        if not self.title or not isinstance(self.title, list):
            return None

        for tr in self.title:
            if isinstance(tr, dict) and tr.get('language_code') == lang:
                return tr.get('text', '') or tr.get('title', '')

        for tr in self.title:
            if isinstance(tr, dict) and tr.get('language_code') == 'en':
                return tr.get('text', '') or tr.get('title', '')
        return None

    def get_description(self, lang):
        if not self.description or not isinstance(self.description, list):
            return None

        for tr in self.description:
            if isinstance(tr, dict) and tr.get('language_code') == lang:
                return tr.get('text', '') or tr.get('title', '')

        for tr in self.description:
            if isinstance(tr, dict) and tr.get('language_code') == 'en':
                return tr.get('text', '') or tr.get('title', '')
        return None

    class Meta:
        verbose_name = _('Author Rutba')
        verbose_name_plural = _('Author Rutbas')

    def save(self, *args, **kwargs):
        super().save(*args, **kwargs)
        self.authors.all().update(rutba=self.title or [])


class BookAuthor(LowercaseSlugMixin, models.Model):
    slug_source_field = 'name'
    """
    Model for book reference authors
    """
    name =  models.JSONField(default=list, verbose_name=_('Name'))
    slug = models.SlugField(max_length=255, verbose_name=_('slug'), null=True, blank=True, unique=True, allow_unicode=True)

    related_narrator = models.OneToOneField(
        'hadis.Transmitters',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='book_author_profile',
        verbose_name=_('Related Narrator Profile')
    )
    
    # 👇 فیلدهای جدید اضافه شده
    known_as = models.JSONField(default=list, blank=True, verbose_name=_('Known as'))
    scholarity = models.JSONField(default=list, blank=True, verbose_name=_('Scholarity'))
    tabaqa = models.JSONField(default=list, blank=True, verbose_name=_('Tabaqa'))
    rutba = models.JSONField(default=list, blank=True, verbose_name=_('Rutba'))
    rutba_status = models.ForeignKey(
        'BookAuthorRutba',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='authors',
        verbose_name=_('Rutba Status')
    )
    features = models.JSONField(default=list, blank=True, verbose_name=_('Features'))
    features_list = models.ManyToManyField(
        'hadis.TransmitterFeature',
        blank=True,
        related_name='authors',
        verbose_name=_('Features (M2M)')
    )

    # Geographic Information
    origin = models.JSONField(default=list, blank=True, verbose_name=_('Origin'))
    lived_in = models.JSONField(default=list, blank=True, verbose_name=_('Lived in'))
    died_in = models.JSONField(default=list, blank=True, verbose_name=_('Died in'))
    origin_city = models.ForeignKey(
        'hadis.City',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='origin_authors',
        verbose_name=_('Origin City'),
    )
    lived_in_city = models.ForeignKey(
        'hadis.City',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='lived_in_authors',
        verbose_name=_('Lived in City'),
    )
    died_in_city = models.ForeignKey(
        'hadis.City',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='died_in_authors',
        verbose_name=_('Died in City'),
    )

    birth_year_hijri = models.CharField(max_length=100, verbose_name=_("Birth Year (Hijri)"), null=True, blank=True)
    death_year_hijri = models.CharField(max_length=100, verbose_name=_("Death Year (Hijri)"), null=True, blank=True)
    age_at_death = models.CharField(max_length=100, verbose_name=_("Age at Death"), null=True, blank=True)
    birth_year_miladi = models.IntegerField(verbose_name=_("Birth Year (Miladi)"), null=True, blank=True)
    death_year_miladi = models.IntegerField(verbose_name=_("Death Year (Miladi)"), null=True, blank=True)
    
    image = models.ImageField(
        upload_to='hadis/author_images/',
        null=True,
        blank=True,
        help_text=_('image allowed'),
        verbose_name=_('Image')
    )

    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_('updated at'))

    class Meta:
        verbose_name = _('Book Author')
        verbose_name_plural = _('Book Authors')
        ordering = ['name']

    def __str__(self):
        return self.name[0]['text'] if self.name else "Unknown Author"

    def get_name(self,lang):
        """
            Get title for a specific language
        """

        if not self.name or not isinstance(self.name, list):
            return None

        for tr in self.name:
            if isinstance(tr, dict) and tr.get('language_code') == lang:
                return tr.get('text', '')

        for tr in self.name:
            if isinstance(tr, dict) and tr.get('language_code') == 'en':
                return tr.get('text', '')
        return None

    def save(self, *args, **kwargs):
        if self.rutba_status_id and self.rutba_status:
            self.rutba = self.rutba_status.title or []
        if self.origin_city_id and self.origin_city:
            self.origin = self.origin_city.title or []
        if self.lived_in_city_id and self.lived_in_city:
            self.lived_in = self.lived_in_city.title or []
        if self.died_in_city_id and self.died_in_city:
            self.died_in = self.died_in_city.title or []

        for date_field in ('birth_year_hijri', 'death_year_hijri', 'age_at_death'):
            val = getattr(self, date_field, None)
            if val is not None:
                val_str = str(val).strip()
                setattr(self, date_field, val_str if val_str else None)

        super().save(*args, **kwargs)
        self.researcher_profiles.all().update(name=self.name, slug=self.slug)
        try:
            self.sync_author_dates()
        except Exception:
            pass

    def sync_author_dates(self):
        """
        Synchronizes birth_year_hijri, death_year_hijri, and age_at_death
        with YearValue and BookAuthorDate tables.
        """
        if not self.pk:
            return

        from .transmitter import YearValue

        date_mapping = {
            'birth': self.birth_year_hijri,
            'death': self.death_year_hijri,
            'age': self.age_at_death,
        }

        for date_type, raw_val in date_mapping.items():
            if not raw_val or not str(raw_val).strip():
                BookAuthorDate.objects.filter(author=self, date_type=date_type).delete()
                continue

            raw_str = str(raw_val).strip()
            yv = YearValue.get_or_create_from_canonical(category=date_type, raw_value=raw_str)
            BookAuthorDate.objects.update_or_create(
                author=self,
                date_type=date_type,
                defaults={
                    'year_value': yv,
                    'raw_value': yv.raw_value,
                }
            )

    def get_formatted_date(self, date_type: str, lang: str = 'ru') -> Optional[str]:
        field_map = {
            'birth': 'birth_year_hijri',
            'death': 'death_year_hijri',
            'age': 'age_at_death',
        }
        field_name = field_map.get(date_type)
        if not field_name:
            return None
        raw_val = getattr(self, field_name, None)
        if raw_val is None or str(raw_val).strip() == '':
            return None
        raw_str = str(raw_val).strip()

        target_lang = (lang or 'ru').split('-')[0].lower()

        # Check prefetched author_dates first if available
        if hasattr(self, '_prefetched_objects_cache') and 'author_dates' in self._prefetched_objects_cache:
            for ad in self._prefetched_objects_cache['author_dates']:
                if ad.date_type == date_type and ad.year_value_id and ad.year_value:
                    txt = ad.year_value.get_translation(target_lang)
                    if txt:
                        return txt

        # If context tag (#...), check YearValue in DB for custom translations
        if raw_str.startswith('#'):
            from .transmitter import YearValue
            yv = YearValue.objects.filter(raw_value=raw_str).first()
            if yv:
                txt = yv.get_translation(target_lang)
                if txt:
                    return txt

        from ..utils.date_engine import format_canonical_date
        engine_lang = target_lang if target_lang in ('ru', 'en', 'ar') else 'en'
        return format_canonical_date(raw_str, category=date_type, lang=engine_lang)

    def get_formatted_birth_year(self, lang: str = 'ru') -> Optional[str]:
        return self.get_formatted_date('birth', lang=lang)

    def get_formatted_death_year(self, lang: str = 'ru') -> Optional[str]:
        return self.get_formatted_date('death', lang=lang)

    def get_formatted_age(self, lang: str = 'ru') -> Optional[str]:
        return self.get_formatted_date('age', lang=lang)


class BookAuthorDate(models.Model):
    """
    Links a BookAuthor to a parsed YearValue for birth, death, or age.
    """
    class DateTypeChoices(models.TextChoices):
        BIRTH = 'birth', _('Birth')
        DEATH = 'death', _('Death')
        AGE = 'age', _('Age')

    author = models.ForeignKey(
        BookAuthor,
        on_delete=models.CASCADE,
        related_name='author_dates',
        verbose_name=_('Book Author')
    )
    date_type = models.CharField(
        max_length=20,
        choices=DateTypeChoices.choices,
        db_index=True,
        verbose_name=_('Date Type')
    )
    year_value = models.ForeignKey(
        'hadis.YearValue',
        on_delete=models.CASCADE,
        related_name='author_dates',
        verbose_name=_('Year Value')
    )
    raw_value = models.CharField(
        max_length=100,
        verbose_name=_('Canonical Raw Value')
    )

    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_('updated at'))

    class Meta:
        verbose_name = _('Book Author Date')
        verbose_name_plural = _('Book Author Dates')
        unique_together = ('author', 'date_type')
        indexes = [
            models.Index(fields=['date_type', 'year_value']),
            models.Index(fields=['author', 'date_type']),
        ]
        ordering = ('author_id', 'date_type')

    def __str__(self):
        return f"{self.author_id} - {self.date_type}: {self.raw_value}"


class BookAttribute(models.Model):
    """
    Model for book reference attributes - custom key-value pairs
    """
    title =  models.JSONField(default = list  , verbose_name=_('Title'))
    value =  models.JSONField(default = list  , verbose_name=_('Value'))
    book_reference = models.ForeignKey(
        BookReference,
        on_delete=models.CASCADE,
        related_name='attributes',
        verbose_name=_('book attribute'),
        default = None,
        null = True
    )
    created_at = models.DateTimeField(auto_now_add=True, verbose_name=_('created at'))
    updated_at = models.DateTimeField(auto_now=True, verbose_name=_('updated at'))

    class Meta:
        verbose_name = _('Book Attribute')
        verbose_name_plural = _('Book Attributes')
        ordering = ['title']

    def __str__(self):
        title = self.title[0]['text'] if self.title else "No Title"
        value = self.value[0]['text'] if self.value else "No Value"
        return f"{title}: {value}"

    def get_title(self,lang):
        """
            Get title for a specific language
        """

        if not self.title or not isinstance(self.title, list):
            return None

        for tr in self.title:
            if isinstance(tr, dict) and tr.get('language_code') == lang:
                return tr.get('text', '')

        for tr in self.title:
            if isinstance(tr, dict) and tr.get('language_code') == 'en':
                return tr.get('text', '')
        return None

    def get_value(self,lang):
        """
            Get title for a specific language
        """

        if not self.value or not isinstance(self.value, list):
            return None

        for tr in self.value:
            if isinstance(tr, dict) and tr.get('language_code') == lang:
                return tr.get('text', '')

        for tr in self.value:
            if isinstance(tr, dict) and tr.get('language_code') == 'en':
                return tr.get('text', '')
        return None


class BookResearcher(LowercaseSlugMixin, models.Model):
    slug_source_field = 'name'
    book_edition = models.ForeignKey(
        'BookEdition',
        on_delete=models.CASCADE,
        related_name='researchers',
        verbose_name=_('Book Edition')
    )
    author = models.ForeignKey(
        'BookAuthor',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='researcher_profiles',
        verbose_name=_('Author')
    )
    name = models.JSONField(default=list, blank=True, verbose_name=_('Name'))
    slug = models.SlugField(max_length=255, verbose_name=_('slug'), null=True, blank=True, allow_unicode=True)

    class Meta:
        verbose_name = _('Book Researcher')
        verbose_name_plural = _('Book Researchers')

    def save(self, *args, **kwargs):
        if self.author:
            self.name = self.author.name
            self.slug = self.author.slug
        super().save(*args, **kwargs)

    def __str__(self):
        try:
            return self.name[0]['text']
        except:
            return self.slug or f"Researcher {self.id}"


class BookEditor(LowercaseSlugMixin, models.Model):
    slug_source_field = 'name'
    book_edition = models.ForeignKey(
        'BookEdition',
        on_delete=models.CASCADE,
        related_name='editors',
        verbose_name=_('Book Edition')
    )
    author = models.ForeignKey(
        'BookAuthor',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='editor_profiles',
        verbose_name=_('Author')
    )
    name = models.JSONField(default=list, blank=True, verbose_name=_('Name'))
    slug = models.SlugField(max_length=255, verbose_name=_('slug'), null=True, blank=True, allow_unicode=True)

    class Meta:
        verbose_name = _('Book Editor')
        verbose_name_plural = _('Book Editors')

    def save(self, *args, **kwargs):
        if self.author:
            self.name = self.author.name
            self.slug = self.author.slug
        super().save(*args, **kwargs)

    def __str__(self):
        try:
            return self.name[0]['text']
        except:
            return self.slug or f"Editor {self.id}"