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


class EntityFieldConfig(models.Model):
    entity_type = models.CharField(max_length=100)
    field_name = models.CharField(max_length=100)
    is_hidden = models.BooleanField(default=False)
    display_label = models.CharField(max_length=200, blank=True)
    sort_order = models.PositiveSmallIntegerField(default=0)

    class Meta:
        unique_together = ('entity_type', 'field_name')
        verbose_name = 'Feldkonfiguration'
        verbose_name_plural = 'Feldkonfigurationen'

    def __str__(self):
        return f'{self.entity_type}.{self.field_name}'


class CustomAttribute(models.Model):
    DATA_TYPE_CHOICES = [
        ('text', 'Text'),
        ('number', 'Zahl'),
        ('date', 'Datum'),
        ('boolean', 'Ja/Nein'),
        ('url', 'URL'),
        ('email', 'E-Mail'),
    ]
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')
    key = models.CharField(max_length=100)
    label = models.CharField(max_length=200)
    value = models.TextField(blank=True)
    data_type = models.CharField(max_length=20, choices=DATA_TYPE_CHOICES, default='text')
    sort_order = models.PositiveSmallIntegerField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['sort_order', 'created_at']
        indexes = [models.Index(fields=['content_type', 'object_id'])]

    def __str__(self):
        return f'{self.label}: {self.value}'


class Freigabe(models.Model):
    TYP_CHOICES = [
        ('teilnahme', 'Teilnahme-Freigabe'),
        ('ablehnung', 'Ablehnungs-Freigabe'),
        ('recht', 'Rechtliche Freigabe'),
        ('preis', 'Preis-Freigabe'),
        ('abgabe', 'Abgabe-Freigabe'),
        ('standarddokument', 'Standarddokument-Freigabe'),
        ('referenz', 'Referenz-Freigabe'),
    ]
    STATUS_CHOICES = [
        ('erteilt', 'Erteilt'),
        ('abgelehnt', 'Abgelehnt'),
        ('ausstehend', 'Ausstehend'),
    ]
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')
    freigabe_typ = models.CharField(max_length=30, choices=TYP_CHOICES)
    freigebende_person = models.ForeignKey(
        settings.AUTH_USER_MODEL, on_delete=models.PROTECT, related_name='erteilte_freigaben'
    )
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='erteilt')
    kommentar = models.TextField(blank=True)
    timestamp = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['-timestamp']
        verbose_name = 'Freigabe'
        verbose_name_plural = 'Freigaben'

    def __str__(self):
        return f'{self.get_freigabe_typ_display()} — {self.status}'


class FlexibleModel(models.Model):
    custom_attributes = GenericRelation(CustomAttribute)
    freigaben = GenericRelation(Freigabe)

    def get_hidden_fields(self):
        model_name = self._meta.model_name
        return set(
            EntityFieldConfig.objects.filter(
                entity_type=model_name, is_hidden=True
            ).values_list('field_name', flat=True)
        )

    def get_visible_field_names(self):
        hidden = self.get_hidden_fields()
        return [
            f.name
            for f in self._meta.get_fields()
            if hasattr(f, 'column') and not f.name.startswith('_') and f.name not in hidden
        ]

    class Meta:
        abstract = True