from django.db import models


class Nomenclature(models.Model):
    VEHICLE = "vehicle"
    CONTAINER = "container"
    APPLIES_TO_CHOICES = [
        (VEHICLE, "Vehicle"),
        (CONTAINER, "Container"),
    ]

    LOOKUP = "lookup"
    FIELD = "field"
    KIND_CHOICES = [
        (LOOKUP, "Lookup Table"),
        (FIELD, "Custom Field"),
    ]

    code = models.CharField(max_length=50, unique=True)
    name = models.CharField(max_length=255)
    applies_to = models.CharField(max_length=50, choices=APPLIES_TO_CHOICES)
    kind = models.CharField(max_length=10, choices=KIND_CHOICES, default=LOOKUP)
    display_field = models.CharField(
        max_length=50,
        default="name",
        blank=True,
        help_text="Key of the NomenclatureField to use as dropdown label (for lookup kind)",
    )
    sort_order = models.IntegerField(default=0)

    class Meta:
        ordering = ["sort_order", "code"]

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


class NomenclatureField(models.Model):
    TEXT = "text"
    NUMBER = "number"
    BOOL = "bool"
    CHOICE = "choice"

    FIELD_TYPES = [
        (TEXT, "Text"),
        (NUMBER, "Number"),
        (BOOL, "Boolean"),
        (CHOICE, "Choice"),
    ]

    nomenclature = models.ForeignKey(
        Nomenclature,
        on_delete=models.CASCADE,
        related_name="fields",
    )
    key = models.CharField(max_length=50)
    label = models.CharField(max_length=100, blank=True)
    field_type = models.CharField(max_length=20, choices=FIELD_TYPES)
    required = models.BooleanField(default=False)
    choices = models.JSONField(
        null=True,
        blank=True,
        help_text='List of allowed values for choice type, e.g. ["Red","Green","Blue"]',
    )
    sort_order = models.IntegerField(default=0)

    class Meta:
        unique_together = [("nomenclature", "key")]
        ordering = ["sort_order", "key"]

    def __str__(self):
        return f"{self.nomenclature.code}.{self.key} ({self.field_type})"


class NomenclatureEntry(models.Model):
    nomenclature = models.ForeignKey(
        Nomenclature,
        on_delete=models.CASCADE,
        related_name="entries",
    )
    data = models.JSONField(default=dict)
    is_active = models.BooleanField(default=True)

    class Meta:
        verbose_name_plural = "Nomenclature entries"
        ordering = ["id"]

    def __str__(self):
        display_key = self.nomenclature.display_field or "name"
        return str(self.data.get(display_key, f"Entry #{self.pk}"))