from __future__ import annotations

from django.core.exceptions import ValidationError
from django.db import models

from .normalization import normalize_text


class SensitiveWord(models.Model):
    class Action(models.TextChoices):
        BLOCK = "block", "拦截"

    word = models.CharField("敏感词", max_length=255)
    normalized_word = models.CharField("归一化敏感词", max_length=255, editable=False)
    category = models.CharField("分类", max_length=64, default="custom", blank=True)
    action = models.CharField("动作", max_length=16, choices=Action.choices, default=Action.BLOCK)
    is_active = models.BooleanField("启用", default=True)
    created_at = models.DateTimeField("创建时间", auto_now_add=True)
    updated_at = models.DateTimeField("更新时间", auto_now=True)

    class Meta:
        db_table = "sensitive_word"
        verbose_name = "敏感词"
        verbose_name_plural = "敏感词"
        ordering = ("category", "word")
        constraints = [
            models.UniqueConstraint(
                fields=("category", "normalized_word"),
                name="unique_sensitive_word_per_category",
            ),
        ]
        indexes = [
            models.Index(fields=("is_active", "category"), name="sw_active_category_idx"),
            models.Index(fields=("normalized_word",), name="sw_normalized_word_idx"),
        ]

    def __str__(self) -> str:
        return self.word

    def clean(self) -> None:
        self.word = (self.word or "").strip()
        self.category = (self.category or "custom").strip() or "custom"
        self.normalized_word = normalize_text(self.word)
        if not self.normalized_word:
            raise ValidationError({"word": "敏感词归一化后不能为空"})
        if self.action != self.Action.BLOCK:
            raise ValidationError({"action": "MVP 只支持 block 动作"})

    def save(self, *args, **kwargs) -> None:
        self.full_clean()
        super().save(*args, **kwargs)