from django.db import models


class Region(models.Model):
    """Region model for hierarchical administrative divisions."""

    LEVEL_CHOICES = [
        ('province', '省'),
        ('city', '市'),
        ('county', '县'),
        ('town', '乡镇/街道'),
        ('village', '村/居委会'),
    ]

    STATUS_CHOICES = [
        ('active', '正常'),
        ('inactive', '停用'),
    ]

    name = models.CharField(max_length=100, verbose_name='版块名称')
    level = models.CharField(max_length=20, choices=LEVEL_CHOICES, verbose_name='版块级别')
    parent = models.ForeignKey(
        'self',
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name='children',
        verbose_name='上级版块'
    )
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='active', verbose_name='状态')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')
    updated_at = models.DateTimeField(auto_now=True, verbose_name='更新时间')

    class Meta:
        db_table = 'regions'
        verbose_name = '版块'
        verbose_name_plural = '版块'
        ordering = ['level', 'name']

    def __str__(self):
        return self.name

    def get_full_path(self):
        """Get the full hierarchical path of this region."""
        path = [self.name]
        parent = self.parent
        while parent:
            path.insert(0, parent.name)
            parent = parent.parent
        return ' → '.join(path)

    def get_children(self):
        """Get all direct children of this region."""
        return self.children.filter(status='active')