from django.db import models
from django.utils import timezone


class Region(models.Model):
    """版块/区域表 - 省市区乡镇村层级结构"""
    LEVEL_CHOICES = [
        ('province', '省级'),
        ('city', '市级'),
        ('county', '县级'),
        ('town', '镇级'),
        ('village', '村级'),
    ]
    
    name = models.CharField('名称', max_length=100)
    level = models.CharField('级别', max_length=20, choices=LEVEL_CHOICES)
    parent = models.ForeignKey(
        'self', 
        null=True, 
        blank=True, 
        on_delete=models.CASCADE,
        related_name='children',
        verbose_name='上级区域'
    )
    code = models.CharField('行政区划代码', max_length=20, blank=True)
    description = models.TextField('描述', blank=True)
    created_at = models.DateTimeField('创建时间', auto_now_add=True)
    updated_at = models.DateTimeField('更新时间', auto_now=True)
    is_active = models.BooleanField('是否启用', default=True)
    
    class Meta:
        verbose_name = '区域'
        verbose_name_plural = '区域'
        ordering = ['level', 'name']
    
    def __str__(self):
        return f"{self.name} ({self.get_level_display()})"
    
    def get_full_path(self):
        """获取完整路径"""
        path = [self.name]
        current = self.parent
        while current:
            path.append(current.name)
            current = current.parent
        return ' > '.join(reversed(path))


class ModeratorApplication(models.Model):
    """版主申请表"""
    STATUS_CHOICES = [
        ('pending', '待审核'),
        ('approved', '已通过'),
        ('rejected', '已拒绝'),
        ('cancelled', '已取消'),
    ]
    
    applicant = models.ForeignKey(
        'users.User', 
        on_delete=models.CASCADE,
        related_name='moderator_applications',
        verbose_name='申请者'
    )
    region = models.ForeignKey(
        Region, 
        on_delete=models.CASCADE,
        related_name='moderator_applications',
        verbose_name='申请区域'
    )
    application_reason = models.TextField('申请理由', blank=True)
    support_count = models.PositiveIntegerField('支持人数', default=0)
    required_support = models.PositiveIntegerField('所需支持人数', default=10)
    deadline = models.DateTimeField('截止时间')
    status = models.CharField('状态', max_length=20, choices=STATUS_CHOICES, default='pending')
    reviewer = models.ForeignKey(
        'users.User',
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name='reviewed_applications',
        verbose_name='审核人'
    )
    reviewed_at = models.DateTimeField('审核时间', null=True, blank=True)
    review_comment = models.TextField('审核意见', blank=True)
    created_at = models.DateTimeField('申请时间', auto_now_add=True)
    
    class Meta:
        verbose_name = '版主申请'
        verbose_name_plural = '版主申请'
        ordering = ['-created_at']
    
    def __str__(self):
        return f"{self.applicant.username} 申请 {self.region.name} 版主"
    
    def is_expired(self):
        return timezone.now() > self.deadline
    
    def auto_cancel_if_failed(self):
        """如果截止且支持人数不足，自动取消"""
        if self.is_expired() and self.status == 'pending' and self.support_count < self.required_support:
            self.status = 'cancelled'
            self.save()
            return True
        return False


class ModeratorSupport(models.Model):
    """版主申请支持表"""
    supporter = models.ForeignKey(
        'users.User',
        on_delete=models.CASCADE,
        related_name='moderator_supports',
        verbose_name='支持者'
    )
    application = models.ForeignKey(
        ModeratorApplication,
        on_delete=models.CASCADE,
        related_name='supports',
        verbose_name='申请'
    )
    created_at = models.DateTimeField('支持时间', auto_now_add=True)
    
    class Meta:
        verbose_name = '支持记录'
        verbose_name_plural = '支持记录'
        unique_together = ['supporter', 'application']
    
    def __str__(self):
        return f"{self.supporter.username} 支持 {self.application}"


class ModeratorPermission(models.Model):
    """版主权限表"""
    RANK_CHOICES = [
        ('general', '将军'),  # 省级
        ('colonel', '校官'),  # 市级
        ('lieutenant', '尉官'),  # 县级
        ('soldier', '士兵'),  # 镇村级
    ]
    
    STATUS_CHOICES = [
        ('active', '正常'),
        ('restricted', '限制'),
        ('revoked', '取消'),
    ]
    
    moderator = models.ForeignKey(
        'users.User',
        on_delete=models.CASCADE,
        related_name='moderator_permissions',
        verbose_name='版主'
    )
    region = models.ForeignKey(
        Region,
        on_delete=models.CASCADE,
        related_name='moderator_permissions',
        verbose_name='管辖区域'
    )
    rank = models.CharField('军衔', max_length=20, choices=RANK_CHOICES)
    status = models.CharField('状态', max_length=20, choices=STATUS_CHOICES, default='active')
    created_at = models.DateTimeField('授权时间', auto_now_add=True)
    restricted_until = models.DateTimeField('限制截止时间', null=True, blank=True)
    
    class Meta:
        verbose_name = '版主权限'
        verbose_name_plural = '版主权限'
        unique_together = ['moderator', 'region']
    
    def __str__(self):
        return f"{self.moderator.username} - {self.region.name} ({self.get_rank_display()})"
    
    def can_moderate(self, content_region):
        """判断是否可以审核某个区域的内容"""
        if self.status != 'active':
            return False
        
        # 检查是否在管辖范围内
        current = content_region
        while current:
            if current.id == self.region.id:
                return True
            current = current.parent
        return False


class PermissionRestriction(models.Model):
    """权限限制表"""
    operator = models.ForeignKey(
        'users.User',
        on_delete=models.CASCADE,
        related_name='permission_restrictions_made',
        verbose_name='操作者'
    )
    restricted_moderator = models.ForeignKey(
        'users.User',
        on_delete=models.CASCADE,
        related_name='permission_restrictions',
        verbose_name='被限制版主'
    )
    restriction_type = models.CharField('限制类型', max_length=20, choices=[
        ('partial', '部分限制'),
        ('full', '完全限制'),
    ])
    started_at = models.DateTimeField('限制开始时间', auto_now_add=True)
    ended_at = models.DateTimeField('限制结束时间', null=True, blank=True)
    reason = models.TextField('限制原因', blank=True)
    
    class Meta:
        verbose_name = '权限限制'
        verbose_name_plural = '权限限制'
        ordering = ['-started_at']
    
    def __str__(self):
        return f"{self.restricted_moderator.username} 被限制 ({self.restriction_type})"