from django.db import models
from django.utils.translation import gettext_lazy as _
from django.utils import timezone

class Users(models.Model):
    """核心用户模型 (继承现有结构)"""
    user_id = models.AutoField(primary_key=True, verbose_name="用户ID")
    name = models.CharField(max_length=80, verbose_name='姓名')
    openid = models.CharField(max_length=100, unique=True, verbose_name='OPENID')
    appid = models.CharField(max_length=100, verbose_name='APPID')
    
    # 权限系统
    vip = models.PositiveIntegerField(default=1, verbose_name='VIP等级')
    vip_time = models.DateTimeField(auto_now_add=True, verbose_name='VIP生效时间')
    
    # 账户状态
    is_delete = models.BooleanField(default=False, verbose_name='删除标记')
    developer = models.BooleanField(default=False, verbose_name='开发者标记')
    
    # 安全信息
    t_code = models.CharField(max_length=100, unique=True, verbose_name='交易验证码')
    ip = models.GenericIPAddressField(verbose_name='注册IP')
    
    # 基本信息
    avatar = models.CharField(max_length=200, default='/static/img/user.jpg', verbose_name='用户头像')
    create_time = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')
    update_time = models.DateTimeField(auto_now=True, verbose_name='更新时间')

    class Meta:
        db_table = 'user_profile'
        verbose_name = '用户档案'
        verbose_name_plural = "用户档案"
        ordering = ['-create_time']

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

class AcademicProfile(models.Model):
    """学术信息扩展模型 (与用户一对一关联)"""
    class AcademicRole(models.TextChoices):
        UNDERGRAD = 'UG', _('本科生')
        MASTER = 'MS', _('硕士生')
        PHD = 'PhD', _('博士生')
        POSTDOC = 'PD', _('博士后')
        FACULTY = 'FAC', _('教职工')
        RESEARCHER = 'RES', _('研究员')
    
    user = models.OneToOneField(
        Users,
        on_delete=models.CASCADE,
        primary_key=True,
        related_name='user_academic_profile',
        verbose_name='关联用户'
    )
    # 学术身份
    role = models.CharField(
        max_length=10,
        choices=AcademicRole.choices,
        default=AcademicRole.MASTER,
        verbose_name='学术身份'
    )
    # 年级信息
    enrollment_year = models.PositiveIntegerField(
        verbose_name='入学年份',
        help_text='格式：YYYY（如2023）'
    )
    graduation_year = models.PositiveIntegerField(
        null=True,
        blank=True,
        verbose_name='预计毕业年份'
    )
    # 学术单位
    department = models.CharField(max_length=100, verbose_name='院系/研究所')
    major = models.CharField(max_length=100, verbose_name='专业方向')
    
    # 研究标签
    research_tags = models.CharField(
        max_length=255,
        blank=True,
        verbose_name='研究方向',
        help_text='用逗号分隔多个方向（如：人工智能,教育技术）'
    )
    skill_tags = models.CharField(
        max_length=255,
        blank=True,
        verbose_name='技能标签',
        help_text='用逗号分隔多个技能（如：Python,数据分析）'
    )
    
    class Meta:
        db_table = 'user_academic_profile'
        verbose_name = '学术档案'
        verbose_name_plural = "学术档案"
    
    def __str__(self):
        return f"{self.user.name}的学术档案"

class ResearchGroup(models.Model):
    """教研小组模型"""
    group_id = models.AutoField(primary_key=True, verbose_name="小组ID")
    name = models.CharField(max_length=100, unique=True, verbose_name="小组名称")
    description = models.TextField(blank=True, verbose_name="小组描述")
    created_by = models.ForeignKey(
        Users,
        on_delete=models.SET_NULL,
        null=True,
        related_name='created_groups',
        verbose_name="创建人"
    )
    created_at = models.DateTimeField(auto_now_add=True, verbose_name="创建时间")
    is_active = models.BooleanField(default=True, verbose_name="是否活跃")
    
    class Meta:
        db_table = 'user_research_group'
        verbose_name = '教研小组'
        verbose_name_plural = "教研小组"
        ordering = ['-created_at']
    
    def __str__(self):
        return f"{self.name}(ID:{self.group_id})"

class GroupMembership(models.Model):
    """小组成员关联模型"""
    class MemberRole(models.TextChoices):
        LEADER = 'LEAD', _('组长')
        DEPUTY = 'DEP', _('副组长')
        CORE = 'CORE', _('核心成员')
        MEMBER = 'MEM', _('普通成员')
        ADVISOR = 'ADV', _('指导老师')
        OBSERVER = 'OBS', _('观察员')
    
    class MemberStatus(models.TextChoices):
        ACTIVE = 'ACT', _('活跃')
        LEAVE = 'LV', _('请假')
        INACTIVE = 'INAC', _('不活跃')
        GRADUATED = 'GRAD', _('已毕业')
        TRANSFERRED = 'TRF', _('已转组')
    
    user = models.ForeignKey(
        Users,
        on_delete=models.CASCADE,
        related_name='group_memberships',
        verbose_name="成员"
    )
    group = models.ForeignKey(
        ResearchGroup,
        on_delete=models.CASCADE,
        related_name='members',
        verbose_name="所属小组"
    )
    role = models.CharField(
        max_length=20,
        choices=MemberRole.choices,
        default=MemberRole.MEMBER,
        verbose_name="小组角色"
    )
    status = models.CharField(
        max_length=10,
        choices=MemberStatus.choices,
        default=MemberStatus.ACTIVE,
        verbose_name="在组状态"
    )
    joined_at = models.DateTimeField(auto_now_add=True, verbose_name="加入时间")
    left_at = models.DateTimeField(null=True, blank=True, verbose_name="离开时间")
    custom_permissions = models.JSONField(
        null=True,
        blank=True,
        default=dict,
        verbose_name="特殊权限",
        help_text="JSON格式存储额外权限"
    )
    
    class Meta:
        db_table = 'user_group_membership'
        verbose_name = '小组成员'
        verbose_name_plural = "小组成员"
        unique_together = ('user', 'group')  # 确保同一用户不会重复加入同一小组
        ordering = ['-joined_at']
    
    def save(self, *args, **kwargs):
        """自动更新离开时间"""
        if self.status in [self.MemberStatus.GRADUATED, self.MemberStatus.TRANSFERRED] and not self.left_at:
            self.left_at = timezone.now()
        super().save(*args, **kwargs)
    
    def __str__(self):
        return f"{self.user.name}在{self.group.name}({self.get_role_display()})"