from django.contrib.auth.models import AbstractBaseUser, PermissionsMixin
from django.db import models
from django.utils import timezone
from django.contrib.auth.base_user import BaseUserManager

from apps.common.models import BaseModel, SoftDeleteModel


class UserManager(BaseUserManager):
    def get_queryset(self):
        # 默认管理器只返回未删除（未停用）用户；停用用户无法登录/被列出
        return super().get_queryset().filter(is_deleted=False)

    def create_user(self, username, password=None, **extra_fields):
        if not username:
            raise ValueError('用户名不能为空')
        user = self.model(username=username, **extra_fields)
        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_superuser(self, username, password=None, **extra_fields):
        extra_fields.setdefault('is_staff', True)
        extra_fields.setdefault('is_superuser', True)
        extra_fields.setdefault('status', 1)
        return self.create_user(username, password, **extra_fields)


class User(AbstractBaseUser, PermissionsMixin, BaseModel):
    """用户表"""
    GENDER_CHOICES = [
        (0, '未知'),
        (1, '男'),
        (2, '女'),
    ]
    STATUS_CHOICES = [
        (0, '禁用'),
        (1, '正常'),
    ]

    id = models.BigAutoField(primary_key=True)
    username = models.CharField('用户名', max_length=50, unique=True)
    password = models.CharField('密码', max_length=255)
    real_name = models.CharField('真实姓名', max_length=50, blank=True)
    phone = models.CharField('手机号', max_length=20, unique=True, blank=True)
    avatar = models.CharField('头像', max_length=255, blank=True)
    gender = models.SmallIntegerField('性别', choices=GENDER_CHOICES, default=0)
    role_type = models.CharField('主角色', max_length=30, blank=True)
    institution = models.ForeignKey(
        'user.Institution', on_delete=models.SET_NULL,
        null=True, blank=True, verbose_name='所属机构'
    )
    department = models.ForeignKey(
        'user.Department', on_delete=models.SET_NULL,
        null=True, blank=True, verbose_name='所属科室'
    )
    title_name = models.CharField('职称', max_length=50, blank=True)
    practice_years = models.CharField('执业年限', max_length=20, blank=True)
    major = models.CharField('专业', max_length=100, blank=True)
    training_stage = models.CharField('培训阶段', max_length=50, blank=True)
    learning_target = models.CharField('学习目标', max_length=255, blank=True)
    competency_profile = models.JSONField('能力画像', default=dict, blank=True)
    weak_dimensions = models.JSONField('薄弱项', default=list, blank=True)
    strong_dimensions = models.JSONField('优势项', default=list, blank=True)
    ai_preference = models.JSONField('AI训练偏好', default=dict, blank=True)
    total_training_count = models.IntegerField('总训练次数', default=0)
    total_case_count = models.IntegerField('完成病例数', default=0)
    current_level = models.CharField('当前能力等级', max_length=30, blank=True)
    status = models.SmallIntegerField('状态', choices=STATUS_CHOICES, default=1)
    last_login_time = models.DateTimeField('最后登录', null=True, blank=True)

    # Django required fields
    is_staff = models.BooleanField('staff status', default=False)
    is_active = models.BooleanField('active', default=True)
    date_joined = models.DateTimeField('date joined', default=timezone.now)

    # 软删除（停用 = 逻辑删除）
    is_deleted = models.BooleanField('是否删除', default=False, db_index=True)
    deleted_at = models.DateTimeField('删除时间', null=True, blank=True)

    objects = UserManager()           # 默认：仅未删除
    all_objects = BaseUserManager()   # 含已删除（管理/恢复用）

    USERNAME_FIELD = 'username'
    REQUIRED_FIELDS = []

    class Meta:
        db_table = 'user'
        verbose_name = '用户'
        verbose_name_plural = '用户'

    def __str__(self):
        return self.username

    def delete(self, using=None, keep_parents=False):
        """停用 = 逻辑删除（不物理删除，避免级联丢数据）。"""
        self.is_deleted = True
        self.deleted_at = timezone.now()
        self.save(using=using, update_fields=['is_deleted', 'deleted_at', 'updated_at'])

    def hard_delete(self, using=None, keep_parents=False):
        super().delete(using=using, keep_parents=keep_parents)


class Role(BaseModel):
    """角色表"""
    id = models.BigAutoField(primary_key=True)
    role_code = models.CharField('角色编码', max_length=50, unique=True)
    role_name = models.CharField('角色名称', max_length=50)

    class Meta:
        db_table = 'role'
        verbose_name = '角色'
        verbose_name_plural = '角色'

    def __str__(self):
        return self.role_name


class TeacherStudentRelation(SoftDeleteModel):
    """师生关系表"""
    STATUS_CHOICES = [
        (0, '已结束'),
        (1, '进行中'),
    ]

    id = models.BigAutoField(primary_key=True)
    teacher = models.ForeignKey(
        User, on_delete=models.CASCADE,
        related_name='teacher_relations', verbose_name='带教老师'
    )
    student = models.ForeignKey(
        User, on_delete=models.CASCADE,
        related_name='student_relations', verbose_name='学员'
    )
    relation_type = models.CharField('关系类型', max_length=30, blank=True)
    start_time = models.DateTimeField('开始时间', null=True, blank=True)
    end_time = models.DateTimeField('结束时间', null=True, blank=True)
    status = models.SmallIntegerField('状态', choices=STATUS_CHOICES, default=1)

    class Meta:
        db_table = 'teacher_student_relation'
        verbose_name = '师生关系'
        verbose_name_plural = '师生关系'

    def __str__(self):
        return f"{self.teacher.real_name or self.teacher.username} -> {self.student.real_name or self.student.username}"


class Institution(SoftDeleteModel):
    """医疗机构表"""

    id = models.BigAutoField(primary_key=True)
    code = models.CharField('机构编码', max_length=100, unique=True)
    name = models.CharField('名称', max_length=255)
    type = models.CharField('类型', max_length=30, default='hospital', blank=True)
    level = models.CharField('等级', max_length=30, blank=True)
    province = models.CharField('省份', max_length=50, blank=True)
    city = models.CharField('城市', max_length=50, blank=True)
    banner_url = models.CharField(
        '机构Banner图', max_length=500, blank=True,
        help_text='机构专属图片：可为静态相对路径（如 institutions/xxx.png）或完整 http(s) URL'
    )

    class Meta:
        db_table = 'institution'
        verbose_name = '机构'
        verbose_name_plural = '机构'

    def __str__(self):
        return self.name


class Department(SoftDeleteModel):
    """科室表（全局分类表，与机构无关；仅超级管理员维护，用于给病例分类）"""
    id = models.BigAutoField(primary_key=True)
    name = models.CharField('科室名称', max_length=100)
    category = models.CharField('科室分类', max_length=50, blank=True)

    class Meta:
        db_table = 'department'
        verbose_name = '科室'
        verbose_name_plural = '科室'

    def __str__(self):
        return self.name