from django.db import models
from datetime import date


class Contact(models.Model):
    name = models.CharField(max_length=100, verbose_name='姓名')
    phone = models.CharField(max_length=20, verbose_name='联系电话')
    email = models.EmailField(blank=True, null=True, verbose_name='邮箱')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = '联系人'
        verbose_name_plural = '联系人'


class Supplier(models.Model):
    company_name = models.CharField(max_length=200, verbose_name='公司名称')
    contact_person = models.CharField(max_length=100, verbose_name='联系人')
    phone = models.CharField(max_length=20, verbose_name='联系电话')
    email = models.EmailField(blank=True, null=True, verbose_name='邮箱')
    address = models.CharField(max_length=500, blank=True, null=True, verbose_name='地址')
    remark = models.TextField(blank=True, null=True, verbose_name='备注')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

    def __str__(self):
        return self.company_name

    class Meta:
        verbose_name = '维保供应商'
        verbose_name_plural = '维保供应商'


class UPSHost(models.Model):
    brand = models.CharField(max_length=100, verbose_name='品牌')
    model = models.CharField(max_length=100, verbose_name='型号')
    ip_address = models.CharField(max_length=50, verbose_name='IP地址')
    quantity = models.IntegerField(default=1, verbose_name='数量')
    location = models.CharField(max_length=200, verbose_name='存放位置')
    last_maintenance_date = models.DateField(blank=True, null=True, verbose_name='上次维保时间')
    contact = models.ForeignKey(Contact, on_delete=models.SET_NULL, blank=True, null=True, verbose_name='联系人')
    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')

    def __str__(self):
        if self.ip_address and not self.ip_address.startswith('-'):
            return f'{self.brand} {self.model} - {self.ip_address}'
        return f'{self.brand} {self.model}'

    class Meta:
        verbose_name = 'UPS主机'
        verbose_name_plural = 'UPS主机'


class Battery(models.Model):
    brand = models.CharField(max_length=100, verbose_name='品牌')
    model = models.CharField(max_length=100, verbose_name='型号')
    weight = models.FloatField(verbose_name='重量(kg)')
    quantity = models.IntegerField(default=1, verbose_name='数量')
    location = models.CharField(max_length=200, verbose_name='存放位置')
    install_date = models.DateField(blank=True, null=True, verbose_name='安装日期')
    last_maintenance_date = models.DateField(blank=True, null=True, verbose_name='上次维保时间')
    ups_host = models.ForeignKey(UPSHost, on_delete=models.SET_NULL, blank=True, null=True, verbose_name='关联UPS主机')
    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')

    @property
    def used_years(self):
        if not self.install_date:
            return None
        today = date.today()
        delta = today - self.install_date
        return round(delta.days / 365.25, 1)

    def __str__(self):
        return f'{self.brand} {self.model}'

    class Meta:
        verbose_name = '电池'
        verbose_name_plural = '电池'


class MaintenanceRecord(models.Model):
    ups_host = models.ForeignKey(UPSHost, on_delete=models.CASCADE, verbose_name='UPS主机')
    battery = models.ForeignKey(Battery, on_delete=models.SET_NULL, blank=True, null=True, verbose_name='电池')
    supplier = models.ForeignKey(Supplier, on_delete=models.SET_NULL, blank=True, null=True, verbose_name='维保供应商')
    maintenance_date = models.DateField(verbose_name='维修日期')
    content = models.TextField(verbose_name='维修内容')
    technician = models.CharField(max_length=100, verbose_name='维修人员')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

    def __str__(self):
        return f'{self.ups_host} - {self.maintenance_date}'

    class Meta:
        verbose_name = '维修记录'
        verbose_name_plural = '维修记录'