from django.db import models
from django.db.models import Sum
from django.db.models.signals import post_save, post_delete
from django.dispatch import receiver
from django.db import transaction  # اصلاح فیکس خطای تراکنش
from django.contrib.auth.models import User
from django.contrib.auth import get_user_model

userModel = get_user_model()


# اصلاح مدل کاربر: تبدیل به پروفایل برای حفظ امنیت و اتصال به سیستم پیش‌فرض جنگو
class UserProfile(models.Model):
    UserTypeList = [
        ('admin', 'admin'),
        ('office', 'office'),
        ('operator', 'operator'),
    ]
    user = models.OneToOneField(User, on_delete=models.CASCADE, related_name='profile')
    user_type = models.CharField(max_length=10, choices=UserTypeList)
    name_family = models.CharField(max_length=200)
    create_date = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return f"{self.user.username} ({self.user_type})"


class Customer(models.Model):
    class Meta:
        permissions = [
            ("AddCustomer", "AddCustomer"),
            ("DelCustomer", "DelCustomer"),
            ("EditCustomer", "EditCustomer"),
            ("ViewCustomer", "ViewCustomer")
        ]
    name_family = models.CharField(max_length=200)
    address = models.CharField(max_length=200)
    phone1 = models.CharField(max_length=20, default='')
    phone2 = models.CharField(max_length=20, default='', null=True, blank=True)
    phone3 = models.CharField(max_length=20, default='', null=True, blank=True)
    idCode = models.CharField(max_length=20, default='', null=True, blank=True)
    installDate = models.DateField(auto_now_add=True)
    create_date = models.DateTimeField(auto_now_add=True)
    last_bazdid_dt = models.DateTimeField(null=True, blank=True)
    laghv_bazdid = models.BooleanField(null=True, blank=True, default=False)

    def __str__(self):
        return self.name_family


class PhoneNumber(models.Model):
    customer = models.ForeignKey(Customer, on_delete=models.CASCADE)
    phone_number = models.CharField(max_length=11)


class StoreRoom(models.Model):
    class Meta:
        permissions = [
            ("ViewStore", "ViewStore"),
            ("AddStore", "AddStore"),
            ("EditStore", "EditStore"),
            ("DelStore", "DelStore")
        ]
    store_name = models.CharField(max_length=200)
    user = models.ManyToManyField(User, blank=True)

    def __str__(self):
        return self.store_name


class ProductCategory(models.Model):
    category_name = models.CharField(max_length=50)

    def __str__(self):
        return self.category_name


class Product(models.Model):
    class Meta:
        permissions = [
            ("ViewProduct", "ViewProduct"),
        ]
    ProductCategory = models.ForeignKey(ProductCategory, on_delete=models.CASCADE)
    product_name = models.CharField(max_length=50)
    product_price = models.IntegerField()
    year = models.IntegerField(default=1400)
    createdDT = models.DateTimeField(auto_now_add=True)
    changeDT = models.DateTimeField(auto_now=True)

    def __str__(self):
        return self.product_name


class Factor(models.Model):
    class Meta:
        permissions = [
            ("ViewFactor", "ViewFactor"),
            ("DelFactor", "DelFactor"),
            ("EditFactor", "EditFactor"),
            ("AddFactor", "AddFactor")
        ]
    customer = models.ForeignKey(Customer, on_delete=models.CASCADE)
    create_date = models.DateTimeField(auto_now_add=True)
    amount = models.IntegerField()
    discount = models.IntegerField(null=True, blank=True)
    deadline = models.DateTimeField(null=True, blank=True)
    desc = models.CharField(max_length=100, default='')
    user = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, blank=True)
    statusList = [
        ('unpaid', 'unpaid'),
        ('paid', 'paid'),
        ('cancell', 'cancell'),
    ]
    pay_status = models.CharField(max_length=10, choices=statusList, default='')
    FactorTypeList = [
        ('Nasb', 'Nasb'),
        ('Khadamat', 'Khadamat'),
        ('Garranty', 'Garranty'),
    ]
    FactorType = models.CharField(max_length=10, choices=FactorTypeList, default='')
    PayTypeList = [
        ('naghd', 'naghd'),
        ('cardToCard', 'cardToCard'),
        ('kartKhan', 'kartKhan'),
        ('nesiye', 'nesiye'),
        ('check', 'check'),
    ]
    PayType = models.CharField(max_length=30, choices=PayTypeList, default='')


# --- مدل اصلاح شده انبار با کارایی فوق‌العاده بالا ---
class ProductInStore(models.Model):
    StoreRoom = models.ForeignKey(StoreRoom, on_delete=models.CASCADE)
    Product = models.ForeignKey(Product, on_delete=models.CASCADE)
    s_in = models.IntegerField(default=0)
    s_out = models.IntegerField(default=0)
    
    # اضافه شدن این فیلد دیتابیسی، نیاز به کوئری‌های سنگین در تمپلیت را صفر می‌کند
    current_stock_at_time = models.IntegerField(default=0, help_text="موجودی انبار در لحظه این تراکنش")
    
    desc = models.CharField(max_length=50, default='')
    year = models.IntegerField(default=1400)
    createdDT = models.DateTimeField(auto_now_add=True)
    changeDT = models.DateTimeField(auto_now=True)
    factor = models.ForeignKey(Factor, on_delete=models.CASCADE, null=True, blank=True)

    def __str__(self):
        return f"{self.Product.product_name} - In: {self.s_in} Out: {self.s_out}"


class ProductStockHistory(models.Model):
    store_room = models.ForeignKey(StoreRoom, on_delete=models.CASCADE, related_name='stock_histories')
    product = models.ForeignKey(Product, on_delete=models.CASCADE, related_name='stock_histories')
    quantity_changed = models.IntegerField(help_text="مقدار تغییر یافته (مثبت برای ورود، منفی برای خروج)")
    current_stock = models.IntegerField(help_text="موجودی کل انبار در این لحظه")
    created_at = models.DateTimeField(auto_now_add=True)
    desc = models.CharField(max_length=255, blank=True, null=True)

    class Meta:
        ordering = ['-created_at']

    def __str__(self):
        return f"{self.product.product_name} in {self.store_room.store_name} - Stock: {self.current_stock}"


# تابع کمکی بهینه‌سازی شده برای محاسبه و ثبت همزمان در تراکنش و تاریخچه
def recalculate_and_log_stock(store_room, product, change_amount, description, current_instance=None):
    with transaction.atomic():
        # قفل کردن ردیف‌ها برای همزمانی ایمن
        qs = ProductInStore.objects.filter(StoreRoom=store_room, Product=product).select_for_update()
        
        totals = qs.aggregate(
            total_in=Sum('s_in'),
            total_out=Sum('s_out')
        )
        
        total_in = totals['total_in'] or 0
        total_out = totals['total_out'] or 0
        current_stock = total_in - total_out
        
        # اگر این تابع از سمت سِیو تراکنش صدا زده شده، فیلد لحظه‌ای آن را پر سرعتمان آپدیت می‌کنیم
        if current_instance:
            ProductInStore.objects.filter(pk=current_instance.pk).update(current_stock_at_time=current_stock)
        
        # ثبت ردیف در جدول تاریخچه کل
        ProductStockHistory.objects.create(
            store_room=store_room,
            product=product,
            quantity_changed=change_amount,
            current_stock=current_stock,
            desc=description
        )


@receiver(post_save, sender=ProductInStore)
def update_stock_history_on_save(sender, instance, created, **kwargs):
    if created:
        change = instance.s_in - instance.s_out
        recalculate_and_log_stock(
            store_room=instance.StoreRoom,
            product=instance.Product,
            change_amount=change,
            description=instance.desc or "ثبت تراکنش جدید انبار",
            current_instance=instance
        )
    else:
        recalculate_and_log_stock(
            store_room=instance.StoreRoom,
            product=instance.Product,
            change_amount=0,
            description=f"ویرایش تراکنش قبلی: {instance.desc}",
            current_instance=instance
        )


@receiver(post_delete, sender=ProductInStore)
def update_stock_history_on_delete(sender, instance, **kwargs):
    recalculate_and_log_stock(
        store_room=instance.StoreRoom,
        product=instance.Product,
        change_amount=-(instance.s_in - instance.s_out),
        description=f"حذف تراکنش قبلی انبار: {instance.desc}"
    )


# --- ادامه مدل‌های سیستم شما بدون تغییر بسامدی ---

class FactorIteam(models.Model):  # پیشنهاد: در آینده املای نام این کلاس را به FactorItem اصلاح کنید
    factor = models.ForeignKey(Factor, on_delete=models.CASCADE)
    product = models.ForeignKey(Product, on_delete=models.CASCADE, null=True, blank=True)
    product_name = models.CharField(max_length=200, default='')
    num = models.IntegerField()
    amount = models.IntegerField()
    garantyEsh = models.CharField(max_length=100, default='', null=True, blank=True)


class VisitQueue(models.Model):
    customer = models.ForeignKey(Customer, on_delete=models.CASCADE)
    dateTime = models.DateTimeField()
    statusList = [
        ('waiting', 'waiting'),
        ('finish', 'finish'),
        ('cancell', 'cancell'),
    ]
    status = models.CharField(max_length=10, choices=statusList, default='waiting')
    user = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, blank=True)
    GradeList = [
        ('3', '3'),
        ('2', '2'),
        ('1', '1'),
    ]
    grade = models.CharField(max_length=1, choices=GradeList)
    grade_desc = models.CharField(max_length=200)


class ArticleType(models.Model):
    name = models.CharField(max_length=50)


class Article(models.Model):
    class Meta:
        permissions = [
            ("ViewReportMali", "ViewReportMali")
        ]
    debit = models.IntegerField(null=True, blank=True)
    credit = models.IntegerField(null=True, blank=True)
    customer = models.ForeignKey(Customer, on_delete=models.CASCADE, null=True, blank=True)
    factor = models.ForeignKey(Factor, on_delete=models.CASCADE, null=True, blank=True)
    type = models.CharField(max_length=50, null=True, blank=True)
    typePy = models.CharField(max_length=50, null=True, blank=True)
    checkNum = models.IntegerField(null=True, blank=True)
    nahvePardakht = models.CharField(max_length=50, null=True, blank=True)
    sarresid = models.DateTimeField(null=True, blank=True)
    payStatus = models.CharField(max_length=50, null=True, blank=True)
    createdDT = models.DateTimeField(auto_now_add=True)
    changeDT = models.DateTimeField(auto_now=True)
    desc = models.CharField(max_length=200)
    user = models.ForeignKey(userModel, on_delete=models.SET_NULL, null=True, blank=True)


class Action(models.Model):
    actionType = models.CharField(max_length=50, null=True, blank=True)
    forUser = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, blank=True)
    customer = models.ForeignKey(Customer, related_name='actionrlt', on_delete=models.CASCADE, null=True, blank=True)
    createdDT = models.DateTimeField(auto_now_add=True)
    changeDT = models.DateTimeField(auto_now=True)
    actionDateTime = models.DateTimeField(null=True, blank=True)
    finishDateTime = models.DateTimeField(null=True, blank=True)
    desc = models.CharField(max_length=500, null=True, blank=True)
    result = models.CharField(max_length=500, null=True, blank=True)
    status = models.CharField(max_length=50, null=True, blank=True)
    nazar = models.CharField(max_length=50, null=True, blank=True, default=None)
    nazarDT = models.DateTimeField(null=True, blank=True, default=None)
    grade = models.IntegerField(null=True, blank=True, default=None)


class Sarresid(models.Model):
    customer = models.ForeignKey(Customer, on_delete=models.CASCADE, null=True, blank=True)
    createdDT = models.DateTimeField(auto_now_add=True)
    changeDT = models.DateTimeField(auto_now=True)
    price = models.IntegerField(null=False, blank=False)
    payStatus = models.CharField(max_length=50, null=True, blank=True)
    type = models.CharField(max_length=50, null=True, blank=True)
    factor = models.ForeignKey(Factor, on_delete=models.CASCADE, null=True, blank=True)
    sarresidDT = models.DateTimeField(null=True, blank=True)
    user = models.ForeignKey(userModel, on_delete=models.SET_NULL, null=True, blank=True)
    desc = models.TextField(null=True, blank=True)


class CacheTable(models.Model):
    key = models.CharField(max_length=50, unique=True)
    value = models.CharField(max_length=400)

    def __str__(self):
        return f'{self.key} # {self.value}'