"""Документы ERP WaterSurf."""
from decimal import Decimal
from django.db import models
from django.db.models import Sum
from references.models import Currency, OrderKind, Client, Organization, Supplier, Employee, CashAccount, Product

class CustomerOrder(models.Model):
    date = models.DateField("Дата")
    number = models.CharField("Номер", max_length=50)
    order_kind = models.ForeignKey(OrderKind, on_delete=models.PROTECT, verbose_name="Вид заказа")
    organization = models.ForeignKey(Organization, on_delete=models.PROTECT, verbose_name="Организация")
    client = models.ForeignKey(Client, on_delete=models.PROTECT, verbose_name="Клиент")
    total_amount = models.DecimalField("Стоимость заказа", max_digits=18, decimal_places=2, default=Decimal("0"), editable=False)
    author = models.ForeignKey(Employee, on_delete=models.SET_NULL, null=True, blank=True, verbose_name="Автор", related_name="customer_orders")
    class Meta:
        verbose_name = "Заказ клиента"
        verbose_name_plural = "Заказы клиентов"
    def __str__(self): return f"{self.number} от {self.date}"
    def recalc_total(self): self.total_amount = sum((i.price * i.quantity for i in self.items.all()), Decimal("0"))

    def get_economics(self):
        """Сводка по поступлениям и расходам по заказу: поступления, расходы (через заказы поставщику + прямые), маржа, маржинальность, рентабельность."""
        total_inflows = self.cash_inflows.aggregate(s=Sum("amount"))["s"] or Decimal("0")
        expenses_via_supplier = CashExpense.objects.filter(supplier_order__customer_order=self).aggregate(s=Sum("amount"))["s"] or Decimal("0")
        expenses_direct = self.cash_expenses.aggregate(s=Sum("amount"))["s"] or Decimal("0")
        total_expenses = expenses_via_supplier + expenses_direct
        margin = total_inflows - total_expenses
        margin_pct = (margin / total_inflows * 100) if total_inflows else None
        profitability_pct = (margin / total_expenses * 100) if total_expenses else None
        return {
            "total_inflows": total_inflows,
            "expenses_via_supplier": expenses_via_supplier,
            "expenses_direct": expenses_direct,
            "total_expenses": total_expenses,
            "margin": margin,
            "margin_pct": margin_pct,
            "profitability_pct": profitability_pct,
        }

class CustomerOrderItem(models.Model):
    document = models.ForeignKey(CustomerOrder, on_delete=models.CASCADE, related_name="items", verbose_name="Заказ")
    product = models.ForeignKey(Product, on_delete=models.PROTECT, verbose_name="Товар")
    price = models.DecimalField("Цена", max_digits=18, decimal_places=2, default=Decimal("0"))
    currency = models.ForeignKey(Currency, on_delete=models.PROTECT, verbose_name="Валюта", null=True, blank=True)
    quantity = models.DecimalField("Количество", max_digits=18, decimal_places=4, default=Decimal("1"))
    amount = models.DecimalField("Стоимость", max_digits=18, decimal_places=2, default=Decimal("0"), editable=False)
    class Meta:
        verbose_name = "Строка заказа клиента"
        verbose_name_plural = "Строки заказа клиента"
    def save(self, *args, **kwargs):
        self.amount = self.price * self.quantity
        super().save(*args, **kwargs)


class SupplierOrder(models.Model):
    date = models.DateField("Дата")
    number = models.CharField("Номер", max_length=50)
    organization = models.ForeignKey(Organization, on_delete=models.PROTECT, verbose_name="Организация")
    supplier = models.ForeignKey(Supplier, on_delete=models.PROTECT, verbose_name="Поставщик")
    customer_order = models.ForeignKey(CustomerOrder, on_delete=models.SET_NULL, null=True, blank=True, verbose_name="Заказ клиента", related_name="supplier_orders")
    currency = models.ForeignKey(Currency, on_delete=models.PROTECT, verbose_name="Валюта")
    rate = models.DecimalField("Курс валюты", max_digits=18, decimal_places=6, default=Decimal("1"))
    total_in_currency = models.DecimalField("Стоимость в валюте", max_digits=18, decimal_places=2, default=Decimal("0"), editable=False)
    total_amount = models.DecimalField("Стоимость заказа", max_digits=18, decimal_places=2, default=Decimal("0"), editable=False)
    author = models.ForeignKey(Employee, on_delete=models.SET_NULL, null=True, blank=True, verbose_name="Автор", related_name="supplier_orders")
    class Meta:
        verbose_name = "Заказ поставщику"
        verbose_name_plural = "Заказы поставщику"
    def __str__(self): return f"{self.number} от {self.date}"
    def recalc_totals(self):
        self.total_in_currency = sum((i.price * i.quantity for i in self.items.all()), Decimal("0"))
        self.total_amount = self.total_in_currency * self.rate

class SupplierOrderItem(models.Model):
    document = models.ForeignKey(SupplierOrder, on_delete=models.CASCADE, related_name="items", verbose_name="Заказ поставщику")
    product = models.ForeignKey(Product, on_delete=models.PROTECT, verbose_name="Товар")
    price = models.DecimalField("Цена", max_digits=18, decimal_places=2, default=Decimal("0"))
    currency = models.ForeignKey(Currency, on_delete=models.PROTECT, verbose_name="Валюта", null=True, blank=True)
    quantity = models.DecimalField("Количество", max_digits=18, decimal_places=4, default=Decimal("1"))
    amount = models.DecimalField("Стоимость", max_digits=18, decimal_places=2, default=Decimal("0"), editable=False)
    class Meta:
        verbose_name = "Строка заказа поставщику"
        verbose_name_plural = "Строки заказа поставщику"
    def save(self, *args, **kwargs):
        self.amount = self.price * self.quantity
        super().save(*args, **kwargs)

class CashInflow(models.Model):
    date = models.DateField("Дата")
    number = models.CharField("Номер", max_length=50)
    recipient = models.ForeignKey(CashAccount, on_delete=models.PROTECT, verbose_name="Получатель", related_name="inflows")
    amount = models.DecimalField("Сумма", max_digits=18, decimal_places=2, default=Decimal("0"))
    customer_order = models.ForeignKey(CustomerOrder, on_delete=models.SET_NULL, null=True, blank=True, verbose_name="Заказ клиента", related_name="cash_inflows")
    comment = models.CharField("Комментарий", max_length=500, blank=True)
    author = models.ForeignKey(Employee, on_delete=models.SET_NULL, null=True, blank=True, verbose_name="Автор", related_name="cash_inflows")
    class Meta:
        verbose_name = "Поступление денежных средств"
        verbose_name_plural = "Поступления денежных средств"
    def __str__(self): return f"{self.number} от {self.date}"

class CashTransfer(models.Model):
    date = models.DateField("Дата")
    number = models.CharField("Номер", max_length=50)
    sender = models.ForeignKey(CashAccount, on_delete=models.PROTECT, verbose_name="Отправитель", related_name="transfers_sent")
    recipient = models.ForeignKey(CashAccount, on_delete=models.PROTECT, verbose_name="Получатель", related_name="transfers_received")
    amount = models.DecimalField("Сумма", max_digits=18, decimal_places=2, default=Decimal("0"))
    comment = models.CharField("Комментарий", max_length=500, blank=True)
    author = models.ForeignKey(Employee, on_delete=models.SET_NULL, null=True, blank=True, verbose_name="Автор", related_name="cash_transfers")
    class Meta:
        verbose_name = "Перемещение денежных средств"
        verbose_name_plural = "Перемещения денежных средств"
    def __str__(self): return f"{self.number} от {self.date}"

class CashExpense(models.Model):
    date = models.DateField("Дата")
    number = models.CharField("Номер", max_length=50)
    sender = models.ForeignKey(CashAccount, on_delete=models.PROTECT, verbose_name="Отправитель", related_name="expenses")
    amount = models.DecimalField("Сумма", max_digits=18, decimal_places=2, default=Decimal("0"))
    supplier_order = models.ForeignKey(SupplierOrder, on_delete=models.SET_NULL, null=True, blank=True, verbose_name="Заказ поставщику", related_name="cash_expenses")
    customer_order = models.ForeignKey(CustomerOrder, on_delete=models.SET_NULL, null=True, blank=True, verbose_name="Заказ клиента", related_name="cash_expenses")
    comment = models.CharField("Комментарий", max_length=500, blank=True)
    author = models.ForeignKey(Employee, on_delete=models.SET_NULL, null=True, blank=True, verbose_name="Автор", related_name="cash_expenses")
    class Meta:
        verbose_name = "Расход денежных средств"
        verbose_name_plural = "Расходы денежных средств"
    def __str__(self): return f"{self.number} от {self.date}"