Initial version of the E-Invoice solution of JR IT Services

jr_einvoice/models.py

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+from __future__ import annotations
+from datetime import date
+from pydantic import BaseModel, Field, field_validator
+from typing import List, Optional
+
+class Address(BaseModel):
+    street: str
+    postal_code: str
+    city: str
+    country: str = Field(min_length=2, max_length=2)
+
+class Party(BaseModel):
+    name: str
+    vat_id: Optional[str] = None
+    tax_number: Optional[str] = None
+    email: Optional[str] = None
+    address: Address
+
+    @field_validator("email")
+    @classmethod
+    def _email_shape(cls, v: Optional[str]):
+        if v is None:
+            return v
+        if "@" not in v or "." not in v.split("@")[-1]:
+            raise ValueError("email does not look valid")
+        return v
+
+class Meta(BaseModel):
+    invoice_number: str = Field(min_length=1)
+    invoice_date: date
+    service_date: date
+    currency: str = Field(min_length=3, max_length=3, default="EUR")
+    language: Optional[str] = "de"
+    notes: Optional[str] = None
+
+class Payment(BaseModel):
+    due_date: date
+    reference: str = Field(min_length=1)
+    iban: Optional[str] = None
+    bic: Optional[str] = None
+    bank_name: Optional[str] = None
+
+class Item(BaseModel):
+    name: str = Field(min_length=1)
+    description: Optional[str] = None
+    quantity: float = Field(gt=0)
+    unit: str = Field(min_length=1)  # e.g. HUR, C62
+    unit_price_net: float = Field(ge=0)
+    tax_rate: float = Field(ge=0, le=100)
+
+class Invoice(BaseModel):
+    meta: Meta
+    seller: Party
+    buyer: Party
+    payment: Payment
+    items: List[Item]