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]