"""Pydantic schemas for contact-related request and response bodies."""

import uuid
from datetime import datetime
from typing import Literal, Optional

from pydantic import BaseModel, ConfigDict, Field, field_validator

from app.utils.ust_validation import validate_vat_id


ContactRole = Literal["kaeufer", "verkaeufer", "beide"]
VatIdStatus = Literal["ungeprueft", "geprueft", "ungueltig", "manuell_bestaetigt"]


class ContactPersonBase(BaseModel):
    """Base contact person fields."""

    name: str = Field(..., min_length=1, max_length=255)
    function: Optional[str] = Field(None, max_length=100)
    phone: Optional[str] = Field(None, max_length=50)
    email: Optional[str] = Field(None, max_length=255)


class ContactPersonCreate(ContactPersonBase):
    """POST /api/v1/contacts/:id/persons request body."""

    pass


class ContactPersonResponse(ContactPersonBase):
    """Contact person response schema."""

    model_config = ConfigDict(from_attributes=True)

    id: uuid.UUID
    contact_id: uuid.UUID
    created_at: Optional[datetime] = None


class ContactBase(BaseModel):
    """Base contact fields shared across schemas."""

    company_name: str = Field(..., min_length=1, max_length=255)
    legal_form: Optional[str] = Field(None, max_length=50)
    address_street: Optional[str] = Field(None, max_length=255)
    address_zip: Optional[str] = Field(None, max_length=10)
    address_city: Optional[str] = Field(None, max_length=100)
    address_country: str = Field("DE", min_length=2, max_length=2)
    vat_id: Optional[str] = Field(None, max_length=20)
    phone: Optional[str] = Field(None, max_length=50)
    email: Optional[str] = Field(None, max_length=255)
    website: Optional[str] = Field(None, max_length=255)
    role: ContactRole
    is_private: bool = False

    @field_validator("vat_id")
    @classmethod
    def validate_vat_id_format(cls, v: str | None) -> str | None:
        """Validate VAT ID format if provided."""
        if v is None or v == "":
            return None
        if not validate_vat_id(v):
            raise ValueError(f"Invalid VAT ID format: '{v}'")
        return v.strip().upper().replace(" ", "")

    @field_validator("address_country")
    @classmethod
    def validate_country_code(cls, v: str) -> str:
        """Normalise country code to uppercase."""
        return v.upper()


class ContactCreate(ContactBase):
    """POST /api/v1/contacts request body."""

    contact_persons: list[ContactPersonCreate] = Field(
        default_factory=list, description="Contact persons to create with the contact"
    )


class ContactUpdate(BaseModel):
    """PUT /api/v1/contacts/:id request body (all fields optional)."""

    company_name: Optional[str] = Field(None, min_length=1, max_length=255)
    legal_form: Optional[str] = Field(None, max_length=50)
    address_street: Optional[str] = Field(None, max_length=255)
    address_zip: Optional[str] = Field(None, max_length=10)
    address_city: Optional[str] = Field(None, max_length=100)
    address_country: Optional[str] = Field(None, min_length=2, max_length=2)
    vat_id: Optional[str] = Field(None, max_length=20)
    phone: Optional[str] = Field(None, max_length=50)
    email: Optional[str] = Field(None, max_length=255)
    website: Optional[str] = Field(None, max_length=255)
    role: Optional[ContactRole] = None
    is_private: Optional[bool] = None

    @field_validator("vat_id")
    @classmethod
    def validate_vat_id_format(cls, v: str | None) -> str | None:
        """Validate VAT ID format if provided."""
        if v is None or v == "":
            return None
        if not validate_vat_id(v):
            raise ValueError(f"Invalid VAT ID format: '{v}'")
        return v.strip().upper().replace(" ", "")

    @field_validator("address_country")
    @classmethod
    def validate_country_code(cls, v: str | None) -> str | None:
        """Normalise country code to uppercase."""
        if v is not None:
            return v.upper()
        return v


class ContactResponse(BaseModel):
    """Contact response schema."""

    model_config = ConfigDict(from_attributes=True)

    id: uuid.UUID
    company_name: str
    legal_form: Optional[str] = None
    address_street: Optional[str] = None
    address_zip: Optional[str] = None
    address_city: Optional[str] = None
    address_country: str
    vat_id: Optional[str] = None
    phone: Optional[str] = None
    email: Optional[str] = None
    website: Optional[str] = None
    role: str
    vat_id_status: str = "ungeprueft"
    is_private: bool = False
    created_at: Optional[datetime] = None
    updated_at: Optional[datetime] = None
    deleted_at: Optional[datetime] = None
    contact_persons: list[ContactPersonResponse] = Field(default_factory=list)


class ContactListResponse(BaseModel):
    """Paginated contact list response."""

    items: list[ContactResponse]
    total: int
    page: int
    page_size: int