"""Registrant request/response schemas.

The read schema has no `ssn` field — only `ssn_masked` (``XXX-XX-1234``).
Masking happens here in the serializer, not the UI, so every API consumer sees
the masked form (ARCHITECTURE.md §6.3; source RFP `C.5.7.50`).

`user_id` is deliberately absent from the write schemas: linking a registrant
to a portal account is a Phase 1 identity flow, not a PATCH.
"""

from __future__ import annotations

import re
from datetime import date, datetime

from pydantic import BaseModel, ConfigDict, EmailStr, Field, field_validator

_ZIP = r"^\d{5}(-\d{4})?$"


def normalize_ssn(value: str | None) -> str | None:
    """Accept ``123-45-6789`` or ``123456789``; return 9 digits.

    Rejects numbers the SSA never issues: area 000, 666, or 900–999; group 00;
    serial 0000. Error messages never echo the input.
    """
    if value is None:
        return None
    digits = re.sub(r"[\s-]", "", value)
    if not re.fullmatch(r"\d{9}", digits):
        raise ValueError("SSN must be 9 digits")
    area, group, serial = digits[:3], digits[3:5], digits[5:]
    if area in {"000", "666"} or area >= "900" or group == "00" or serial == "0000":
        raise ValueError("SSN is not a valid issued number")
    return digits


def _not_future(value: date | None) -> date | None:
    if value is not None and value > date.today():
        raise ValueError("dob cannot be in the future")
    return value


class RegistrantCreate(BaseModel):
    first_name: str = Field(min_length=1, max_length=100)
    middle_name: str | None = Field(default=None, max_length=100)
    last_name: str = Field(min_length=1, max_length=100)
    dob: date
    ssn: str | None = None
    email: EmailStr | None = None
    phone: str | None = Field(default=None, max_length=32)
    address_line1: str | None = Field(default=None, max_length=255)
    address_line2: str | None = Field(default=None, max_length=255)
    city: str | None = Field(default=None, max_length=100)
    state: str | None = Field(default=None, min_length=2, max_length=2)
    zip: str | None = Field(default=None, pattern=_ZIP)

    _ssn = field_validator("ssn")(normalize_ssn)
    _dob = field_validator("dob")(_not_future)


class RegistrantUpdate(BaseModel):
    first_name: str | None = Field(default=None, min_length=1, max_length=100)
    middle_name: str | None = Field(default=None, max_length=100)
    last_name: str | None = Field(default=None, min_length=1, max_length=100)
    dob: date | None = None
    ssn: str | None = None
    email: EmailStr | None = None
    phone: str | None = Field(default=None, max_length=32)
    address_line1: str | None = Field(default=None, max_length=255)
    address_line2: str | None = Field(default=None, max_length=255)
    city: str | None = Field(default=None, max_length=100)
    state: str | None = Field(default=None, min_length=2, max_length=2)
    zip: str | None = Field(default=None, pattern=_ZIP)

    _ssn = field_validator("ssn")(normalize_ssn)
    _dob = field_validator("dob")(_not_future)

    @field_validator("first_name", "last_name", "dob")
    @classmethod
    def _required_not_null(cls, v: object) -> object:
        # Omit to leave unchanged; explicit null would violate NOT NULL.
        if v is None:
            raise ValueError("cannot be null")
        return v


class RegistrantRead(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    id: int
    first_name: str
    middle_name: str | None
    last_name: str
    dob: date
    ssn_masked: str | None
    minor_flag: bool
    email: str | None
    phone: str | None
    address_line1: str | None
    address_line2: str | None
    city: str | None
    state: str | None
    zip: str | None
    version: int
    created_at: datetime
    updated_at: datetime
    deleted_at: datetime | None