dre/backend/models.py

"""Pydantic v2 request/response models. extra='forbid' on every request body.
Includes PII rejection (SSN/PAN regex) on all free-text fields.
"""
from __future__ import annotations

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

# ---------------------------------------------------------------
# PII rejection — compliance-critical
# ---------------------------------------------------------------
_SSN_RE = re.compile(r"\b\d{3}-?\d{2}-?\d{4}\b")
_PAN_RE = re.compile(r"\b(?:\d[ -]?){13,19}\b")


def _scan_pii(value: str) -> str:
    """Raise ValueError if value matches SSN or PAN regex."""
    if value is None:
        return value
    if _SSN_RE.search(value):
        raise ValueError("Do not include Social Security or bank/card numbers.")
    if _PAN_RE.search(value):
        raise ValueError("Do not include Social Security or bank/card numbers.")
    return value


def _pii_validator(field_name: str):
    return field_validator(field_name)(lambda v: _scan_pii(v))


# ---------------------------------------------------------------
# Intake request
# ---------------------------------------------------------------
BUSINESS_TYPES = (
    "INDIVIDUAL", "SOLE_PROPRIETORSHIP", "LLC", "CORPORATION", "PARTNERSHIP", "OTHER"
)
MESSAGE_SUBJECTS = (
    "Question about my claim",
    "New information about the debtor",
    "Payment received / want to stop recovery",
    "Update my contact info",
    "Complaint or concern",
    "Other",
)
CLAIM_STATUSES = (
    "NEW", "UNDER_REVIEW", "ACTIVE", "NEGOTIATION", "LEGAL",
    "SETTLED", "CLOSED", "WRITE_OFF", "REJECTED",
)
TIERS = ("TIER_1", "TIER_2", "TIER_2_5", "TIER_3", "TIER_4")


class IntakeClient(BaseModel):
    model_config = ConfigDict(extra="forbid")
    company_name: str = Field(..., min_length=1, max_length=200)
    contact_name: str = Field(..., min_length=1, max_length=200)
    email: EmailStr
    phone: str | None = Field(None, max_length=50)

    @field_validator("company_name", "contact_name", "phone")
    @classmethod
    def _v(cls, v):
        return _scan_pii(v)


class IntakeDebtor(BaseModel):
    model_config = ConfigDict(extra="forbid")
    name: str = Field(..., min_length=1, max_length=200)
    business_type: str = Field("OTHER")
    contact_email: str | None = Field(None, max_length=254)
    contact_phone: str | None = Field(None, max_length=50)
    physical_address: str | None = Field(None, max_length=500)

    @field_validator("business_type")
    @classmethod
    def _bt(cls, v):
        v = v.upper()
        if v not in BUSINESS_TYPES:
            raise ValueError(f"business_type must be one of {BUSINESS_TYPES}")
        return v

    @field_validator("name", "contact_email", "contact_phone", "physical_address")
    @classmethod
    def _v(cls, v):
        return _scan_pii(v)


class IntakeClaim(BaseModel):
    model_config = ConfigDict(extra="forbid")
    amount_cents: int = Field(..., gt=0, le=100_000_000)
    description: str | None = Field(None, max_length=5000)
    client_reference: str | None = Field(None, max_length=200)
    invoice_date: str | None = Field(None, max_length=20)

    @field_validator("description", "client_reference", "invoice_date")
    @classmethod
    def _v(cls, v):
        return _scan_pii(v)


class IntakeRequest(BaseModel):
    model_config = ConfigDict(extra="forbid")
    client: IntakeClient
    debtor: IntakeDebtor
    claim: IntakeClaim
    tos_accepted: bool = True
    turnstile_token: str | None = None

    @field_validator("tos_accepted")
    @classmethod
    def _tos(cls, v):
        if v is not True:
            raise ValueError("tos_accepted must be true")
        return v


# ---------------------------------------------------------------
# Auth
# ---------------------------------------------------------------
class AuthRequest(BaseModel):
    model_config = ConfigDict(extra="forbid")
    email: EmailStr


class AuthVerify(BaseModel):
    model_config = ConfigDict(extra="forbid")
    token: str = Field(..., min_length=10, max_length=200)


# ---------------------------------------------------------------
# Messages
# ---------------------------------------------------------------
class MessageCreate(BaseModel):
    model_config = ConfigDict(extra="forbid")
    subject: str
    content: str = Field(..., min_length=1, max_length=10000)

    @field_validator("subject")
    @classmethod
    def _subj(cls, v):
        if v not in MESSAGE_SUBJECTS:
            raise ValueError(f"subject must be one of {MESSAGE_SUBJECTS}")
        return v

    @field_validator("content")
    @classmethod
    def _cont(cls, v):
        return _scan_pii(v)


# ---------------------------------------------------------------
# Staff
# ---------------------------------------------------------------
class StaffClaimPatch(BaseModel):
    model_config = ConfigDict(extra="forbid")
    status: str | None = None
    tier: str | None = None
    reason: str | None = Field(None, max_length=500)

    @field_validator("status")
    @classmethod
    def _st(cls, v):
        if v is not None and v not in CLAIM_STATUSES:
            raise ValueError(f"status must be one of {CLAIM_STATUSES}")
        return v

    @field_validator("tier")
    @classmethod
    def _tr(cls, v):
        if v is not None and v not in TIERS:
            raise ValueError(f"tier must be one of {TIERS}")
        return v


class StaffNoteCreate(BaseModel):
    model_config = ConfigDict(extra="forbid")
    content: str = Field(..., min_length=1, max_length=10000)
    visibility: str = "INTERNAL"
    author_name: str = Field(..., min_length=1, max_length=200)

    @field_validator("visibility")
    @classmethod
    def _vis(cls, v):
        if v not in ("SHARED", "INTERNAL"):
            raise ValueError("visibility must be SHARED or INTERNAL")
        return v

    @field_validator("content", "author_name")
    @classmethod
    def _v(cls, v):
        return _scan_pii(v)