"""Pydantic schemas for procurement-domain API responses + requests.

Conventions mirror the rest of the codebase:
* Read schemas (``*Read``) expose every field the UI may need, with
  derived display fields (e.g. ``supplier_name`` next to ``supplier_id``)
  so the FE doesn't need to denormalise on every render.
* Create / update schemas accept the minimum fields the UI must
  provide; the service layer fills in derived values (e.g.
  ``supplier_code`` auto-generation, ``contract_number`` sequence).
* Multi-currency fields carry ``currency`` + ``amount`` together and
  expose ``amount_cny`` (frozen at submit time via fx_rate service)
  as a separate field for reporting.
"""
from __future__ import annotations

import uuid
from collections.abc import Mapping
from datetime import date, datetime
from decimal import Decimal
from typing import Any

from pydantic import BaseModel, ConfigDict, Field

from app.domains.procurement.models import (
    CONTRACT_STATUSES,
    CONTRACT_TYPES,
    PAYMENT_STATUSES,
    PO_ORDER_TYPES,
    PO_STATUSES,
    PROCUREMENT_CATEGORY_CODES,
    RECEIPT_SEMANTICS,
    RECEIPT_STATUSES,
    SUPPLIER_STATUSES,
)

_OrmCfg = ConfigDict(from_attributes=True)


# ── Category ──────────────────────────────────────────────────────────


class CategoryBase(BaseModel):
    code: str = Field(..., max_length=32)
    name_zh: str = Field(..., max_length=64)
    name_en: str = Field(..., max_length=64)
    parent_id: uuid.UUID | None = None
    description: str | None = Field(default=None, max_length=2000)
    default_owner_person_id: uuid.UUID | None = None
    default_cost_center: str | None = None
    default_legal_entity_id: uuid.UUID | None = None
    default_reminder_days: int | None = None
    receipt_semantics: str
    is_active: bool = True
    sort_order: int = 100


class CategoryCreate(CategoryBase):
    pass


class CategoryUpdate(BaseModel):
    name_zh: str | None = None
    name_en: str | None = None
    parent_id: uuid.UUID | None = None
    description: str | None = Field(default=None, max_length=2000)
    default_owner_person_id: uuid.UUID | None = None
    default_cost_center: str | None = None
    default_legal_entity_id: uuid.UUID | None = None
    default_reminder_days: int | None = None
    receipt_semantics: str | None = None
    is_active: bool | None = None
    sort_order: int | None = None


class CategoryRead(CategoryBase):
    model_config = _OrmCfg
    id: uuid.UUID
    created_at: datetime
    updated_at: datetime
    # Derived display field — service.py fills this from a person JOIN.
    default_owner_name: str | None = None


# ── Supplier ──────────────────────────────────────────────────────────


class SupplierContact(BaseModel):
    name: str = ""
    role: str | None = None
    email: str | None = None
    phone: str | None = None
    is_primary: bool = False


class SupplierBase(BaseModel):
    # max_length on each string field matches its DB column so overlong
    # (paste-prone) input 422s at the schema layer instead of hitting a
    # MySQL/TiDB 1406 DataError -> 500 at insert time.
    name: str = Field(..., max_length=128)
    legal_name: str | None = Field(default=None, max_length=256)
    country: str | None = Field(default=None, max_length=64)
    tax_id: str | None = Field(default=None, max_length=64)
    registered_address: str | None = Field(default=None, max_length=512)
    website: str | None = Field(default=None, max_length=256)
    status: str = "active"
    default_currency: str | None = Field(default=None, max_length=8)
    payment_terms: str | None = Field(default=None, max_length=32)
    bank_name: str | None = Field(default=None, max_length=128)
    bank_account: str | None = Field(default=None, max_length=128)
    bank_account_name: str | None = Field(default=None, max_length=128)
    swift_code: str | None = Field(default=None, max_length=32)
    contacts: list[SupplierContact] = Field(default_factory=list)
    credit_rating: str | None = None
    last_evaluation_at: date | None = None
    supports_legal_entities: list[uuid.UUID] = Field(default_factory=list)
    notes: str | None = Field(default=None, max_length=2000)


class SupplierCreate(SupplierBase):
    # Optional — auto-generated when omitted.
    supplier_code: str | None = Field(None, min_length=1, max_length=32)


class SupplierUpdate(BaseModel):
    # max_length mirrors SupplierBase / the DB columns so an overlong
    # PATCH 422s at the schema layer instead of hitting a MySQL/TiDB
    # 1406 DataError -> 500 at update time.
    name: str | None = Field(default=None, max_length=128)
    legal_name: str | None = Field(default=None, max_length=256)
    country: str | None = Field(default=None, max_length=64)
    tax_id: str | None = Field(default=None, max_length=64)
    registered_address: str | None = Field(default=None, max_length=512)
    website: str | None = Field(default=None, max_length=256)
    status: str | None = None
    default_currency: str | None = Field(default=None, max_length=8)
    payment_terms: str | None = Field(default=None, max_length=32)
    bank_name: str | None = Field(default=None, max_length=128)
    bank_account: str | None = Field(default=None, max_length=128)
    bank_account_name: str | None = Field(default=None, max_length=128)
    swift_code: str | None = Field(default=None, max_length=32)
    contacts: list[SupplierContact] | None = None
    credit_rating: str | None = None
    last_evaluation_at: date | None = None
    supports_legal_entities: list[uuid.UUID] | None = None
    notes: str | None = Field(default=None, max_length=2000)


class SupplierRead(BaseModel):
    """Read-only supplier view — fields with DB NULLs are normalised to
    empty containers via field_validators so the FE always sees
    consistent shapes."""
    model_config = _OrmCfg
    id: uuid.UUID
    supplier_code: str
    name: str
    legal_name: str | None = None
    country: str | None = None
    tax_id: str | None = None
    registered_address: str | None = None
    website: str | None = None
    status: str = "active"
    default_currency: str | None = None
    payment_terms: str | None = None
    bank_name: str | None = None
    bank_account: str | None = None
    bank_account_name: str | None = None
    swift_code: str | None = None
    contacts: list[SupplierContact] = Field(default_factory=list)
    credit_rating: str | None = None
    last_evaluation_at: date | None = None
    supports_legal_entities: list[uuid.UUID] = Field(default_factory=list)
    notes: str | None = None
    created_at: datetime
    updated_at: datetime
    legacy_supplier_id: uuid.UUID | None = None
    # Derived counts so the supplier-list page can show "5 contracts /
    # 12 POs" inline without a second round-trip.
    contract_count: int = 0
    active_contract_count: int = 0
    po_count: int = 0
    # True when the sensitive 银行/税号 fields above were masked for the
    # caller (non finance/admin). The FE renders a "reveal" affordance
    # that hits POST /suppliers/{id}/reveal (rate-limited + audited).
    sensitive_masked: bool = False

    @classmethod
    def model_validate(cls, obj, **kwargs):  # type: ignore[override]
        # Normalise SQL NULL → empty containers BEFORE Pydantic
        # validates. ORM rows occasionally come back with
        # ``contacts=None`` / ``supports_legal_entities=None`` when the
        # column is set to NULL; the schema treats those as empty lists.
        # Never assign those defaults back to an ORM instance: the shared
        # request dependency commits successful GET transactions, so doing
        # so would turn response serialisation into an unaudited DB write.
        contacts = (
            obj.get("contacts")
            if isinstance(obj, Mapping)
            else getattr(obj, "contacts", None)
        )
        legal_entities = (
            obj.get("supports_legal_entities")
            if isinstance(obj, Mapping)
            else getattr(obj, "supports_legal_entities", None)
        )
        if contacts is not None and legal_entities is not None:
            return super().model_validate(obj, **kwargs)

        if isinstance(obj, Mapping):
            values = dict(obj)
        else:
            values = {
                field_name: getattr(obj, field_name)
                for field_name in cls.model_fields
                if hasattr(obj, field_name)
            }
        if contacts is None:
            values["contacts"] = []
        if legal_entities is None:
            values["supports_legal_entities"] = []
        return super().model_validate(values, **kwargs)


# ── Contract ──────────────────────────────────────────────────────────


class ContractAttachmentRead(BaseModel):
    model_config = _OrmCfg
    id: uuid.UUID
    contract_id: uuid.UUID
    file_name: str
    s3_key: str
    content_type: str | None
    size_bytes: int | None
    description: str | None
    uploaded_by_id: uuid.UUID | None
    uploaded_at: datetime
    download_url: str | None = None


class ContractVersionRead(BaseModel):
    model_config = _OrmCfg
    id: uuid.UUID
    contract_id: uuid.UUID
    version_no: int
    changed_fields: dict[str, Any]
    change_summary: str | None
    changed_by_id: uuid.UUID | None
    changed_by_name: str | None = None
    changed_at: datetime


class ContractBase(BaseModel):
    title: str = Field(..., max_length=256)
    supplier_id: uuid.UUID
    legal_entity_id: uuid.UUID | None = None
    category_id: uuid.UUID | None = None
    contract_type: str = "standalone"
    parent_contract_id: uuid.UUID | None = None
    total_amount: Decimal | None = None
    currency: str = "CNY"
    signed_date: date | None = None
    effective_date: date | None = None
    expiry_date: date | None = None
    auto_renew: bool = False
    renew_notice_days: int | None = None
    status: str = "draft"
    business_owner_id: uuid.UUID | None = None
    it_contact_id: uuid.UUID | None = None
    finance_contact_id: uuid.UUID | None = None
    procurement_owner_id: uuid.UUID | None = None
    description: str | None = Field(default=None, max_length=2000)
    notes: str | None = Field(default=None, max_length=4000)
    external_contract_no: str | None = Field(default=None, max_length=128)


class ContractCreate(ContractBase):
    contract_number: str | None = Field(None, min_length=1, max_length=64)


class ContractUpdate(BaseModel):
    title: str | None = None
    supplier_id: uuid.UUID | None = None
    legal_entity_id: uuid.UUID | None = None
    category_id: uuid.UUID | None = None
    contract_type: str | None = None
    parent_contract_id: uuid.UUID | None = None
    total_amount: Decimal | None = None
    currency: str | None = None
    signed_date: date | None = None
    effective_date: date | None = None
    expiry_date: date | None = None
    auto_renew: bool | None = None
    renew_notice_days: int | None = None
    status: str | None = None
    business_owner_id: uuid.UUID | None = None
    it_contact_id: uuid.UUID | None = None
    finance_contact_id: uuid.UUID | None = None
    procurement_owner_id: uuid.UUID | None = None
    description: str | None = Field(default=None, max_length=2000)
    notes: str | None = Field(default=None, max_length=4000)
    external_contract_no: str | None = Field(default=None, max_length=128)
    change_summary: str | None = None


class ContractRead(ContractBase):
    model_config = _OrmCfg
    id: uuid.UUID
    contract_number: str
    created_at: datetime
    updated_at: datetime
    # Derived display fields.
    supplier_name: str | None = None
    legal_entity_name: str | None = None
    category_name: str | None = None
    business_owner_name: str | None = None
    it_contact_name: str | None = None
    finance_contact_name: str | None = None
    procurement_owner_name: str | None = None
    # Days until expiry (negative if already past). NULL if no expiry.
    days_until_expiry: int | None = None
    attachment_count: int = 0
    po_count: int = 0


class ContractDetail(ContractRead):
    attachments: list[ContractAttachmentRead] = Field(default_factory=list)
    versions: list[ContractVersionRead] = Field(default_factory=list)


# ── Purchase order + items ────────────────────────────────────────────


class OrderItemBase(BaseModel):
    # Auto-assigned by the service (next available line_no in order)
    # when the client omits it.
    line_no: int | None = Field(default=None, ge=1, le=2_147_483_647)
    description: str = Field(..., max_length=512)
    # Money / quantity fields are non-negative — a negative line_total
    # would flow into the PO total rollup and produce a negative or
    # understated total_amount, which lock_budget_for_order silently
    # skips (<= 0), so the PO looks committed while consuming no budget.
    quantity: Decimal = Field(Decimal(1), ge=0)
    # DB-column caps so an over-length value 422s at the schema instead of
    # raising MySQL/TiDB 1406 DataError → uncaught 500 (same hardening the
    # Supplier* schemas already have).
    unit: str | None = Field(default=None, max_length=32)
    unit_price: Decimal | None = Field(None, ge=0)
    line_total: Decimal | None = Field(None, ge=0)
    currency: str | None = Field(default=None, max_length=8)
    target_asset_id: uuid.UUID | None = None
    target_software_id: uuid.UUID | None = None
    target_license_plan_id: uuid.UUID | None = None
    target_descriptor: str | None = Field(default=None, max_length=256)
    notes: str | None = None


class OrderItemCreate(OrderItemBase):
    pass


class OrderItemUpdate(BaseModel):
    description: str | None = None
    quantity: Decimal | None = Field(None, ge=0)
    unit: str | None = None
    unit_price: Decimal | None = Field(None, ge=0)
    line_total: Decimal | None = Field(None, ge=0)
    currency: str | None = None
    target_asset_id: uuid.UUID | None = None
    target_software_id: uuid.UUID | None = None
    target_license_plan_id: uuid.UUID | None = None
    target_descriptor: str | None = None
    receipt_status: str | None = None
    received_at: datetime | None = None
    received_qty: Decimal | None = Field(None, ge=0)
    notes: str | None = None


class OrderItemRead(OrderItemBase):
    model_config = _OrmCfg
    id: uuid.UUID
    order_id: uuid.UUID
    receipt_status: str
    received_at: datetime | None
    received_qty: Decimal | None
    created_at: datetime
    updated_at: datetime
    target_asset_tag: str | None = None
    target_software_name: str | None = None


class OrderBase(BaseModel):
    order_type: str = "purchase"
    status: str = "draft"
    category_id: uuid.UUID | None = None
    supplier_id: uuid.UUID | None = None
    contract_id: uuid.UUID | None = None
    legal_entity_id: uuid.UUID | None = None
    software_catalog_id: uuid.UUID | None = None
    department: str | None = Field(default=None, max_length=128)
    cost_center: str | None = Field(default=None, max_length=64)
    currency: str = "CNY"
    total_amount: Decimal | None = Field(None, ge=0)
    business_owner_id: uuid.UUID | None = None
    it_contact_id: uuid.UUID | None = None
    finance_contact_id: uuid.UUID | None = None
    procurement_owner_id: uuid.UUID | None = None
    requested_at: datetime | None = None
    notes: str | None = None
    external_po_number: str | None = Field(default=None, max_length=128)
    external_link: str | None = Field(default=None, max_length=512)


class OrderCreate(OrderBase):
    order_number: str | None = Field(default=None, min_length=1, max_length=64)
    applicant_id: uuid.UUID | None = None
    items: list[OrderItemCreate] = Field(default_factory=list)


class OrderUpdate(BaseModel):
    order_type: str | None = None
    status: str | None = None
    category_id: uuid.UUID | None = None
    supplier_id: uuid.UUID | None = None
    contract_id: uuid.UUID | None = None
    legal_entity_id: uuid.UUID | None = None
    software_catalog_id: uuid.UUID | None = None
    department: str | None = None
    cost_center: str | None = None
    currency: str | None = None
    total_amount: Decimal | None = Field(None, ge=0)
    business_owner_id: uuid.UUID | None = None
    it_contact_id: uuid.UUID | None = None
    finance_contact_id: uuid.UUID | None = None
    procurement_owner_id: uuid.UUID | None = None
    receipt_status: str | None = None
    received_at: datetime | None = None
    receipt_evidence_url: str | None = None
    payment_status: str | None = None
    requested_at: datetime | None = None
    approved_at: datetime | None = None
    approved_by_id: uuid.UUID | None = None
    completed_at: datetime | None = None
    external_po_number: str | None = None
    external_link: str | None = None
    notes: str | None = None


class OrderRead(OrderBase):
    model_config = _OrmCfg
    id: uuid.UUID
    order_number: str
    applicant_id: uuid.UUID
    receipt_status: str
    received_at: datetime | None
    receipt_evidence_url: str | None
    payment_status: str
    fx_rate_to_cny: Decimal | None
    total_cny: Decimal | None
    budget_id: uuid.UUID | None
    budget_locked_at: datetime | None
    budget_released_at: datetime | None
    approved_at: datetime | None
    approved_by_id: uuid.UUID | None
    completed_at: datetime | None
    legacy_order_id: uuid.UUID | None
    legacy_unresolved_fields: dict[str, Any] | None
    created_at: datetime
    updated_at: datetime
    # Derived display.
    applicant_name: str | None = None
    supplier_name: str | None = None
    contract_number: str | None = None
    category_name: str | None = None
    business_owner_name: str | None = None
    procurement_owner_name: str | None = None
    item_count: int = 0


class OrderDetail(OrderRead):
    items: list[OrderItemRead] = Field(default_factory=list)


# ── Payments ──────────────────────────────────────────────────────────


class PaymentBase(BaseModel):
    order_id: uuid.UUID | None = None
    contract_id: uuid.UUID | None = None
    supplier_id: uuid.UUID | None = None
    legal_entity_id: uuid.UUID | None = None
    software_catalog_id: uuid.UUID | None = None
    payment_frequency: str | None = None
    payment_method: str | None = None
    requester_id: uuid.UUID | None = None
    finance_contact_id: uuid.UUID | None = None
    amount: Decimal | None = Field(None, ge=0)
    currency: str = Field(default="CNY", max_length=32)
    status: str = "pending"
    invoice_number: str | None = Field(default=None, max_length=128)
    invoice_received_at: date | None = None
    paid_at: date | None = None
    external_voucher_no: str | None = Field(default=None, max_length=128)
    notes: str | None = None


class PaymentCreate(PaymentBase):
    payment_number: str | None = Field(default=None, min_length=1, max_length=64)


class PaymentUpdate(BaseModel):
    order_id: uuid.UUID | None = None
    contract_id: uuid.UUID | None = None
    supplier_id: uuid.UUID | None = None
    legal_entity_id: uuid.UUID | None = None
    software_catalog_id: uuid.UUID | None = None
    payment_frequency: str | None = None
    payment_method: str | None = None
    requester_id: uuid.UUID | None = None
    finance_contact_id: uuid.UUID | None = None
    amount: Decimal | None = Field(None, ge=0)
    currency: str | None = Field(default=None, max_length=32)
    status: str | None = None
    invoice_number: str | None = Field(default=None, max_length=128)
    invoice_received_at: date | None = None
    paid_at: date | None = None
    external_voucher_no: str | None = Field(default=None, max_length=128)
    notes: str | None = None


class PaymentRead(PaymentBase):
    model_config = _OrmCfg
    id: uuid.UUID
    payment_number: str
    fx_rate_to_cny: Decimal | None
    amount_cny: Decimal | None
    legacy_payment_id: uuid.UUID | None
    legacy_unresolved_fields: dict[str, Any] | None
    created_at: datetime
    updated_at: datetime
    supplier_name: str | None = None
    order_number: str | None = None
    legal_entity_name: str | None = None
    software_name: str | None = None


# ── Software procurement meta ─────────────────────────────────────────


class SoftwareProcurementMetaBase(BaseModel):
    current_contract_id: uuid.UUID | None = None
    current_supplier_id: uuid.UUID | None = None
    expected_renewal_at: date | None = None
    current_period_amount: Decimal | None = None
    current_period_currency: str | None = None
    business_owner_id: uuid.UUID | None = None
    it_contact_id: uuid.UUID | None = None
    finance_contact_id: uuid.UUID | None = None
    procurement_owner_id: uuid.UUID | None = None
    notes: str | None = None


class SoftwareProcurementMetaUpdate(SoftwareProcurementMetaBase):
    pass


class SoftwareProcurementMetaRead(SoftwareProcurementMetaBase):
    model_config = _OrmCfg
    id: uuid.UUID
    software_id: uuid.UUID
    created_at: datetime
    updated_at: datetime
    current_contract_number: str | None = None
    current_contract_title: str | None = None
    current_supplier_name: str | None = None
    business_owner_name: str | None = None


# ── Validators (sets exposed to FastAPI; used by service.py guards) ───


VALID_CATEGORY_CODES = PROCUREMENT_CATEGORY_CODES
VALID_RECEIPT_SEMANTICS = RECEIPT_SEMANTICS
VALID_SUPPLIER_STATUSES = SUPPLIER_STATUSES
VALID_CONTRACT_STATUSES = CONTRACT_STATUSES
VALID_CONTRACT_TYPES = CONTRACT_TYPES
VALID_PO_STATUSES = PO_STATUSES
VALID_PO_ORDER_TYPES = PO_ORDER_TYPES
VALID_RECEIPT_STATUSES = RECEIPT_STATUSES
VALID_PAYMENT_STATUSES = PAYMENT_STATUSES