"""Pydantic v2 request schemas — inventory domain (fork's contract, unchanged)."""
from datetime import datetime
from decimal import Decimal
from typing import Literal
from uuid import UUID

from pydantic import Field, model_validator

from app.models.inventory import INVENTORY_TRANSACTION_TYPES
from app.schemas.common import APIModel

TransactionType = Literal[
    "PURCHASE",
    "WITHDRAWAL",
    "RETURN",
    "TRANSFER_IN",
    "TRANSFER_OUT",
    "DAMAGE",
    "WASTE",
    "LOSS",
    "FOUND",
    "STOCK_COUNT",
]


class WarehouseCreate(APIModel):
    project_id: UUID
    name: str = Field(min_length=1, max_length=255)
    description: str | None = None


class WarehouseUpdate(APIModel):
    """Rename/re-describe a warehouse.

    `project_id` is accepted only to be rejected: a warehouse belongs
    permanently to its parent project and cannot be reassigned (the router
    answers 400 unless the value equals the current project).
    """

    name: str | None = Field(default=None, min_length=1, max_length=255)
    description: str | None = None
    project_id: UUID | None = None


class InventoryTransactionCreate(APIModel):
    """One inventory operation.

    - For all types except STOCK_COUNT: `quantity` is the amount to add/remove.
    - STOCK_COUNT uses `physical_qty` (the counted quantity); the difference
      against the recorded quantity is computed and applied by the service.
    - TRANSFER_OUT requires `dest_warehouse_id`; the service creates the linked
      TRANSFER_IN row in the destination warehouse (transfer_pair_id).
    - `specs` is a dict of technical specifications (dynamic multi-spec entries).
    - `transaction_date` defaults to server now() when omitted.
    """

    transaction_type: TransactionType
    warehouse_id: UUID
    dest_warehouse_id: UUID | None = None
    material_id: UUID
    brand_id: UUID | None = None
    quantity: Decimal | None = Field(default=None, gt=0)
    physical_qty: Decimal | None = Field(default=None, ge=0)
    unit_id: int | None = None
    specs: dict | None = None
    note: str | None = None
    delivered_to: str | None = None
    transaction_date: datetime | None = None

    @model_validator(mode="after")
    def validate_type_rules(self):
        t = self.transaction_type
        if t == "STOCK_COUNT":
            if self.physical_qty is None:
                raise ValueError("برای شمارش موجودی، تعداد شمارش‌شده (physical_qty) الزامی است")
        else:
            if self.quantity is None:
                raise ValueError("تعداد (quantity) الزامی است")
            if t == "TRANSFER_OUT":
                if self.dest_warehouse_id is None:
                    raise ValueError("برای انتقال خروجی، انبار مقصد (dest_warehouse_id) الزامی است")
                if self.dest_warehouse_id == self.warehouse_id:
                    raise ValueError("انبار مبدأ و مقصد نمی‌توانند یکسان باشند")
        if t not in INVENTORY_TRANSACTION_TYPES:
            raise ValueError(f"نوع تراکنش نامعتبر است: {t}")
        return self