from datetime import datetime
from decimal import Decimal
from pydantic import BaseModel, Field
from app.schemas.currency import CurrencyOut
from app.schemas.category import CategoryOut
from app.schemas.location import LocationOut


class OperationTypeOut(BaseModel):
    id: int
    name: str
    description: str | None = None

    model_config = {"from_attributes": True}


class OperationCreate(BaseModel):
    account_id: int
    category_id: int | None = None
    operation_type_id: int
    amount: Decimal = Field(..., gt=0)
    currency_id: int
    amount_converted: Decimal | None = None
    exchange_rate: Decimal | None = None
    date: datetime
    description: str | None = None
    location_id: int | None = None
    is_planned: bool = False


class OperationUpdate(BaseModel):
    category_id: int | None = None
    amount: Decimal | None = Field(None, gt=0)
    date: datetime | None = None
    description: str | None = None
    location_id: int | None = None
    is_planned: bool | None = None


class OperationOut(BaseModel):
    id: int
    user_id: int
    account_id: int
    category_id: int | None = None
    category: CategoryOut | None = None
    operation_type_id: int
    operation_type: OperationTypeOut
    amount: Decimal
    currency_id: int
    currency: CurrencyOut
    amount_converted: Decimal | None = None
    exchange_rate: Decimal | None = None
    date: datetime
    description: str | None = None
    location_id: int | None = None
    location: LocationOut | None = None
    is_planned: bool
    created_at: datetime

    model_config = {"from_attributes": True}


class OperationRelationCreate(BaseModel):
    operation_from_id: int
    operation_to_id: int
    relation_type: str = Field(..., pattern="^(transfer|split|correction)$")


class OperationRelationOut(BaseModel):
    id: int
    operation_from_id: int
    operation_to_id: int
    relation_type: str
    created_at: datetime

    model_config = {"from_attributes": True}


class TransferCreate(BaseModel):
    """Convenience schema: creates two linked operations in one request."""
    from_account_id: int
    to_account_id: int
    amount: Decimal = Field(..., gt=0)
    currency_id: int
    amount_converted: Decimal | None = None
    exchange_rate: Decimal | None = None
    date: datetime
    description: str | None = None
    location_id: int | None = None