"""Schemata für Budgets, Budgetvorlagen und Sparziele."""

from datetime import date, datetime
from decimal import Decimal

from pydantic import Field, field_validator

from app.schemas.common import (
    ApiModel,
    HexColor,
    InputModel,
    Money,
    NonNegativeMoney,
    PositiveMoney,
)


def _to_month_start(value: date) -> date:
    """Budgets gelten immer für einen ganzen Monat."""
    return value.replace(day=1)


class BudgetCreate(InputModel):
    category_id: int
    period_month: date = Field(description="Beliebiger Tag im Monat; wird auf den Ersten gesetzt.")
    limit_amount: PositiveMoney
    rollover: bool = Field(
        default=False, description="Nicht verbrauchtes Budget in den Folgemonat übernehmen."
    )

    @field_validator("period_month")
    @classmethod
    def _normalise(cls, value: date) -> date:
        return _to_month_start(value)


class BudgetUpdate(InputModel):
    limit_amount: PositiveMoney | None = None
    rollover: bool | None = None


class BudgetOut(ApiModel):
    id: int
    category_id: int
    period_month: date
    limit_amount: Money
    rollover: bool
    created_at: datetime


class BudgetTemplateCreate(InputModel):
    category_id: int
    valid_from: date = Field(description="Ab diesem Monat gilt die Vorlage dauerhaft.")
    valid_until: date | None = Field(default=None, description="Letzter Monat, sonst unbegrenzt.")
    limit_amount: PositiveMoney
    rollover: bool = False

    @field_validator("valid_from", "valid_until")
    @classmethod
    def _normalise(cls, value: date | None) -> date | None:
        return _to_month_start(value) if value else None


class BudgetTemplateUpdate(InputModel):
    valid_until: date | None = None
    limit_amount: PositiveMoney | None = None
    rollover: bool | None = None

    @field_validator("valid_until")
    @classmethod
    def _normalise(cls, value: date | None) -> date | None:
        return _to_month_start(value) if value else None


class BudgetTemplateOut(ApiModel):
    id: int
    category_id: int
    valid_from: date
    valid_until: date | None
    limit_amount: Money
    rollover: bool


class SavingsGoalCreate(InputModel):
    name: str = Field(min_length=1, max_length=160, examples=["Neues Fahrrad"])
    target_amount: PositiveMoney
    target_date: date | None = None
    current_amount: NonNegativeMoney = Decimal("0.00")
    account_id: int | None = None
    monthly_contribution: PositiveMoney | None = None
    color: HexColor = "#10b981"
    icon: str = Field(default="piggy-bank", max_length=64)
    is_archived: bool = False


class SavingsGoalUpdate(InputModel):
    name: str | None = Field(default=None, min_length=1, max_length=160)
    target_amount: PositiveMoney | None = None
    target_date: date | None = None
    current_amount: NonNegativeMoney | None = None
    account_id: int | None = None
    monthly_contribution: PositiveMoney | None = None
    color: HexColor | None = None
    icon: str | None = Field(default=None, max_length=64)
    is_archived: bool | None = None


class SavingsGoalOut(ApiModel):
    id: int
    name: str
    target_amount: Money
    target_date: date | None
    current_amount: Money
    account_id: int | None
    monthly_contribution: Money | None
    color: str
    icon: str
    is_archived: bool
    created_at: datetime
    updated_at: datetime