expenses_manager/expenses_manager/expenses/forms.py

from django import forms
from .models import (
    Expense,
    Category,
    Income,
    Tag,
    Account,
    FuelEntry,
    Goal,
    Transfer,
)


def _hide_is_transfer_when_editing(form):
    """Quita la casilla de traspaso al editar un movimiento que ya existe.

    Al crear, la casilla es un atajo: lleva al formulario de traspaso, que es
    quien crea las dos patas. Al editar no significa nada, porque convertir un
    gasto suelto en traspaso no es editarlo (habría que inventarse la otra
    cuenta), y marcarla solo dejaría el movimiento marcado pero sin pareja: justo
    el estado a medias que Transfer viene a evitar.
    """
    if form.instance.pk:
        form.fields.pop("is_transfer", None)


class ExpenseForm(forms.ModelForm):

    def __init__(self, *args, **kwargs):
        # Get user
        user = kwargs.pop("user", None)

        super().__init__(*args, **kwargs)

        if user:
            self.fields["category"].queryset = Category.objects.filter(owner=user)
            self.fields["tags"].queryset = Tag.objects.filter(owner=user)
            self.fields["account"].queryset = Account.objects.filter(
                owner=user, active=True
            )
            self.fields["date"].input_formats = ["%Y-%m-%d"]

        _hide_is_transfer_when_editing(self)

    class Meta:
        model = Expense
        fields = [
            "date",
            "amount",
            "description",
            "category",
            "account",
            "tags",
            "is_transfer",
        ]
        widgets = {
            "date": forms.DateInput(format="%Y-%m-%d", attrs={"type": "date"}),
            "tags": forms.CheckboxSelectMultiple(),
        }


class TagForm(forms.ModelForm):
    class Meta:
        model = Tag
        fields = ["name"]


class AccountForm(forms.ModelForm):

    class Meta:
        model = Account
        fields = ["name", "initial_balance", "active"]


class IncomeForm(forms.ModelForm):
    class Meta:
        model = Income
        fields = ["account", "name", "amount", "date", "is_transfer"]
        widgets = {"date": forms.DateInput(format="%Y-%m-%d", attrs={"type": "date"})}

    def __init__(self, *args, **kwargs):
        user = kwargs.pop("user")
        super().__init__(*args, **kwargs)
        self.fields["account"].queryset = Account.objects.filter(
            owner=user,
            active=True,
        )
        _hide_is_transfer_when_editing(self)


class TransferForm(forms.ModelForm):
    """Formulario del traspaso. Las patas no se editan aquí ni en ninguna parte:
    las deriva Transfer.sync() de estos campos."""

    class Meta:
        model = Transfer
        fields = ["date", "amount", "from_account", "to_account", "fee_amount"]
        widgets = {"date": forms.DateInput(format="%Y-%m-%d", attrs={"type": "date"})}
        labels = {
            "from_account": "Cuenta de origen",
            "to_account": "Cuenta de destino",
            "fee_amount": "Comisión",
        }
        help_texts = {
            "fee_amount": (
                "Déjalo vacío si el traspaso no tiene comisión. La comisión sí "
                "cuenta como gasto real en el dashboard y en los presupuestos."
            ),
        }

    def __init__(self, *args, **kwargs):
        user = kwargs.pop("user")
        super().__init__(*args, **kwargs)

        accounts = Account.objects.filter(owner=user, active=True)
        self.fields["from_account"].queryset = accounts
        self.fields["to_account"].queryset = accounts
        self.fields["date"].input_formats = ["%Y-%m-%d"]


class FuelEntryForm(forms.ModelForm):
    odometer = forms.DecimalField(label="Kilómetros actuales")
    liters = forms.DecimalField(max_digits=8, decimal_places=2, label="Litros")
    
    class Meta:
        model = Expense
        fields = ["date", "amount", "account"]
        widgets = {
            "date": forms.DateInput(format="%Y-%m-%d", attrs={"type":"date"}),
        }

    def __init__(self, *args, **kwargs):
        user = kwargs.pop("user")
        super().__init__(*args, **kwargs)

        if user:
            self.fields["account"].queryset = user.accounts.filter(active=True)
        
        if self.instance.pk and hasattr(self.instance, "fuel_data"):
            fuel = self.instance.fuel_data
            self.fields["odometer"].initial = fuel.odometer
            self.fields["liters"].initial = fuel.liters


class CategoryForm(forms.ModelForm):
    class Meta:
        model = Category
        fields = ["name", "parent"]

    def __init__(self, *args, **kwargs):
        user = kwargs.pop("user")
        super().__init__(*args, **kwargs)
        
        if user:
            queryset = Category.objects.filter(owner=user)

            if self.instance.pk:
                queryset = queryset.exclude(
                    pk__in=self.instance.descendant_ids()
                )

            self.fields["parent"].queryset = queryset

    def clean_parent(self):
        parent = self.cleaned_data.get("parent")

        if parent and self.instance.pk:
            if parent.pk in self.instance.descendant_ids():
                raise forms.ValidationError(
                    "Una categoría no puede ser su propio padre ni depender "
                    "de una de sus subcategorías."
                )

        return parent


class GoalForm(forms.ModelForm):
    class Meta:
        model = Goal
        fields = [
            "name",
            "kind",
            "target_amount",
            "category",
            "include_subcategories",
            "account",
            "start_date",
            "period",
            "show_on_home",
        ]
        widgets = {
            "start_date": forms.DateInput(
                format="%Y-%m-%d", attrs={"type": "date"}
            ),
        }
    
    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user')
        super().__init__(*args, **kwargs)
        
        self.fields['category'].queryset = user.categories.all()
        self.fields['account'].queryset = user.accounts.filter(active=True)
        
        self.fields['category'].required = False
        self.fields['account'].required = False
        self.fields['start_date'].input_formats = ["%Y-%m-%d"]
        
    def clean(self):
        cleaned = super().clean()
        kind = cleaned.get("kind")
        
        if kind in (Goal.KIND_PAYMENT, Goal.KIND_BUDGET):
            if not cleaned.get('category'):
                self.add_error(
                    "category",
                    "Selecciona una categoría para este tipo de objetivo.",
                )
            cleaned["account"] = None
        
        if kind == Goal.KIND_SAVING:
            if not cleaned.get("account"):
                self.add_error(
                    "account",
                    "Selecciona la cuenta donde se acumula el ahorro.",
                )
            cleaned["category"] = None
        
        if kind == Goal.KIND_BUDGET:
            if cleaned.get("period") == Goal.PERIOD_NONE:
                self.add_error(
                    "period",
                    "Un presupuesto necesita un periodo: mensual o anual",
                )
        else:
            cleaned["period"] = Goal.PERIOD_NONE
        
        return cleaned