Add budget block allocation screen

expenses_manager/expenses/forms.py

@@ -1,3 +1,5 @@
+from decimal import Decimal
+
 from django import forms
 from .csv_export import DEFAULT_DIALECT
 from .models import (
@@ -9,6 +11,7 @@ from .models import (
     FuelEntry,
     Goal,
     Transfer,
+    BudgetBlock,
 )
 
 
@@ -107,7 +110,7 @@ class AccountForm(forms.ModelForm):
 
     class Meta:
         model = Account
-        fields = ["name", "initial_balance", "active"]
+        fields = ["name", "initial_balance", "active", "is_savings"]
 
 
 class IncomeForm(_GoalLinksMixin, forms.ModelForm):
@@ -290,6 +293,55 @@ class GoalForm(forms.ModelForm):
         return cleaned
 
 
+class BudgetBlockForm(forms.Form):
+    """El reparto del ingreso por bloques: un campo por cada uno de los cinco.
+
+    La suma no puede pasar de 100, pero no se obliga a que llegue: lo que falte
+    es "sin asignar", que es información útil y no un error.
+    """
+
+    def __init__(self, *args, user, **kwargs):
+        self.user = user
+        saved = {
+            row.block: row.percentage
+            for row in BudgetBlock.objects.filter(owner=user)
+        }
+        kwargs.setdefault(
+            "initial",
+            # Un bloque sin fila guardada vale 0.
+            {block: saved.get(block, Decimal("0")) for block, _ in BudgetBlock.BLOCK_CHOICES},
+        )
+        super().__init__(*args, **kwargs)
+
+        for block, label in BudgetBlock.BLOCK_CHOICES:
+            self.fields[block] = forms.DecimalField(
+                label=f"{label} (%)",
+                min_value=0,
+                max_value=100,
+                max_digits=5,
+                decimal_places=2,
+            )
+
+    def clean(self):
+        cleaned = super().clean()
+        values = [cleaned.get(block) for block, _ in BudgetBlock.BLOCK_CHOICES]
+        # Si algún campo ya falló, su error basta: la suma saldría con huecos.
+        if None not in values and sum(values) > 100:
+            raise forms.ValidationError(
+                "Los bloques suman %s %%; entre todos no pueden pasar del 100 %%."
+                % sum(values)
+            )
+        return cleaned
+
+    def save(self):
+        for block, _ in BudgetBlock.BLOCK_CHOICES:
+            BudgetBlock.objects.update_or_create(
+                owner=self.user,
+                block=block,
+                defaults={"percentage": self.cleaned_data[block]},
+            )
+
+
 class ExportForm(forms.Form):
     """Filtros de la exportación a CSV. Valida la pantalla y la descarga.
 

expenses_manager/expenses/templates/expenses/account_list.html

@@ -14,6 +14,7 @@
                 <th>Saldo inicial</th>
                 <th>Saldo actual</th>
                 <th>Activa</th>
+                <th>Ahorro</th>
                 <th></th>
             </tr>
         </thead>
@@ -30,6 +31,11 @@
                             <span class="badge badge-inactive">Inactiva</span>
                         {% endif %}
                     </td>
+                    <td>
+                        {% if row.account.is_savings %}
+                            <span class="badge badge-neutral">De ahorro</span>
+                        {% endif %}
+                    </td>
                     <td class="table-actions">
                         <a href="{% url 'account_edit' row.account.id %}">Editar</a>
                         {% if row.account.active %}
@@ -39,7 +45,7 @@
                 </tr>
             {% empty %}
             <tr>
-                <td colspan="5" class="empty-state">
+                <td colspan="6" class="empty-state">
                     <p>No hay cuentas</p>
                     <a href="{% url 'account_create' %}">Añade la primera</a>
                 </td>

expenses_manager/expenses/templates/expenses/base.html

@@ -43,6 +43,7 @@
                             <a href="{% url 'category_list' %}">Categorías</a>
                             <a href="{% url 'tag_list' %}">Etiquetas</a>
                             <a href="{% url 'goal_list' %}">Objetivos</a>
+                            <a href="{% url 'budget_blocks' %}">Reparto por bloques</a>
                             <a href="{% url 'export_index' %}">Exportar datos</a>
                         </div>
                     </div>

expenses_manager/expenses/templates/settings/budget_blocks.html

@@ -0,0 +1,76 @@
+{% extends "expenses/base.html" %}
+
+{% block title %}Reparto por bloques{% endblock %}
+
+{% block content %}
+    <h1>Reparto por bloques</h1>
+
+    <p>Qué porcentaje de tus ingresos debería ir a cada bloque. Los bloques de gasto son los tipos que asignas a tus categorías; el ahorro son los traspasos a tus cuentas de ahorro.</p>
+
+    {# Arranca con el reparto guardado; el script de abajo lo recalcula al teclear. #}
+    <p id="budgetTotals" aria-live="polite">Asignado: {{ assigned|floatformat:"-2" }} %. Sin asignar: {{ unassigned|floatformat:"-2" }} %.</p>
+
+    {% if proposal %}
+        <p class="muted">
+            Junto a cada bloque tienes lo que fue de verdad del {{ proposal.date_from|date:"d/m/Y" }} al {{ proposal.date_to|date:"d/m/Y" }}, sobre tus ingresos de ese periodo.
+            {% if proposal.unclassified %}El {{ proposal.unclassified }} % se fue en gastos sin tipo, que no cuentan en ningún bloque.{% endif %}
+        </p>
+    {% else %}
+        <p class="muted">No hay ingresos en los últimos 12 meses completos, así que no se puede calcular una propuesta.</p>
+    {% endif %}
+
+    <form method="post" action="{% url 'budget_blocks' %}" class="app-form" id="budgetForm">
+        {% csrf_token %}
+        {% include "expenses/_form_fields.html" %}
+
+        <div class="form-actions">
+            <button type="submit" class="btn btn-primary">Guardar</button>
+            {% if proposal %}
+                <a class="btn btn-secondary" href="{% url 'budget_blocks' %}?propuesta=1">Usar valores calculados</a>
+            {% endif %}
+            <a class="btn btn-secondary" href="{% url 'settings_index' %}">Volver</a>
+        </div>
+        {% if proposal_total > 100 %}
+            <p class="form-errors">Los valores calculados suman un {{ proposal_total }} %: en ese periodo gastaste más de lo que ingresaste. Puedes cargarlos, pero tendrás que bajar algún bloque hasta que la suma no pase de 100 para poder guardar.</p>
+        {% endif %}
+    </form>
+
+    <script>
+        // Suma en vivo de los cinco bloques. Es solo comodidad: quien decide si
+        // se puede guardar es la validación del servidor.
+        (function () {
+            const form = document.getElementById('budgetForm');
+            const totals = document.getElementById('budgetTotals');
+            const names = [{% for field in form %}"{{ field.html_name }}",{% endfor %}];
+
+            function format(cents) {
+                return (cents / 100).toLocaleString('es-ES', { maximumFractionDigits: 2 });
+            }
+
+            function update() {
+                // En céntimos enteros y redondeados: sin el redondeo,
+                // 18,1 × 100 + 81,9 × 100 da 10000,000000000002 y avisaría
+                // de que pasa de 100.
+                let cents = 0;
+                names.forEach(function (name) {
+                    const value = parseFloat(form.elements[name].value);
+                    if (!isNaN(value)) {
+                        cents += Math.round(value * 100);
+                    }
+                });
+
+                if (cents > 10000) {
+                    totals.textContent = 'Asignado: ' + format(cents) + ' %. Pasa de 100 por '
+                        + format(cents - 10000) + ' %: así no se podrá guardar.';
+                    totals.className = 'form-errors';
+                } else {
+                    totals.textContent = 'Asignado: ' + format(cents) + ' %. Sin asignar: '
+                        + format(10000 - cents) + ' %.';
+                    totals.className = '';
+                }
+            }
+
+            form.addEventListener('input', update);
+        })();
+    </script>
+{% endblock %}

expenses_manager/expenses/templates/settings/index.html

@@ -25,6 +25,11 @@
         <p>Define y controla tus metas de gasto.</p>
     </a>
 
+    <a class="settings-card" href="{% url 'budget_blocks' %}">
+        <h2>Reparto por bloques</h2>
+        <p>Decide qué parte de tus ingresos va a cada tipo de gasto y al ahorro.</p>
+    </a>
+
     <a class="settings-card" href="{% url 'export_index' %}">
         <h2>Exportar datos</h2>
         <p>Descarga tus gastos, ingresos o traspasos en CSV.</p>

expenses_manager/expenses/tests/test_budget_blocks.py

@@ -0,0 +1,317 @@
+import pytest
+from datetime import date, timedelta
+from decimal import Decimal
+
+from django.db import connection
+from django.test.utils import CaptureQueriesContext
+from django.urls import reverse
+
+from expenses.forms import BudgetBlockForm
+from expenses.models import Account, BudgetBlock, Category, Expense, Income, Transfer
+from expenses.views import _budget_block_proposal, _savings_total
+
+pytestmark = pytest.mark.django_db
+
+# Con este "hoy" la propuesta mira del 01/07/2023 al 30/06/2024.
+TODAY = date(2024, 7, 15)
+WINDOW = (date(2023, 7, 1), date(2024, 7, 1))
+
+
+def _account(user, name, is_savings=False):
+    return Account.objects.create(
+        owner=user, name=name, initial_balance=Decimal("0"), active=True,
+        is_savings=is_savings,
+    )
+
+
+def _transfer(user, from_account, to_account, amount, on=date(2024, 3, 10)):
+    transfer = Transfer(
+        owner=user, date=on, amount=Decimal(amount),
+        from_account=from_account, to_account=to_account,
+    )
+    transfer.sync()
+    return transfer
+
+
+def _expense(user, account, category, amount, on=date(2024, 3, 1)):
+    return Expense.objects.create(
+        owner=user, account=account, category=category,
+        amount=Decimal(amount), date=on,
+    )
+
+
+def _block_data(**values):
+    data = {block: "0" for block, _ in BudgetBlock.BLOCK_CHOICES}
+    data.update(values)
+    return data
+
+
+# --------------------------------------------------------------------------
+# Ahorro: los tres casos de traspaso
+# --------------------------------------------------------------------------
+
+def test_transfer_into_a_savings_account_counts_as_saving(user):
+    _transfer(user, _account(user, "Nómina"), _account(user, "Hucha", is_savings=True), "300")
+
+    assert _savings_total(user, *WINDOW) == Decimal("300")
+
+
+def test_transfer_out_of_a_savings_account_subtracts(user):
+    checking = _account(user, "Nómina")
+    savings = _account(user, "Hucha", is_savings=True)
+    _transfer(user, checking, savings, "300")
+    _transfer(user, savings, checking, "120")
+
+    # Sacar dinero del colchón es desahorro, no ahorro.
+    assert _savings_total(user, *WINDOW) == Decimal("180")
+
+
+def test_transfer_between_two_savings_accounts_does_not_count(user):
+    piggy = _account(user, "Hucha", is_savings=True)
+    deposit = _account(user, "Depósito", is_savings=True)
+    _transfer(user, piggy, deposit, "1000")
+    _transfer(user, deposit, piggy, "250")
+
+    # Mover dinero de una hucha a otra no es ahorro nuevo, en ningún sentido.
+    assert _savings_total(user, *WINDOW) == Decimal("0")
+
+
+# --------------------------------------------------------------------------
+# Validación de la suma
+# --------------------------------------------------------------------------
+
+def test_form_accepts_exactly_100(user):
+    form = BudgetBlockForm(_block_data(fixed_essential="50", saving="50"), user=user)
+
+    assert form.is_valid(), form.errors
+
+
+def test_form_rejects_more_than_100(user):
+    form = BudgetBlockForm(_block_data(fixed_essential="51", saving="50"), user=user)
+
+    assert not form.is_valid()
+    assert "no pueden pasar del 100" in str(form.non_field_errors())
+
+
+def test_saving_80_leaves_20_unassigned(auth_client, user):
+    response = auth_client.post(
+        reverse("budget_blocks"),
+        _block_data(fixed_essential="50", variable_essential="20", saving="10"),
+        follow=True,
+    )
+
+    assert BudgetBlock.objects.filter(owner=user).count() == 5
+    assert response.context["assigned"] == Decimal("80")
+    assert response.context["unassigned"] == Decimal("20")
+    assert "Sin asignar: 20 %" in response.content.decode()
+
+
+def test_blocks_without_rows_are_zero_and_all_five_are_shown(auth_client, user):
+    BudgetBlock.objects.create(owner=user, block="saving", percentage=Decimal("15"))
+
+    response = auth_client.get(reverse("budget_blocks"))
+
+    form = response.context["form"]
+    assert list(form.fields) == [block for block, _ in BudgetBlock.BLOCK_CHOICES]
+    assert form.initial == {
+        "fixed_essential": Decimal("0"),
+        "fixed_discretionary": Decimal("0"),
+        "variable_essential": Decimal("0"),
+        "variable_discretionary": Decimal("0"),
+        "saving": Decimal("15"),
+    }
+    content = response.content.decode()
+    for block, _ in BudgetBlock.BLOCK_CHOICES:
+        assert 'name="%s"' % block in content
+
+
+# --------------------------------------------------------------------------
+# Propuesta a partir de los datos reales
+# --------------------------------------------------------------------------
+
+def _known_data(user):
+    checking = _account(user, "Nómina")
+    savings = _account(user, "Hucha", is_savings=True)
+    Income.objects.create(
+        owner=user, account=checking, name="Nómina",
+        amount=Decimal("2000"), date=date(2024, 3, 5),
+    )
+    home = Category.objects.create(
+        name="Casa", owner=user, expense_type=Category.EXPENSE_TYPE_FIXED_ESSENTIAL
+    )
+    # Hija sin tipo propio: hereda "Fijo esencial" de Casa.
+    power = Category.objects.create(name="Luz", owner=user, parent=home)
+    fun = Category.objects.create(
+        name="Ocio", owner=user, expense_type=Category.EXPENSE_TYPE_VARIABLE_DISCRETIONARY
+    )
+    loose = Category.objects.create(name="Varios", owner=user)
+    _expense(user, checking, home, "500")
+    _expense(user, checking, power, "100")
+    _expense(user, checking, fun, "200")
+    _expense(user, checking, loose, "100")
+    _transfer(user, checking, savings, "300")
+    # Fuera de la ventana de 12 meses completos: no cuentan.
+    _expense(user, checking, home, "999", on=date(2024, 7, 2))
+    _expense(user, checking, home, "999", on=date(2023, 6, 30))
+    return checking, savings
+
+
+def test_proposal_percentages_with_known_data(user):
+    _known_data(user)
+
+    proposal = _budget_block_proposal(user, TODAY)
+
+    assert proposal["date_from"] == date(2023, 7, 1)
+    assert proposal["date_to"] == date(2024, 6, 30)
+    assert proposal["blocks"] == {
+        "fixed_essential": Decimal("30.0"),        # (500 + 100) / 2000
+        "fixed_discretionary": Decimal("0.0"),
+        "variable_essential": Decimal("0.0"),
+        "variable_discretionary": Decimal("10.0"),  # 200 / 2000
+        "saving": Decimal("15.0"),                  # 300 / 2000
+    }
+    assert proposal["unclassified"] == Decimal("5.0")
+
+
+def test_proposal_uses_inherited_expense_type(user):
+    checking = _account(user, "Nómina")
+    Income.objects.create(
+        owner=user, account=checking, name="Nómina",
+        amount=Decimal("1000"), date=date(2024, 3, 5),
+    )
+    parent = Category.objects.create(
+        name="Coche", owner=user, expense_type=Category.EXPENSE_TYPE_VARIABLE_ESSENTIAL
+    )
+    child = Category.objects.create(name="Gasolina", owner=user, parent=parent)
+    _expense(user, checking, child, "80")
+
+    proposal = _budget_block_proposal(user, TODAY)
+
+    assert proposal["blocks"]["variable_essential"] == Decimal("8.0")
+    assert proposal["unclassified"] == Decimal("0.0")
+
+
+def test_proposal_is_none_without_income(user):
+    assert _budget_block_proposal(user, TODAY) is None
+
+
+def test_proposal_query_count_does_not_grow(user):
+    checking, _ = _known_data(user)
+
+    with CaptureQueriesContext(connection) as small:
+        _budget_block_proposal(user, TODAY)
+
+    parent = Category.objects.get(name="Casa")
+    for i in range(10):
+        parent = Category.objects.create(name=f"Nivel {i}", owner=user, parent=parent)
+        _expense(user, checking, parent, "1")
+
+    with CaptureQueriesContext(connection) as large:
+        _budget_block_proposal(user, TODAY)
+
+    assert len(large.captured_queries) == len(small.captured_queries) == 4
+
+
+def test_use_proposal_prefills_without_saving(auth_client, user):
+    # La vista usa el "hoy" real: los datos van al mes pasado, que siempre cae
+    # dentro de los 12 meses completos.
+    last_month = date.today().replace(day=1) - timedelta(days=1)
+    checking = _account(user, "Nómina")
+    Income.objects.create(
+        owner=user, account=checking, name="Nómina",
+        amount=Decimal("1000"), date=last_month,
+    )
+    _transfer(user, checking, _account(user, "Hucha", is_savings=True), "250", on=last_month)
+
+    response = auth_client.get(reverse("budget_blocks"), {"propuesta": "1"})
+
+    form = response.context["form"]
+    assert form.initial["saving"] == Decimal("25.0")
+    # Con coma decimal, como el resto de números de la interfaz.
+    assert "Calculado: 25,0 %" in form.fields["saving"].help_text
+    assert not BudgetBlock.objects.filter(owner=user).exists()
+
+
+def _last_month_income_and_expense(user, income, expense):
+    # La vista usa el "hoy" real: el mes pasado siempre cae dentro de los 12
+    # meses completos de la propuesta.
+    last_month = date.today().replace(day=1) - timedelta(days=1)
+    checking = _account(user, "Nómina")
+    Income.objects.create(
+        owner=user, account=checking, name="Nómina",
+        amount=Decimal(income), date=last_month,
+    )
+    rent = Category.objects.create(
+        name="Alquiler", owner=user, expense_type=Category.EXPENSE_TYPE_FIXED_ESSENTIAL
+    )
+    _expense(user, checking, rent, expense, on=last_month)
+
+
+def test_proposal_over_100_is_flagged_next_to_the_button(auth_client, user):
+    # Más gasto que ingreso: Fijo esencial sale al 120 %.
+    _last_month_income_and_expense(user, income="1000", expense="1200")
+
+    response = auth_client.get(reverse("budget_blocks"))
+
+    assert response.context["proposal_total"] == Decimal("120.0")
+    assert "suman un 120,0 %" in response.content.decode()
+
+
+def test_proposal_up_to_100_has_no_warning(auth_client, user):
+    _last_month_income_and_expense(user, income="1000", expense="600")
+
+    response = auth_client.get(reverse("budget_blocks"))
+
+    assert response.context["proposal_total"] == Decimal("60.0")
+    assert "suman un" not in response.content.decode()
+
+
+# --------------------------------------------------------------------------
+# Aislamiento y login
+# --------------------------------------------------------------------------
+
+def test_budget_of_another_user_is_neither_shown_nor_edited(auth_client, user, django_user_model):
+    other = django_user_model.objects.create_user(username="otro", password="x-pass-123")
+    BudgetBlock.objects.create(owner=other, block="saving", percentage=Decimal("40"))
+
+    response = auth_client.get(reverse("budget_blocks"))
+    assert response.context["form"].initial["saving"] == Decimal("0")
+    assert response.context["assigned"] == Decimal("0")
+
+    auth_client.post(reverse("budget_blocks"), _block_data(saving="25"))
+
+    assert BudgetBlock.objects.get(owner=other, block="saving").percentage == Decimal("40")
+    assert BudgetBlock.objects.get(owner=user, block="saving").percentage == Decimal("25")
+
+
+def test_budget_screen_requires_login(client):
+    response = client.get(reverse("budget_blocks"))
+
+    assert response.status_code == 302
+    assert reverse("login") in response["Location"]
+
+
+def test_budget_screen_is_linked_from_hub_and_menu(auth_client):
+    # Son dos sitios independientes: el hub de Configuración y el desplegable
+    # del menú. Con la exportación se puso solo uno y desde el menú no se
+    # llegaba.
+    hub = auth_client.get(reverse("settings_index")).content.decode()
+    menu = auth_client.get(reverse("home")).content.decode()
+    link = 'href="%s"' % reverse("budget_blocks")
+
+    assert link in hub
+    assert link in menu
+
+
+# --------------------------------------------------------------------------
+# Campo de cuenta de ahorro
+# --------------------------------------------------------------------------
+
+def test_account_form_saves_savings_flag_and_list_shows_it(auth_client, user):
+    auth_client.post(
+        reverse("account_create"),
+        {"name": "Hucha", "initial_balance": "0", "active": "on", "is_savings": "on"},
+    )
+
+    assert Account.objects.get(owner=user, name="Hucha").is_savings is True
+    assert "De ahorro" in auth_client.get(reverse("account_list")).content.decode()

expenses_manager/expenses/urls.py

@@ -33,6 +33,7 @@ urlpatterns = [
     path('categories/<int:pk>/edit/', views.category_edit, name='category_edit'),
     path('categories/<int:pk>/delete/', views.category_delete, name='category_delete'),
     path('settings/', views.settings_index, name='settings_index'),
+    path('budget/', views.budget_blocks, name='budget_blocks'),
     path('export/', views.export_index, name='export_index'),
     path('export/download/', views.export_download, name='export_download'),
     path('goals/', views.goal_list, name='goal_list'),

expenses_manager/expenses/views.py

@@ -13,6 +13,7 @@ from .models import (
     Income,
     Goal,
     Transfer,
+    BudgetBlock,
 )
 from .forms import (
     ExpenseForm,
@@ -24,11 +25,12 @@ from .forms import (
     GoalForm,
     TransferForm,
     ExportForm,
+    BudgetBlockForm,
 )
 from .csv_export import DIALECTS, EXPORTS, csv_filename, stream_csv
 
 from django.core.paginator import Paginator
-from django.db.models import Sum, Count, Min, ProtectedError
+from django.db.models import Sum, Count, Min, ProtectedError, Q
 from django.db.models.functions import (
     ExtractMonth,
     ExtractYear,
@@ -39,6 +41,7 @@ from django.db.models.functions import (
 
 from django.contrib.auth.decorators import login_required
 from django.http import HttpResponseBadRequest, StreamingHttpResponse
+from django.utils.formats import number_format
 from django.utils.http import url_has_allowed_host_and_scheme
 from django.shortcuts import get_object_or_404, render, redirect
 from django.urls import reverse
@@ -185,6 +188,75 @@ def _expense_type_breakdown(user, expenses):
     return rows, classified_count
 
 
+def _savings_total(user, date_from, date_to):
+    """Ahorro neto del periodo, medido por los traspasos entre cuentas.
+
+    No todos los traspasos cuentan igual:
+    - de una cuenta normal a una de ahorro: suma, es ahorrar;
+    - de una de ahorro a una normal: resta, es desahorro, y sacar dinero del
+      colchón no puede contar como ahorrar;
+    - entre dos de ahorro: ni suma ni resta. Mover dinero de una hucha a otra
+      no es ahorro nuevo, y contarlo inflaría el bloque cada vez que se
+      reorganizan cuentas.
+
+    Solo cuenta el importe del traspaso; la comisión ya es un gasto normal.
+    Una sola consulta. `date_to` es exclusivo."""
+    totals = Transfer.objects.filter(
+        owner=user, date__gte=date_from, date__lt=date_to
+    ).aggregate(
+        saved=Sum(
+            "amount",
+            filter=Q(to_account__is_savings=True, from_account__is_savings=False),
+        ),
+        withdrawn=Sum(
+            "amount",
+            filter=Q(from_account__is_savings=True, to_account__is_savings=False),
+        ),
+    )
+    return (totals["saved"] or Decimal("0")) - (totals["withdrawn"] or Decimal("0"))
+
+
+def _budget_block_proposal(user, today):
+    """Reparto propuesto a partir de los últimos 12 meses completos.
+
+    Cada bloque es su parte del ingreso real del periodo, sin traspasos. Como
+    es la misma división para los dos lados, el bloque sobre el ingreso medio
+    mensual es lo mismo que el bloque sobre el ingreso total, así que da igual
+    si hay 12 meses de datos o menos.
+
+    Devuelve None si no hubo ingresos: sin denominador no hay porcentaje.
+    Son cuatro consultas fijas (dos de _expense_type_breakdown, ingresos y
+    traspasos), crezca lo que crezca el número de categorías o de gastos."""
+    date_to = today.replace(day=1)
+    date_from = date(*sub_months(date_to.year, date_to.month, 12), 1)
+
+    income = _analysis_incomes(user).filter(
+        date__gte=date_from, date__lt=date_to
+    ).aggregate(total=Sum("amount"))["total"]
+    if not income:
+        return None
+
+    expenses = _analysis_expenses(user).filter(date__gte=date_from, date__lt=date_to)
+    breakdown, _ = _expense_type_breakdown(user, expenses)
+    totals = {row["expense_type"]: row["total"] for row in breakdown}
+    totals[BudgetBlock.BLOCK_SAVING] = _savings_total(user, date_from, date_to)
+
+    def pct(amount):
+        # Un desahorro neto daría un porcentaje negativo, que el formulario no
+        # admite: la propuesta se queda en 0 para ese bloque.
+        return max(amount / income * 100, Decimal("0")).quantize(Decimal("0.1"))
+
+    return {
+        "date_from": date_from,
+        # El último día incluido, para enseñarlo en la pantalla.
+        "date_to": date_to - timedelta(days=1),
+        "blocks": {block: pct(totals[block]) for block, _ in BudgetBlock.BLOCK_CHOICES},
+        # El gasto sin clasificar no va a ningún bloque. Se enseña aparte para
+        # que se entienda por qué la propuesta no llega al 100 %.
+        "unclassified": pct(totals[""]),
+    }
+
+
 def _without_transfers(movements):
     """Quita las patas de traspaso de un queryset de gastos o de ingresos.
 
@@ -1782,6 +1854,54 @@ def settings_index(request):
     return render(request, "settings/index.html", {"active_menu": "settings"})
 
 
+@login_required
+def budget_blocks(request):
+    proposal = _budget_block_proposal(request.user, date.today())
+
+    if request.method == "POST":
+        form = BudgetBlockForm(request.POST, user=request.user)
+        if form.is_valid():
+            form.save()
+            messages.success(request, "Reparto guardado.")
+            return redirect("budget_blocks")
+    elif proposal and request.GET.get("propuesta"):
+        # "Usar valores calculados" solo precarga el formulario: no se guarda
+        # nada hasta que el usuario pulsa Guardar.
+        form = BudgetBlockForm(user=request.user, initial=proposal["blocks"])
+    else:
+        form = BudgetBlockForm(user=request.user)
+
+    proposal_total = None
+    if proposal:
+        for block, value in proposal["blocks"].items():
+            # number_format para que salga con coma decimal, como en las
+            # plantillas; con %s quedaría "25.0" al lado de "25,0".
+            form.fields[block].help_text = "Calculado: %s %%" % number_format(value)
+        # Con más gasto que ingreso en el periodo la propuesta pasa de 100 y,
+        # aplicada tal cual, la rechazaría la validación al guardar: la
+        # plantilla lo avisa junto al botón.
+        proposal_total = sum(proposal["blocks"].values())
+
+    # Lo que queda sin asignar con el reparto guardado, no con lo que se esté
+    # tecleando: es lo que vale de verdad mientras no se guarde.
+    assigned = BudgetBlock.objects.filter(owner=request.user).aggregate(
+        total=Sum("percentage")
+    )["total"] or Decimal("0")
+
+    return render(
+        request,
+        "settings/budget_blocks.html",
+        {
+            "active_menu": "settings",
+            "form": form,
+            "proposal": proposal,
+            "proposal_total": proposal_total,
+            "assigned": assigned,
+            "unassigned": Decimal("100") - assigned,
+        },
+    )
+
+
 @login_required
 def transfer_list(request):
     transfers = Transfer.objects.filter(owner=request.user).select_related(