Add expense type classification to categories

expenses_manager/expenses/migrations/0018_category_expense_type.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.2.10 on 2026-10-14 16:10
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('expenses', '0017_goal_linked_expenses_goal_linked_incomes_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='category',
+            name='expense_type',
+            field=models.CharField(blank=True, choices=[('fixed_essential', 'Fijo esencial'), ('fixed_discretionary', 'Fijo prescindible'), ('variable_essential', 'Variable esencial'), ('variable_discretionary', 'Variable prescindible')], help_text='Si lo dejas vacío, hereda el de la categoría padre.', max_length=30, verbose_name='Tipo de gasto'),
+        ),
+    ]

expenses_manager/expenses/models.py

@@ -10,6 +10,22 @@ from django.db.models.functions import ExtractMonth, Lower
 
 
 class Category(models.Model):
+    EXPENSE_TYPE_FIXED_ESSENTIAL = "fixed_essential"
+    EXPENSE_TYPE_FIXED_DISCRETIONARY = "fixed_discretionary"
+    EXPENSE_TYPE_VARIABLE_ESSENTIAL = "variable_essential"
+    EXPENSE_TYPE_VARIABLE_DISCRETIONARY = "variable_discretionary"
+
+    EXPENSE_TYPE_CHOICES = [
+        (EXPENSE_TYPE_FIXED_ESSENTIAL, "Fijo esencial"),
+        (EXPENSE_TYPE_FIXED_DISCRETIONARY, "Fijo prescindible"),
+        (EXPENSE_TYPE_VARIABLE_ESSENTIAL, "Variable esencial"),
+        (EXPENSE_TYPE_VARIABLE_DISCRETIONARY, "Variable prescindible"),
+    ]
+
+    # Saltos máximos al heredar el tipo de gasto. Los ciclos los impide
+    # CategoryForm, pero uno colado por shell o migración no debe colgar nada.
+    EXPENSE_TYPE_MAX_DEPTH = 10
+
     name = models.CharField(max_length=100)
     slug = models.SlugField(blank=True)
 
@@ -32,6 +48,14 @@ class Category(models.Model):
         help_text="Categoría creada por la app (traspasos, comisiones). No borrable.",
     )
 
+    expense_type = models.CharField(
+        max_length=30,
+        choices=EXPENSE_TYPE_CHOICES,
+        blank=True,
+        verbose_name="Tipo de gasto",
+        help_text="Si lo dejas vacío, hereda el de la categoría padre.",
+    )
+
     class Meta:
         unique_together = ("name", "parent", "owner", "slug")
         verbose_name_plural = "categories"
@@ -63,6 +87,22 @@ class Category(models.Model):
 
         return list(seen) if include_self else [i for i in seen if i != self.pk]
 
+    @property
+    def effective_expense_type(self):
+        """Tipo de gasto propio o, si está vacío, el del ancestro más cercano
+        que lo tenga. Cadena vacía si nadie en la cadena lo tiene.
+
+        Cada salto lee self.parent: no lo uses por fila en un listado (N+1).
+        El listado de categorías lo resuelve en _category_tree."""
+        category = self
+        for _ in range(self.EXPENSE_TYPE_MAX_DEPTH):
+            if category is None:
+                return ""
+            if category.expense_type:
+                return category.expense_type
+            category = category.parent
+        return ""
+
 
 class Account(models.Model):
     owner = models.ForeignKey(