Support category .csv import (#326)

* Allow category imports to set icons

* Linter

* Update category import description in English locale

Signed-off-by: Juan José Mata <juanjo.mata@gmail.com>

* Rename icon in CSV header to `lucide-icon`

* Make sure we export the icon while we're at this

---------

Signed-off-by: Juan José Mata <juanjo.mata@gmail.com>

app/models/category_import.rb

@@ -0,0 +1,86 @@
+class CategoryImport < Import
+  def import!
+    transaction do
+      rows.each do |row|
+        category_name = row.name.to_s.strip
+        category = family.categories.find_or_initialize_by(name: category_name)
+        category.color = row.category_color.presence || category.color || Category::UNCATEGORIZED_COLOR
+        category.classification = row.category_classification.presence || category.classification || "expense"
+        category.lucide_icon = row.category_icon.presence || category.lucide_icon || "shapes"
+        category.parent = nil
+        category.save!
+
+        ensure_placeholder_category(row.category_parent)
+      end
+
+      rows.each do |row|
+        category = family.categories.find_by!(name: row.name.to_s.strip)
+        parent = ensure_placeholder_category(row.category_parent)
+
+        if parent && parent == category
+          errors.add(:base, "Category '#{category.name}' cannot be its own parent")
+          raise ActiveRecord::RecordInvalid.new(self)
+        end
+
+        next if category.parent == parent
+
+        category.update!(parent: parent)
+      end
+    end
+  end
+
+  def column_keys
+    %i[name category_color category_parent category_classification category_icon]
+  end
+
+  def required_column_keys
+    %i[name]
+  end
+
+  def mapping_steps
+    []
+  end
+
+  def dry_run
+    { categories: rows.count }
+  end
+
+  def csv_template
+    template = <<-CSV
+      name*,color,parent_category,classification,lucide-icon
+      Food & Drink,#f97316,,expense,carrot
+      Groceries,#407706,Food & Drink,expense,shopping-basket
+      Salary,#22c55e,,income,briefcase
+    CSV
+
+    CSV.parse(template, headers: true)
+  end
+
+  def generate_rows_from_csv
+    rows.destroy_all
+
+    csv_rows.each do |row|
+      rows.create!(
+        name: row["name"].to_s.strip,
+        category_color: row["color"].to_s.strip,
+        category_parent: row["parent_category"].to_s.strip,
+        category_classification: row["classification"].to_s.strip,
+        category_icon: (row["lucide-icon"].presence || row["icon"]).to_s.strip,
+        currency: default_currency
+      )
+    end
+  end
+
+  private
+
+    def ensure_placeholder_category(name)
+      trimmed_name = name.to_s.strip
+      return if trimmed_name.blank?
+
+      family.categories.find_or_create_by!(name: trimmed_name) do |placeholder|
+        placeholder.color = Category::UNCATEGORIZED_COLOR
+        placeholder.classification = "expense"
+        placeholder.lucide_icon = "shapes"
+      end
+    end
+end