Added the limitation so that essential accounts, like cash, and the accounts in use, cannot be deleted.

src/accounting/account/views.py

@@ -157,6 +157,9 @@ def delete_account(account: Account) -> redirect:
     :return: The redirection to the account list on success, or the account
         detail on error.
     """
+    if not account.can_delete:
+        flash(s(lazy_gettext("The account cannot be deleted.")), "error")
+        return redirect(inherit_next(__get_detail_uri(account)))
     account.delete()
     sort_accounts_in(account.base_code, account.id)
     db.session.commit()

src/accounting/models.py

@@ -236,6 +236,16 @@ class Account(db.Model):
                 return True
         return False
 
+    @property
+    def can_delete(self) -> bool:
+        """Returns whether the account can be deleted.
+
+        :return: True if the account can be deleted, or False otherwise.
+        """
+        if self.code in {"1111-001", "3351-001", "3353-001"}:
+            return False
+        return len(self.line_items) == 0
+
     def delete(self) -> None:
         """Deletes this account.
 

src/accounting/templates/accounting/account/detail.html

@@ -41,10 +41,17 @@ First written: 2023/1/31
     <span class="d-none d-md-inline">{{ A_("Order") }}</span>
   </a>
   {% if accounting_can_edit() %}
-    <button class="btn btn-danger" type="button" data-bs-toggle="modal" data-bs-target="#accounting-delete-modal">
-      <i class="fa-solid fa-trash"></i>
-      <span class="d-none d-md-inline">{{ A_("Delete") }}</span>
-    </button>
+    {% if obj.can_delete %}
+      <button class="btn btn-danger" type="button" data-bs-toggle="modal" data-bs-target="#accounting-delete-modal">
+        <i class="fa-solid fa-trash"></i>
+        <span class="d-none d-md-inline">{{ A_("Delete") }}</span>
+      </button>
+    {% else %}
+      <button class="btn btn-secondary" type="button" disabled="disabled">
+        <i class="fa-solid fa-trash"></i>
+        <span class="d-none d-md-inline">{{ A_("Delete") }}</span>
+      </button>
+    {% endif %}
   {% endif %}
 </div>
 
@@ -56,7 +63,7 @@ First written: 2023/1/31
   </div>
 {% endif %}
 
-{% if accounting_can_edit() %}
+{% if accounting_can_edit() and obj.can_delete %}
   <form action="{{ url_for("accounting.account.delete", account=obj) }}" method="post">
     <input type="hidden" name="csrf_token" value="{{ csrf_token() }}">
     {% if request.args.next %}