fix(admin): delete feedback alerts + informative block errors (issue #127)

- locations/categories GET pass req.query.error/success to views
- locations/categories EJS render dismissible error/success alerts (modeled on catalog.ejs)
- Delete errors include blocking counts + 'Remove X first' hints
- 🔒 lock hint on rows with linked categories/products/subcategories
- 18 new tests (adminDeleteFeedback.test.js); 48 total pass

src/__tests__/adminDeleteFeedback.test.js

@@ -0,0 +1,181 @@
+import { describe, it, expect } from 'vitest';
+import { readFileSync } from 'fs';
+import { fileURLToPath } from 'url';
+import { dirname, join } from 'path';
+import ejs from 'ejs';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+const viewsDir = join(__dirname, '..', 'admin', 'views');
+const locationsTemplate = readFileSync(join(viewsDir, 'locations.ejs'), 'utf-8');
+const categoriesTemplate = readFileSync(join(viewsDir, 'categories.ejs'), 'utf-8');
+const routesDir = join(__dirname, '..', 'admin', 'routes');
+const locationsSource = readFileSync(join(routesDir, 'locations.js'), 'utf-8');
+const categoriesSource = readFileSync(join(routesDir, 'categories.js'), 'utf-8');
+
+describe('admin delete feedback UI', () => {
+  describe('locations.ejs', () => {
+    it('renders a danger alert when error is set', () => {
+      const html = ejs.render(locationsTemplate, {
+        error: 'Cannot delete location with categories (count: 3). Remove categories first.',
+        success: '',
+        csrfToken: 'csrf',
+        locations: []
+      });
+      expect(html).toContain('alert-danger');
+      expect(html).toContain('Cannot delete location with categories (count: 3). Remove categories first.');
+    });
+
+    it('does not render an error alert when error is empty', () => {
+      const html = ejs.render(locationsTemplate, {
+        error: '',
+        success: '',
+        csrfToken: 'csrf',
+        locations: []
+      });
+      expect(html).not.toContain('alert-danger');
+    });
+
+    it('renders a success alert when success is set', () => {
+      const html = ejs.render(locationsTemplate, {
+        error: '',
+        success: 'Location deleted',
+        csrfToken: 'csrf',
+        locations: []
+      });
+      expect(html).toContain('alert-success');
+      expect(html).toContain('Location deleted');
+    });
+
+    it('renders the lock hint when a location has categories', () => {
+      const html = ejs.render(locationsTemplate, {
+        error: '',
+        success: '',
+        csrfToken: 'csrf',
+        locations: [{ id: 1, country: 'DE', city: 'Berlin', district: '', category_count: 2, product_count: 0, is_active: 1 }]
+      });
+      expect(html).toContain('🔒');
+    });
+
+    it('renders the lock hint when a location has products', () => {
+      const html = ejs.render(locationsTemplate, {
+        error: '',
+        success: '',
+        csrfToken: 'csrf',
+        locations: [{ id: 1, country: 'DE', city: 'Berlin', district: '', category_count: 0, product_count: 5, is_active: 1 }]
+      });
+      expect(html).toContain('🔒');
+    });
+
+    it('does not render the lock hint when a location has no links', () => {
+      const html = ejs.render(locationsTemplate, {
+        error: '',
+        success: '',
+        csrfToken: 'csrf',
+        locations: [{ id: 1, country: 'DE', city: 'Berlin', district: '', category_count: 0, product_count: 0, is_active: 1 }]
+      });
+      expect(html).not.toContain('🔒');
+    });
+  });
+
+  describe('categories.ejs', () => {
+    const baseData = {
+      error: '',
+      success: '',
+      csrfToken: 'csrf',
+      locations: [],
+      subcategories: [],
+      subcategoriesByCategory: {}
+    };
+
+    it('renders a danger alert when error is set', () => {
+      const html = ejs.render(categoriesTemplate, {
+        ...baseData,
+        error: 'Cannot delete category with products (count: 2). Remove products first.',
+        categories: []
+      });
+      expect(html).toContain('alert-danger');
+      expect(html).toContain('Cannot delete category with products (count: 2). Remove products first.');
+    });
+
+    it('renders a success alert when success is set', () => {
+      const html = ejs.render(categoriesTemplate, {
+        ...baseData,
+        success: 'Category deleted',
+        categories: []
+      });
+      expect(html).toContain('alert-success');
+      expect(html).toContain('Category deleted');
+    });
+
+    it('renders the lock hint when a category has products', () => {
+      const html = ejs.render(categoriesTemplate, {
+        ...baseData,
+        categories: [{ id: 1, name: 'Food', product_count: 3, is_active: 1, country: null, city: null }]
+      });
+      expect(html).toContain('🔒');
+    });
+
+    it('renders the lock hint when a category has subcategories', () => {
+      const html = ejs.render(categoriesTemplate, {
+        ...baseData,
+        categories: [{ id: 1, name: 'Food', product_count: 0, is_active: 1, country: null, city: null }],
+        subcategories: [{ id: 10, category_id: 1, name: 'Snacks', product_count: 0, is_active: 1 }],
+        subcategoriesByCategory: { 1: [{ id: 10, category_id: 1, name: 'Snacks', product_count: 0, is_active: 1 }] }
+      });
+      expect(html).toContain('🔒');
+    });
+
+    it('renders the lock hint for a subcategory with products', () => {
+      const html = ejs.render(categoriesTemplate, {
+        ...baseData,
+        categories: [{ id: 1, name: 'Food', product_count: 0, is_active: 1, country: null, city: null }],
+        subcategories: [{ id: 10, category_id: 1, name: 'Snacks', product_count: 4, is_active: 1 }],
+        subcategoriesByCategory: { 1: [{ id: 10, category_id: 1, name: 'Snacks', product_count: 4, is_active: 1 }] }
+      });
+      expect(html).toContain('🔒');
+    });
+
+    it('does not render the lock hint when a category has no links', () => {
+      const html = ejs.render(categoriesTemplate, {
+        ...baseData,
+        categories: [{ id: 1, name: 'Food', product_count: 0, is_active: 1, country: null, city: null }]
+      });
+      expect(html).not.toContain('🔒');
+    });
+  });
+
+  describe('route source assertions', () => {
+    it('locations GET passes error and success from query', () => {
+      expect(locationsSource).toContain('error: req.query.error || \'\'');
+      expect(locationsSource).toContain('success: req.query.success || \'\'');
+    });
+
+    it('locations DELETE error messages include counts for categories and products', () => {
+      expect(locationsSource).toContain('(count:+${count.cnt}).+Remove+categories+first.');
+      expect(locationsSource).toContain('(count:+${productCount.cnt}).+Remove+products+first.');
+      expect(locationsSource).toContain('Remove+categories+first');
+      expect(locationsSource).toContain('Remove+products+first');
+    });
+
+    it('locations DELETE success message is set on redirect', () => {
+      expect(locationsSource).toContain("res.redirect('/locations?success=Location+deleted')");
+    });
+
+    it('categories GET passes error and success from query', () => {
+      expect(categoriesSource).toContain('error: req.query.error || \'\'');
+      expect(categoriesSource).toContain('success: req.query.success || \'\'');
+    });
+
+    it('categories DELETE error messages include counts for products and subcategories', () => {
+      expect(categoriesSource).toContain('(count:+${count.cnt}).+Remove+products+first.');
+      expect(categoriesSource).toContain('(count:+${subCount.cnt}).+Remove+products+first.');
+    });
+
+    it('categories DELETE and subcategory DELETE success messages are set', () => {
+      expect(categoriesSource).toContain("res.redirect('/categories?success=Category+deleted')");
+      expect(categoriesSource).toContain("res.redirect('/categories?success=Subcategory+deleted')");
+    });
+  });
+});

src/admin/routes/categories.js

@@ -21,7 +21,15 @@ router.get('/', asyncHandler(async (req, res) => {
     subcategoriesByCategory[s.category_id].push(s);
   }
 
-  res.render('categories', { title: 'Categories', categories, locations, subcategories, subcategoriesByCategory });
+  res.render('categories', {
+    title: 'Categories',
+    categories,
+    locations,
+    subcategories,
+    subcategoriesByCategory,
+    error: req.query.error || '',
+    success: req.query.success || '',
+  });
 }));
 
 router.post('/', asyncHandler(async (req, res) => {
@@ -48,18 +56,18 @@ router.post('/:id/toggle', asyncHandler(async (req, res) => {
 router.post('/:id/delete', asyncHandler(async (req, res) => {
   const count = await db.getAsync('SELECT COUNT(*) as cnt FROM products WHERE category_id = ?', [req.params.id]);
   if (count && count.cnt > 0) {
-    return res.redirect('/categories?error=Cannot+delete+category+with+products');
+    return res.redirect(`/categories?error=Cannot+delete+category+with+products+(count:+${count.cnt}).+Remove+products+first.`);
   }
   const subCount = await db.getAsync(
     'SELECT COUNT(*) as cnt FROM products WHERE subcategory_id IN (SELECT id FROM subcategories WHERE category_id = ?)',
     [req.params.id]
   );
   if (subCount && subCount.cnt > 0) {
-    return res.redirect('/categories?error=Cannot+delete+category+with+products+in+subcategories');
+    return res.redirect(`/categories?error=Cannot+delete+category+with+products+in+subcategories+(count:+${subCount.cnt}).+Remove+products+first.`);
   }
   await db.runAsync('DELETE FROM subcategories WHERE category_id = ?', [req.params.id]);
   await db.runAsync('DELETE FROM categories WHERE id = ?', [req.params.id]);
-  res.redirect('/categories');
+  res.redirect('/categories?success=Category+deleted');
 }));
 
 router.post('/:id/subcategories', asyncHandler(async (req, res) => {
@@ -93,10 +101,10 @@ router.post('/subcategories/:id/delete', asyncHandler(async (req, res) => {
     [req.params.id]
   );
   if (count && count.cnt > 0) {
-    return res.redirect('/categories?error=Cannot+delete+subcategory+with+products');
+    return res.redirect(`/categories?error=Cannot+delete+subcategory+with+products+(count:+${count.cnt}).+Remove+products+first.`);
   }
   await db.runAsync('DELETE FROM subcategories WHERE id = ?', [req.params.id]);
-  res.redirect('/categories');
+  res.redirect('/categories?success=Subcategory+deleted');
 }));
 
 export default router;

src/admin/routes/locations.js

@@ -9,7 +9,12 @@ router.get('/', asyncHandler(async (req, res) => {
     (SELECT COUNT(*) FROM categories WHERE location_id = l.id) as category_count,
     (SELECT COUNT(*) FROM products WHERE location_id = l.id) as product_count
     FROM locations l ORDER BY l.country, l.city, l.district`);
-  res.render('locations', { title: 'Locations', locations });
+  res.render('locations', {
+    title: 'Locations',
+    locations,
+    error: req.query.error || '',
+    success: req.query.success || '',
+  });
 }));
 
 router.post('/', asyncHandler(async (req, res) => {
@@ -49,17 +54,17 @@ router.post('/:id/delete', asyncHandler(async (req, res) => {
     [req.params.id]
   );
   if (count && count.cnt > 0) {
-    return res.redirect('/locations?error=Cannot+delete+location+with+categories');
+    return res.redirect(`/locations?error=Cannot+delete+location+with+categories+(count:+${count.cnt}).+Remove+categories+first.`);
   }
   const productCount = await db.getAsync(
     'SELECT COUNT(*) as cnt FROM products WHERE location_id = ?',
     [req.params.id]
   );
   if (productCount && productCount.cnt > 0) {
-    return res.redirect('/locations?error=Cannot+delete+location+with+products');
+    return res.redirect(`/locations?error=Cannot+delete+location+with+products+(count:+${productCount.cnt}).+Remove+products+first.`);
   }
   await db.runAsync('DELETE FROM locations WHERE id = ?', [req.params.id]);
-  res.redirect('/locations');
+  res.redirect('/locations?success=Location+deleted');
 }));
 
 export default router;

src/admin/views/categories.ejs

@@ -1,3 +1,15 @@
+<% if (error) { %>
+<div class="alert alert-danger alert-dismissible fade show" role="alert">
+    <%= error %>
+    <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
+</div>
+<% } %>
+<% if (success) { %>
+<div class="alert alert-success alert-dismissible fade show" role="alert">
+    <%= success %>
+    <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
+</div>
+<% } %>
 <a href="/catalog" class="btn btn-sm btn-outline-secondary mb-2">« Back to Catalog</a>
 <div class="panel panel-icon">
     <div class="panel-hdr">
@@ -69,6 +81,9 @@
                                     <input type="hidden" name="_csrf" value="<%= csrfToken %>">
                                     <button class="btn btn-sm btn-danger">Delete</button>
                                 </form>
+                                <% if (c.product_count > 0 || (subcategoriesByCategory[c.id] && subcategoriesByCategory[c.id].length > 0)) { %>
+                                <span class="text-warning" title="Blocks deletion">🔒</span>
+                                <% } %>
                             </td>
                         </tr>
                         <% var subs = subcategoriesByCategory[c.id] || []; %>
@@ -108,6 +123,9 @@
                                     <input type="hidden" name="_csrf" value="<%= csrfToken %>">
                                     <button class="btn btn-sm btn-danger">Delete</button>
                                 </form>
+                                <% if (s.product_count > 0) { %>
+                                <span class="text-warning" title="Blocks deletion">🔒</span>
+                                <% } %>
                             </td>
                         </tr>
                         <% }); %>

src/admin/views/locations.ejs

@@ -1,3 +1,15 @@
+<% if (error) { %>
+<div class="alert alert-danger alert-dismissible fade show" role="alert">
+    <%= error %>
+    <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
+</div>
+<% } %>
+<% if (success) { %>
+<div class="alert alert-success alert-dismissible fade show" role="alert">
+    <%= success %>
+    <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
+</div>
+<% } %>
 <a href="/catalog" class="btn btn-sm btn-outline-secondary mb-2">« Back to Catalog</a>
 <div class="panel panel-icon mb-3">
     <div class="panel-hdr">
@@ -71,6 +83,9 @@
                                     <input type="hidden" name="_csrf" value="<%= csrfToken %>">
                                     <button class="btn btn-sm btn-danger">Delete</button>
                                 </form>
+                                <% if (l.category_count > 0 || l.product_count > 0) { %>
+                                <span class="text-warning" title="Blocks deletion">🔒</span>
+                                <% } %>
                             </td>
                         </tr>
                         <% }); %>