feat(backend): validate custom preferences on save

Foxnouns.Backend/Utils/ValidationUtils.Preferences.cs

@@ -0,0 +1,72 @@
+// Copyright (C) 2023-present sam/u1f320 (vulpine.solutions)
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published
+// by the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+using Foxnouns.Backend.Controllers;
+
+namespace Foxnouns.Backend.Utils;
+
+public static partial class ValidationUtils
+{
+    public const int MaxCustomPreferences = 25;
+    public const int MaxPreferenceTooltipLength = 128;
+
+    public static List<(string, ValidationError?)> ValidateCustomPreferences(
+        List<UsersController.CustomPreferenceUpdate> preferences
+    )
+    {
+        var errors = new List<(string, ValidationError?)>();
+
+        if (preferences.Count > MaxCustomPreferences)
+            errors.Add(
+                (
+                    "custom_preferences",
+                    ValidationError.LengthError(
+                        "Too many custom preferences",
+                        0,
+                        MaxCustomPreferences,
+                        preferences.Count
+                    )
+                )
+            );
+        if (preferences.Count > 50)
+            return errors;
+
+        foreach (var (p, i) in preferences.Select((p, i) => (p, i)))
+        {
+            if (!BootstrapIcons.IsValid(p.Icon))
+                errors.Add(
+                    (
+                        $"custom_preferences.{i}.icon",
+                        ValidationError.DisallowedValueError("Invalid icon name", [], p.Icon)
+                    )
+                );
+
+            if (p.Tooltip.Length is 1 or > MaxPreferenceTooltipLength)
+                errors.Add(
+                    (
+                        $"custom_preferences.{i}.tooltip",
+                        ValidationError.LengthError(
+                            "Tooltip is too short or too long",
+                            1,
+                            MaxPreferenceTooltipLength,
+                            p.Tooltip.Length
+                        )
+                    )
+                );
+        }
+
+        return errors;
+    }
+}