From 68bee501d8252521cb6110c134e33863235ff2d1 Mon Sep 17 00:00:00 2001
From: oppiliappan <me@oppi.li>
Date: Wed, 10 Sep 2025 16:09:54 +0100
Subject: [PATCH] appview/validator: add model validation for label defs

Signed-off-by: oppiliappan <me@oppi.li>
---
 appview/validator/label.go | 77 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 appview/validator/label.go

diff --git a/appview/validator/label.go b/appview/validator/label.go
new file mode 100644
index 00000000..d839c2b3
--- /dev/null
+++ b/appview/validator/label.go
@@ -0,0 +1,77 @@
+package validator
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/bluesky-social/indigo/atproto/syntax"
+	"golang.org/x/exp/slices"
+	"tangled.sh/tangled.sh/core/api/tangled"
+	"tangled.sh/tangled.sh/core/appview/db"
+)
+
+var (
+	// Label name should be alphanumeric with hyphens/underscores, but not start/end with them
+	labelNameRegex = regexp.MustCompile(`^[a-zA-Z0-9]([a-zA-Z0-9_-]*[a-zA-Z0-9])?$`)
+	// Color should be a valid hex color
+	colorRegex = regexp.MustCompile(`^#[a-fA-F0-9]{6}$`)
+	// You can only label issues and pulls presently
+	validScopes = []syntax.NSID{tangled.RepoIssueNSID, tangled.RepoPullNSID}
+)
+
+func (v *Validator) ValidateLabelDefinition(label *db.LabelDefinition) error {
+	if label.Name == "" {
+		return fmt.Errorf("label name is empty")
+	}
+	if len(label.Name) > 40 {
+		return fmt.Errorf("label name too long (max 40 graphemes)")
+	}
+	if len(label.Name) < 1 {
+		return fmt.Errorf("label name too short (min 1 grapheme)")
+	}
+	if !labelNameRegex.MatchString(label.Name) {
+		return fmt.Errorf("label name contains invalid characters (use only letters, numbers, hyphens, and underscores)")
+	}
+
+	if !label.ValueType.IsConcreteType() {
+		return fmt.Errorf("invalid value type: %q (must be one of: null, boolean, integer, string)", label.ValueType)
+	}
+
+	if label.ValueType.IsNull() && label.ValueType.IsEnumType() {
+		return fmt.Errorf("null type cannot be used in conjunction with enum type")
+	}
+
+	// validate scope (nsid format)
+	if label.Scope == "" {
+		return fmt.Errorf("scope is required")
+	}
+	if _, err := syntax.ParseNSID(string(label.Scope)); err != nil {
+		return fmt.Errorf("failed to parse scope: %w", err)
+	}
+	if !slices.Contains(validScopes, label.Scope) {
+		return fmt.Errorf("invalid scope: scope must be one of %q", validScopes)
+	}
+
+	// validate color if provided
+	if label.Color != nil {
+		color := strings.TrimSpace(*label.Color)
+		if color == "" {
+			// empty color is fine, set to nil
+			label.Color = nil
+		} else {
+			if !colorRegex.MatchString(color) {
+				return fmt.Errorf("color must be a valid hex color (e.g. #79FFE1 or #000)")
+			}
+			// expand 3-digit hex to 6-digit hex
+			if len(color) == 4 { // #ABC
+				color = fmt.Sprintf("#%c%c%c%c%c%c", color[1], color[1], color[2], color[2], color[3], color[3])
+			}
+			// convert to uppercase for consistency
+			color = strings.ToUpper(color)
+			label.Color = &color
+		}
+	}
+
+	return nil
+}
-- 
2.51.2