theme: add WCAG data

core/internal/themes/registry.go

@@ -104,6 +104,28 @@ type ThemeVariants struct {
 	Accents  []ThemeAccent         `json:"accents,omitempty"`
 }
 
+type ThemeWCAGGroup struct {
+	Level     string   `json:"level"`
+	MinRatio  float64  `json:"minRatio"`
+	WorstPair []string `json:"worstPair,omitempty"`
+}
+
+type ThemeWCAGMode struct {
+	Level     string            `json:"level"`
+	MinRatio  float64           `json:"minRatio"`
+	WorstPair []string          `json:"worstPair,omitempty"`
+	Body      *ThemeWCAGGroup   `json:"body,omitempty"`
+	Accent    *ThemeWCAGGroup   `json:"accent,omitempty"`
+	NonText   *ThemeWCAGGroup   `json:"nonText,omitempty"`
+	Variants  map[string]string `json:"variants,omitempty"`
+}
+
+type ThemeWCAG struct {
+	Level string         `json:"level"`
+	Dark  *ThemeWCAGMode `json:"dark,omitempty"`
+	Light *ThemeWCAGMode `json:"light,omitempty"`
+}
+
 type Theme struct {
 	ID          string         `json:"id"`
 	Name        string         `json:"name"`
@@ -113,6 +135,7 @@ type Theme struct {
 	Dark        ColorScheme    `json:"dark"`
 	Light       ColorScheme    `json:"light"`
 	Variants    *ThemeVariants `json:"variants,omitempty"`
+	WCAG        *ThemeWCAG     `json:"wcag,omitempty"`
 	PreviewPath string         `json:"-"`
 	SourceDir   string         `json:"sourceDir,omitempty"`
 }
@@ -240,6 +263,7 @@ func (r *Registry) loadThemes() error {
 			theme.ID = entry.Name()
 		}
 		theme.SourceDir = entry.Name()
+		theme.WCAG = loadThemeWCAG(r.fs, themeDir)
 
 		previewPath := filepath.Join(themeDir, "preview.svg")
 		if exists, _ := afero.Exists(r.fs, previewPath); exists {
@@ -252,6 +276,20 @@ func (r *Registry) loadThemes() error {
 	return nil
 }
 
+func loadThemeWCAG(fs afero.Fs, themeDir string) *ThemeWCAG {
+	data, err := afero.ReadFile(fs, filepath.Join(themeDir, "wcag.json"))
+	if err != nil {
+		return nil
+	}
+
+	var wcag ThemeWCAG
+	if err := json.Unmarshal(data, &wcag); err != nil {
+		return nil
+	}
+
+	return &wcag
+}
+
 func (r *Registry) List() ([]Theme, error) {
 	if len(r.themes) == 0 {
 		if err := r.Update(); err != nil {

core/internal/themes/registry_test.go

@@ -0,0 +1,66 @@
+package themes
+
+import (
+	"testing"
+
+	"github.com/spf13/afero"
+)
+
+func TestLoadThemeWCAG(t *testing.T) {
+	fs := afero.NewMemMapFs()
+	themeDir := "/themes/example"
+	wcagJSON := `{
+		"level": "AA",
+		"dark": {
+			"level": "AAA", "minRatio": 8.5, "worstPair": ["surfaceText", "surface"],
+			"body": {"level": "AAA", "minRatio": 8.5},
+			"accent": {"level": "AAA", "minRatio": 9.1}
+		},
+		"light": {
+			"level": "AA", "minRatio": 5.2,
+			"body": {"level": "AAA", "minRatio": 7.4},
+			"accent": {"level": "AA", "minRatio": 5.2},
+			"variants": {"blue": "AA", "red": "fail"}
+		}
+	}`
+	if err := afero.WriteFile(fs, themeDir+"/wcag.json", []byte(wcagJSON), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	wcag := loadThemeWCAG(fs, themeDir)
+	if wcag == nil {
+		t.Fatal("expected wcag report, got nil")
+	}
+	if wcag.Level != "AA" {
+		t.Fatalf("expected level AA, got %s", wcag.Level)
+	}
+	if wcag.Dark.Level != "AAA" || wcag.Dark.MinRatio != 8.5 {
+		t.Fatalf("unexpected dark mode report: %+v", wcag.Dark)
+	}
+	if wcag.Light.Variants["red"] != "fail" {
+		t.Fatalf("unexpected light variants: %+v", wcag.Light.Variants)
+	}
+	if wcag.Light.Body == nil || wcag.Light.Body.Level != "AAA" {
+		t.Fatalf("expected light body AAA, got %+v", wcag.Light.Body)
+	}
+	if wcag.Light.Accent == nil || wcag.Light.Accent.Level != "AA" {
+		t.Fatalf("expected light accent AA, got %+v", wcag.Light.Accent)
+	}
+}
+
+func TestLoadThemeWCAGMissingFile(t *testing.T) {
+	if wcag := loadThemeWCAG(afero.NewMemMapFs(), "/themes/none"); wcag != nil {
+		t.Fatalf("expected nil for missing wcag.json, got %+v", wcag)
+	}
+}
+
+func TestLoadThemeWCAGInvalidJSON(t *testing.T) {
+	fs := afero.NewMemMapFs()
+	if err := afero.WriteFile(fs, "/themes/bad/wcag.json", []byte("{"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	if wcag := loadThemeWCAG(fs, "/themes/bad"); wcag != nil {
+		t.Fatalf("expected nil for invalid wcag.json, got %+v", wcag)
+	}
+}