feat(matugen): add color preview pallette & outline border option theme settings

- Closes #1738

core/cmd/dms/commands_matugen.go

@@ -38,10 +38,17 @@ var matugenCheckCmd = &cobra.Command{
 	Run:   runMatugenCheck,
 }
 
+var matugenPreviewCmd = &cobra.Command{
+	Use:   "preview",
+	Short: "Preview Matugen scheme colors without applying them",
+	Run:   runMatugenPreview,
+}
+
 func init() {
 	matugenCmd.AddCommand(matugenGenerateCmd)
 	matugenCmd.AddCommand(matugenQueueCmd)
 	matugenCmd.AddCommand(matugenCheckCmd)
+	matugenCmd.AddCommand(matugenPreviewCmd)
 
 	for _, cmd := range []*cobra.Command{matugenGenerateCmd, matugenQueueCmd} {
 		cmd.Flags().String("state-dir", "", "State directory for cache files")
@@ -62,6 +69,8 @@ func init() {
 
 	matugenQueueCmd.Flags().Bool("wait", true, "Wait for completion")
 	matugenQueueCmd.Flags().Duration("timeout", 90*time.Second, "Timeout for waiting")
+	matugenPreviewCmd.Flags().String("source-color", "", "Source color used to generate previews")
+	matugenPreviewCmd.Flags().Float64("contrast", 0, "Contrast value from -1 to 1 (0 = standard)")
 }
 
 func buildMatugenOptions(cmd *cobra.Command) matugen.Options {
@@ -200,3 +209,17 @@ func runMatugenCheck(cmd *cobra.Command, args []string) {
 	}
 	fmt.Println(string(data))
 }
+
+func runMatugenPreview(cmd *cobra.Command, args []string) {
+	sourceColor, _ := cmd.Flags().GetString("source-color")
+	contrast, _ := cmd.Flags().GetFloat64("contrast")
+	previews, err := matugen.PreviewSchemes(sourceColor, contrast)
+	if err != nil {
+		log.Fatalf("Failed to generate Matugen previews: %v", err)
+	}
+	data, err := json.Marshal(previews)
+	if err != nil {
+		log.Fatalf("Failed to marshal Matugen previews: %v", err)
+	}
+	fmt.Println(string(data))
+}

core/internal/matugen/matugen.go

@@ -118,6 +118,50 @@ type ColorsOutput struct {
 	} `json:"colors"`
 }
 
+type SchemePreview struct {
+	Dark  string `json:"dark"`
+	Light string `json:"light"`
+}
+
+var previewSchemeTypes = []string{
+	"scheme-tonal-spot",
+	"scheme-vibrant",
+	"scheme-content",
+	"scheme-expressive",
+	"scheme-fidelity",
+	"scheme-fruit-salad",
+	"scheme-monochrome",
+	"scheme-neutral",
+	"scheme-rainbow",
+}
+
+func PreviewSchemes(sourceColor string, contrast float64) (map[string]SchemePreview, error) {
+	if sourceColor == "" {
+		return nil, fmt.Errorf("source color is required")
+	}
+
+	previews := make(map[string]SchemePreview, len(previewSchemeTypes))
+	for _, schemeType := range previewSchemeTypes {
+		output, err := runMatugenDryRun(&Options{
+			Kind:        "hex",
+			Value:       sourceColor,
+			MatugenType: schemeType,
+			Contrast:    contrast,
+		})
+		if err != nil {
+			return nil, fmt.Errorf("preview %s: %w", schemeType, err)
+		}
+
+		dark := extractMatugenColor(output, "primary", "dark")
+		light := extractMatugenColor(output, "primary", "light")
+		if dark == "" || light == "" {
+			return nil, fmt.Errorf("preview %s: primary colors missing from matugen output", schemeType)
+		}
+		previews[schemeType] = SchemePreview{Dark: dark, Light: light}
+	}
+	return previews, nil
+}
+
 func (o *Options) ColorsOutput() string {
 	return filepath.Join(o.StateDir, "dms-colors.json")
 }