Add GetColorByName()/GetColorNames() for preset colors, adjust errors…

… for Open*

find.go

@@ -1,6 +1,7 @@
 package blink1
 
 import (
+	"fmt"
 	"sort"
 	"sync"
 
@@ -28,7 +29,7 @@ func FindDeviceInfoBySerialNumber(sn string) (*hid.DeviceInfo, error) {
 	})
 	// not found
 	if dev == nil {
-		return nil, errDeviceNotFound
+		return nil, fmt.Errorf("%w for %q", errDeviceNotFound, sn)
 	}
 	return dev, nil
 }

parser.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"image/color"
 	"regexp"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -55,6 +56,9 @@ var (
 	fadeMsecRegexPats = make(map[int]*regexp.Regexp)
 	ledIdxRegexPats   = make(map[int]*regexp.Regexp)
 
+	nameOnce   sync.Once
+	colorNames []string
+
 	errNoRepeatMatch = errors.New("b1: no repeat times match")
 	errNoColorMatch  = errors.New("b1: no color match")
 	errNoFadeMatch   = errors.New("b1: no fade time match")
@@ -93,6 +97,29 @@ func initRegex() {
 	ledIdxRegexPats[12] = regexp.MustCompile(`\b(led|light)[:#=\s]*([012]|top|bottom|btm|all|both|zero|one|two)\b`)
 }
 
+func initNames() {
+	colorNames = make([]string, 0, len(colorMap))
+	for k := range colorMap {
+		colorNames = append(colorNames, k)
+	}
+	sort.Strings(colorNames)
+}
+
+// GetColorByName returns the color corresponding to the given name from the preset color map.
+// If the color is found, it returns the color and true, otherwise it returns nil and false.
+func GetColorByName(name string) (cl color.Color, found bool) {
+	cl, found = colorMap[name]
+	return
+}
+
+// GetColorNames returns the color names from the preset color map.
+func GetColorNames() []string {
+	nameOnce.Do(initNames)
+	cls := make([]string, len(colorNames))
+	copy(cls, colorNames)
+	return cls
+}
+
 // ParseRepeatTimes parses the case-insensitive unstructured description of repeat times and returns the number of times to repeat.
 func ParseRepeatTimes(query string) (uint, error) {
 	// init regex