first version

cmd/set/set.go

@@ -0,0 +1,132 @@
+package set
+
+import (
+	"backlight-control/internal/backlight"
+	"errors"
+	"fmt"
+	"regexp"
+	"strconv"
+
+	"github.com/spf13/cobra"
+)
+
+func NewCommand(parent *cobra.Command) {
+	cmd := &cobra.Command{
+		Use:     "set [+/-]VAL[%]",
+		Aliases: []string{"s"},
+		Args:    cobra.ExactArgs(1),
+		RunE:    run,
+		Short:   "set backlight value",
+	}
+
+	parent.AddCommand(cmd)
+}
+
+type operate int
+
+const (
+	None operate = 1 << iota
+	Equal
+	Add
+	Subtract
+)
+
+var changeValueRegex = regexp.MustCompile(`^([+-])?(\d+(\.\d+)?)%?$`)
+
+func parseChange(val string) (op operate, value float32, err error) {
+
+	find := changeValueRegex.FindAllStringSubmatch(val, -1)
+	if find == nil || len(find) < 1 {
+		return None, 0, errors.New("input value pattern invalid")
+	}
+
+	findList := find[0]
+	if len(findList) < 3 {
+		return None, 0, fmt.Errorf("parsed value invalid, %v", findList)
+	}
+
+	opStr := findList[1]
+	valStr := findList[2]
+
+	switch opStr {
+	case "+":
+		op = Add
+	case "-":
+		op = Subtract
+	default:
+		op = Equal
+	}
+
+	f64, err := strconv.ParseFloat(valStr, 32)
+	if err != nil {
+		return None, 0, fmt.Errorf("parse value to float fail: (%w)", err)
+	}
+
+	value = float32(f64)
+
+	return
+}
+
+func run(cmd *cobra.Command, args []string) (err error) {
+	dirPath, err := cmd.Flags().GetString("path")
+	if err != nil {
+		return fmt.Errorf("get directory path from flags fail: (%w)", err)
+	}
+	_ = dirPath
+
+	op, value, err := parseChange(args[0])
+	if err != nil {
+		return err
+	}
+
+	lightInstance, err := backlight.NewInstance(dirPath)
+	if err != nil {
+		return fmt.Errorf("create backlight instance fail: %w", err)
+	}
+
+	cur, err := lightInstance.GetCurrent()
+	if err != nil {
+		return fmt.Errorf("get current brightness fail: %w", err)
+	}
+	max, err := lightInstance.GetMax()
+	if err != nil {
+		return fmt.Errorf("get max brightness fail: %w", err)
+	}
+
+	// cale percentage
+	curP := float32(int(float32(cur)/float32(max)*10000)) / 100
+
+	// 1% base
+	oneP := float32(max) / 100
+
+	finalVal := 0
+
+	switch op {
+	case Add:
+		finalVal = int((curP + value) * oneP)
+		if finalVal > max {
+			finalVal = max
+		}
+	case Subtract:
+		finalVal = int((curP - value) * oneP)
+		if finalVal < 0 {
+			finalVal = 0
+		}
+	case Equal:
+		if value > 100 {
+			value = 100
+		} else if value < 0 {
+			value = 0
+		}
+		finalVal = int((value) * oneP)
+	default:
+		return errors.New("operate invalid")
+	}
+
+	err = lightInstance.SetValue(finalVal)
+	if err != nil {
+		return fmt.Errorf("set backlight to target value fail: %w", err)
+	}
+
+	return
+}