chore: refactor plugin structure (#18335)

plugin/switch.go

@@ -0,0 +1,89 @@
+package plugin
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+
+	"github.com/evcc-io/evcc/util"
+)
+
+type Case struct {
+	Case string
+	Set  Config
+}
+
+type switchPlugin struct {
+	ctx   context.Context
+	cases []Case
+	dflt  *Config
+}
+
+func init() {
+	registry.AddCtx("switch", NewSwitchFromConfig)
+}
+
+// NewSwitchFromConfig creates switch provider
+func NewSwitchFromConfig(ctx context.Context, other map[string]interface{}) (Plugin, error) {
+	var cc struct {
+		Switch  []Case
+		Default *Config
+	}
+
+	if err := util.DecodeOther(other, &cc); err != nil {
+		return nil, err
+	}
+
+	cases := make(map[string]struct{})
+	for _, c := range cc.Switch {
+		if _, ok := cases[c.Case]; ok {
+			return nil, fmt.Errorf("switch: duplicate case: %s", c.Case)
+		}
+		cases[c.Case] = struct{}{}
+	}
+
+	o := &switchPlugin{
+		ctx:   ctx,
+		cases: cc.Switch,
+		dflt:  cc.Default,
+	}
+
+	return o, nil
+}
+
+var _ IntSetter = (*switchPlugin)(nil)
+
+func (o *switchPlugin) IntSetter(param string) (func(int64) error, error) {
+	set := make([]func(int64) error, 0, len(o.cases))
+	for _, cc := range o.cases {
+		s, err := cc.Set.IntSetter(o.ctx, param)
+		if err != nil {
+			return nil, err
+		}
+		set = append(set, s)
+	}
+
+	dflt, err := o.dflt.IntSetter(o.ctx, param)
+	if err != nil {
+		return nil, err
+	}
+
+	return func(val int64) error {
+		for i, s := range o.cases {
+			ival, err := strconv.ParseInt(s.Case, 10, 64)
+			if err != nil {
+				return err
+			}
+
+			if ival == val {
+				return set[i](val)
+			}
+		}
+
+		if dflt != nil {
+			return dflt(val)
+		}
+
+		return fmt.Errorf("switch: value not found: %d", val)
+	}, nil
+}