Add Surge MITM and scripts

script/source.go

@@ -0,0 +1,33 @@
+//go:build with_script
+
+package script
+
+import (
+	"context"
+
+	"github.com/sagernet/sing-box/adapter"
+	C "github.com/sagernet/sing-box/constant"
+	"github.com/sagernet/sing-box/option"
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/common/logger"
+
+	"github.com/dop251/goja"
+)
+
+type Source interface {
+	StartContext(ctx context.Context, startContext *adapter.HTTPStartContext) error
+	PostStart() error
+	Program() *goja.Program
+	Close() error
+}
+
+func NewSource(ctx context.Context, logger logger.Logger, options option.Script) (Source, error) {
+	switch options.Source {
+	case C.ScriptSourceTypeLocal:
+		return NewLocalSource(ctx, logger, options)
+	case C.ScriptSourceTypeRemote:
+		return NewRemoteSource(ctx, logger, options)
+	default:
+		return nil, E.New("unknown source type: ", options.Source)
+	}
+}