Refactor modify and replace to their own files

utils/replacecommand.go

@@ -0,0 +1,47 @@
+package utils
+
+import (
+	"fmt"
+	"modify/logger"
+)
+
+type ReplaceCommand struct {
+	From int
+	To   int
+	With string
+}
+
+func ExecuteModifications(modifications []ReplaceCommand, fileData string) (string, int) {
+	var err error
+	executed := 0
+	for _, modification := range modifications {
+		fileData, err = modification.Execute(fileData)
+		if err != nil {
+			logger.Error("Failed to execute modification: %v", err)
+			continue
+		}
+		executed++
+	}
+	logger.Info("Executed %d modifications", executed)
+	return fileData, executed
+}
+
+func (m *ReplaceCommand) Execute(fileDataStr string) (string, error) {
+	err := m.Validate(len(fileDataStr))
+	if err != nil {
+		return "", fmt.Errorf("failed to validate modification: %v", err)
+	}
+
+	logger.Trace("Replace pos %d-%d with %q", m.From, m.To, m.With)
+	return fileDataStr[:m.From] + m.With + fileDataStr[m.To:], nil
+}
+
+func (m *ReplaceCommand) Validate(maxsize int) error {
+	if m.To < m.From {
+		return fmt.Errorf("command to is less than from: %v", m)
+	}
+	if m.From > maxsize || m.To > maxsize {
+		return fmt.Errorf("command from or to is greater than replacement length: %v", m)
+	}
+	return nil
+}