cmd: Validate cmd names

Fix #269

cobra/cmd/add.go

@@ -17,12 +17,14 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"unicode"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 )
 
 func init() {
+	addCmd.Flags().StringVarP(&parentName, "parent", "p", "RootCmd", "name of parent command for this command")
 	RootCmd.AddCommand(addCmd)
 }
 
@@ -50,12 +52,55 @@ Example: cobra add server -> resulting in a new cmd/server.go`,
 			er(err)
 		}
 		project := NewProjectFromPath(wd)
-		createCmdFile(project, args[0])
+		cmdName := validateCmdName(args[0])
+		createCmdFile(project, cmdName)
 	},
 }
 
-func init() {
-	addCmd.Flags().StringVarP(&parentName, "parent", "p", "RootCmd", "name of parent command for this command")
+// validateCmdName returns source without any dashes and underscore.
+// If there will be dash or underscore, next letter will be uppered.
+// It supports only ASCII (1-byte character) strings.
+func validateCmdName(source string) string {
+	i := 0
+	l := len(source)
+	// The output is initialized on demand, then first dash or underscore
+	// occurs.
+	var output string
+
+	for i < l {
+		if source[i] == '-' || source[i] == '_' {
+			if output == "" {
+				output = source[:i]
+			}
+
+			// If next character is dash or underscore,
+			// just skip the current character.
+			if source[i+1] == '-' || source[i+1] == '_' {
+				i++
+				continue
+			}
+
+			// If the current character is dash or underscore,
+			// upper next letter and add to output.
+			output += string(unicode.ToUpper(rune(source[i+1])))
+			// We know, what source[i] is dash or underscore and source[i+1] is
+			// uppered character, so make i = i+2.
+			i += 2
+			continue
+		}
+
+		// If the current character isn't dash or underscore,
+		// just add it.
+		if output != "" {
+			output += string(source[i])
+		}
+		i++
+	}
+
+	if output == "" {
+		return source // source is initially valid name.
+	}
+	return output
 }
 
 func createCmdFile(project *Project, cmdName string) {

cobra/cmd/add_test.go

@@ -0,0 +1,25 @@
+package cmd
+
+import "testing"
+
+func TestValidateCmdName(t *testing.T) {
+	testCases := []struct {
+		input    string
+		expected string
+	}{
+		{"cmdName", "cmdName"},
+		{"cmd_name", "cmdName"},
+		{"cmd-name", "cmdName"},
+		{"cmd______Name", "cmdName"},
+		{"cmd------Name", "cmdName"},
+		{"cmd______name", "cmdName"},
+		{"cmd------name", "cmdName"},
+	}
+
+	for _, testCase := range testCases {
+		got := validateCmdName(testCase.input)
+		if testCase.expected != got {
+			t.Errorf("Expected %q, got %q", testCase.expected, got)
+		}
+	}
+}