chore: rewrite rot13 title and description

Fixes #46

processors/processor.go

@@ -48,7 +48,7 @@ var List = []list.Item{
 	Reverse{},
 	ReverseLines{},
 	ReverseLines{},
-	ROT13Encode{},
+	ROT13{},
 	SHA1{},
 	SHA224{},
 	SHA256{},

processors/rot13.go

@@ -0,0 +1,60 @@
+package processors
+
+import (
+	"fmt"
+	"strings"
+)
+
+// ROT13 converts string with ROT13 cypher.
+// https://en.wikipedia.org/wiki/ROT13
+type ROT13 struct{}
+
+func (p ROT13) Name() string {
+	return "rot13"
+}
+
+func (p ROT13) Alias() []string {
+	return []string{"rot13-encode", "rot13-decode", "rot13-enc", "rot13-dec"}
+}
+
+func (p ROT13) Transform(data []byte, _ ...Flag) (string, error) {
+	return strings.Map(rot13, string(data)), nil
+}
+
+func (p ROT13) Flags() []Flag {
+	return nil
+}
+
+func (p ROT13) Title() string {
+	title := "ROT13 Letter Substitution"
+	return fmt.Sprintf("%s (%s)", title, p.Name())
+}
+
+func (p ROT13) Description() string {
+	return "Cipher/Decipher your text with ROT13 letter substitution"
+}
+
+func (p ROT13) FilterValue() string {
+	return p.Title()
+}
+
+// rot13 private helper function for converting rune into rot13.
+func rot13(r rune) rune {
+	if r >= 'a' && r <= 'z' {
+		// Rotate lowercase letters 13 places.
+		if r >= 'm' {
+			return r - 13
+		}
+
+		return r + 13
+	} else if r >= 'A' && r <= 'Z' {
+		// Rotate uppercase letters 13 places.
+		if r >= 'M' {
+			return r - 13
+		}
+
+		return r + 13
+	}
+	// Do nothing.
+	return r
+}

processors/rot_test.go → processors/rot13_test.go

@@ -5,7 +5,7 @@ import (
 	"testing"
 )
 
-func TestROT13Encode_Transform(t *testing.T) {
+func TestROT13_Transform(t *testing.T) {
 	type args struct {
 		data []byte
 		in1  []Flag
@@ -36,7 +36,7 @@ func TestROT13Encode_Transform(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			p := ROT13Encode{}
+			p := ROT13{}
 			got, err := p.Transform(tt.args.data, tt.args.in1...)
 			if (err != nil) != tt.wantErr {
 				t.Errorf("Transform() error = %v, wantErr %v", err, tt.wantErr)
@@ -49,7 +49,7 @@ func TestROT13Encode_Transform(t *testing.T) {
 	}
 }
 
-func TestROT13Encode_Command(t *testing.T) {
+func TestROT13_Command(t *testing.T) {
 	test := struct {
 		alias       []string
 		description string
@@ -58,14 +58,14 @@ func TestROT13Encode_Command(t *testing.T) {
 		name        string
 		title       string
 	}{
-		alias:       []string{"rot13", "rot13-enc"},
-		description: "Encode your text to ROT13",
-		filterValue: "ROT13 Encode (rot13-encode)",
+		alias:       []string{"rot13-encode", "rot13-decode", "rot13-enc", "rot13-dec"},
+		description: "Cipher/Decipher your text with ROT13 letter substitution",
+		filterValue: "ROT13 Letter Substitution (rot13)",
 		flags:       nil,
-		name:        "rot13-encode",
-		title:       "ROT13 Encode (rot13-encode)",
+		name:        "rot13",
+		title:       "ROT13 Letter Substitution (rot13)",
 	}
-	p := ROT13Encode{}
+	p := ROT13{}
 	if got := p.Alias(); !reflect.DeepEqual(got, test.alias) {
 		t.Errorf("Alias() = %v, want %v", got, test.alias)
 	}