Change to the way of writing using receiver.

.gitignore

@@ -0,0 +1 @@
+.DS_Store

README.md

@@ -2,6 +2,7 @@
 md2confl is a CLI tool to convert the markdown text to confluence wiki format.
 
 ## Demo
+![](./demo.gif)
 
 ## Install
 ```
@@ -18,7 +19,8 @@ Usage:
 
 Available Commands:
   copy        Copy a confluence wiki text converted from markdown.
-  preview     Shows a confluence wiki text converted from markdown.
+  preview     Show a confluence wiki text converted from markdown.
+  version     Print the version number of md2confl
   help        Help about any command
 
 Flags:

cmd/copy.go

@@ -1,11 +1,9 @@
 package cmd
 
 import (
-	"fmt"
-
 	"github.com/spf13/cobra"
-	"github.com/atotto/clipboard"
-	"github.com/kentaro-m/md2confl/util"
+	"github.com/kentaro-m/md2confl/utils/util"
+	"github.com/kentaro-m/md2confl/utils/file"
 	"github.com/kentaro-m/md2confl/confluence"
 )
 
@@ -17,10 +15,14 @@ var copyCmd = &cobra.Command{
 }
 
 func copy(cmd *cobra.Command, args []string) error {
-	data := util.ReadFile(args[0])
-	output := confluence.Convert(data)
-	fmt.Println("Copied to clipboard!")
-  return clipboard.WriteAll(output)
+	file := file.File{}
+	if err := file.Open(args[0]); err != nil {
+		return err
+	}
+
+  confluence := confluence.Confluence{}
+	confluence.Convert(file.Data)
+	return util.Copy(confluence.Contents)
 }
 
 func init() {

cmd/preview.go

@@ -1,24 +1,28 @@
 package cmd
 
 import (
-	"fmt"
-
 	"github.com/spf13/cobra"
-	"github.com/kentaro-m/md2confl/util"
 	"github.com/kentaro-m/md2confl/confluence"
+	"github.com/kentaro-m/md2confl/utils/file"
 )
 
 var previewCmd = &cobra.Command{
 	Use:   "preview [file path]",
-	Short: "Shows a confluence wiki text converted from markdown.",
-	Long: "Shows a confluence wiki text converted from markdown.",
+	Short: "Show a confluence wiki text converted from markdown.",
+	Long: "Show a confluence wiki text converted from markdown.",
 	RunE: preview,
 }
 
 func preview(cmd *cobra.Command, args []string) error {
-	data := util.ReadFile(args[0])
-	output := confluence.Convert(data)
-	fmt.Println(output)
+	file := file.File{}
+	if err := file.Open(args[0]); err != nil {
+		return err
+	}
+
+	confluence := confluence.Confluence{}
+	confluence.Convert(file.Data)
+	confluence.Preview()
+
 	return nil
 }
 

cmd/root.go

@@ -7,6 +7,10 @@ import (
 	"github.com/spf13/cobra"
 )
 
+const (
+	VERSION = "0.1.0"
+)
+
 var RootCmd = &cobra.Command{
 	Use:   "md2confl",
 	Short: "md2confl - Convert markdown text to confluence wiki",
@@ -15,13 +19,22 @@ var RootCmd = &cobra.Command{
 	SilenceUsage:  true,
 }
 
+var versionCmd = &cobra.Command{
+	Use:   "version",
+	Short: "Print the version number of md2confl",
+	Long:  "Print the version number of md2confl",
+	Run: func(cmd *cobra.Command, args []string) {
+		fmt.Printf("v%v\n", VERSION)
+	},
+}
+
 func Execute() {
 	if err := RootCmd.Execute(); err != nil {
-		fmt.Println(err)
-		os.Exit(-1)
+		fmt.Fprintf(os.Stdout, "Error: %v\n", err)
 	}
 }
 
 func init()  {
 	cobra.EnableCommandSorting = false
+	RootCmd.AddCommand(versionCmd)
 }

confluence/confluence.go

@@ -1,10 +1,16 @@
 package confluence
 
 import (
+  "fmt"
+
   "github.com/kentaro-m/blackfriday"
 )
 
-func Convert(input []byte) string {
+type Confluence struct {
+  Contents string
+}
+
+func (c *Confluence) Convert(input []byte) {
   renderer := blackfriday.ConfluenceRenderer(0)
 	extensions := 0
 	extensions |= blackfriday.EXTENSION_FENCED_CODE
@@ -13,6 +19,9 @@ func Convert(input []byte) string {
 	extensions |= blackfriday.EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK
 
   output := blackfriday.Markdown(input, renderer, extensions)
+  c.Contents = string(output)
+}
 
-  return string(output)
+func (c *Confluence) Preview() {
+  fmt.Println(c.Contents)
 }

utils/file/file.go

@@ -0,0 +1,29 @@
+package file
+
+import (
+  "path/filepath"
+  "io/ioutil"
+  "errors"
+)
+
+type File struct {
+  Data []byte
+}
+
+func (f *File) Open(path string) error {
+    ext := filepath.Ext(path)
+
+    if ext != ".md" && ext != ".markdown" {
+      return errors.New("This file is not in markdown format.")
+    }
+
+    data, err := ioutil.ReadFile(path)
+
+    if err != nil {
+      return errors.New("Can't open this file.")
+    }
+
+    f.Data = data
+
+    return nil
+}

utils/util/util.go

@@ -0,0 +1,20 @@
+package util
+
+import (
+  "fmt"
+  "log"
+
+  "github.com/atotto/clipboard"
+)
+
+func Copy(text string) error {
+  err := clipboard.WriteAll(text)
+
+  if err != nil {
+    log.Fatal(err)
+    return err
+  }
+
+  fmt.Println("Copied to clipboard!")
+  return nil
+}