create a cli module

cli/cli.go

@@ -0,0 +1,80 @@
+package cli
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"vcs/storage"
+	"vcs/tree"
+)
+
+var Commands map[string]*Command
+
+type Command struct {
+	Function      func(args []string)
+	flagset       *flag.FlagSet
+	parameters    map[string]string
+	parsedOutputs map[string]*string
+	usage         string
+}
+
+func init() {
+	Commands = map[string]*Command{
+		"commit": {
+			Function:      commit,
+			parameters:    map[string]string{"m": "The message of the commit inside double quotes"},
+			parsedOutputs: map[string]*string{},
+			usage:         "Snapshot the current directory in VCS and return the oid",
+		},
+		"init": {
+			Function: uinit,
+			usage:    "<directory>",
+		},
+		"log": {
+			Function: ulog,
+			usage:    "<ref>",
+		},
+		"checkout": {usage: "<ref>"},
+	}
+
+	for name, cmd := range Commands {
+		cmd.flagset = flag.NewFlagSet(name, flag.ExitOnError)
+		for p, u := range cmd.parameters {
+			cmd.parsedOutputs[p] = cmd.flagset.String(p, "", u)
+		}
+	}
+
+	flag.Usage = func() {
+		fmt.Printf("Usage of vcs \n")
+		for name, cmd := range Commands {
+			fmt.Printf(" %s : %s\n", name, cmd.usage)
+			cmd.flagset.PrintDefaults()
+		}
+	}
+}
+
+func commit(args []string) {
+	Commands["commit"].flagset.Parse(args)
+	if val, _ := Commands["commit"].parsedOutputs["m"]; *val != "" {
+		log.Println("Commit hash : ", tree.Commit("./", *Commands["commit"].parsedOutputs["m"]))
+		os.Exit(0)
+	} else {
+		Commands["commit"].flagset.PrintDefaults()
+		os.Exit(1)
+	}
+}
+
+func uinit(args []string) {
+	path := "./"
+	if len(os.Args) >= 3 {
+		path = os.Args[2]
+	}
+	storage.UInit(path)
+	os.Exit(0)
+}
+
+func ulog(args []string) {
+	tree.PrintLog(tree.Log())
+	os.Exit(0)
+}

main.go

@@ -2,62 +2,20 @@ package main
 
 import (
 	"flag"
-	"fmt"
-	"log"
 	"os"
-	"vcs/storage"
-	"vcs/tree"
+	"vcs/cli"
 )
 
-var commands = map[string]*flag.FlagSet{
-	"commit": flag.NewFlagSet("commit", flag.ExitOnError),
-	"init":   flag.NewFlagSet("init", flag.ExitOnError),
-	"log":    flag.NewFlagSet("log", flag.ExitOnError),
-}
-
-var usage = func() {
-	fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
-	for k, v := range commands {
-		fmt.Fprintf(os.Stderr, "%s\n", k)
-		v.PrintDefaults()
-	}
-	flag.PrintDefaults()
-}
-
-var commitMessage *string
-
-func init() {
-	commitMessage = commands["commit"].String("m", "", "The message of the commit inside double quotes")
-}
-
 func main() {
-	flag.Usage = usage
 	if len(os.Args) < 2 {
 		flag.Usage()
 		os.Exit(1)
 	}
-	if _, ok := commands[os.Args[1]]; !ok {
+	if _, ok := cli.Commands[os.Args[1]]; !ok {
 		flag.Usage()
 		os.Exit(1)
 	}
-	switch os.Args[1] {
-	case "commit":
-		commands["commit"].Parse(os.Args[2:])
-		if *commitMessage != "" {
-			log.Println("Commit hash : ", tree.Commit("./", *commitMessage))
-			return
-		}
-	case "init":
-		path := "./"
-		if len(os.Args) >= 3 {
-			path = os.Args[2]
-		}
-		storage.UInit(path)
-		return
-	case "log":
-		tree.PrintLog(tree.Log())
-		return
-	}
+	cli.Commands[os.Args[1]].Function(os.Args[2:])
 
 	flag.Usage()
 }