git-checkout-history: Passing an arg checks out a branch

If you pass in the index of a branch in the checkout-history branch
list, the branch at that index in the history will be checked out.

TODO: Store the newly checked out branch in the branch history

1 files changed, 17 insertions, 2 deletions

diff --git a/git-checkout-history/main.go b/git-checkout-history/main.go
index fa9747c..8bf6e24 100644
--- a/git-checkout-history/main.go
+++ b/git-checkout-history/main.go
@@ -4,7 +4,10 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
+	"os"
+	"os/exec"
 	"os/user"
+	"strconv"
 	
 	"gopkg.in/yaml.v2"
 )
@@ -37,7 +40,19 @@ func main() {
 		log.Fatal(err)
 	}
 	
-	for i := 1; i < len(branchList.Branches); i++ {
-		fmt.Printf("[%d] %s\n", i, branchList.Branches[i])
+	args := os.Args[1:]
+	
+	if len(args) > 0 {
+		branchIndex, _ := strconv.Atoi(args[0])
+		cmd := exec.Command("git", "checkout", branchList.Branches[branchIndex])
+		err := cmd.Run()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, err.Error())
+		}
+	} else {
+		// List branches in history
+		for i := 1; i < len(branchList.Branches); i++ {
+			fmt.Printf("[%d] %s\n", i, branchList.Branches[i])
+		}
 	}
 }