1 files changed, 70 insertions, 2 deletions
diff --git a/git-bug.go b/git-bug.go
index e82fdf42..08d9d04a 100644
--- a/git-bug.go
+++ b/git-bug.go
@@ -1,7 +1,75 @@
 package main
 
-import "fmt"
+import (
+	"fmt"
+	"os"
+	"sort"
+	"strings"
+	"github.com/MichaelMure/git-bug/repository"
+	"github.com/MichaelMure/git-bug/commands"
+)
+
+const usageMessageTemplate = `Usage: %s <command>
+
+Where <command> is one of:
+  %s
+
+For individual command usage, run:
+  %s help <command>
+`
+
+func usage() {
+	command := os.Args[0]
+	var subcommands []string
+	for subcommand := range commands.CommandMap {
+		subcommands = append(subcommands, subcommand)
+	}
+	sort.Strings(subcommands)
+	fmt.Printf(usageMessageTemplate, command, strings.Join(subcommands, "\n  "), command)
+}
+
+func help() {
+	if len(os.Args) < 3 {
+		usage()
+		return
+	}
+	subcommand, ok := commands.CommandMap[os.Args[2]]
+	if !ok {
+		fmt.Printf("Unknown command %q\n", os.Args[2])
+		usage()
+		return
+	}
+	subcommand.Usage(os.Args[0])
+}
 
 func main() {
-	fmt.Println("Hello git !")
+	if len(os.Args) > 1 && os.Args[1] == "help" {
+		help()
+		return
+	}
+	cwd, err := os.Getwd()
+	if err != nil {
+		fmt.Printf("Unable to get the current working directory: %q\n", err)
+		return
+	}
+	repo, err := repository.NewGitRepo(cwd)
+	if err != nil {
+		fmt.Printf("%s must be run from within a git repo.\n", os.Args[0])
+		return
+	}
+	if len(os.Args) < 2 {
+		// default behavior
+		fmt.Println("Not implemented")
+		return
+	}
+	subcommand, ok := commands.CommandMap[os.Args[1]]
+	if !ok {
+		fmt.Printf("Unknown command: %q\n", os.Args[1])
+		usage()
+		return
+	}
+	if err := subcommand.Run(repo, os.Args[2:]); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
 }